What does the research say?
In a study of 144 patients with advanced cancer who were receiving supportive care, patients were randomly assigned to CBD oil or placebo. After two weeks, there was no clear difference between the two groups in overall symptom burden; there was also no difference in pain, quality of life, anxiety or depression. An independent review group (Cochrane) states that CBD oil provided no added benefit to supportive care, but that the certainty of this result is low.
In large studies with a prescription mouth spray containing THC and CBD (nabiximols), the spray was not clearly different from placebo for cancer pain that continued despite opioid painkillers. The positive results seen in the first two spray studies were not repeated in three large studies involving more than 1,200 patients, and the opioid needs of those using the spray did not decrease; the strength of evidence for this result is moderate. In a six-month open-label extension study, pain scores also did not change from baseline. In two small studies from the 1970s with single oral doses of THC, high doses reduced pain more than placebo, but they were not more effective than codeine and caused marked drowsiness and mental clouding; the strength of evidence from these old studies is low. In two small studies with nabilone, a synthetic drug similar to THC, there was no difference in pain. In a recent study with an oil containing equal amounts of THC and CBD, a small improvement in pain was seen; however, side effects such as confusion also increased, and overall well-being was better in the placebo group.
In patients with nerve damage caused by chemotherapy (neuropathy), two small studies were done with capsules containing THC and CBD: in the 46-patient study there was no difference from placebo on the main measure, and in the 12-patient study neuropathy scores were worse in the cannabis group than with placebo. Two small studies with a THC and CBD mouth spray (16 people) and with a pure CBD cream applied to the skin (40 people) also found no difference from placebo in pain. For the joint pain caused by aromatase inhibitors, which are used to treat breast cancer, a study with a pure CBD medicine and no comparison group found that worst pain decreased by at least 2 points in 44% of patients; because there was no placebo group, this result is hard to interpret. A 21-person study comparing CBD and THC ointments for the same joint pain also had no placebo group. As for preventing nerve damage: in a retrospective study in Israel that looked at the records of 513 patients receiving oxaliplatin-based chemotherapy, moderate or severe nerve damage was less common in those using medical cannabis (15% versus 28%). However, in this study the groups were not formed by lottery and were not similar to each other, the type and amount of cannabis used were not recorded, nerve damage was assessed retrospectively from doctors' notes, and pain was not measured; so this finding does not count as evidence of an effect (very weak strength of evidence).
The American Society of Clinical Oncology (ASCO) in 2024 finds the evidence insufficient to make a recommendation for or against their use in cancer pain; the international supportive cancer care society (MASCC) in 2023 recommends that these products not be used as add-on painkillers. A 2021 BMJ guideline that covers cancer and non-cancer long-term pain together gives a weak recommendation for trying cannabinoids taken by mouth or applied to the skin when standard treatment is not enough; most of the studies behind this recommendation were in non-cancer pain, and there was no clear difference in the cancer pain studies.
In registries following cancer patients who were prescribed cannabis (358 in Canada, 168 in the United Kingdom, 324 in Israel and about 2,900 in Thailand), pain decreased from baseline within a few months. These studies had no comparison group, and in the Israeli and Thai registries a large share of patients left the study during follow-up; the daily amount of THC in the oil used in Thailand was also far below the doses in pain studies. So it is not known how much of the improvement was due to cannabis; the strength of evidence from this kind of data is low. In a 2026 review that pooled placebo-controlled studies, cannabinoids did not reduce the use of opioid painkillers (low strength of evidence). In a small study without a comparison group in 14 women whose breast cancer had spread to the bone and who were using opioids, 4 women reduced their opioid dose by about one fifth or more during 8 weeks of using dronabinol, a synthetic THC; in 3 women, however, the disease progressed and their need for opioids increased. Because there was no placebo group and the patients knew what they were taking, this result also does not count as evidence of an effect (very weak strength of evidence).
Strength of evidence: ●●○○ Weak evidence. Finding: No effect found. What does this mean?
Ongoing research on this topic
Trials testing CBD for this topic on ClinicalTrials.gov: 5 under way (3 recruiting); results are awaited from 2 that ended in the last two years. A trial being under way does not show that CBD works.
- NCT06787118: Phase 3, not yet recruiting, target 130 participants
- NCT06266611: Phase 2, recruiting, target 185 participants
- NCT03948074: Phase 2, completed, results awaited, 91 participants
Possible side effects and drug interactions
In the pure CBD oil study, side effects were similar in the two groups; shortness of breath was reported slightly more often in the CBD group. With THC-containing products, drowsiness and dizziness were more common; confusion and a feeling of being “high” were also reported. In a 6-month open-label study of a THC and CBD spray in advanced cancer, more than a third of participants stopped because of adverse events (including disease progression); nausea, vomiting and dizziness were reported most often. In one of the large studies with a spray containing THC and CBD, during the phase in which patients whose pain had decreased with the spray were randomly assigned to the spray or placebo group, more patients died in the spray group (23 of 103 patients versus 9 of 103 patients with placebo). Almost all deaths were due to cancer progression; the numbers of deaths during treatment were close (12 versus 9), and the difference appeared mostly after treatment ended (11 versus 0). The authors (most of whom were employees of the companies that developed or marketed the drug) did not consider any of the deaths to be related to treatment, and an independent safety board saw no safety problem that would stop the drug's development; still, the authors write that the reason for the difference could not be explained. In the other large study in the same publication, deaths were slightly more common in the placebo group (25 of 199 patients versus 20 of 200 patients with the spray).
CBD can slow the breakdown of some medicines in the body. Everolimus, tacrolimus, warfarin and some cancer medicines taken by mouth are important in this respect. Drowsiness may increase when CBD is combined with opioid painkillers and sleep-inducing medicines; the risk of falls should also be kept in mind in older people and those taking many medicines.
Interactions with medicines used for this condition
Interactions reported for these medicines in peer-reviewed publications and official prescribing information. A medicine that is not listed can still interact with CBD; tell your doctor about every medicine you take.
| Medicine | Importance | Warning | Source |
|---|---|---|---|
| Everolimus | High importance | Everolimus, sirolimus: In a controlled study in healthy volunteers taking approved CBD, the blood level of everolimus rose about 2.5-fold; in patients with TSC (tuberous sclerosis complex), everolimus and sirolimus levels rose in most patients when CBD was added. The prescribing information for both medicines recommends close monitoring of blood levels with CBD, and lowering the dose if needed. Do not start without talking to your doctor; your drug level should be monitored. | EMA Epidyolex SmPC 4.5, PMID 37132402, PMID 31924480, Everolimus (Afinitor) prescribing information §2.11 and §7.1, dailymed.nlm.nih.gov, Everolimus (Zortress) prescribing information §5.22 and §7.1, dailymed.nlm.nih.gov, Sirolimus prescribing information §5.21 and §7.5, dailymed.nlm.nih.gov |
| Warfarin | High importance | Warfarin: If you take warfarin, tell your doctor before starting CBD. Case reports have described INR rising and the warfarin dose needing to be lowered; more frequent INR monitoring is recommended. | PMID 29387536, PMID 33016308, PMID 30326170 |
| Immunotherapy (checkpoint inhibitors, e.g., nivolumab) | Caution | Immunotherapy (checkpoint inhibitors): In some observational studies, cannabis users had a lower response to immunotherapy or shorter survival; other studies found no difference, and the results conflict. Cause and effect has not been proven, most studies were done with cannabis containing THC, and there are no data specific to pure CBD. Guidelines advise caution; do not start without talking to your oncologist. | PMID 30670598, PMID 32872248, PMID 35454955, PMID 38610922, PMID 39737331, PMID 36535195, PMID 40184324, PMID 38478773, PMID 36872397 |
| Tamoxifen | Caution | Tamoxifen: In one case, the active breakdown product of tamoxifen (endoxifen) was found to be lower while the person was taking 40 mg of CBD a day. In a small study of 15 patients taking tamoxifen, about 50 mg a day of THC-free CBD oil lowered endoxifen by 12.6% on average; the researchers did not consider this difference important at this dose, and the effect of higher doses is not known. Do not start without talking to your oncologist. | PMID 33191836, PMID 37543688 |
| Other opioids (morphine, oxycodone, fentanyl, tramadol, etc.) | Caution | Methadone and other opioids: In a child, a high methadone level was found and drowsiness developed while CBD was being used; two weeks after CBD was stopped, the level fell to less than half and the symptoms resolved. In small controlled studies with morphine and buprenorphine, no clear change in drug levels was seen; with a single intravenous dose of fentanyl, there was no respiratory depression. Drowsiness may increase together with opioids. Tell the doctor who manages your pain or addiction treatment. | PMID 32444381, PMID 41622700, PMID 41467610, PMID 25748562, FDA Epidiolex label §7.4 (05/2026) |
| Chemotherapy / cancer medicines (general) | Information | Chemotherapy and cancer medicines: Data on interactions between CBD and cancer medicines are very limited. Talk to your oncologist before using it. | PMID 30776990, PMID 38478773 |
| Apixaban (DOAC), Rivaroxaban (DOAC) | Information | DOAC blood thinners: If you take a blood thinner, tell your doctor about CBD. There are no clinical data on interactions between these medicines and CBD; there is only a general warning in the package leaflet. | dailymed.nlm.nih.gov |
To check interactions with the medicines you take: CBD drug interaction checker.
How was CBD used in studies?
In the pure CBD oil study, the dose was adjusted between 50 mg and 600 mg a day (study dose; not a personal recommendation), increasing every three days; half of the patients chose a dose of 400 mg a day (study dose; not a personal recommendation) or less. ASCO does not recommend oral CBD at 300 mg a day or more for symptoms outside clinical trials (guideline opinion; not a personal recommendation).
In the mouth spray studies, patients adjusted the dose themselves over two weeks and used between 1 and 16 sprays a day (study dose; not a personal recommendation); average use in the studies was about 6 to 9 sprays a day (study dose; not a personal recommendation).
Study details (for health professionals)
In advanced cancer, CBD oil (median 400 mg/day chosen by patients) provided no added benefit to palliative care (low certainty). In large studies with THC-containing nabiximols (Sativex), opioid-refractory cancer pain was no different from placebo (moderate certainty): the positive primary result of the 2010 study and the positive findings of the 2012 study, which were seen only in secondary analyses, were not repeated in three phase 3 studies involving a total of 1,202 patients, and opioid use did not decrease either. The positive measures referred to as 'quality of life' in these studies were global impression and satisfaction questionnaires. The positive results seen in US patients come from post hoc exploratory subgroup analyses; in one study, the result in patients outside the US favored placebo, so these findings do not count as evidence of an effect. In two small studies from the 1970s with single oral doses of THC, high doses reduced pain more than placebo but were not superior to codeine and caused marked drowsiness and mental clouding (low certainty); in two small RCTs with nabilone, a synthetic THC-like drug, pain was no different from placebo (low certainty). With a 1:1 THC:CBD oil, a small pain benefit was seen at the cost of more psychotomimetic side effects (single study, secondary outcome). In chemotherapy-induced neuropathy, in none of four small RCTs with cannabinoids (a THC:CBD spray, two CBD-dominant low-THC capsules, a pure CBD cream applied to the skin) did pain decrease more than with placebo (in one, neuropathy scores in the cannabis arm were worse than with placebo; low certainty); in aromatase inhibitor–related joint pain, pure CBD (up to 200 mg/day) reduced worst pain by ≥2 points in 44% of patients in an uncontrolled phase 2 study; in a 21-person randomized study comparing CBD and THC ointments for the same pain, there was no placebo and the pain results were not given in the abstract. In registries following cancer patients prescribed cannabis (Canada, United Kingdom, Israel, Thailand), pain decreased from baseline over months; but these studies had no comparison group, a large share of patients dropped out of follow-up in the Israeli and Thai registries, the daily amount of THC in the oil used in Thailand (about 0.2 mg) was far below the doses in pain studies, and the improvement in a 2025 meta-analysis pooling this kind of data is not a comparison with placebo (low or very low certainty). In a 6-month open-label spray study in advanced cancer, pain did not change from baseline and more than a third of participants stopped because of adverse events (including disease progression). In a single-arm, open-label dronabinol study in 14 women with breast cancer that had spread to the bone and who were using opioids, according to the authors 4 women reduced their opioid dose by at least 20% by a predefined criterion (according to the paper's table, the reduction in one of them was 19.7%; no control group; very low certainty). In a retrospective chart review of 513 patients receiving oxaliplatin, grade 2–3 nerve damage was less common in those using medical cannabis (15.3% versus 27.9%); the groups were not balanced, product and dose were not recorded, and pain was not measured (very low certainty). ASCO 2024 finds the evidence insufficient to make a recommendation for or against their use in cancer pain; MASCC 2023 recommends against using cannabinoids as add-on painkillers; the BMJ guideline (2021), which covers cancer and non-cancer long-term pain together, gives a weak recommendation for trying non-inhaled (oral or topical) cannabinoids when standard treatment is not enough, but most of the studies it relied on were in non-cancer pain and there was no significant difference in the cancer pain studies. October 2026 search (PubMed, Cochrane, ClinicalTrials.gov): on this topic, 18 randomized studies with cannabinoids (15 of them placebo-controlled; one publication reports two studies together), 1 observational study comparing people taking nabilone with those not taking it, 1 retrospective study comparing the frequency of chemotherapy-related nerve damage between cannabis users and non-users (pain not measured), 3 studies without a control group, 4 systematic reviews and meta-analyses (one of them Cochrane), 3 guidelines and 4 patient registries or cohorts were found; all are in the table below. Not included in the table: two 1970s single-dose studies with experimental synthetic THC analogs (Jochimsen 1978, Staquet 1978; outside the site's scope), two expert documents repeating the same recommendation as the guidelines in the table (European Pain Federation 2018, São Paulo Society of Anesthesiology 2024), a review (2026) that summarizes the three small neuropathy studies in the table without pooling them, an uncontrolled pure CBD study in which pain was measured only together with exercise, and other small studies without a control group. The recommendation on cannabinoids in the ESMO 2018 cancer pain guideline could not be re-verified in this search (see the unverifiable points section).
Evidence assessment: Weak (pure CBD)
CBD alone
Pure CBD oil did not improve symptoms, including pain, more than placebo in advanced cancer (Hardy 2023; Cochrane 2023 interpretation: low certainty); in chemotherapy-induced nerve pain, a CBD cream applied to the skin was also no different from placebo (D'Andre 2024, 40-person pilot). For aromatase inhibitor–related joint pain, there is only a small study of oral pure CBD without a control group (Fleege 2025).
Products containing THC
In opioid-refractory cancer pain, nabiximols/THC was no different from placebo (Cochrane 2023, moderate certainty); with a 1:1 THC:CBD oil, a small benefit came with more side effects (single study, secondary outcome); opioid needs did not decrease (Creangă-Murariu 2026 meta-analysis, low certainty), and in none of the three small RCTs of THC-containing products in chemotherapy-induced nerve pain did pain decrease more than with placebo (low certainty). In the small single-dose studies of the 1970s, THC was better than placebo but no different from codeine (low certainty).
Evidence: Moderate, pointing to no effect: in cancer pain that continues despite opioids, a mouth spray containing THC and CBD (nabiximols) is no different from placebo; for single-dose THC, nabilone and other products, the evidence is low
Dose range in studies
Pure CBD: 50–600 mg/day (median chosen 400 mg/day), 50–200 mg/day in aromatase inhibitor pain; in chemotherapy neuropathy ~130 mg CBD + 6–11 mg THC/day or at most 300 mg CBD + 15 mg THC/day; THC-containing products: nabiximols 1–16 sprays/day, 1:1 oil from 2.5+2.5 mg up to 30+30 mg/day; in the 1970s single-dose studies, 5–20 mg oral THC (marked side effects at 20 mg); nabilone 0.5–2 mg/day
Starting dose and titration
In MedCan1, an increase every 3 days; in the nabiximols studies, 2 weeks of self-titration
These are doses researchers gave under medical supervision; they are not a recommended dose for you. "mg/kg/day" means milligrams per kilogram of body weight per day.
| Study | Participants | Product | Dose and titration | Duration | Result | Source |
|---|---|---|---|---|---|---|
| Hardy 2023 (MedCan1-CBD) Phase IIb, double-blind, placebo-controlled, dose-escalation RCT | 144 randomized (58 CBD / 63 placebo in the primary analysis) Advanced cancer, palliative care, ESAS ≥10/90 | Synthetic CBD oil 100 mg/mL (pure CBD produced by synthesis, not from the plant) and placebo oil | 0.5 mL once a day (50 mg/day) at the start → 2 mL 3 times a day (600 mg/day); median chosen by patients 400 mg/day Increase every 3 days (ASCO 2024 text) | 28 days (primary: day 14) | At day 14, change in total symptom distress score: CBD −3.0, placebo −6.2 (p=0.24, no difference). Responder rate 44.8% vs. 58.7% (p=0.13). No effect on quality of life, depression and anxiety. For pain, the measure for this topic, no added benefit of CBD was seen either (Cochrane 2023, low certainty): according to the data reported by Cochrane, at day 28 the pain score (0–100) fell from 40 to 38 in the CBD group and from 51 to 44 in the placebo group; according to Cochrane's estimate from baseline and final values, at least a 30% reduction in pain was seen in 26 of 70 people and 29 of 72 people (no statistical test for these comparisons); opioid doses followed a similar course in both groups Side effects: No difference between arms; dyspnea more frequent with CBD | PMID 36409969, doi:10.1200/JCO.22.01632, ANZCTR ACTRN12618001220257, protocol: Good 2019, PMID 31810437, PMID 39539239, PMID 41429435, 2 authors received funds on behalf of their institutions from the company that supplied the CBD (Cochrane 2023) |
| Häuser 2023 (Cochrane) Cochrane systematic review and meta-analysis (double-blind RCTs; search January 26, 2023) | 14 studies, 1823 participants Adults with cancer pain | Nabiximols, THC, nabilone, synthetic THC analogs, CBD oil | 2–5 weeks (nabiximols RCTs) | In opioid-refractory cancer pain, nabiximols/THC did not reduce average pain differently from placebo (SMD −0.19; 95% CI −0.40 to 0.02; 4 studies; moderate certainty); the small difference in the proportion saying they were 'much or very much improved' was not considered clinically meaningful (risk difference 0.06; 0.01 to 0.12; moderate certainty). Nabilone (2 studies, 89 people) did not reduce pain differently from placebo (low certainty). In the single-dose studies of the 1970s, THC and its analogs were superior to placebo and no different from codeine (low certainty). CBD oil added no value for pain to palliative care (low certainty). No herbal cannabis studies Side effects: No clinically meaningful difference in stopping because of side effects or in serious side effects (moderate certainty); according to the authors, nervous system and psychiatric side effects are common | PMID 37283486, doi:10.1002/14651858.CD014915.pub2, Previous review by the same authors: Häuser 2019, PMID 31073761, Staquet 1978) were done with experimental synthetic THC analogs and therefore have no separate row in the table | |
| Boland 2020 Systematic review and meta-analysis | 6 RCTs, 1460 participants Cancer-related pain | Cannabinoids (mostly nabiximols) | No difference in average pain NRS (MD −0.21; −0.02 in the phase III studies) Side effects: Somnolence OR 2.69; dizziness OR 1.58 | PMID 31959586, doi:10.1136/bmjspcare-2019-002032 | ||
| Lichtman 2018 Phase 3, double-blind RCT | 397 (199/198) Advanced cancer with pain NRS 4–8 despite opioids | Nabiximols spray (THC 27 mg/mL : CBD 25 mg/mL) | At most 10 sprays a day; on average 6.4 sprays/day with the spray and 7.3 with placebo (Cochrane 2023) 2 weeks of self-titration | 2 + 3 weeks | The primary endpoint was not met: median improvement 10.7% vs. 4.5% (p=0.0854, ITT); in per-protocol patients, 15.5% vs. 6.3% (p = 0.038). Average pain decreased by 0.8 points with the spray and 0.6 with placebo; opioid use did not change in either group (registry). The measures referred to as 'quality of life' in the abstract that favored the spray were, according to the secondary measures in the registry, the patient's and physician's global impression of change and a satisfaction questionnaire. The benefit seen in US patients comes from a post hoc exploratory analysis and was not seen in patients outside the US Side effects: Safety profile consistent with previous studies | PMID 28923526, doi:10.1016/j.jpainsymman.2017.09.001, NCT01262651, sponsor GW Pharmaceuticals, which developed the drug, partner Otsuka). According to the author affiliations on PubMed, 6 of the 9 authors are employees of companies that developed or market the drug (5 Otsuka, 1 GW), according to Cochrane 2023, NCT01337089 |
| Fallon 2017 Two phase 3 RCTs | Study 1: 399 randomized (200/199); Study 2: 406 patients entered titration, 206 randomized (103/103) Advanced cancer, NRS 4–8 despite opioids | Nabiximols (27:25 mg/mL) | Start with 1 spray in the evening, increase by 1 spray a day; at most 10 sprays/day; in Study 1, average 6.3 sprays/day 2 weeks, self-titrated | Study 1: 2 weeks of titration + 3 weeks; Study 2: 2 weeks of single-blind titration + 5-week randomized period | The primary outcome was not met in either study. In Study 1, median improvement in pain was 7.2% with the spray and 9.5% with placebo (p = 0.27). In Study 2, everyone first received the spray, and those whose pain decreased by at least 15% were randomized; pain worsened to the same extent in both groups (difference −0.02; 95% CI −0.42 to 0.38; p = 0.92). The spray had no significant effect on opioid use (total daily dose in Study 1, p = 0.053). In a post hoc exploratory analysis, a difference favoring the spray was seen in US patients younger than 65 in Study 1, and a difference favoring placebo in patients outside the US (p = 0.03); this two-directional finding does not count as evidence of an effect. The measures called 'quality of life' in the abstract that favored the spray were the patient's and physician's global impression of change (patient impression in Study 1, p = 0.022); in Study 2, there was no difference in these measures either Side effects: Consistent with previous studies; no evidence of abuse. In Study 1, 32% of patients with the spray and 21% with placebo left the study; drowsiness 12% vs. 4%. In the first period of Study 2, when everyone received the spray, 17.5% of patients stopped because of side effects; in the randomized period, stopping because of side effects was 13.6% with the spray and 5.8% with placebo. In the randomized period of Study 2, more deaths occurred in the spray group (23 vs. 9; hazard ratio 2.68; p = 0.012); almost all deaths were due to cancer progression, most of the excess was seen in the period after treatment ended (12 vs. 9 during treatment, 11 vs. 0 after treatment); the authors considered none of the deaths treatment-related, and the independent safety board saw no safety issue that would stop development of the medicine, but according to the authors the reason for the difference could not be explained. In Study 1, deaths were slightly more frequent with placebo (25 of 199 patients vs. 20 of 200 patients with the spray) | PMID 28785408, doi:10.1177/2049463717710042, NCT01361607, results in the registry. Funding: Otsuka, 6 of the 9 authors are employees of companies that developed or market the drug (5 Otsuka, 1 GW Pharmaceuticals), in the article, NCT01337089 |
| Portenoy 2012 Phase 2, dose-group RCT | 360 randomized Opioid-refractory cancer pain | Nabiximols | Low 1–4, medium 6–10, high 11–16 sprays/day By group | 5 weeks | Primary analysis of 30% response not significant (p=0.59); benefit at the low/medium doses in a secondary analysis. In the low-dose group, the score for pain interfering with sleep (secondary outcome) also decreased more than with placebo (−1.5 vs. −0.8 on a 0–10 scale; estimated difference −0.88, 95% CI −1.45 to −0.31; p = 0.003); no difference in sleep at the medium and high doses (p = 0.26 and 0.78) Side effects: Dose-dependent; only the high dose unfavorable compared with placebo | PMID 22483680, doi:10.1016/j.jpain.2012.01.003, NCT00530764 |
| Johnson 2010 Double-blind, placebo-controlled RCT | 177 Inadequate analgesia despite opioids | THC:CBD extract vs. THC extract vs. placebo | At most 8 sprays in 3 hours and at most 48 sprays a day (registry); on average THC:CBD 8.8, THC 8.4, placebo 9.1 sprays/day (Cochrane 2023) Self-titrated by the patient (registry) | 2 weeks | Primary outcome: average pain (0–10) decreased by 1.37 points with the THC:CBD spray and 0.69 with placebo (difference in the registry −0.67; 95% CI −1.21 to −0.14; p = 0.014); with the THC-only spray, the difference was not significant (p = 0.24). More than 30% reduction in pain in 43% with THC:CBD and 21% with placebo. Opioid and rescue medication use did not change. In the registry's secondary outcomes, appetite (p = 0.016), concentration (p = 0.021) and memory (p = 0.045) were worse with the THC:CBD spray than with placebo. Two-week study Side effects: Most mild/moderate; the nausea-vomiting subscore worsened with THC:CBD | PMID 19896326, doi:10.1016/j.jpainsymman.2009.06.008, NCT00674609, PMID 23141881, no comparison group, no new safety problems or loss of effect reported with long-term use, NCT00675948, Cochrane 2023 gives the funder as Otsuka |
| Hardy 2025 (MedCan2) Double-blind, placebo-controlled RCT | 144 randomized Advanced cancer, palliative care | Oil: THC 10 mg + CBD 10 mg/mL (1:1) | 0.25 mL/day (2.5 mg THC + 2.5 mg CBD) at the start → 3 mL/day (30 mg + 30 mg); median dose chosen given in the article as '15 mg/day' Increase over 14 days based on tolerance/effect | 28 days | No difference in total symptom distress (p=0.76). Small benefit in ESAS pain (−1.42 vs. −0.46; p=0.04), at the cost of more psychotomimetic toxicity. Placebo better for overall well-being. No opioid-sparing effect Side effects: Confusion, feeling 'high' and an exaggerated sense of well-being more common; most grade 1–2 | PMID 40705150, doi:10.1007/s00520-025-09763-5, ANZCTR ACTRN12619000037101. Funding: Australian government (MRFF) and the Mater Foundation, the manufacturer provided the drug and placebo and had no role in the study. At baseline, more people in the THC:CBD group were using opioids |
| Weiss 2025 Double-blind, placebo-controlled RCT (+12 weeks of open follow-up) | 46 randomized (43 completed; target 100) Patients with breast, colorectal, endometrial or ovarian cancer who had finished chemotherapy and had grade 2–3 chemotherapy neuropathy | Gel capsule: CBD + a little THC (13.9–15.1 mg CBD, 0.67–1.20 mg THC per capsule) | After week 1, 125.3–135.9 mg/day CBD + 6.0–10.8 mg/day THC Days 1–3: 1 capsule × 3; days 4–6: 2 × 3; from day 7: 3 × 3 | 12 weeks | No difference on the primary outcome (sensory neuropathy score); in a secondary analysis, 10.4 points better than placebo for sensory impairment (p=0.044); no difference in pain (a difference favoring placebo in the impact of pain on daily life disappeared after adjusting for the baseline difference); half the targeted number of participants was reached Side effects: No difference in side effects between groups; no serious side effects | PMID 41211445, doi:10.3389/fonc.2025.1590168, NCT04398446, the authors declared no conflicts of interest |
| Haney 2025 Double-blind, placebo-controlled pilot RCT | 12 (6/6) Women with breast cancer with painful taxane-induced neuropathy | Cannabis capsule (100 mg CBD : 5 mg THC) | 100 mg CBD + 5 mg THC 3 times a day (participants reduced the dose; average 2.0 capsules/day) | 8 weeks | Pain and sleep improved over time in both groups; in the cannabis arm, neuropathy scores were worse than with placebo every week, and sleep and the impact of pain on daily life also worsened Side effects: Everyone completed; dose reductions were requested in both groups | PMID 40611810, doi:10.1089/can.2025.0028, NCT03782402, results in the registry) |
| Fleege 2025 Phase 2, single-arm (no control group) | 39 (28 completed; 5 people stopped because of side effects, 6 because they saw no benefit) Women with stage 0–3, hormone receptor–positive breast cancer with aromatase inhibitor–related joint and muscle pain | Epidiolex (pure CBD) | 25 mg twice a day → 100 mg twice a day Increase of 25 mg × 2 every week over 4 weeks | 15 weeks | ≥2-point reduction in worst pain in 17/39 (43.6%); average 2.36-point reduction in those who completed; no placebo Side effects: 40 side effects in 18 patients, all grade 1–2; 5 people stopped because of side effects | PMID 40751295, doi:10.1002/cam4.71117, NCT04754399, Rising Tide Foundation and the US National Institutes of Health |
| Noyes 1975 (THC–codeine comparison) Double-blind, placebo- and codeine-controlled, single-dose crossover study (randomized according to Cochrane 2023; few method details) | 36 Patients with continuous moderate cancer pain who were not taking high-dose opioids (US, single center; most often breast cancer and lymphoma) | Oral THC (delta-9-THC); comparators codeine and placebo | Single dose of THC 10 mg or 20 mg; codeine 60 mg or 120 mg None (fixed single dose) | Single dose of each drug and 7 hours of observation (previous painkillers stopped 4.5 hours before) | According to the abstract, THC showed a mild analgesic effect; 10 mg was well tolerated. According to the authors, the side effects of 20 mg were at a level that would prevent its use in treatment. Cochrane 2023 pooled this and similar single-dose studies (including studies with experimental synthetic THC analogs that are outside the site's scope) and writes that they reduced pain more than placebo but were not superior to codeine (both low certainty). A small, single-dose study lasting a few hours, from 1975 Side effects: At 20 mg, drowsiness, dizziness, impaired balance, blurred vision and 'disturbing' reactions; sedation in 94% with THC 20 mg, 71% with 10 mg, 47–50% with codeine and 29% with placebo (as reported by Cochrane) | PMID 50159, doi:10.1002/cpt197518184, Listed as 'Noyes 1975a' in Cochrane 2023. Funding: clinical research center support from the US National Institutes of Health (NIH). The same team's dose–response study: Noyes 1975 (THC dose–response), in this table |
| Noyes 1975 (THC dose–response) Double-blind, placebo-controlled, single-dose crossover preliminary study | 10 Patients with continuous moderate cancer pain who were not taking high-dose opioids (US; 5 with breast cancer) | Oral THC (delta-9-THC) and placebo | Single doses of 5, 10, 15 and 20 mg THC None (fixed single doses) | Single dose for each dose level and same-day observation | 15 and 20 mg of THC reduced pain significantly more than placebo; the abstract does not report superiority for the lower doses (5 and 10 mg). Marked drowsiness and mental clouding were seen at the effective doses. A 10-person, single-dose preliminary study from 1975 Side effects: Marked drowsiness and mental clouding; reports of nervous system side effects increased with dose (14 at 5 mg, 36 at 20 mg, 21 with placebo; as reported by Cochrane) | PMID 1091664, doi:10.1002/j.1552-4604.1975.tb02348.x, Listed as 'Noyes 1975b' in Cochrane 2023. Funding: US National Institutes of Health (NIH) |
| Lynch 2014 Double-blind, placebo-controlled, crossover pilot RCT; followed by an open-label extension | 16 (abstract); Cochrane 2023 gives 18 participants Established chemotherapy-induced neuropathic pain (Canada, Halifax) | THC + CBD mouth spray (nabiximols) and placebo spray | At most 12 sprays a day; on average 8 sprays/day with the active spray and 11 with placebo (Cochrane 2023) Self-titrated by the patient | Two 4-week periods with a 2-week break in between (Cochrane 2023) | On the primary outcome (0–10 pain score), there was no significant difference from placebo in the whole group. Pain decreased by at least 2 points in 5 of 16 people (average 2.6 points; 0.6 with placebo); this responder analysis also did not reach significance (number needed to treat 5). By Cochrane 2023's calculation, at least a 30% reduction in pain occurred in 5 of 18 people with the active spray and 3 with placebo (p = 0.16; low certainty). Pilot study Side effects: Not reported (in the abstract) | PMID 23742737, doi:10.1016/j.jpainsymman.2013.02.018, NCT00872144, no funding, the authors declared no conflicts of interest |
| Côté 2016 Double-blind, placebo-controlled RCT (single center) | 56 randomized (28 nabilone, 28 placebo); 24 people left before the end of the study Patients with squamous cell head and neck cancer (mouth, pharynx, larynx) receiving radiotherapy (Canada); pain was not an inclusion criterion | Nabilone (a synthetic THC-like cannabinoid, by mouth) and placebo | Week 1: 0.5 mg at bedtime; week 2: 0.5 mg twice a day; after week 3, adjusted by the radiation oncologist up to at most 4 tablets a day (2 mg/day) Fixed increase in the first two weeks, adjusted by the physician after week 3 | Throughout radiotherapy (about 7 weeks) + 4 weeks of follow-up | For pain (visual pain scale), the measure for this topic, nabilone was no different from placebo (p = 0.60). The time to a 15% worsening of quality of life, the primary outcome, was also not prolonged (p = 0.43); no difference in nausea, appetite, weight, mood or sleep either. Baseline pain was not reported (Cochrane 2023) Side effects: No difference from placebo in the frequency of drowsiness (p = 0.32), anxiety and dry mouth as side effects (as reported in the Ceolin 2024 review; Cochrane 2023 gives the same result for drowsiness and anxiety; full text could not be read) | PMID 26503964, doi:10.1177/0003489415612801, Funding: Canadian public research funds (CIHR, FRSQ), the manufacturer provided nabilone and placebo (as reported in Cochrane 2023) |
| Turcott 2018 Double-blind, placebo-controlled pilot RCT (single center) | 47 randomized; 33 analyzed (14 nabilone, 19 placebo) Advanced non-small cell lung cancer with loss of appetite (Mexico); pain was not an inclusion criterion | Nabilone (a synthetic THC-like cannabinoid, oral capsule) and placebo | 0.5 mg (2 weeks) → 1.0 mg (6 weeks) (wording in the abstract and the registry) Dose increase after 2 weeks | 8 weeks | Pain was measured with the pain subscale of the quality-of-life questionnaire (EORTC QLQ-C30): borderline within-group improvement in the nabilone group (p = 0.06), no change in the placebo group; the abstract gives no direct comparison of the two groups. By Cochrane 2023's calculation, at least a 30% reduction in pain occurred in 7 of 14 people with nabilone and 7 of 19 with placebo (p = 0.45; low certainty). The primary aim was appetite and nutrition; the only result reported as significantly different from placebo was carbohydrate intake (p = 0.040). Full text could not be read Side effects: The abstract reported the treatment as safe. According to the Ceolin 2024 review, grade 3 nausea occurred only in the placebo group, and at most grade 2 side effects were reported in the nabilone group at week 8 (as reported in the review; full text could not be read) | PMID 29550881, doi:10.1007/s00520-018-4154-9, NCT02802540 |
| Zylla 2021 Randomized pilot study: early start compared with a 3-month delayed start (no placebo, open-label) | 30 randomized (15 early, 15 delayed) Patients with stage 4 cancer using opioids (US, Minnesota) | Products from the state medical cannabis program, chosen together with the dispensary pharmacist (product type, ratio and route individualized) | Individual; at month 3, estimated average daily THC 34 mg, CBD 17 mg Individual, as recommended by the pharmacist | 3-month comparison period | The primary aim was feasibility (36% of eligible patients took part). According to the abstract, the proportion of patients who reduced opioid use and had better pain control was higher in the early-start group; the abstract gives no numbers or statistical test, and the full text could not be read. No placebo, and patients knew they were taking cannabis; Cochrane 2023 did not include it in its review for this reason. Very small pilot Side effects: No serious safety problems reported; high patient satisfaction (abstract) | PMID 34085149, doi:10.1007/s00520-021-06301-x, Products were provided free of charge through the state program. 2 of the 13 authors are affiliated with medical cannabis manufacturers in the state (PubMed affiliation information). Letter of criticism in the journal: Davis 2022, PMID 35083541, in this table |
| D'Andre 2024 Double-blind, placebo-controlled, crossover pilot RCT | 40 randomized (20 + 20); 36 completed both periods Chemotherapy-induced peripheral neuropathy with pain or tingling of at least 4/10, in people who had finished chemotherapy and had no evidence of cancer (USA, Mayo Clinic) | Pure CBD (isolate) cream applied to the skin; placebo cream | Twice a day to the affected areas (the amount of CBD in the cream is not in the abstract or the registry) | 2 × 2 weeks | Neuropathy symptoms (QLQ-CIPN20 sensory subscale) were similar in the CBD and placebo periods; according to the researchers, the results do not support that this CBD cream improves painful neuropathy. Small and short pilot study Side effects: Side-effect scores were similar in both periods; generally well tolerated; no serious side effects (registry) | PMID 39016024, doi:10.1089/can.2023.0253, NCT05388058 |
| Zylla 2026 (CanPan) Waitlist-controlled, open-label pilot RCT | 34 enrolled; 32 started (16 early, 16 delayed start) Newly diagnosed locally advanced or metastatic pancreatic cancer, at least one symptom; moderate to severe pain in 77% (US, Minnesota) | Products chosen for each patient from the state medical cannabis program (THC-dominant, THC:CBD-balanced or CBD-dominant; by mouth, as a spray or inhaled) | Individual; median THC 7.3 mg/day at week 8 | 8-week comparison period (16 weeks in total) | The feasibility goals, the primary outcome, were met. At week 8, pain improved in 44% of the early-start group and 20% of the waiting group (p = 0.35; not significant); numerical but non-significant differences in appetite and insomnia as well. No placebo, and patients knew what they were using; very small pilot Side effects: Worsening of cannabis-related complaints such as dry mouth similar in both groups (11% vs. 20%; p = 0.99) | PMID 41510814, doi:10.1200/OP-25-01165, NCT06605430, 16-week dose-response analysis: Gupta 2026, PMID 42767994, funding by donation, no conflicts of interest reported. The same group's stage 4 cancer study: Zylla 2021, in this table |
| Zylla 2026 (ointment for joint pain) Randomized, open-label feasibility study; no placebo (CBD-dominant vs. THC-dominant ointment) | 24 registered (ClinicalTrials.gov); 21 women completed the study Women with stage 1–3 breast cancer taking an aromatase inhibitor, with drug-related joint, muscle and bone pain (AIMSS) (US, Minnesota) | Ointments provided free of charge by a medical cannabis company: CBD-dominant (2210 mg CBD per jar, THC below 0.3%) or THC-dominant (375 mg THC per jar, CBD below 20 mg); applied to the hands | 3 times a day, one scoop (1.25 mL spoon) applied to the back of each hand and spread over the hand, wrist and fingers | 2 weeks randomized + 2-week open extension with the chosen ointment | The primary aim was feasibility: 71% of participants continued into the 2-week extension. In the second week, 86% of participants reported improvement in hand symptoms (M-SACRAH); improvement of more than 50% was reported as 50% in the THC ointment group and 18% in the CBD ointment group, but the two groups were not compared statistically. Results for pain (Brief Pain Inventory), the main measure for this topic, are not in the abstract read (the full text could not be read). There was no placebo and participants knew which ointment they were using; the improvements cannot be interpreted as an effect of the ointment Side effects: Mild skin irritation in 24% of participants; 1 person stopped because of the ointment's greasy texture | PMID 41467893, doi:10.1177/25785125251398286, NCT05935891, the ointments were provided free of charge by a medical cannabis company, the authors declared no conflicts of interest |
| NCT01337089 (nabiximols long-term open-label extension, registry results) Multicenter, open-label, uncontrolled extension study (phase 3) | 660 (patients continuing from three phase 3 studies and newly enrolled patients); 256 completed Patients with advanced cancer whose pain continued despite opioids | Nabiximols (THC + CBD mouth spray) | Morning and evening, at most 10 sprays a day (registry) 1 spray in the evening on the first day; adjusted individually by increasing by 1 spray a day over 14 days, then continued at the same dose (registry) | 6 months (183 days) | The primary aim was safety: 82.9% of participants had at least one adverse event. The average pain score over the last 4 weeks (in those who stopped early, over the last 27 days of treatment) did not change from baseline (0.0; SD 1.8), and sleep disruption also did not change (0.1; SD 1.9). At the last visit, 471 (76%) of the 618 people who answered the satisfaction question reported being at least 'slightly satisfied'. No comparison group; some participants had previously received the spray or placebo, which makes the baseline measurement harder to interpret. No peer-reviewed publication Side effects: 404 people did not finish the study; 237 (36%) stopped because of adverse events (including progressing cancer). Serious adverse events in 301 of 660 people (most often cancer progression: 209). Common events: nausea (86 people), vomiting (59), dizziness (51), fatigue (50), loss of appetite (49), drowsiness (38) | NCT01337089, April 23, 2018, no publication found on PubMed in October 2026). The sponsors in the registry are Jazz Pharmaceuticals, the drug's current owner, and its development partner Otsuka. Main studies: Fallon 2017 and Lichtman 2018 (in this table) |
| To 2023 (MASCC guideline) Guideline based on a systematic review of RCTs and systematic reviews (MASCC; search up to November 12, 2021; Jadad scoring) | 34 systematic reviews and RCTs for cancer pain (7 of them RCTs in cancer pain); 7 publications for harms Adults with cancer pain; all cancer patients for harms | Cannabis and cannabinoid products | The positive primary results of two of the cancer pain RCTs could not be repeated in studies with a similar design; high-quality meta-analyses found little evidence that cannabinoids are an effective adjuvant drug or painkiller in cancer pain. The guideline's recommendation: cannabinoids should not be used as adjuvant painkillers in cancer pain; the risk of harm and side effects should be weighed carefully, especially in people taking checkpoint inhibitors. Full text could not be read (abstract) Side effects: Evidence on the type and level of harms was found to be inconsistent | PMID 36872397, doi:10.1007/s00520-023-07662-1, PMID 37148393, does not affect the results). No funding was received for the guideline (publisher's page). The same society's guideline on anxiety, depression and insomnia in cancer: De Feo 2023, PMID 36809575 | ||
| Braun 2024 (ASCO guideline) Clinical practice guideline; based on a systematic review (13 systematic reviews and 5 primary studies; search January 2023) | Adults with cancer | Cannabis and cannabinoids (pure, synthetic and plant-based) | Recommendation 3.3: evidence is insufficient to recommend for or against cannabis or cannabinoids for treatment-related side effects and symptoms, including cancer pain (outside clinical trials). In the guideline table, the quality of evidence for cancer pain is 'moderate' for nabiximols, with no clear evidence of benefit or harm and no recommendation; in the 2021 meta-analysis it relied on, the difference with nabiximols in cancer pain was not significant (−0.10 on a 10 cm scale; 95% CI −0.28 to 0.09). Recommendation 3.2: oral CBD at 300 mg a day or more should not be recommended for symptom burden outside clinical trials (low quality of evidence, weak recommendation). Two of the 15 panel members reported ties with companies in the cannabinoid field (one with stock and consulting in companies in this field, one with consulting for GW Pharmaceuticals, which developed nabiximols); one member also reported an unpaid tie with a cannabinoid research consortium | PMID 38478773, doi:10.1200/JCO.23.02596, Q&A summary: Braun 2024, PMID 38478793 | ||
| Busse 2021 (BMJ Rapid Recommendation) Clinical practice guideline (BMJ Rapid Recommendations; GRADE; international panel that included patient representatives) | People with chronic pain due to cancer or non-cancer causes | Non-inhaled (oral or topical) medical cannabis and cannabinoids | Weak recommendation for trying non-inhaled medical cannabis or cannabinoids in addition to standard treatment when standard treatment is not enough; because the balance of benefit and harm is close, shared decision-making is needed. In the meta-analysis it relied on (Wang 2021; 32 RCTs, 5,174 people), there was a small improvement in pain (−0.50 cm on a 10 cm scale; moderate certainty), but 28 of the studies were in non-cancer pain; in the nabiximols studies in cancer pain, the difference was not significant (as reported in ASCO 2024: −0.10; 95% CI −0.28 to 0.09) Side effects: According to the underlying meta-analysis, a small increase in the risk of dizziness, drowsiness, nausea, vomiting, impaired attention and temporary cognitive impairment | PMID 34497062, doi:10.1136/bmj.n2040, Underlying systematic review: Wang 2021, PMID 34497047, the average pain analysis of Wang 2021 included only one cancer pain study | ||
| Creangă-Murariu 2026 (meta-analysis of opioid use) Systematic review and meta-analysis (randomized and non-randomized studies; search October 24, 2025; GRADE) | 15 studies (10 in the meta-analysis); 5 RCTs, 769 people in the total opioid analysis Adult cancer patients using opioids for pain | THC-dominant, CBD-dominant and balanced THC:CBD products | In placebo-controlled analyses, cannabinoids did not change total opioid use (SMD −0.03; 95% CI −0.17 to 0.12; 5 RCTs, 769 people), the regular opioid dose or extra (rescue) opioid use differently from placebo. In before-and-after analyses, reductions in the regular opioid dose varied by product and came from individual studies; these analyses are not comparisons with placebo. Certainty of evidence low for all outcomes; the authors write that cannabinoids should not be seen as a reliable way to reduce opioids | PMID 42262611, doi:10.1007/s00520-026-10856-y, PROSPERO CRD420251175971. Funding: research fund of a Romanian public health program, the authors declared no conflicts of interest | ||
| Creangă-Murariu 2025 Systematic review and meta-analysis (interventional and observational studies; search up to November 4, 2023) | 98 publications (all cancer symptoms); 12 single-group studies, 2,591 patients in the pain analysis Symptom management in cancer patients | All types of cannabinoids (THC-dominant, CBD-dominant, balanced) | Pain was pooled only from single-group studies, as change from baseline: on a 0–10 scale it decreased by an average of 1.22 points (95% CI 0.52 to 1.92; very high inconsistency between studies, I² 100%); this is not a placebo comparison. In the placebo comparison, the small difference seen with nabiximols (mean difference −0.25; 95% CI −0.50 to −0.01) was judged by the authors as a failure to reduce pain. The authors nevertheless conclude that cannabinoids may be useful in cancer pain; this interpretation is based on change from baseline, not on a placebo comparison. Certainty of evidence low or very low for all outcomes; high risk of publication bias for pain Side effects: With THC-dominant products, the risk of psychiatric (OR 10.62; 1.35–83.57) and neurological (OR 2.24; 1.15–4.35) side effects increased | PMID 40748522, doi:10.1007/s11912-025-01695-x, PROSPERO CRD42023479375 | ||
| Maida 2008 Prospective observational study: patients taking and not taking nabilone were compared after balancing with propensity scores (not randomized or blinded) | 112 (47 nabilone, 65 not taking nabilone) Patients with advanced cancer with pain and other symptoms (Canada) | Nabilone (a synthetic THC-like cannabinoid, by mouth), added to existing treatment | Not reported (in the abstract) | 30 days | The primary outcomes were pain and opioid use: at day 30, propensity-adjusted pain scores and total morphine-equivalent use were lower in the nabilone group (both p < 0.0001). Nausea, anxiety and total symptom score were also better in the nabilone group; those taking nabilone started fewer other pain and nausea medicines. Nabilone was not given randomly, and the study was not blinded; the groups were balanced with propensity scores Side effects: Not reported (in the abstract) | PMID 18402303 |
| Aviram 2022 Prospective observational cohort (multicenter; no comparison group) | 324 started; 212, 158 and 126 people responded at months 1, 3 and 6 Oncology patients receiving a medical cannabis license for the first time for cancer symptoms (Israel) | Licensed medical cannabis: dried flower (smoked or vaporized) or oil extract; at month 6, of those who reported their product, 61% used THC-dominant, 25% mixed and 15% CBD-dominant products | Individual; median 20 g of product per month | 6 months | In those who reached month 6, weekly average pain fell from a median of 7 to 5 (−0.98; 95% CI −1.43 to −0.54), and worst pain from 8 to 6 (−1.78; −2.31 to −1.26); total symptom burden, the primary outcome, decreased by a median of 18%. Of the 74 people using analgesics at baseline, 30 (40%) had stopped by month 6, and 10 people had newly started; very few of those reaching month 6 were using opioids (median morphine equivalent 0). According to the authors, the change in pain was small and the clinical importance of the effect may be limited. No control group; only 39% of those who started responded at month 6 Side effects: Side effects were common (20–30%) but most were not serious and stayed stable throughout follow-up | PMID 35669038, doi:10.3389/fpain.2022.861037, 1-month study by the same group: Aviram 2020, PMID 33265945, pain intensity improved, no difference in pain between THC- and CBD-dominant products, worst and least pain had not changed significantly at month 1). Funding: a charitable foundation, the authors declared no conflicts of interest |
| Aprikian 2024 (Quebec Cannabis Registry) Patient registry analysis (prospective, multicenter registry; no comparison group) | 358 Patients starting medical cannabis for cancer pain and other cancer symptoms (Canada, Quebec) | Medical cannabis: THC-dominant, THC:CBD-balanced or CBD-dominant products | Not reported (in the abstract) | Up to 12 months (measurements at months 3, 6, 9 and 12) | Worst pain (Brief Pain Inventory, 0–10) fell from 5.5 to 3.6 at month 3, and average pain from 4.1 to 2.4; the decrease was significant at months 3, 6 and 9 (p < 0.01). THC:CBD-balanced products were associated with better pain reduction than THC- or CBD-dominant products. Total medication burden decreased at all follow-ups, and the daily morphine-equivalent dose at the first three follow-ups. No control group; the numbers of patients remaining in follow-up are not in the abstract; the authors write that the result needs to be confirmed in placebo-controlled studies. Full text could not be accessed Side effects: 15 side effects in 11 patients; 2 serious events (pneumonia and a cardiovascular event) were not considered likely to be related to cannabis | PMID 37130724, doi:10.1136/spcare-2022-004003, Analysis of symptoms and sex differences in the same 358 patients: Kasvis 2022, PMID 35723729 |
| Varadpande 2025 (UK Medical Cannabis Registry) Case series (prospective patient registry; no comparison group) | 168 Patients prescribed cannabis-based medicines for cancer pain (United Kingdom) | Cannabis-based medicines (product breakdown not in the abstract) | Not reported (in the abstract) | 6 months (measurements at months 1, 3 and 6) | All pain-specific measures (Brief Pain Inventory, pain visual scale) improved significantly from baseline at months 1, 3 and 6 (p < 0.05; magnitudes not in the abstract); anxiety, sleep quality and quality of life also improved. No control group; the authors state that cause and effect cannot be established. 8 of the 12 authors are affiliated with a private clinic that prescribes cannabis medicines Side effects: 29 side effects in 5 patients (3%); most mild or moderate | PMID 39921589, doi:10.1080/15360288.2025.2457101, Preliminary 16-patient palliative care report from the same registry: Nimalan 2022, PMID 34980282 |
| Stienrut 2024 (Thai national cohort) Prospective observational cohort (30 centers; no comparison group) | 21,284 patients, 2,873 with cancer; by week 12, 32% of participants had dropped out of follow-up Patients prescribed cannabis oil by traditional Thai medicine practitioners for symptoms such as pain, loss of appetite and insomnia (Thailand) | Cannabis extract in coconut oil produced by the Ministry of Health (about 0.07 mg THC per drop; almost no CBD) | Most often 3 drops a day at bedtime (about 0.2 mg THC/day) | 3 months | In patients with cancer, pain (ESAS, 0–10) decreased by 2.01 points from baseline over 3 months (95% CI 1.87 to 2.16); by 2.75 points in patients without cancer. Quality of life and other symptoms also improved. No control group; the daily THC dose was about 0.2 mg (far below the doses in cancer pain RCTs); the authors write that efficacy needs to be shown in controlled studies Side effects: Side effects at 0.42% of 67,681 visits (most often dry mouth, dizziness, drowsiness) | PMID 39144529, doi:10.1159/000540153, Thai Clinical Trials Registry TCTR20191231001. Funding: the Department of Thai Traditional and Alternative Medicine of the Ministry of Health, which also makes the product, the authors declared no conflicts of interest |
Reported side effects
- Pure CBD (Hardy 2023): no difference between arms; dyspnea more frequent with CBD
- THC-containing: somnolence OR 2.69, dizziness OR 1.58 (Boland 2020); confusion, feeling 'high' (Hardy 2025)
- THC-containing, long-term use (NCT01337089, 6 months, 660 patients, open-label): 237 people (36%) stopped because of adverse events (including progressing cancer); most common: nausea, vomiting, dizziness, fatigue, drowsiness
Monitoring done in studies
- Prescription CBD label: liver tests at baseline and at months 1, 3 and 6, then periodically; stop if ALT/AST >3×ULN + bilirubin >2×ULN, or if transaminases stay >5×ULN
- INR in people taking warfarin
- Drug blood levels in people taking everolimus/tacrolimus/sirolimus
- ASCO 2024 recommendation 3.2: oral CBD ≥300 mg/day is not recommended for symptom burden outside clinical trials (no efficacy; risk of reversible liver enzyme abnormalities)
Who should be careful
- People with liver disease / liver metastases / on hepatotoxic treatment: with prescription CBD, ALT >3×ULN in 12–13% (placebo 1%), dose-dependent; in moderate/severe hepatic impairment the label specifies a lower starting dose
- People taking warfarin or clopidogrel and those at high risk of bleeding: there is an interaction mechanism (CYP2C9, CYP2C19); no clinical data have been reported showing that CBD directly increases bleeding risk
- Before surgery/procedures: ASRA 2023 recommends asking about cannabinoid use and including it in the anesthesia plan; the anesthesia team must be told
- People on immunotherapy (checkpoint inhibitors): there is an observational signal and a guideline warning
- People taking everolimus, tacrolimus, sirolimus or oral targeted drugs: CBD should not be added without consulting the oncologist/pharmacist
- Older adults, people taking many medicines, and those on sedatives/opioids: somnolence, dizziness, risk of falls; with THC-containing products, confusion and psychotomimetic effects
- Use for 'treating' tumors: uncontrolled case series are not evidence; ASCO strongly recommends against abandoning standard treatment
- Pregnancy/breastfeeding, history of psychiatric illness (with THC-containing products): cancer studies excluded these groups
Drug interactions
- Everolimus: exposure increased ~2.5-fold; label: start everolimus at a lower dose and monitor levels (high, human PK data)
- Tacrolimus, sirolimus, digoxin (P-gp substrates): the label states that levels may increase (moderate)
- Oral P-gp substrate chemotherapy/targeted drugs (e.g., many tyrosine kinase inhibitors): theoretical; no human data
- CYP2C19 substrates and prodrugs (clopidogrel): substrate levels rise, and the active metabolite of prodrugs may decrease; no human data for oncology drugs
- Warfarin: case report of INR rise; INR should be monitored
- CYP3A4 substrates (taxanes, irinotecan, docetaxel, many TKIs): midazolam unchanged on the label (licensed CBD 750 mg twice daily); a single dose of a CBD-dominant extract (640 mg CBD + 20 mg THC) increased midazolam AUC by 56% (Bansal 2023, PMID 37313955); herbal cannabis tea did not affect irinotecan and docetaxel PK (n=24); nabiximols did not affect temozolomide PK; these results cannot be generalized
- Immunotherapy: nivolumab response rate 15.9% vs. 37.5% in cannabis users (mostly THC-containing cannabis) (Taha 2019, PMID 30670598, n=140); in a prospective observational study, time to progression and survival were shorter (Bar-Sela 2020, PMID 32872248, n=102); causality not proven, no data specific to pure CBD
- Opioids: in MedCan1, CBD dose was unrelated to opioid use; no opioid-sparing effect shown with THC-containing products; somnolence increases with CNS depressants
- Citalopram/escitalopram: citalopram levels rose significantly in 6 patients who added CBD (200–800 mg/day) (Anderson 2021, PMID 34121064)
- Valproate and liver-toxic drugs (some chemotherapies, methotrexate): no data on use together with hepatotoxic chemotherapies
- Tamoxifen: in one case, endoxifen was found to be low with CBD 40 mg/day (Parihar 2020, PMID 33191836)
- No clinical studies reported with direct oral anticoagulants (apixaban, rivaroxaban)
Abbreviations: RCT, randomized controlled trial (a study in which participants are assigned to groups by chance); placebo, an inactive substance; SMD, OR and RR, effect measures used in analyses that pool studies; CYP, liver enzymes that break down medicines.
If you are considering CBD
- If your pain is not under control, tell your care team clearly; your pain treatment can be readjusted to fit your needs.
- Do not reduce your opioid painkillers on your own; studies have not shown that CBD or THC-containing products reduce the need for opioids.
- Review your cancer medicines (including immunotherapy), blood thinners and sleep-inducing medicines with your oncologist and pharmacist for interactions with CBD.
Choose your age group, medicines and situation to prepare a short summary you can take to your doctor. Nothing you enter is sent anywhere.
Bottom line
In cancer pain, pure CBD oil has not been shown to provide added benefit to supportive care; large studies of THC-containing products found no benefit (moderate-strength evidence); the occasional small benefits seen also came with side effects. You do not have to deal with your pain alone; talking openly with your care team is the best place to start.
Frequently asked questions
Does CBD oil work for cancer pain?
In a well-designed study in advanced cancer, pure CBD oil did not improve symptoms, including pain, more than an inactive treatment (placebo); in chemotherapy-induced nerve pain, a CBD cream applied to the skin was also no different from placebo. The evidence is weak. For this reason, there is not enough basis today to say that CBD oil works for cancer pain.
Do THC-containing products help with cancer pain?
In large studies, a mouth spray containing THC and CBD was not clearly different from placebo for cancer pain that continued despite opioids. With an oil containing equal amounts of THC and CBD, a small improvement was seen, but with more side effects (single study). The strength of evidence for the 'no difference' result, based on the large spray studies, is moderate. In small single-dose studies done in the 1970s, THC reduced pain but was not more effective than codeine and caused marked drowsiness; the strength of evidence from these old studies is low.
Can I lower the dose of painkillers such as morphine with CBD?
Studies have not shown that CBD or THC-containing products reduce the need for opioid painkillers; a 2026 review that pooled placebo-controlled studies also found no reduction (low strength of evidence). In a small 14-person study without a comparison group, 4 people taking dronabinol (synthetic THC) reduced their opioid dose; because there was no placebo group, this does not count as evidence of an effect (very weak strength of evidence). Make every change to your painkillers together with your doctor.
Does CBD interact with my cancer medicines?
It may. CBD can slow the breakdown of some medicines in the body; it has been shown to increase everolimus levels about 2.5-fold. There are no human data for many cancer medicines; that is why it is important to talk to your oncologist and pharmacist.
Can CBD oil be obtained with a prescription for cancer pain in Turkey?
In Turkey, products derived from cannabis are regulated by the Kenevirden Elde Edilen Ürünlere Dair Yönetmelik (Regulation on Products Derived from Hemp) dated January 31, 2026. These products, including CBD, can be sold only in pharmacies. Those classified as medicines and health products are dispensed with a prescription; the regulation does not state a prescription requirement for supplement products and cosmetics with a THC content of at most 0.3%. As of October 2026, there is no approved CBD medicine in Turkey. If you are thinking of using it, talk to your doctor first.
References
Show 31 references
- Hardy 2023 (MedCan1-CBD). Phase IIb, double-blind, placebo-controlled, dose-escalation RCT. PMID 36409969, doi:10.1200/JCO.22.01632, ANZCTR ACTRN12618001220257, protocol: Good 2019, PMID 31810437, PMID 39539239, PMID 41429435, 2 authors received funds on behalf of their institutions from the company that supplied the CBD (Cochrane 2023)
- Häuser 2023 (Cochrane). Cochrane systematic review and meta-analysis (double-blind RCTs; search January 26, 2023). PMID 37283486, doi:10.1002/14651858.CD014915.pub2, Previous review by the same authors: Häuser 2019, PMID 31073761, Staquet 1978) were done with experimental synthetic THC analogs and therefore have no separate row in the table
- Boland 2020. Systematic review and meta-analysis. PMID 31959586, doi:10.1136/bmjspcare-2019-002032
- Lichtman 2018. Phase 3, double-blind RCT. PMID 28923526, doi:10.1016/j.jpainsymman.2017.09.001, NCT01262651, sponsor GW Pharmaceuticals, which developed the drug, partner Otsuka). According to the author affiliations on PubMed, 6 of the 9 authors are employees of companies that developed or market the drug (5 Otsuka, 1 GW), according to Cochrane 2023, NCT01337089
- Fallon 2017. Two phase 3 RCTs. PMID 28785408, doi:10.1177/2049463717710042, NCT01361607, results in the registry. Funding: Otsuka, 6 of the 9 authors are employees of companies that developed or market the drug (5 Otsuka, 1 GW Pharmaceuticals), in the article, NCT01337089
- Portenoy 2012. Phase 2, dose-group RCT. PMID 22483680, doi:10.1016/j.jpain.2012.01.003, NCT00530764
- Johnson 2010. Double-blind, placebo-controlled RCT. PMID 19896326, doi:10.1016/j.jpainsymman.2009.06.008, NCT00674609, PMID 23141881, no comparison group, no new safety problems or loss of effect reported with long-term use, NCT00675948, Cochrane 2023 gives the funder as Otsuka
- Hardy 2025 (MedCan2). Double-blind, placebo-controlled RCT. PMID 40705150, doi:10.1007/s00520-025-09763-5, ANZCTR ACTRN12619000037101. Funding: Australian government (MRFF) and the Mater Foundation, the manufacturer provided the drug and placebo and had no role in the study. At baseline, more people in the THC:CBD group were using opioids
- Weiss 2025. Double-blind, placebo-controlled RCT (+12 weeks of open follow-up). PMID 41211445, doi:10.3389/fonc.2025.1590168, NCT04398446, the authors declared no conflicts of interest
- Haney 2025. Double-blind, placebo-controlled pilot RCT. PMID 40611810, doi:10.1089/can.2025.0028, NCT03782402, results in the registry)
- Fleege 2025. Phase 2, single-arm (no control group). PMID 40751295, doi:10.1002/cam4.71117, NCT04754399, Rising Tide Foundation and the US National Institutes of Health
- Noyes 1975 (THC–codeine comparison). Double-blind, placebo- and codeine-controlled, single-dose crossover study (randomized according to Cochrane 2023; few method details). PMID 50159, doi:10.1002/cpt197518184, Listed as 'Noyes 1975a' in Cochrane 2023. Funding: clinical research center support from the US National Institutes of Health (NIH). The same team's dose–response study: Noyes 1975 (THC dose–response), in this table
- Noyes 1975 (THC dose–response). Double-blind, placebo-controlled, single-dose crossover preliminary study. PMID 1091664, doi:10.1002/j.1552-4604.1975.tb02348.x, Listed as 'Noyes 1975b' in Cochrane 2023. Funding: US National Institutes of Health (NIH)
- Lynch 2014. Double-blind, placebo-controlled, crossover pilot RCT; followed by an open-label extension. PMID 23742737, doi:10.1016/j.jpainsymman.2013.02.018, NCT00872144, no funding, the authors declared no conflicts of interest
- Côté 2016. Double-blind, placebo-controlled RCT (single center). PMID 26503964, doi:10.1177/0003489415612801, Funding: Canadian public research funds (CIHR, FRSQ), the manufacturer provided nabilone and placebo (as reported in Cochrane 2023)
- Turcott 2018. Double-blind, placebo-controlled pilot RCT (single center). PMID 29550881, doi:10.1007/s00520-018-4154-9, NCT02802540
- Zylla 2021. Randomized pilot study: early start compared with a 3-month delayed start (no placebo, open-label). PMID 34085149, doi:10.1007/s00520-021-06301-x, Products were provided free of charge through the state program. 2 of the 13 authors are affiliated with medical cannabis manufacturers in the state (PubMed affiliation information). Letter of criticism in the journal: Davis 2022, PMID 35083541, in this table
- D'Andre 2024. Double-blind, placebo-controlled, crossover pilot RCT. PMID 39016024, doi:10.1089/can.2023.0253, NCT05388058
- Zylla 2026 (CanPan). Waitlist-controlled, open-label pilot RCT. PMID 41510814, doi:10.1200/OP-25-01165, NCT06605430, 16-week dose-response analysis: Gupta 2026, PMID 42767994, funding by donation, no conflicts of interest reported. The same group's stage 4 cancer study: Zylla 2021, in this table
- Zylla 2026 (ointment for joint pain). Randomized, open-label feasibility study; no placebo (CBD-dominant vs. THC-dominant ointment). PMID 41467893, doi:10.1177/25785125251398286, NCT05935891, the ointments were provided free of charge by a medical cannabis company, the authors declared no conflicts of interest
- NCT01337089 (nabiximols long-term open-label extension, registry results). Multicenter, open-label, uncontrolled extension study (phase 3). NCT01337089, April 23, 2018, no publication found on PubMed in October 2026). The sponsors in the registry are Jazz Pharmaceuticals, the drug's current owner, and its development partner Otsuka. Main studies: Fallon 2017 and Lichtman 2018 (in this table)
- To 2023 (MASCC guideline). Guideline based on a systematic review of RCTs and systematic reviews (MASCC; search up to November 12, 2021; Jadad scoring). PMID 36872397, doi:10.1007/s00520-023-07662-1, PMID 37148393, does not affect the results). No funding was received for the guideline (publisher's page). The same society's guideline on anxiety, depression and insomnia in cancer: De Feo 2023, PMID 36809575
- Braun 2024 (ASCO guideline). Clinical practice guideline; based on a systematic review (13 systematic reviews and 5 primary studies; search January 2023). PMID 38478773, doi:10.1200/JCO.23.02596, Q&A summary: Braun 2024, PMID 38478793
- Busse 2021 (BMJ Rapid Recommendation). Clinical practice guideline (BMJ Rapid Recommendations; GRADE; international panel that included patient representatives). PMID 34497062, doi:10.1136/bmj.n2040, Underlying systematic review: Wang 2021, PMID 34497047, the average pain analysis of Wang 2021 included only one cancer pain study
- Creangă-Murariu 2026 (meta-analysis of opioid use). Systematic review and meta-analysis (randomized and non-randomized studies; search October 24, 2025; GRADE). PMID 42262611, doi:10.1007/s00520-026-10856-y, PROSPERO CRD420251175971. Funding: research fund of a Romanian public health program, the authors declared no conflicts of interest
- Creangă-Murariu 2025. Systematic review and meta-analysis (interventional and observational studies; search up to November 4, 2023). PMID 40748522, doi:10.1007/s11912-025-01695-x, PROSPERO CRD42023479375
- Maida 2008. Prospective observational study: patients taking and not taking nabilone were compared after balancing with propensity scores (not randomized or blinded). PMID 18402303
- Aviram 2022. Prospective observational cohort (multicenter; no comparison group). PMID 35669038, doi:10.3389/fpain.2022.861037, 1-month study by the same group: Aviram 2020, PMID 33265945, pain intensity improved, no difference in pain between THC- and CBD-dominant products, worst and least pain had not changed significantly at month 1). Funding: a charitable foundation, the authors declared no conflicts of interest
- Aprikian 2024 (Quebec Cannabis Registry). Patient registry analysis (prospective, multicenter registry; no comparison group). PMID 37130724, doi:10.1136/spcare-2022-004003, Analysis of symptoms and sex differences in the same 358 patients: Kasvis 2022, PMID 35723729
- Varadpande 2025 (UK Medical Cannabis Registry). Case series (prospective patient registry; no comparison group). PMID 39921589, doi:10.1080/15360288.2025.2457101, Preliminary 16-patient palliative care report from the same registry: Nimalan 2022, PMID 34980282
- Stienrut 2024 (Thai national cohort). Prospective observational cohort (30 centers; no comparison group). PMID 39144529, doi:10.1159/000540153, Thai Clinical Trials Registry TCTR20191231001. Funding: the Department of Thai Traditional and Alternative Medicine of the Ministry of Health, which also makes the product, the authors declared no conflicts of interest
Points that could not be verified from the full text
- Studies that were completed but whose results, as of October 2026, had neither been published nor posted to the registry: nabilone in chemotherapy-induced nerve pain (NCT00380965, completed in 2007), a personalized (N-of-1) cannabis oil trial for cancer symptoms (NCT03948074, 91 people, completed in July 2025), dronabinol in pancreatic cancer (NCT03984214, 109 people, completed in September 2024), cannabis during chemoradiotherapy in head and neck cancer (NCT03431363, 30 people, completed in January 2026) and a capsule containing THC, CBD and CBC for advanced cancer pain (NCT06533657, 11 people, completed in April 2026). The status of a planned phase 3 study of a THC:CBD spray for bone metastasis pain (NCT04808531) is unknown in the registry.
- ESMO 2018 cancer pain guideline: the site previously stated that this guideline found the added contribution of a mouth spray containing THC and CBD uncertain for pain continuing despite opioids and generally did not recommend it (level of evidence II, grade of recommendation D). In the October 2026 audit, this statement could not be re-verified because the full text of the guideline could not be accessed and the PubMed record has no abstract; it was removed from the evidence summary until it is verified.
Research history
Here we record what changed on this page, when and why, with dates. The newest change is at the top.
October 2026 additional review: a source found for this page during the searches for other topics was read and added to the page. The sleep result in the low-dose group was added to the dose study of the THC and CBD mouth spray in cancer pain not responding to opioids (Portenoy 2012): the score for pain interfering with sleep, a secondary measure, decreased more than with placebo only at the low dose, with no difference at the medium and high doses; on the study's primary outcome, there was also no difference between the spray and placebo. The conclusion and the strength of evidence did not change.
In the October 2026 search (PubMed, Cochrane, ClinicalTrials.gov), 20 studies were added to this topic: 9 randomized studies (two single-dose THC studies from 1975, Lynch 2014, Côté 2016, Turcott 2018, Zylla 2021, D'Andre 2024, Zylla 2026 CanPan and the ointment study in joint pain), the registry results of the 6-month open-label extension study of nabiximols, the MASCC, ASCO and BMJ guidelines, 2 systematic reviews and 5 observational studies. Registry numbers, funding and company ties, and the figures from Cochrane and from the registry results, were added to the rows of the nabiximols studies; the page now states that the measures referred to as 'quality of life' were global impression and satisfaction questionnaires, that the positive subgroup findings in US patients were post hoc and went in both directions, and that more deaths occurred in the spray group during the randomized period of one study (the authors and the independent safety board saw no link with the spray); the pain data reported by Cochrane were added to the MedCan1 row. The sentence based on the ESMO 2018 guideline was removed from the evidence summary and moved to the unverifiable points because the full text of the guideline could not be accessed; completed studies whose results have not been published were also listed under the unverifiable points. The conclusion and the strength of evidence did not change; the scope of the strength of evidence for THC was clarified.
Related studies: Noyes 1975 (THC–codeine comparison), published July 1975 (PMID 50159, doi:10.1002/cpt197518184, Listed as 'Noyes 1975a' in Cochrane 2023. Funding: clinical research center support from the US National Institutes of Health (NIH). The same team's dose–response study: Noyes 1975 (THC dose–response), in this table); Noyes 1975 (THC dose–response), published February–March 1975 (PMID 1091664, doi:10.1002/j.1552-4604.1975.tb02348.x, Listed as 'Noyes 1975b' in Cochrane 2023. Funding: US National Institutes of Health (NIH)); Lynch 2014, published January 2014 (PMID 23742737, doi:10.1016/j.jpainsymman.2013.02.018, NCT00872144, no funding, the authors declared no conflicts of interest); Côté 2016, published April 2016 (PMID 26503964, doi:10.1177/0003489415612801, Funding: Canadian public research funds (CIHR, FRSQ), the manufacturer provided nabilone and placebo (as reported in Cochrane 2023)); Turcott 2018, published September 2018 (PMID 29550881, doi:10.1007/s00520-018-4154-9, NCT02802540); Zylla 2021, published December 2021 (PMID 34085149, doi:10.1007/s00520-021-06301-x, Products were provided free of charge through the state program. 2 of the 13 authors are affiliated with medical cannabis manufacturers in the state (PubMed affiliation information). Letter of criticism in the journal: Davis 2022, PMID 35083541, in this table); D'Andre 2024, published December 2024 (PMID 39016024, doi:10.1089/can.2023.0253, NCT05388058); Zylla 2026 (CanPan), published January 9, 2026 (PMID 41510814, doi:10.1200/OP-25-01165, NCT06605430, 16-week dose-response analysis: Gupta 2026, PMID 42767994, funding by donation, no conflicts of interest reported. The same group's stage 4 cancer study: Zylla 2021, in this table); Zylla 2026 (ointment for joint pain), published February 2026 (online December 2025) (PMID 41467893, doi:10.1177/25785125251398286, NCT05935891, the ointments were provided free of charge by a medical cannabis company, the authors declared no conflicts of interest); NCT01337089 (nabiximols long-term open-label extension, registry results), published April 23, 2018 (registry results) (NCT01337089, April 23, 2018, no publication found on PubMed in October 2026). The sponsors in the registry are Jazz Pharmaceuticals, the drug's current owner, and its development partner Otsuka. Main studies: Fallon 2017 and Lichtman 2018 (in this table)); To 2023 (MASCC guideline), published March 6, 2023 (PMID 36872397, doi:10.1007/s00520-023-07662-1, PMID 37148393, does not affect the results). No funding was received for the guideline (publisher's page). The same society's guideline on anxiety, depression and insomnia in cancer: De Feo 2023, PMID 36809575); Braun 2024 (ASCO guideline), published May 1, 2024 (PMID 38478773, doi:10.1200/JCO.23.02596, Q&A summary: Braun 2024, PMID 38478793); Busse 2021 (BMJ Rapid Recommendation), published September 8, 2021 (PMID 34497062, doi:10.1136/bmj.n2040, Underlying systematic review: Wang 2021, PMID 34497047, the average pain analysis of Wang 2021 included only one cancer pain study); Creangă-Murariu 2026 (meta-analysis of opioid use), published June 9, 2026 (PMID 42262611, doi:10.1007/s00520-026-10856-y, PROSPERO CRD420251175971. Funding: research fund of a Romanian public health program, the authors declared no conflicts of interest); Creangă-Murariu 2025, published September 2025 (PMID 40748522, doi:10.1007/s11912-025-01695-x, PROSPERO CRD42023479375); Maida 2008, published March 2008 (PMID 18402303); Aviram 2022, published May 2022 (PMID 35669038, doi:10.3389/fpain.2022.861037, 1-month study by the same group: Aviram 2020, PMID 33265945, pain intensity improved, no difference in pain between THC- and CBD-dominant products, worst and least pain had not changed significantly at month 1). Funding: a charitable foundation, the authors declared no conflicts of interest); Aprikian 2024 (Quebec Cannabis Registry), published January 2024 (PMID 37130724, doi:10.1136/spcare-2022-004003, Analysis of symptoms and sex differences in the same 358 patients: Kasvis 2022, PMID 35723729); Varadpande 2025 (UK Medical Cannabis Registry), published June 2025 (PMID 39921589, doi:10.1080/15360288.2025.2457101, Preliminary 16-patient palliative care report from the same registry: Nimalan 2022, PMID 34980282); Stienrut 2024 (Thai national cohort), published July 17, 2024 (PMID 39144529, doi:10.1159/000540153, Thai Clinical Trials Registry TCTR20191231001. Funding: the Department of Thai Traditional and Alternative Medicine of the Ministry of Health, which also makes the product, the authors declared no conflicts of interest)
Display fix: internal working file names left in the text were removed; content and evidence did not change.
Older changes (4)
The names of the finding labels were simplified: on this page the "No benefit seen" label became "No effect found." The assessment did not change.
PubMed and ClinicalTrials.gov were searched for newly published and previously missed clinical studies. 3 studies added: Weiss 2025, Haney 2025 and Fleege 2025. The conclusion and the strength of evidence did not change.
Related studies: Weiss 2025, published October 23, 2025 (PMID 41211445, doi:10.3389/fonc.2025.1590168, NCT04398446, the authors declared no conflicts of interest); Haney 2025, published October 2025 (PMID 40611810, doi:10.1089/can.2025.0028, NCT03782402, results in the registry)); Fleege 2025, published August 2025 (PMID 40751295, doi:10.1002/cam4.71117, NCT04754399, Rising Tide Foundation and the US National Institutes of Health)
The full texts of the studies were reread and the information on the page was checked against its sources. Corrected: duration, participant numbers and dose information in the study table; drug interaction notes; evidence summary. No points remain that could not be verified from the full text (previously 3 items). The conclusion and the strength of evidence did not change.
Page published. In this first assessment, 8 studies were reviewed.