Adverse effects of medical cannabinoids: a systematic review
Open accessAbstract
BACKGROUND: The therapeutic use of cannabis and cannabis-based medicines raises safety concerns for patients, clinicians, policy-makers, insurers, researchers and regulators. Although the efficacy of cannabinoids is being increasingly demonstrated in randomized controlled trials, most safety information comes from studies of recreational use. METHODS: We performed a systematic review of safety studies of medical cannabinoids published over the past 40 years to create an evidence base for cannabis-related adverse events and to facilitate future cannabis research initiatives. We critically evaluated the quality of published studies with a view to identifying ways to improve future studies. RESULTS: A total of 321 articles were eligible for evaluation. After excluding those that focused on recreational cannabis use, we included 31 studies (23 randomized controlled trials and 8 observational studies) of medical cannabis use in our analysis. In the 23 randomized controlled trials, the median duration of cannabinoid exposure was 2 weeks (range 8 hours to 12 months). A total of 4779 adverse events were reported among participants assigned to the intervention. Most (4615 [96.6%]) were not serious. Of the 164 serious adverse events, the most common was relapse of multiple sclerosis (21 events [12.8%]), vomiting (16 events [9.8%]) and urinary tract infection (15 events [9.1%]). The rate of nonserious adverse events was higher among participants assigned to medical cannabinoids than among controls (rate ratio [RR] 1.86, 95% confidence interval [CI] 1.57-2.21); the rates of serious adverse events did not differ significantly between these 2 groups (RR 1.04, 95% CI 0.78-1.39). Dizziness was the most commonly reported nonserious adverse event (714 events [15.5%]) among people exposed to cannabinoids. INTERPRETATION: Short-term use of existing medical cannabinoids appeared to increase the risk of nonserious adverse events. The risks associated with long-term use were poorly characterized in published clinical trials and observational studies. High-quality trials of long-term exposure are required to further characterize safety issues related to the use of medical cannabinoids.
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Written from the paper’s full text.
TL;DR
This systematic review of medical cannabinoid safety found that nonserious adverse events were significantly more common with cannabinoids than control, while serious adverse events were not significantly increased. Most reported events were not serious, and none were unexpected according to International Conference on Harmonisation criteria.
Key findings
- Across 31 included studies (23 randomized controlled trials and 8 observational studies), the review identified 8371 adverse events related to medical cannabinoid use: 4779 in randomized controlled trials and 3592 in observational studies.
- In 23 randomized controlled trials, serious adverse events were not significantly more frequent with cannabinoids than control (164 vs 60 events; rate ratio [RR] 1.04, 95% CI 0.78–1.39). Deaths occurred in 15 cannabinoid users and 3 controls (RR 2.66, 95% CI 0.77–9.28, not statistically significant).
- Nonserious adverse events were significantly more frequent with cannabinoids: 4615 events among cannabinoid-assigned participants (10.37 events/person-year) vs 1641 among controls (6.87 events/person-year), with a pooled RR of 1.86 (95% CI 1.57–2.21).
- By preparation, nonserious adverse event rates were higher for oromucosal Δ-9-tetrahydrocannabinol-cannabidiol (RR 1.88, 95% CI 1.48–2.39) and oral Δ-9-tetrahydrocannabinol (RR 2.18, 95% CI 1.59–2.99), but not for oral Δ-9-tetrahydrocannabinol-cannabidiol (RR 1.31, 95% CI 0.88–1.96). Nervous system disorders were the most common nonserious category in both cannabinoid (36.7%) and control (31.3%) groups; dizziness was the most commonly reported nonserious event among cannabinoid-exposed participants.
Methods
- The authors searched Ovid MEDLINE, PsycINFO, and EMBASE through October 2007, plus reference lists, for studies of cannabis/cannabinoids with human safety, adverse event, or relevant epidemiologic terms. They included randomized controlled trials with quantified adverse events, observational studies with cannabis as the main exposure and adverse events as the outcome, and case reports; they excluded studies of synthetic cannabinoids such as nabilone, cannabis dependence/cessation, mechanisms, pharmacokinetics/pharmacodynamics, and several nonmedical outcomes.
- Two reviewers independently selected studies and assessed quality using the Jadad scale for randomized controlled trials and the Downs and Black checklist for observational studies. Adverse events were classified as serious or nonserious using International Conference on Harmonisation definitions and coded with Medical Dictionary for Regulatory Activities system organ classes and preferred terms.
- For the 23 randomized controlled trials, the authors estimated incidence rates by dividing event counts by cumulative person-years and conducted random-effects meta-analyses to derive rate ratios and 95% confidence intervals, with heterogeneity assessed by χ² and I² statistics. Predefined subgroup analyses examined cannabinoid preparation, duration of exposure, study design, and study population.
Limitations
- The paper states that many published cannabinoid trials did not provide safety information; 28 randomized controlled trials were excluded because they did not quantify adverse events or reported events for only one intervention group. The Jadad score did not adequately reflect safety-reporting quality, and most trials did not provide both absolute event numbers and the number of participants reporting at least one event, as recommended by CONSORT.
- Because per-patient event frequency was lacking, the authors assumed adverse events were independent, which they state is likely invalid if a patient experienced more than one event and could produce artificially narrow confidence intervals. Observational studies lacked control groups and adjustment for potential confounders such as tobacco, alcohol, other recreational drugs, and drug-cannabis interactions.
- The authors excluded nabilone and the 2 published randomized controlled trials of smoked cannabis because of lack of quantifiable adverse event data; they caution that the safety data cannot be extended to nabilone and that recreational cannabis adverse effects should not be assumed to apply to medical cannabinoid use. They also note that 99% of serious adverse events from randomized controlled trials came from only 2 trials, so more long-term studies are needed.
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Claims the paper makes
0 of 8 cited sources checked · 0 supported · 0 flagged
- Findingown data§ Interpretation
The rate of nonserious adverse events was 1.86 times higher among medical cannabinoid users than among controls.
“We found that the rate of nonserious adverse events was 1.86 times higher among medical cannabinoid users than among controls.”
- Also stated in: § Oromucosal spray cannabis extract v. control · plain
“Overall 1.86 (1.57-2.21)”
Quote in the paperSubstantial claim - Also stated in: § Oromucosal spray cannabis extract v. control · plain
- Findingown data§ Interpretation
99% of the serious adverse events from randomized controlled trials were reported in only 2 trials.
“The fact that 99% of the serious adverse events from randomized controlled trials were reported in only 2 trials suggests that more studies with long-term exposure are required to further characterize safety issues.”
Quote in the paperSubstantial claim - Findingown data§ Adverse events
Respiratory (16.5%), gastrointestinal (16.5%) and nervous system disorders (15.2%) were the most frequently reported categories of serious adverse events among those assigned to cannabinoids.
“Respiratory (16.5%), gastrointestinal (16.5%) and nervous system disorders (15.2%) were the most frequently reported categories of serious adverse events among those assigned to cannabinoids”
Quote in the paperNot a substantial claim - Findingown data§ Adverse events
The average rate of nonserious adverse events was significantly higher among people receiving oromucosal Δ-9-tetrahydrocannabinol-cannabidiol (RR 1.88, 95% CI 1.48-2.39) than among controls.
“The average rate of nonserious adverse events was significantly higher among people receiving oromucosal Δ-9tetrahydrocannabinol-cannabidiol (RR 1.88, 95% CI 1.48-2.39)”
Quote in the paperSubstantial claim - Findingown data§ Adverse events
There was no evidence of a higher incidence of serious adverse events following medical cannabis use compared with control (rate ratio 1.04, 95% CI 0.78-1.39).
“There was no evidence of a higher incidence of serious adverse events following medical cannabis use compared with control (rate ratio [RR] 1.04, 95% CI 0.78-1.39).”
Quote in the paperSubstantial claim
- Findingown data§ Adverse events
There was no difference between the oral Δ-9-tetrahydrocannabinol-cannabidiol and control groups in the average rate of nonserious adverse events (RR 1.31, 95% CI 0.88-1.96).
“there was no difference between the oral Δ-9-tetrahydrocannabinol-cannabidiol and control groups (RR 1.31, 95% CI 0.88-1.96).”
Quote in the paperNot a substantial claim - Findingown data§ Adverse events
Nervous system disorders were the most frequently reported category for both serious (9 [23.1%]) and nonserious (1412 [39.7%]) adverse events in observational studies.
“Nervous system disorders were the most frequently reported category for both serious adverse events (9 [23.1%]) and nonserious adverse events (1412 [39.7%]).”
Quote in the paperNot a substantial claim - Findingown data§ Interpretation
The 8 observational studies lacked adjustment for potential confounders, such as use of tobacco, alcohol or other recreational drugs and drug-cannabis interactions.
“those studies were limited by lack of control groups and lack of adjustment for potential confounders, such as use of tobacco, alcohol or other recreational drugs and drug-cannabis interactions.”
Quote in the paperSubstantial claim - Findingown data§ Adverse events
Nervous system disorders (30.0%) were the most frequently reported category of serious adverse events among controls.
“whereas nervous system disorders (30.0%) were the most frequently reported among controls.”
Quote in the paperNot a substantial claim - Findingown data§ Interpretation
Most of the adverse events were not serious.
“Most of the events were not serious.”
Quote in the paperSubstantial claim - Findingown data§ Adverse events
Nervous system disorders was the most frequently reported category for both groups (36.7% of events among people assigned to cannabinoids and 31.3% of events among controls).
“Nervous system disorders was the most frequently reported category for both groups (accounting for 36.7% of events among people assigned to cannabinoids and 31.3% of events among controls)”
Quote in the paperNot a substantial claim - Findingown data§ Adverse events
The average rate of nonserious adverse events was significantly higher among people receiving oral Δ-9-tetrahydrocannabinol (RR 2.18, 95% CI 1.59-2.99) than among controls.
“or oral Δ-9-tetrahydrocannabinol (RR 2.18, 95% CI 1.59-2.99)than among controls”
Quote in the paperSubstantial claim - Findingown data§ Adverse events
There were 164 serious adverse events among people assigned to cannabinoid therapy and 60 among controls.
“we identified 164 serious adverse events among people assigned to cannabinoid therapy and 60 among controls.”
Quote in the paperSubstantial claim - Findingcitation§ Interpretation
Most of the trials selected did not provide both the absolute number of adverse events and the number of participants reporting at least 1 event, as recommended by the Consolidated Standards of Reporting Trials (CONSORT) statement.
“most of the trials selected did not provide both the absolute number of adverse events and the number of participants reporting at least 1 event, as recommended by the Consolidated Standards of Reporting Trials (CONSORT) statement.60”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [60]
Not checked in the free run.
- Findingown data§ Adverse events
Subgroup analysis by type of cannabinoid preparation reduced the heterogeneity.
“Subgroup analysis by type of cannabinoid prepara-tion reduced the heterogeneity”
Quote in the paperNot a substantial claim - Findingown data§ Adverse events
Further subgroup analysis by study design and study population did not significantly alter the pooled RR for nonserious adverse events for each medical cannabinoid preparation.
“Further subgroup analysis by study design and study population did not significantly alter the pooled RR for nonserious adverse events for each medical cannabinoid preparation”
Quote in the paperNot a substantial claim - Findingown data§ Adverse events
Dizziness was the most commonly reported nonserious adverse event among cannabinoid-exposed participants.
“Dizziness was the most commonly reported nonserious adverse event among cannabinoid-exposed participants”
Quote in the paperNot a substantial claim - Findingown data§ Adverse events
None of the 8 observational studies had a control group.
“None of these studies had a control group.”
Quote in the paperNot a substantial claim - Findingown data§ Adverse events
Psychiatric disorders were the second most frequently reported category (4 serious adverse events [10.3%] and 1265 nonserious adverse events [35.6%]) in observational studies.
“Psychiatric disorders were the second frequently reported category (4 serious adverse events [10.3%] and 1265 nonserious adverse events [35.6%]).”
Quote in the paperNot a substantial claim - Findingown data§ Adverse events
Exclusion of this study increased the pooled RR for oral Δ-9-tetrahydrocannabinol-cannabidiol from 1.31 (95% CI 0.88-1.96) to 1.54 (95% CI 1.14-2.08).
“Exclusion of this study increased the pooled RR for oral Δ-9-tetrahydrocannabinolcannabidiol from 1.31 (95% CI 0.88-1.96) to 1.54 (95% CI 1.14-2.08).”
Quote in the paperSubstantial claim - Findingown data§ Adverse events
The majority of serious adverse events (163 among cannabinoid users and 58 among controls) were reported in 2 trials, which contributed 88.8% of person-years of cannabinoid exposure and 84.1% of exposure to control.
“The majority of serious adverse events (163 among cannabinoid users and 58 among controls) were reported in 2 trials, which contributed 88.8% of person-years of cannabinoid exposure and 84.1% of exposure to control.”
Quote in the paperNot a substantial claim - Findingown data§ Adverse events
The difference in death rate between cannabinoid users and controls was not statistically significant (RR 2.66, 95% CI 0.77-9.28).
“The difference in death rate between these 2 groups was not statistically significant (RR 2.66, 95% CI 0.77-9.28).”
Quote in the paperNot a substantial claim - Findingown data§ Results
The review identified 31 studies (23 randomized controlled trials and 8 observational studies) evaluating the safety of medical cannabinoid use.
“We analyzed data from the remaining 31 studies (9.7%), 23 randomized controlled trials and 8 observational studies, in which the safety of medical cannabinoid use could be evaluated.”
Quote in the paperSubstantial claim - Findingown data§ Interpretation
No higher incidence rate of serious adverse events was associated with medical cannabinoid use.
“However, we did not find a higher incidence rate of serious adverse events associated with medical cannabinoid use.”
Quote in the paperSubstantial claim - Findingcitation§ Interpretation
None of the reported adverse events was unexpected, according to the International Conference on Harmonisation criteria.
“None of the reported adverse events was unexpected, according to the International Conference on Harmonisation criteria.30”
Quote in the paperNot a substantial claim - Findingown data§ Adverse events
There was a high degree of variance among the studies (heterogeneity χ2 = 187.42, p < 0.001; I2 = 86.7%).
“We found a high degree of variance among the studies (heterogeneity χ 2 = 187.42,p < 0.001; I 2 = 86.7%).”
Quote in the paperSubstantial claim - Findingown data§ Adverse events
The incidence rate of nonserious adverse events was significantly higher among subjects assigned to cannabinoid therapy than among controls (RR 1.86, 95% CI 1.57-2.21).
“The incidence rate of nonserious adverse events was significantly higher among subjects assigned to cannabinoid therapy than among controls (RR 1.86, 95% CI 1.57-2.21)”
Quote in the paperSubstantial claim - Findingown data§ Results
Among the 23 randomized controlled trials, the median Jadad score was 4/5 (range 2 to 5).
“the median Jadad score was 4/5 (range 2 to 5, where higher score indicates better quality).”
Quote in the paperNot a substantial claim - Interpretationreasoning§ Interpretation
The adverse effects of recreational cannabis use cannot be assumed to occur with medical cannabinoid use.
“We also caution against assuming that the adverse effects of recreational cannabis use can be expected to occur with medical cannabinoid use.”
Quote in the paperSubstantial claim- Rests on an assumption: Recreational and medical cannabis use differ in amounts used, existence of comorbidities, and methods of drug delivery.
- Premisecitation§ Abstract
Prior systematic reviews and reports on adverse effects of cannabis focused on recreational use, not medical use.
“The adverse effects of cannabis have been summarized in several reports, [19][20][21][22][23][24] and systematic reviews have found cannabis to be a risk factor for psychosis, 25 cancer 26 and neurocognitive effects, 27 but these reports all focused on the recreational use of cannabis.”
Quote in the paperSubstantial claim0 of 3 sources checked- cites [19]
Not checked in the free run.
- cites [25]
Not checked in the free run.
- cites [27]
Not checked in the free run.
- May combine two claims. 14
- Classified as probably not a substantial claim. 8
May combine two claims.
Findingcitation§ Adverse eventsOne study had a different duration of exposure for the intervention (oral Δ-9-tetrahydrocannabinol-cannabidiol, 2 weeks) and placebo (1 week) groups, and the incidence rate was significantly lower in the intervention group.
“One study had a different duration of exposure for the intervention (oral Δ-9tetrahydrocannabinol-cannabidiol, 2 weeks) and placebo (1 week) groups, and the incidence rate was significantly lower in the intervention group.”
Quote in the paperSubstantial claimMay combine two claims.
Findingown data§ Adverse eventsRelapse of multiple sclerosis (21 events [12.8%]), vomiting (16 events [9.8%]) and urinary tract infection (15 events [9.1%]) were the most commonly reported serious adverse events among people assigned to receive cannabinoids.
“Relapse of multiple sclerosis (21 events [12.8%]), vomiting (16 events [9.8%]) and urinary tract infection (15 events [9.1%]) were the most commonly reported serious adverse events among people assigned to receive cannabinoids.”
Quote in the paperNot a substantial claimMay combine two claims.
Findingown data§ Adverse eventsIn the 8 observational studies, 39 serious adverse events and 3553 nonserious adverse events were reported.
“of 39 serious adverse events and 3553 nonserious adverse events were reported”
Quote in the paperNot a substantial claimMay combine two claims.
Findingown data§ InterpretationNot all published cannabinoid trials provided safety information; 28 randomized controlled trials were excluded because they did not quantify adverse events or reported events for only one intervention group.
“not all published cannabinoid trials provided safety information; we excluded 28 randomized controlled trials, including 2 trials that examined cannabis smoked by patients with HIV infection, 14,15 because they did not quantify adverse events or they reported events for only one intervention group.”
Quote in the paperSubstantial claim0 of 2 sources checked- cites [14]
Not checked in the free run.
- cites [15]
Not checked in the free run.
May combine two claims.
Findingown data§ Adverse eventsIn the 23 randomized controlled trials, there were 4615 nonserious adverse events among people assigned to cannabinoid therapy (incidence rate 10.37 events/person-year) and 1641 events among controls (incidence rate 6.87 events/person-year).
“In the 23 randomized controlled trials, there were 4615 nonserious adverse events among people assigned to cannabinoid therapy (incidence rate 10.37 events/personyear) and 1641 events among controls (incidence rate 6.87 events/person-year).”
Quote in the paperSubstantial claimProbably not a substantial claim: may not pass S3 (load-bearing).
Findingown data§ ResultsSeventeen (74%) of the 23 randomized controlled trials had a sample size less than 100.
“Seventeen (74%) of the 23 trials had a sample size less than 100”
Quote in the paperNot a substantial claimMay combine two claims.
Findingown data§ ResultsThe total number of participants exposed to cannabinoid therapy was 1932, yielding 445 person-years of cannabinoid exposure.
“The total number of participants exposed to cannabinoid therapy was 1932, yielding 445 person-years of cannabinoid exposure.”
Quote in the paperNot a substantial claimMay combine two claims.
Findingown data§ InterpretationThe review identified 8371 adverse events related to medical cannabinoid use, 4779 in 23 randomized controlled trials and 3592 in 8 observational studies.
“In our review, we identified 8371 adverse events related to medical cannabinoid use, 4779 of which were reported in 23 randomized controlled trials and 3592 in 8 observational studies.”
Quote in the paperSubstantial claimProbably not a substantial claim: may not pass S3 (load-bearing).
Findingown data§ ResultsThe median duration of cannabinoid exposure was 2 weeks (range 8 hours to 12 months).
“The median duration of cannabinoid exposure was 2 weeks (range 8 hours to 12 months).”
Quote in the paperNot a substantial claimProbably not a substantial claim: may not pass S3 (load-bearing).
Findingown data§ ResultsEleven (48%) of the 23 randomized controlled trials had fewer than 50 participants.
“and 11 (48%) of them had fewer than 50 participants.”
Quote in the paperNot a substantial claimMay combine two claims.
Findingown data§ Adverse eventsFifteen deaths (3.4 per 100 person-years) were reported among cannabinoid users, and 3 deaths (1.3 per 100 person-years) were reported among controls.
“Fifteen deaths (3.4 per 100 person-years) were reported among cannabinoid users (3 because of pneumonia, 1 because of cervix carcinoma, 1 because of convulsion, 10 not specified), and 3 deaths (1.3 per 100 person-years) were reported among controls (1 pneumonia, 1 myocardial ischemia, 1 not specified).”
Quote in the paperNot a substantial claimMay combine two claims.
Findingown data§ ResultsNo randomized controlled trials of medical cannabis administered by smoking were included in the review, because adverse events were not quantified in any such studies.
“No randomized controlled trials of medical cannabis administered by smoking were included in the review, since adverse events were not quantified in any such studies.”
Quote in the paperSubstantial claimMay combine two claims.
Interpretationreasoning§ InterpretationThe safety data from this review cannot be extended to nabilone, and the safety of nabilone must be studied separately.
“we caution that our safety data cannot be extended to this drug, and the safety of nabilone must be studied separately.”
Quote in the paperSubstantial claim- Rests on an assumption: Nabilone has different pharmacokinetic and pharmacodynamic properties, and its safety profile may differ from that of Δ-9-tetrahydrocannabinol.
May combine two claims.
Interpretationreasoning§ InterpretationThe Jadad score does not adequately reflect the quality of safety reporting in randomized controlled trials, which meant that rating by the Jadad scale indicated good methodologic quality for these studies, despite their poor reporting of safety.
“The Jadad score does not adequately reflect the quality of safety reporting in randomized controlled trials, which meant that rating by the Jadad scale indicated good methodologic quality for these studies, despite their poor reporting of safety.”
Quote in the paperSubstantial claimProbably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.
Study design and conductcitation§ Assessment of study qualityStudy quality was assessed using the Jadad scale for randomized controlled trials and the Downs and Black checklist for observational studies.
“We used the scale proposed by Jadad and associates 28 to assess the methodologic quality of randomized controlled trials and the Downs and Black checklist 29 to assess the quality of observational studies involving a control group.”
Quote in the paperNot a substantial claim0 of 2 sources checked- cites [28]
Not checked in the free run.
- cites [29]
Not checked in the free run.
Probably not a substantial claim: may not pass S3 (load-bearing).
Study design and conductown data§ Study selectionDisagreements among reviewers regarding study selection and quality assessment were resolved through discussion.
“The 2 primary reviewers resolved disagreements regarding study selection through discussion.”
- Also stated in: § Assessment of study quality · plain
“The raters resolved disagreements regarding quality assessment through discussion.”
Quote in the paperNot a substantial claim- Also stated in: § Assessment of study quality · plain
Probably not a substantial claim: may not pass S3 (load-bearing).
Study design and conductown data§ Study selectionTwo reviewers independently reviewed titles and abstracts for relevance.
“Two reviewers (T.W. and M.W.) independently reviewed the titles and abstracts for relevance according to the following criteria.”
Quote in the paperNot a substantial claimProbably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.
Study design and conductown data§ Data extractionOne reviewer performed data extraction and MedDRA coding, and a second medically qualified reviewer verified the data extraction and coding.
“One of us (T.W.) performed the data extraction and Medical Dictionary for Regulatory Activities coding, and a second medically qualified re- viewer (M.W.) verified the data extraction and coding.”
Quote in the paperNot a substantial claimProbably not a substantial claim: may not pass S3 (load-bearing).
Study design and conductown data§ Assessment of study qualityTwo raters independently assessed study quality.
“Two raters (T.W. and one other person) independently assessed study quality.”
Quote in the paperNot a substantial claimMay combine two claims.
Interpretationreasoning§ InterpretationThe assumption that the occurrence of adverse events was independent would result in generation of artificially narrow confidence intervals around the rate ratio estimates, which might have affected the results of significance testing.
“This assumption would result in generation of artificially narrow CIs around the RR estimates, which might have affected the results of significance testing.”
Quote in the paperSubstantial claim- The authors state this as an assumption: The occurrence of adverse events was independent.
The authors state this as an assumption.
The occurrence of adverse events was independent.
“we had to assume that the occurrence of adverse events was independent, which would not be a valid assumption if a patient had experienced more than 1 event”
The paper relies on this without support.
Nabilone has different pharmacokinetic and pharmacodynamic properties, and its safety profile may differ from that of Δ-9-tetrahydrocannabinol.
“because this agent has different pharmacokinetic and pharmacodynamic properties, and its safety profile may differ from that of Δ-9-tetrahydrocannabinol.”
The paper relies on this without support.
Recreational and medical cannabis use differ in amounts used, existence of comorbidities, and methods of drug delivery.
“The amounts used, the existence of comorbidities and the methods of drug delivery are different in the 2 populations”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
A recent systematic review of adverse effects of medical cannabinoids concluded that most adverse events (96.6%) were not serious and no serious adverse events were related exclusively to cannabinoid administration.
“A recent systematic review of adverse effects of medical cannabinoids concluded that most adverse events (96.6%) were not serious and no serious adverse events were related exclusively to cannabinoid administration.”
From Cannabinoids as Pharmacotherapies for Neuropathic Pain: From the Bench to the Bedside (2009) · cites this paper as [170]
Side-effects were equally associated with the different cannabinoid pharmacotherapies; the average rate of nonserious adverse events was higher in patients receiving Sativex or oral Δ9-THC than controls.
“Side-effects were equally associated with the different cannabinoid pharmacotherapies; the average rate of nonserious adverse events was higher in patients receiving Sativex® or oral Δ9-THC than controls. 170”
From Cannabinoids as Pharmacotherapies for Neuropathic Pain: From the Bench to the Bedside (2009) · cites this paper as [170]
Greater numbers of nonserious adverse events were observed following cannabinoid treatment, as expected.
“Greater numbers of nonserious adverse events were observed following cannabinoid treatment, as expected.170”
From Cannabinoids as Pharmacotherapies for Neuropathic Pain: From the Bench to the Bedside (2009) · cites this paper as [170]
Ninety-nine percent of serious adverse events from randomized clinical trials were reported in only two trials.
“Moreover, 99% of serious adverse events from randomized clinical trials were reported in only two trials.170”
From Cannabinoids as Pharmacotherapies for Neuropathic Pain: From the Bench to the Bedside (2009) · cites this paper as [170]
The citation lists haven’t been fetched yet
References 61 · Cited by 357
Research works printed but not linked: 1
- ICH Steering Committee. ICH harmonised tripartite guideline. Clinical safety data management: definitions and standards for expedited reporting E2A. Step 4 ver- sion. International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use; 1994. Available: www.ich.org /LOB/media/MEDIA436.pdf (accessed 2008 Mar 25).
- Authors
- Wang, T., Collet, J.-P., Shapiro, S., & Ware, M. A.
- Affiliations
- McGill University (CA)
- University of British Columbia (CA)
- Corresponding author
- Ware, M. A.
- ORCID
- Venue
- Canadian Medical Association Journal
- Publisher
- CMA Joule Inc.
- Published
- 2008-06-17
- Volume
- 178
- Issue
- 13
- Pages
- 1669-1678
- ISSN
- 0820-3946 (ISSN-L)
- 1488-2329
- PMC
- PMC2413308
- OpenAlex
- W2111202432
- Semantic Scholar
- bca276792013d151e4775448e6e33f3aaec259ee
- Cited by
- 357
- References
- 61
- Citations by year
- 2026: 7 · 2025: 18 · 2024: 15 · 2023: 21 · 2022: 21 · 2021: 31 · 2020: 29 · 2019: 20 · 2018: 31 · 2017: 23 · 2016: 28 · 2015: 20 · 2014: 21 · 2013: 15 · 2012: 18
- FWCI
- 1.36
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Locations
- Canadian Medical Association Journal (publishedVersion)
- PubMed Central (publishedVersion)
- PubMed (publishedVersion)
- Funders
- McGill University
- Louise and Alan Edwards Foundation
- Canadian Institutes of Health Research
- Topics
- Health Sciences › Medicine › Pharmacology › Cannabis and Cannabinoid Research
- Life Sciences › Pharmacology, Toxicology and Pharmaceutics › Toxicology › Pharmacovigilance and Adverse Drug Reactions
- Health Sciences › Medicine › Complementary and alternative medicine › Complementary and Alternative Medicine Studies
- Keywords
- cannabis-based medicines, adverse events, drug safety, multiple sclerosis relapse, vomiting, urinary tract infection, dizziness, serious adverse events
- MeSH terms
- Canada, Cannabinoids, Humans, Pain, Drug Prescriptions, Adverse Drug Reaction Reporting Systems
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