Evidence map›Paper›PMID 29449262›Full record

SynthesisCanadian family physician Medecin de famille canadien2018

Systematic review of systematic reviews for medical cannabinoids: Pain, nausea and vomiting, spasticity, and harms.

G Michael Allan, Caitlin R Finley, Joey Ton, Danielle Perry, Jamil Ramji, Karyn Crawford, Adrienne J Lindblad, Christina Korownyk, Michael R Kolber

Abstract readMeta-AnalysisSystematic Review
PubMed Full text at PMC
In one paragraph

Synthesis in Canadian family physician Medecin de famille canadien, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 66 papers, 11 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
66citing papers in PubMed, 11 pooled it
12.4field-weighted citation impact, top 1% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

66 citing papers in PubMed, 11 syntheses or guidelines pooled it, 143 citations in OpenAlex.

  1. Pooled it
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  10. Opioid use disorder in primary care: PEER umbrella systematic review of systematic reviews.Canadian family physician Medecin de famille canadien · 2019
    Pooled it
  11. Simplified guideline for prescribing medical cannabinoids in primary care.Canadian family physician Medecin de famille canadien · 2018
    Guideline
  12. Trial
  13. Review
  14. Article
  15. Article
  16. Review
  17. Motherhood and medicinal cannabis.Drug and alcohol review · 2025
    Article
  18. Cannabis Use Among Older Adults.JAMA network open · 2025
    Article
  19. Review
  20. Article

6 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

9 authors at 4 institutions in 3 countries.

G Michael AllanProfessor of Evidence-Based Medicine in the Department of Family Medicine at the University of Alberta in Edmonton. michael.allan@ualberta.ca.
Caitlin R FinleyKnowledge Translation Expert in the Physician Learning Program with the Alberta Medical Association and in Lifelong Learning and the Department of Family Medicine at the University of Alberta.
Joey TonKnowledge Translation Expert in the Physician Learning Program with the Alberta Medical Association and in Lifelong Learning and the Department of Family Medicine at the University of Alberta.
Danielle PerryKnowledge Translation Expert in the Physician Learning Program with the Alberta Medical Association and in Lifelong Learning and the Department of Family Medicine at the University of Alberta.
Jamil RamjiKnowledge Translation Expert in the Physician Learning Program with the Alberta Medical Association and in Lifelong Learning and the Department of Family Medicine at the University of Alberta.
Karyn CrawfordCoordinator of the Integrated Knowledge Translation Network of the Physician Learning Program with the Alberta Medical Association and in Lifelong Learning and the Department of Family Medicine at the University of Alberta.
Adrienne J LindbladKnowledge Translation and Evidence Coordinator for the Alberta College of Family Physicians and Associate Clinical Professor in the Department of Family Medicine at the University of Alberta.
Christina KorownykAssociate Professor of Evidence-Based Medicine in the Department of Family Medicine at the University of Alberta.
Michael R KolberAssociate Professor of Evidence-Based Medicine in the Department of Family Medicine at the University of Alberta.
Alberta Medical Association · CAEvidence Based Research (United States) · USAlberta College · LVUniversity of Alberta · CA

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

objectiveTo determine the effects of medical cannabinoids on pain, spasticity, and nausea and vomiting, and to identify adverse events. DATA SOURCES: MEDLINE, the Cochrane Database, and the references of included studies were searched. STUDY SELECTION: Systematic reviews with 2 or more randomized controlled trials (RCTs) that focused on medical cannabinoids for pain, spasticity, or nausea and vomiting were included. For adverse events, any meta-analysis for the conditions listed or of adverse events of cannabinoids was included. SYNTHESIS: From 1085 articles, 31 relevant systematic reviews were identified including 23 for pain, 5 for spasticity, 6 for nausea and vomiting, and 12 for adverse events. Meta-analysis of 15 RCTs found more patients taking cannabinoids attained at least a 30% pain reduction: risk ratio (RR) of 1.37 (95% CI 1.14 to 1.64), number needed to treat (NNT) of 11. Sensitivity analysis found study size and duration affected findings (subgroup differences,

conclusionThere is reasonable evidence that cannabinoids improve nausea and vomiting after chemotherapy. They might improve spasticity (primarily in multiple sclerosis). There is some uncertainty about whether cannabinoids improve pain, but if they do, it is neuropathic pain and the benefit is likely small. Adverse effects are very common, meaning benefits would need to be considerable to warrant trials of therapy.

Indexed as

HumansMedical MarijuanaMuscle SpasticityNauseaNeuralgiaRandomized Controlled Trials as TopicVomitingMedical Marijuana

Identifiers

PMID29449262
PMCPMC5964405
OpenAlexW2789197845

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.