Cited by 265Cannabis and Cannabinoid ResearchPain Management and Opioid UseAnesthesia and Pain Management

The DOI matches its Crossref record; 72 of the 72 references it cites were found in a registry or an index; none of the 40 sources its claims cite is checked for support yet.

Opioid-Sparing Effect of Cannabinoids: A Systematic Review and Meta-Analysis

Open access
Nielsen, Suzanne, Sabioni, Pamela, Trigo, Jose M, Ware, Mark A, Betz-Stablein, Brigid D, Murnion, Bridin, Lintzeris, Nicholas, Khor, Kok Eng, Farrell, Michael, Smith, Andrew, Le Foll, Bernard·2017·Neuropsychopharmacology

Abstract

Cannabinoids, when co-administered with opioids, may enable reduced opioid doses without loss of analgesic efficacy (ie, an opioid-sparing effect). The aim of this study was to conduct a systematic review to determine the opioid-sparing potential of cannabinoids. Eligible studies included pre-clinical and clinical studies for which the outcome was either analgesia or opioid dose requirements. Clinical studies included controlled studies and case series. We searched Scopus, Cochrane Database of Systematic Reviews, Medline, and Embase. Nineteen pre-clinical and nine clinical studies met the search criteria. Seventeen of the 19 pre-clinical studies provided evidence of synergistic effects from opioid and cannabinoid co-administration. Our meta-analysis of pre-clinical studies indicated that the median effective dose (ED 50) of morphine administered in combination with delta-9-tetrahydrocannabinol (delta-9-THC) is 3.6 times lower (95% confidence interval (CI) 1.95, 6.76; n=6) than the ED 50 of morphine alone. In addition, the ED 50 for codeine administered in combination with delta-9-THC was 9.5 times lower (95% CI 1.6, 57.5, n=2) than the ED 50 of codeine alone. One case series (n=3) provided very-low-quality evidence of a reduction in opioid requirements with cannabinoid co-administration. Larger controlled clinical studies showed some clinical benefits of cannabinoids; however, opioid dose changes were rarely reported and mixed findings were observed for analgesia. In summary, pre-clinical studies provide robust evidence of the opioid-sparing effect of cannabinoids, whereas one of the nine clinical studies identified provided very-low-quality evidence of such an effect. Prospective high-quality-controlled clinical trials are required to determine the opioid-sparing effect of cannabinoids.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

This systematic review and meta-analysis found robust preclinical evidence that cannabinoids, especially delta-9-THC, can reduce opioid doses needed for equivalent antinociception, but clinical evidence for an opioid-sparing effect was very limited and low quality. The authors conclude that high-quality controlled clinical trials are needed.

Key findings

  • Nineteen preclinical and nine clinical studies met inclusion criteria; 17 of 19 preclinical studies provided evidence of synergistic opioid–cannabinoid effects.
  • Meta-analysis of preclinical studies found the median effective dose (ED50) of morphine co-administered with delta-9-THC was 3.6 times lower than morphine alone (95% CI 1.95, 6.76; n = 6), and the ED50 of codeine co-administered with delta-9-THC was 9.5 times lower than codeine alone (95% CI 1.6, 57.5; n = 2).
  • Among clinical studies, one case series (n = 3) provided very low-quality evidence of reduced opioid requirements with cannabinoid co-administration; larger controlled studies rarely reported opioid dose changes and showed mixed findings for analgesia.
  • GRADE ratings of clinical studies were: one very low, three low, two moderate, and three high quality; none of the high-quality studies provided evidence of an opioid-sparing effect.

Methods

  • Systematic review conducted according to PRISMA, searching Scopus, Cochrane Database of Systematic Reviews, Medline, and Embase on October 29, 2015, with no date limits; eligible studies included human or animal studies with outcomes of pain/analgesia or opioid requirements from concurrently administered opioids and cannabinoids, including controlled clinical studies and case series.
  • Preclinical studies were narratively reviewed; six studies with sufficient data were meta-analyzed for morphine and two for codeine, using log10 ED50 values, inverse variance, and a random effects model because of heterogeneity; a funnel plot assessed publication/small study bias.
  • Clinical studies were heterogeneous and not suitable for meta-analysis, so a narrative synthesis was conducted with quality scored using GRADE criteria.

Limitations

  • The paper states that preclinical studies used a range of animal populations, antinociceptive assays, opioids, and cannabinoids, often with small numbers of animals per group, resulting in statistical heterogeneity; funnel plot interpretation was limited because fewer than 10 studies were included.
  • The paper states that no studies examined the opioid-sparing effect of cannabidiol alone, delta-9-THC:CBD outside a 1:1 ratio, or other cannabinoids, and that the lack of high-quality human studies means evidence for opioid-sparing is largely limited to preclinical studies.
  • Clinical limitations stated in the paper include lack of placebo control, difficulty extrapolating from experimental to clinical pain, use of single doses, small sample sizes, mixed study design quality, subtherapeutic morphine doses in one study, fixed cannabinoid dose ranges, and discouraging opioid dose reduction in another study; evident from the text, only one very low-quality clinical study directly showed an opioid-sparing effect.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1038/npp.2017.51

Cites

72 of 72 references verified0 citation errors · 0 not checkable

Statistics

Verification

Claims the paper makes

0 of 40 cited sources checked · 0 supported · 0 flagged

Show all 37 claims

  • Probably not a substantial claim. 18
  • It may state two separate claims as one. 24
  • The quote only partly states this claim. 3
38 of 38

Claims other papers make about this one

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Statistics recomputed

Every reported test result, recomputed from its test statistic and degrees of freedom. A result shows as not adding up only once an independent check has confirmed it.

  • Consistentz = 5.59reported p < .001 · recomputed p < .001

    “Z = 5.59, p < .001”

  • Consistentz = 2.49reported p = .01 · recomputed p = .013

    “Z = 2.49, p = .01”

2 of 2

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Morphine meta-analysis Z statistic conflicts with its confidence interval

    Minor

    The reported mean difference of −0.56 and 95% CI of −0.83 to −0.29 imply a Z statistic of approximately 4.07, not 5.59.

  • Wilson hot-plate latency differs between text and table

    Minor

    The text reports 38.9 seconds for morphine combined with HU-210, while Table 1 reports 39.9 seconds for that combination.

2 of 2

Citations

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Research works printed but not linked: 1

  1. Lissoni P, Porro G, Messina G, Porta E, Rovelli F, Roselli MG et al (2014). Morphine, melatonin, Marijuana, Magnolia and MYRRH as the "five m" schedule in the treatment of cancer pain and the possible dose-dependency of the antitumor and analgesic effects of the pineal hormone melatonin. Anticancer Res 34: 6033–6034.

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Metadata

Authors
Nielsen, S., Sabioni, P., Trigo, J. M., Ware, M. A., Betz-Stablein, B. D., Murnion, B., Lintzeris, N., Khor, K. E., Farrell, M., Smith, A., & Le Foll, B.
Affiliations
  • UNSW Sydney (AU)
  • Centre for Addiction and Mental Health (CA)
  • McGill University (CA)
  • The University of Sydney (AU)
  • Prince of Wales Hospital (AU)
Corresponding author
Nielsen, Suzanne
Venue
Neuropsychopharmacology
Published
2017-03-22
Volume
42
Issue
9
Pages
1752-1765
ISSN
  • 0893-133X (ISSN-L)
  • 1740-634X
OpenAlex
W2601973957
Cited by
265
References
72
Citations by year
2026: 19 · 2025: 22 · 2024: 24 · 2023: 25 · 2022: 24 · 2021: 44 · 2020: 35 · 2019: 40 · 2018: 30 · 2017: 2
FWCI
3.71
Type
journal article
Language
en
Open access
Locations
  • Neuropsychopharmacology (publishedVersion)
  • Europe PMC (PubMed Central) (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • UNSWorks (University of New South Wales, Sydney, Australia) (submittedVersion, cc-by-nc-nd)
  • UNSWorks (UNSW Sydney) (submittedVersion, cc-by-nc-nd)
Topics
  • Health Sciences › Medicine › Pharmacology (medical) › Cannabis and Cannabinoid Research
  • Health Sciences › Medicine › Anesthesiology and Pain Medicine › Pain Management and Opioid Use
  • Health Sciences › Medicine › Anesthesiology and Pain Medicine › Anesthesia and Pain Management
Keywords
cannabinoids, opioid-sparing effect, opioid dose reduction, delta-9-tetrahydrocannabinol, morphine, codeine, analgesia, ED50, pain management
MeSH terms
Analgesics, Opioid, Animals, Cannabinoids, Drug Synergism, Humans, Pain

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