Medical cannabis may reduce opioid doses by 64-75% for chronic pain, but evidence is weak

A systematic review of 9 studies (7,222 participants) found a 64-75% reduction in opioid dosage when combined with medical cannabis for non-cancer chronic pain, but all studies had high risk of bias.

Okusanya, Babasola O et al.·Systematic reviews·2020·Moderate EvidenceSystematic Review
RTHC-02755Systematic ReviewModerate Evidence2020RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Systematic Review
Evidence
Moderate Evidence
Sample
N=7,222

What This Study Found

Across 9 studies involving 7,222 participants, combining medical cannabis with opioids was associated with 64-75% reduction in opioid dosage for non-cancer chronic pain. Between 32-59% of patients reported using cannabis as an opioid substitute. One study showed trends toward fewer hospital admissions and ED visits. However, all studies had high risk of bias.

Key Numbers

9 studies; 7,222 participants; 64-75% opioid dose reduction; 32-59% used cannabis as opioid substitute; all studies high risk of bias.

How They Did This

Systematic review of 9 studies (RCTs, cohort, cross-sectional, case reports) from Ovid/Medline, PsycINFO, PubMed, Web of Science assessing medical cannabis effects on opioid dosage in non-cancer chronic pain, using ROBINS-I and AXIS bias tools.

Why This Research Matters

The opioid crisis makes any strategy to reduce opioid use critically important. These findings suggest medical cannabis could play a role in opioid dose reduction, but the evidence quality is insufficient to make firm recommendations.

The Bigger Picture

The potential for 64-75% opioid reduction is striking but must be tempered by the uniformly high bias risk. If confirmed by rigorous RCTs, cannabis-assisted opioid reduction could significantly impact the opioid epidemic.

What This Study Doesn't Tell Us

All 9 studies had high risk of bias; heterogeneous study designs; cannabis doses and products varied; optimal cannabis dose unknown; systematic review was not pre-registered.

Questions This Raises

  • ?Would a well-designed RCT confirm the 64-75% opioid reduction?
  • ?What are the long-term outcomes of cannabis-opioid co-therapy?

Trust & Context

Key Stat:
64-75% opioid dose reduction, but all 9 studies had high bias risk
Evidence Grade:
Moderate: systematic methodology but limited by uniformly high bias risk across all included studies.
Study Age:
Published 2020.
Original Title:
Medical cannabis for the reduction of opioid dosage in the treatment of non-cancer chronic pain: a systematic review.
Published In:
Systematic reviews, 9(1), 167 (2020)
Database ID:
RTHC-02755

Evidence Hierarchy

Meta-Analysis / Systematic ReviewCombines many studies into one answer
This study
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / Observational
Case Report / Animal Study

Analyzes all available research on a topic using a structured method.

What do these levels mean? →

Frequently Asked Questions

Can medical cannabis replace opioids for chronic pain?

This review found 64-75% opioid dose reduction when cannabis was added, and 32-59% of patients used cannabis as an opioid substitute. However, all studies had high risk of bias, so the evidence cannot yet support firm recommendations.

Is this strong enough evidence to change prescribing practices?

No. The authors explicitly state the evidence "cannot be relied upon to promote medical cannabis as an adjunct to opioids." More rigorous studies are needed.

Read More on RethinkTHC

Cite This Study

RTHC-02755·https://rethinkthc.com/research/RTHC-02755

APA

Okusanya, Babasola O; Asaolu, Ibitola O; Ehiri, John E; Kimaru, Linda Jepkoech; Okechukwu, Abidemi; Rosales, Cecilia. (2020). Medical cannabis for the reduction of opioid dosage in the treatment of non-cancer chronic pain: a systematic review.. Systematic reviews, 9(1), 167. https://doi.org/10.1186/s13643-020-01425-3

MLA

Okusanya, Babasola O, et al. "Medical cannabis for the reduction of opioid dosage in the treatment of non-cancer chronic pain: a systematic review.." Systematic reviews, 2020. https://doi.org/10.1186/s13643-020-01425-3

RethinkTHC

RethinkTHC Research Database. "Medical cannabis for the reduction of opioid dosage in the t..." RTHC-02755. Retrieved from https://rethinkthc.com/research/okusanya-2020-medical-cannabis-for-the

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.