Study register · detailMeta-Analyse · Chronic Pain · 2021
Opioid-sparing effects of medical cannabis or cannabinoids for chronic pain: a systematic review and meta-analysis of randomised and observational studies
Noori et al.·BMJ OpenImpact 2.2
No benefit demonstratedGRADEHigh108 citations
Samplek = 17 Studien
Durationunclear
ControlPlacebo
EndpointOpioid dose reduction
Blindingn.a.
DesignMeta-Analyse
”Key finding
Cannabis showed no clear benefit for opioid sparing or pain relief; randomized studies yielded very low to high levels of evidence for no or minimal effect on opioid reduction and pain relief, while nausea and vomiting were likely increased.
Summary
Systematic review on opioid-sparing effects of cannabis in chronic pain; k=17 studies (5 RCTs in cancer pain, 12 observational studies). RCTs: high-certainty evidence for minimal effect on pain relief (WMD -0.18 cm on 10-cm VAS, 95% CI -0.38 to 0.02) and opioid dose (WMD -3.4 MME, 95% CI -12.7 to 5.8). Cannabis increased nausea (RR 1.43, 95% CI 1.04–1.96) and vomiting (RR 1.5, 95% CI 1.01–2.24). Observational studies: opioid reduction -22.5 MME (95% CI -43.06 to -1.97), very low certainty.
P
PopulationChronic pain patients under opioid therapy; pooled n from 5 RCTs and 12 observational studies
I
InterventionMedical cannabis as add-on to prescribed opioids (various preparations)
C
ControlPlacebo (in RCTs)
O
OutcomeRCTs: no significant effect on opioid reduction (WMD −3,4 MME; 95% CI −12,7 to 5,8; very low evidence); no clinically relevant effect on pain (WMD −0,18 cm VAS; 95% CI −0,38 to 0,02; high evidence); increased nausea (RR 1,43; 95% CI 1,04–1,96) and vomiting (RR 1,5; 95% CI 1,01–2,24). Observational studies: opioid reduction −22,5 MME (95% CI −43,06 to −1,97; very low evidence).
Confidence in the evidence
Very lowLowModerateHigh
High
The highest of four GRADE levels, the effect estimate is very reliable.
Objective: To assess the efficacy and harms of adding medical cannabis to prescription opioids among people living with chronic pain.
Design: Systematic review.
Data Sources: CENTRAL, EMBASE and
Medline. Main Outcomes And Measures: Opioid dose reduction, pain relief, sleep disturbance, physical and emotional functioning and adverse events.
Study Selection Criteria And Methods: We included studies that enrolled patients with chronic pain receiving prescription opioids and explored the impact of adding medical cannabis. We used Grading of Recommendations Assessment, Development and Evaluation to assess the certainty of evidence for each outcome.
Results: Eligible studies included five randomised trials (all enrolling chronic cancer-pain patients) and 12 observational studies. All randomised trials instructed participants to maintain their opioid dose, which resulted in a very low certainty evidence that adding cannabis has little or no impact on opioid use (weighted mean difference (WMD) -3.4 milligram morphine equivalent (MME); 95% CI (CI) -12.7 to 5.8). Randomised trials provided high certainty evidence that cannabis addition had little or no effect on pain relief (WMD -0.18 cm; 95% CI -0.38 to 0.02; on a 10 cm Visual Analogue Scale (VAS) for pain) or sleep disturbance (WMD -0.22 cm; 95% CI -0.4 to -0.06; on a 10 cm VAS for sleep disturbance; minimally important difference is 1 cm) among chronic cancer pain patients. Addition of cannabis likely increases nausea (relative risk (RR) 1.43; 95% CI 1.04 to 1.96; risk difference (RD) 4%, 95% CI 0% to 7%) and vomiting (RR 1.5; 95% CI 1.01 to 2.24; RD 3%; 95% CI 0% to 6%) (both moderate certainty) and may have no effect on constipation (RR 0.85; 95% CI 0.54 to 1.35; RD -1%; 95% CI -4% to 2%) (low certainty). Eight observational studies provided very low certainty evidence that adding cannabis reduced opioid use (WMD -22.5 MME; 95% CI -43.06 to -1.97).
Conclusion: Opioid-sparing effects of medical cannabis for chronic pain remain uncertain due to very low certainty evidence.PROSPERO registration numberCRD42018091098.