Table 1.

Medical cannabinoids’ estimated benefit when treating chronic pain, chemotherapy-induced nausea and vomiting, or spasticity with GRADE rating of evidence

ESTIMATED BENEFIT
INDICATIONCANNABINOIDSCONTROL (PLACEBO UNLESS INDICATED)NNTGRADE QUALITY OF EVIDENCE
Chronic pain (median follow-up 4 wk)
  • ≥ 30% reduction in chronic (neuropathic plus cancer) pain*39%30%11Very low
  • ≥ 30% reduction in neuropathic pain38%30%14Very low
  • ≥ 30% reduction in palliative pain30%23%NS (approximately 15)Very low
  • Change in chronic pain scales (possible score 0–10)Baseline: approximately 6
Decrease: 1.2–1.6
Baseline: approximately 6
Decrease: 0.8
NAVery low
Chemotherapy-induced nausea and vomiting (median follow-up 1 d)
  • Control of nausea and vomiting (cannabinoids vs placebo)47%13%3Moderate
  • Control of nausea and vomiting (cannabinoids vs neuroleptics)31%16% (vs neuroleptics)7Low
Spasticity (median follow-up 6 wk)
  • Global impression of change50%35%7Low
  • ≥ 30% improvement in spasticity35%25%10Low
  • Change in spasticity (possible score 0–10)Baseline: 6.2
Decrease: 1.3–1.7
Baseline: 6.2
Decrease: 1.0
NAVery low
  • GRADE—Grading of Recommendations Assessment, Development and Evaluation, NA—not applicable, NNT—number needed to treat, NS—not statistically significant. Data from accompanying systematic review by Allan et al (page e78).12

  • * Meta-analysis results included 13 studies on neuropathic pain and 2 studies on cancer pain.

  • Confidence intervals suggest that benefit is likely (risk ratio = 1.34, 95% CI 0.96 to 1.86), so estimated NNT provided.

  • Scales are visual analogue scales or numeric rating scales with higher scores indicating worse pain or spasticity. Changes with cannabinoids are given as a range based on varying results.