Medical cannabis patients reduced opioid use by 78% over six months

Among participants who used opioids at baseline (28%), the proportion dropped to 11% at six months. Mean daily opioid dosage fell from 152 mg to 32.2 mg morphine milligram equivalent, a 78% reduction. Similar reductions occurred across four other prescription drug classes, and all four quality-of-life domains improved significantly.

The Tilray Observational Patient Study enrolled patients from 21 medical clinics across Canada, following 1,145 patients with at least one post-baseline visit at 1, 3, and 6 months. Assessments included cannabis use inventory, WHOQOL-BREF quality of life measure, and detailed prescription drug questionnaire.

This is one of the larger prospective studies to track individual-level changes in opioid use after starting medical cannabis. The magnitude of opioid reduction and breadth of prescription drug substitution reported here are clinically significant.

Amid ongoing opioid crisis deaths, prospective data showing this magnitude of opioid dose reduction in real-world medical cannabis patients strengthens the case for cannabis as a harm reduction tool, though the absence of a control group limits causal conclusions.

No control group. Industry-sponsored (Tilray). Self-selected patient population. Patients who dropped out may have had different outcomes. Self-reported prescription drug data.