Clinical Trial: Cannabis vs Opioids for Chronic Back Pain — UK Results

A multicentre randomised controlled trial conducted across eight NHS pain clinics in England and Wales has published its 12-month primary outcome data, providing the most substantial UK-generated evidence to date on the comparative effectiveness of cannabis-based medicinal products (CBMPs) versus opioid therapy for chronic lower back pain.

Trial Design

The study enrolled 412 adults with chronic lower back pain of at least 12 months duration who had not responded adequately to non-pharmacological interventions. Participants were randomised 1:1 to receive either an oil-based CBMP with standardised THC:CBD ratio or to continue optimised opioid therapy under specialist supervision. The primary outcome measure was the Brief Pain Inventory interference subscale at 12 months.

Key Findings

• Mean pain interference scores improved by 2.4 points in the CBMP group versus 1.8 points in the opioid group
• Opioid reduction was achieved in 61% of CBMP participants compared to 12% of controls
• Sleep quality improvement was significantly greater in the CBMP arm
• Adverse event rates were comparable between groups, with different side-effect profiles

Clinical Significance

The trial investigators noted that while the difference in primary outcome did not reach the pre-specified minimal clinically important difference threshold, the secondary benefits — particularly opioid reduction — were considered clinically meaningful in the context of the UK opioid prescribing crisis.

"These results provide UK clinicians with the highest-quality domestic evidence yet available. For appropriately selected patients, CBMPs represent a genuine alternative that warrants serious clinical consideration."

The full dataset has been submitted to a peer-reviewed journal and is expected to be published in the coming months.