THC/CBD spray maintained pain relief for 38 weeks in neuropathic pain patients without dose escalation | Research

The takeaway

In a 38-week follow-up of 380 neuropathic pain patients, THC/CBD spray maintained pain reduction from 6.9 to 4.2 on a 10-point scale, with 62% completing the study and no dose escalation over time.

Read this if you have neuropathic pain and are considering long-term cannabinoid treatment.

Pain reduced from 6.9 to 4.2/10 over 38 weeks without dose escalation

What the researchers found

This open-label extension study followed 380 patients with peripheral neuropathic pain (from diabetes or allodynia) who had participated in two prior randomized controlled trials of THC/CBD oromucosal spray. Patients received the spray for an additional 38 weeks alongside their current pain medications.

Pain scores on a 0-10 scale decreased from a mean of 6.9 at the original baseline to 4.2 at the end of the extension. At least half of patients reported a clinically meaningful 30% improvement at all time points, with the proportion continuing to increase up to 9 months. Improvements were also seen in sleep quality, neuropathic pain subscales, patient global impression of change, and quality of life.

Critically, patients did not seek to increase their dose over time, suggesting tolerance did not develop. The spray was well tolerated with no new safety concerns from long-term use.

Why it matters

Long-term pain management data for cannabinoids is scarce. This study demonstrates that THC/CBD spray can maintain effectiveness for nearly a year without dose escalation, addressing concerns about tolerance that limit the long-term utility of many pain medications.

The numbers in context

380 patients entered; 234 completed (62%). Pain NRS: 6.9 baseline to 4.2 at end. At least 50% had 30% improvement at all time points. 38 weeks of follow-up. No dose escalation observed.

How the study worked

Open-label, 38-week extension study of 380 patients from two parent randomized controlled trials. Patients had peripheral neuropathic pain from diabetes or allodynia. Primary outcome: 0-10 pain NRS. Secondary outcomes: sleep, neuropathic pain subscales, global impression, quality of life. Safety and dosing patterns tracked throughout.

What this study cannot tell us

Open-label design means no placebo comparison for the extension phase. Patients who entered the extension were selected from prior RCTs (likely biased toward those who responded). 38% dropout rate may bias results toward better outcomes. Neuropathic pain from diabetes and allodynia may not represent all neuropathic pain types.

How to read the evidence

Open-label extension study following RCTs. Good long-term data but lacks placebo comparison in the extension phase.

When this study was published

Published in 2015. Long-term data on THC/CBD spray has continued to accumulate.

The bigger picture

Chronic pain management is a major clinical challenge, with many treatments losing effectiveness over time or requiring increasing doses. THC/CBD spray maintaining benefit without dose escalation for 38 weeks is clinically significant, particularly for a difficult-to-treat population.

Questions still open

Would the benefit persist beyond 38 weeks? Does the lack of dose escalation hold over years? How does THC/CBD spray compare to other long-term neuropathic pain treatments? Would patients with other types of neuropathic pain show similar benefit?

Common questions

Does THC/CBD spray lose effectiveness over time?

In this 38-week study, the spray maintained its pain-relieving effect without patients needing to increase their dose. The proportion reporting meaningful improvement continued to increase up to 9 months.

Is THC/CBD spray safe for long-term use?

Over 38 weeks, the spray was well tolerated with no new safety concerns. However, this was an open-label study without a long-term placebo comparison, so results should be interpreted with some caution.

Read the original research

A multicentre, open-label, follow-on study to assess the long-term maintenance of effect, tolerance and safety of THC/CBD oromucosal spray in the management of neuropathic pain.

Journal of neurology, 262(1), 27-40

View on PubMed ↗Publisher’s paper ↗

Citation

Hoggart, B; Ratcliffe, S; Ehler, E; Simpson, K H; Hovorka, J; Lejčko, J; Taylor, L; Lauder, H; Serpell, M. (2015). A multicentre, open-label, follow-on study to assess the long-term maintenance of effect, tolerance and safety of THC/CBD oromucosal spray in the management of neuropathic pain.. Journal of neurology, 262(1), 27-40. https://doi.org/10.1007/s00415-014-7502-9