Proof of Concept Trial of Cannabis Derivatives in Neuropathic Pain

Veterans with diabetes are more likely than diabetic civilians to develop disabling chronic diabetic neuropathic pain (CDNP). Research on frontline treatments for CDNP (enhanced glycemic control, exercise, pharmacological agents), shows inconsistent outcomes and dissatisfaction among Veterans. Veterans and clinicians have shown significant interest in cannabis derivatives (THC, CBD) for neuropathic pain control, but there are no well-controlled trials guiding expectations for benefit and adverse outcomes associated with cannabis for CDNP. Because Veterans are likely to present with pain and pain-related polymorbidity significantly differing from that of civilians, a well-structured clinical trial of cannabinoids for Veterans with CDNP is vital.

The present phase II study will offer the first evidence describing the potential benefits and adverse effects of cannabinoids for CDNP in Veterans using a four-arm, double-blind, multisite randomized trial comparing THC, CBD, THC+CBD and placebo on neuropathic pain outcomes.

Chronic pain is a significant burden to United States Veterans and is a particular concern for Veterans with diabetes. Diabetic Veterans have a higher risk of chronic diabetic neuropathic pain (CDNP) than civilians with diabetes, and CDNP is more disabling for Veterans than it is for civilians. Frontline treatment for CDNP, including enhanced glycemic control, exercise, and pharmacotherapies, show inconsistent outcomes for individuals with CDNP due to poor adherence and side effects. The ongoing opioid crisis has led to significant interest in safe and effective alternatives for pain control, and there is a significant need for research on desirable options for pain control that are likely to improve treatment adherence and outcomes. Veterans groups and Veterans Affairs clinicians have expressed significant interest in cannabis and its principal constituents (delta-9-tetrahydrocannabinol, THC; cannabidiol, CBD) for pain management, but the extant research describing the potential risks and benefits of cannabis for pain is weak. This randomized trial was developed as a proof of concept study to determine if cannabis constituents (THC, CBD, and THC+CBD) are superior to placebo in reducing pain in Veterans with CDNP. The study is to recruit a sample of 320 adult Veterans who meet diagnostic criteria for high-impact CDNP, are on stable treatment(s) for CDNP, are not current cannabis users and who do not meet diagnostic criteria for Cannabis Use Disorder. This randomized phase II, 4-arm clinical trial aims to determine if cannabis constituents (THC, CBD) or their combination (THC+CBD) are superior to placebo in reducing pain in Veterans with CDNP. This trial will offer the first evidence describing the potential benefits and adverse effects of cannabinoids for CDNP in Veterans.