A Randomized, Cross-Over Controlled Trial of Dronabinol and Vaporized Cannabis in Neuropathic Low Back Pain

INVESTIGATORS: Thomas Marcotte, Ph.D. & Barth Wilsey, M.D.

STUDY LOCATION: University of California, San Diego

PROJECT TITLE: A Randomized, Cross-Over Controlled Trial of Dronabinol and Vaporized Cannabis in Neuropathic Low Back Pain

PROJECT TYPE: Clinical Study

STATUS: COMPLETED

ABSTRACT:

This study involved treating low back pain associated with nerve injury with oral delta-9-tetrahydrocannabinol (Δ9-THC) or whole plant cannabis for eight weeks. Research subjects consumed either oral Δ9-THC (dronabinol), vaporized 3.5% Δ9-THC, or placebo.

The primary outcome was a pain intensity numerical rating scale bordered by 0=no pain and 10=worst possible pain. As a major goal in the development of cannabinoid-based medications is the separation of pain relief from side-effects, numerous other assessments will also be performed. Neuropsychological testing with the Digit Symbol Modalities Test (attention), the Hopkins Verbal Learning Test (learning and memory) and the Grooved Pegboard Test (psychomotor performance) were be performed. In addition, driving simulation was completed to assess the effect of study medications on this important component of everyday life. Subjective effects were evaluated with the Marijuana subscale (M-scale) from the Addiction Research Center Inventory to evaluate cannabis intoxication. In addition, questions that include measures of 'high' or 'liking' were analyzed.

The degree of pain relief was then compared with the adverse consequences of cannabis to assess the risk-benefit ratio of dronabinol and 3.5% Δ9-THC.