Rintala DH, Fiess RN, Tan G, Holmes SA, Bruel BM: Effect of dronabinol on central neuropathic pain after spinal cord injury: A pilot study.
Objective: To test the efficacy and safety of a cannabinoid, dronabinol, compared with an active control, diphenhydramine, in relieving neuropathic pain in persons with spinal cord injury.
Design: A randomized, controlled, double-blind, crossover pilot study.
Results: Seven adults with spinal cord injury and neuropathic pain below the level of injury participated. Two participants withdrew while receiving dronabinol, their first medication. For the remaining five participants, change in pain on a scale of 0–10 from baseline to the end of the maintenance phase did not differ significantly between the two medications (mean change, dronabinol: 0.20 ± 0.837, range = −1.00 to 1.00; diphenhydramine: −1.80 ± 2.490, range = −6.00 to 0; Wilcoxon Z = 1.63, P = 0.102). Similar results were found when the average of the two ratings during the maintenance phase was used (dronabinol: −0.20 ± 0.671, range = −0.50 to 1.00; diphenhydramine: −1.40 ± 1.245, range = −3.50 to −0.50; Wilcoxon Z = 1.60, P = 0.109). The most common side effects were dry mouth, constipation, fatigue, and drowsiness for both medications.
Conclusions: On average, dronabinol was no more effective than diphenhydramine for relieving chronic neuropathic pain below the level of injury.
From the Michael E. DeBakey Veterans Affairs Medical Center (DHR, RNF, GT, SAH), Houston, Texas; and the Departments of Physical Medicine and Rehabilitation (DHR, RNF, GT, SAH, BMB) and Anesthesiology (GT), Baylor College of Medicine, Houston, Texas. Brian M. Bruel is currently at the Departments of Physical Medicine and Rehabilitation and Anesthesiology and Pain Management, University of Texas Southwestern Medical School, Dallas, Texas.
All correspondence and requests for reprints should be addressed to Diana H. Rintala, PhD, 5451 Indigo Street, Houston, TX 77096.
Supported in part by grant 2355-01 from the Paralyzed Veterans of America Research Foundation. Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article.