This enriched-enrollment, randomized, double-blind, placebo-controlled, flexible-dose adjuvant study demonstrated that nabilone provided improvements in pain, anxiety, quality of life and patient satisfaction for patients with diabetic neuropathic pain.
Cannabinoids are emerging as potential options for neuropathic pain treatment. This study evaluated an oral cannabinoid, nabilone, in the treatment of refractory human diabetic peripheral neuropathic pain (DPN). We performed a single-center, randomized, double-blind, placebo-controlled, flexible-dose study with an enriched enrolment randomized withdrawal design. DPN subjects with a pain score ≥4 (0-10 scale) continued regular pain medications and were administered single-blinded adjuvant nabilone for 4 weeks. Subjects achieving ≥30% pain relief (26/37) were then randomized and treated with either flexible-dose nabilone 1-4 mg/day (n = 13) or placebo (n = 13) in a further 5-week double-blind treatment period, with 30% (11/37) of subjects deemed run-in-phase nabilone nonresponders. For nabilone run-in-phase responders, there was an improvement in the change in mean end-point neuropathic pain vs placebo (mean treatment reduction of 1.27; 95% confidence interval 2.29-0.25, P = 0.02), with an average nabilone dose at end point of 2.9 ± 1.1 mg/day, and improvements from baseline for the anxiety subscale of the Hospital Anxiety and Depression Scale, the Medical Outcomes Study sleep scale problems index, and the European Quality of Life-5-Domains index score (each P < 0.05). Nabilone run-in-phase responders reported greater global end-point improvement with nabilone than with placebo (100% vs 31%; P < 0.05). Medication-related confusion led to discontinuation in 2/37 subjects during single-blind nabilone treatment. Potential unmasking occurred in 62% of both groups. Flexible-dose nabilone 1-4 mg/day was effective in relieving DPN symptoms, improving disturbed sleep, quality of life, and overall patient status. Nabilone was well tolerated and successful as adjuvant in patients with DPN.
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The Department of Clinical Neurosciences, the Hotchkiss Brain Institute, and the University of Calgary, Calgary, Alberta, Canada
*Corresponding author. Address: Department of Clinical Neurosciences, University of Calgary, 3330 Hospital Drive NW, HMRB Room 155, Calgary, AB, Canada T2N 4N1. Tel.: +1 403 220 8831; fax: +1 403 283 8731.
Article history: Received 30 November 2011; Received in revised form 6 June 2012; Accepted 20 June 2012.