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Human Abuse Potential and Cognitive Effects of Taranabant, a Cannabinoid 1 Receptor Inverse Agonist: A Randomized, Double-Blind, Placebo- and Active-Controlled, Crossover Study in Recreational Polydrug Users

Schoedel, Kerri A. PhD*; Addy, Carol MD, MMSc; Chakraborty, Bijan M Stat*; Rosko, Kim BS; Dunbar, Stephanie PhD; Maes, Andrea PhD†‡; Chen, Nancy PhD*; Stoch, Selwyn Aubrey MD; Wagner, John MD, PhD; Chodakewitz, Jeff MD; Sellers, Edward M. MD, PhD, FRCPC, FACP

Journal of Clinical Psychopharmacology: August 2012 - Volume 32 - Issue 4 - p 492–502
doi: 10.1097/JCP.0b013e31825d380d
Original Contributions

Introduction Taranabant is a cannabinoid 1 receptor inverse agonist that was in development for treatment of obesity. Because of central nervous system effects, the study was performed to assess the abuse potential and cognitive effects of taranabant in recreational polydrug users compared with phentermine, dronabinol, and placebo.

Methods Stimulant- and cannabis-experienced polydrug users (N = 30) were randomized in a double-blind crossover study to receive taranabant 2, 4, 10, and 20 mg; phentermine 45 and 90 mg; dronabinol 20 mg; and placebo. Subjective and neurocognitive measures were administered for 24 hours, and peak/peak change from baseline effects were analyzed using a linear mixed-effects model.

Results Phentermine 45 and 90 mg showed abuse-related subjective effects versus placebo, including drug liking, overall drug liking, and other positive/stimulant effects, whereas dronabinol 20 mg showed abuse-related positive, cannabis-like, and sedative effects. Taranabant was not significantly different from placebo on most of the subjective measures other than negative/dysphoric effects at the highest dose, and its effects were significantly less pronounced relative to phentermine and dronabinol on most measures. Phentermine improved cognitive/motor performance and dronabinol impaired motor/cognitive performance on some measures, whereas taranabant 4 and 20 mg had minor impairment effects on manual tracking.

Conclusions The phentermine and dronabinol results demonstrate the validity and sensitivity of the study. Taranabant did not consistently show stimulant/cannabis-like effects or abuse potential in recreational polydrug users, indicating that cannabinoid 1 receptor inverse agonists/antagonists are unlikely to be recreationally abused.

Supplemental digital content is available in the text.

From *INC Research (formerly Kendle Early Stage-Toronto), Toronto, Ontario, Canada; †Merck & Co., Inc., Whitehouse Station; and ‡Novartis Pharmaceuticals Corporation, East Hanover, NJ; and; §Departments of Pharmacology, Medicine and Psychiatry, University of Toronto, Toronto, Ontario, Canada.

Received April 15, 2011; accepted after revision January 24, 2012.

Reprints: Kerri A. Schoedel, PhD, INC Research, 720 King Street West, 7th Floor, Toronto, Ontario, Canada M5V 2T3 (e-mail:

Dr Dunbar is now with Teva USA, North Wales, PA.

Supplemental digital content is available for this article. Direct URL citation appears in the printed text and is provided in the HTML and PDF versions of this article on the journal’s Web site ( ).

© 2012 Lippincott Williams & Wilkins, Inc.