Contrave, under development by Orexigen Therapeutics Inc for the potential treatment of obesity, is an oral, sustained-release combination of the dopamine and norepinephrine reuptake antagonist bupropion and the opioid antagonist naltrexone. The proposed dual mechanism of action of the compound involves complementary stimulation of central melanocortin pathways, resulting in increased energy expenditure and reduced appetite. At the time of publication, Contrave was being assessed in phase III clinical trials. Preliminary data demonstrated placebo-subtracted weight losses of 3 to 7% and improvements in obesity-related comorbidities and cardiovascular risk factors. The primary adverse effect leading to discontinuation of treatment was nausea. Assuming that the results of the Contrave phase III clinical program reaffirm the efficacy and safety of the drug combination, this agent could be approved and launched to become a market leader in the anti-obesity therapeutic arena.