The effects of venlafaxine on the subjective, reinforcing, and cardiovascular effects of cocaine in opioid-dependent and non-opioid-dependent humans

The effects of maintenance on venlafaxine, which blocks both norepinephrine and serotonin reuptake, on the response to smoked cocaine (0, 12, 25, or 50 mg) in 7 opioid-free and 7 methadone-maintained cocaine abusers was examined during a 42-day study. Participants received venlafaxine (225 mg daily) and placebo as part of a double-blind crossover design. Cocaine significantly increased heart rate, blood pressure, cocaine choice, cocaine ratings, and ratings of positive subjective effects (e.g., "I feel high") in both groups. Venlafaxine significantly decreased the subjective effects of cocaine by 10-20% without affecting cocaine choice or cardiovascular response in both groups. Although the reduction in cocaine's effects was small, further studies using a longer venlafaxine maintenance period or a larger venlafaxine dose are warranted.