Carvedilol does not reduce cocaine use in methadone-maintained cocaine users

Abstract

Introduction The goal of this study was too test the efficacy of carvedilol (CAR), an adrenergic blocker, for reducing cocaine use in individuals with cocaine use disorder (CUD). We conducted a 17-week, double-blind, randomized controlled trial with 3 treatment arms: 25 mg CAR, 50 mg CAR, and placebo. Methods One hundred and six treatment-seeking opioid and cocaine-dependent participants, who were also maintained on methadone during study participation, were randomized to placebo (n = 34), 25 mg/day CAR (n = 37) or 50 mg/day CAR (n = 35). The main outcome measures were cocaine and opioid use as assessed by urine drug screening and self-reported drug use. Results No significant group differences were found for treatment retention with 56% of the placebo, 76% of the 25 mg and 66% of the 50 mg CAR groups (p > 0.05) completing treatment. The percentage (SD) of cocaine positive urines during the trial showed an overall treatment effect: 59.2 (38.9) for the placebo, 50.8 (33.8) for the 25 mg and 75.1 (33.2) for the 50 mg CAR group. In post hoc comparisons, neither the 25 nor 50 mg CAR condition differed significantly from the placebo; however, the 25 mg CAR group had a significantly lower proportion of cocaine-positive urines than the 50 mg group. No significant group differences were found for the percentage of self-reported days of cocaine abstinence during the trial: 72.9 (25.3) for placebo, 72.9 (29) for CAR 25 mg, and 59.3 (31.7) for CAR 50 mg. Significant groups differences in the proportion of opioid positive urines submitted were not observed (p > 0.05). Baseline cocaine withdrawal severity did not predict treatment response (p > 0.05). Conclusions These findings did not support the efficacy of CAR for the treatment of cocaine use in cocaine and opioid dependent participants maintained on methadone. Further, CAR doses > 25 mg should not be used to avoid possible increases in cocaine and opioid use.