Efficacy of Topiramate in the Treatment of Crack Cocaine Dependence: A Double-Blind, Randomized, Placebo-Controlled Trial

Objective: We performed a double-blind, randomized, placebo-controlled trial to assess the efficacy of topiramate in the treatment of crack cocaine dependence.

Method: Sixty men who were dependent on cocaine (DSM-IV) (exclusive use of crack cocaine) were selected. The subjects were randomly assigned to either a topiramate group (subjects received 50-200 mg of topiramate per day for 12 weeks) or a control group (subjects received placebo). The initial daily treatment dose was 50 mg, and this dose was increased weekly at increments of 25 to 50 mg, based on the subject’s tolerability, to a maximum of 200 mg. All of the subjects also participated in motivational interviews and group therapy. The primary outcome measures were detection of benzoylecgonine in the urine, study retention, frequency of cocaine smoking, amount of cocaine use, and mean amount of money spent on cocaine per week. The study was conducted from February 2013 to February 2014.

Results: Twenty-nine subjects in the topiramate group and 29 subjects in the control group completed the study. Longitudinal assessment revealed that retention was not significant (odds ratio [OR] = 1.072, P = .908) between the 2 groups. Negative results from a urine test for benzoylecgonine (a cocaine metabolite), which is a measure of cocaine abstinence, were more frequently obtained from the topiramate group (OR = 8.687, P < .001). Topiramate reduced the quantity of cocaine used (mean reduction = −3.108 g, P < .001), the frequency of cocaine use (mean = −0.784 times per week, P = .005), and the amount of money spent on cocaine (mean [US dollars] = −$25.38, P = .015; this variable did not achieve statistical significance after Bonferroni correction) compared with the placebo during the 12 weeks (or 84 days) of the assessment. However, the differences in reductions between the 2 groups in the quantity of cocaine used, the frequency of cocaine use, and money spent on cocaine over time (time × group interaction) were present only during the first 4 weeks, and none of these variables by 12 weeks. The studied groups did not differ with regard to secondary end points, such as study dropout and the number of subjects who reported side effects.

Conclusions: The present findings indicate that topiramate is effective and safe and thus reinforce previous data suggesting that topiramate is a potentially useful treatment for crack cocaine dependence. However, we found that topiramate is only useful as an adjunctive treatment during the first 4 weeks of the treatment. Future studies with larger samples are needed to confirm these results.

Trial Registration: Registro Brasileiro de Ensaios Clí­nicos (ReBEC) RBR-3vwfjs and UTN: U1111-1131-4443