Anticonvulsants for cocaine dependence

Minozzi S, Amato L, Davoli M, Farrell M, Lima Reisser AARL, Pani PP, Silva de Lima M, Soares B, Vecchi S

Summary

Cocaine is an illicit drug used as a powder for intranasal or intravenous use or smoked as crack. Short and long-term use of this drug spreads infectious diseases (for example AIDS, hepatitis and tuberculosis), crime, violence and prenatal drug exposure. Cocaine dependence has medical and psychosocial complications and is a major public health problem. No proven pharmacological treatment exists for cocaine dependence. Antidepressant, anticonvulsants and dopaminergic medications have all been trialled. The present review looked at the efficacy and safety of anticonvulsant drugs for treating cocaine dependence, as a class and individually. The review authors identified 17 randomised controlled trials involving 1194 participants, 80% male, with a mean age of 36 years. The mean duration of the trials was 11 weeks (range 1 to 24 weeks). All the trials were conducted in USA, 16 as outpatients. Very limited evidence can be drawn from the included trials. No significant differences were found between a placebo and any anticonvulsant in reducing the number of dropouts from treatment, use of cocaine, craving, and severity of dependence, depression or anxiety. Placebo was superior to gabapentin in reducing the number of dropouts from treatment (two studies) and use of cocaine. Gabapentin (one study, 95 participants) and phenytoin (two studies, 56 participants) had a greater number of side effects than the placebo.

Although the methodological quality of the included studies was good, the sample sizes were small. Most anticonvulsants were used in single studies. Health effects of various substances of abuse seem to be strongly dependent on social context and the location of the studies could affect the treatment effect. Different rating systems were used and symptoms were not categorised as mild, moderate or severe to allow comparison of results between studies.