Are anticonvulsants for cocaine dependence efficient?

Cochrane: Cocaine is an illicit drug available as a powder for intranasal or intravenous use or smoked as crack. Short- and long-term use of this drug results in the spread of infectious diseases (for example, AIDS, hepatitis, tuberculosis), crime, violence and prenatal drug exposure. Cocaine dependence is associated with medical and psychosocial complications and is a major public health problem. No proven pharmacological treatment for cocaine dependence is known. Antidepressant, anticonvulsant and dopaminergic medications have all been studied. The present review looked at the efficacy and safety of anticonvulsant drugs for treating cocaine dependence, both as a class and individually.

 
Study characteristics

The review authors searched scientific databases and Internet resources to identify randomised controlled trials (in which participants were allocated at random to any anticonvulsant drug or placebo or another type of drug or non-pharmacological intervention intended to reduce,the use of cocaine). We assessed also dropout from treatment and frequency of side effects .We included people of any gender, age or ethnicity.
 

Key results

The review authors identified 20 studies with 2068 participants, 77% male, with a mean age of 36 years. The mean duration of the trials was 11.8 weeks (range eight to 24 weeks). All but two of the trials were conducted in the USA, all with outpatients. The anticonvulsant drugs studied were carbamazepine, gabapentin, lamotrigine, phenytoin, tiagabine, topiramate and vigabatrin. All studies compared anticonvulsants versus placebo. No significant differences were found between placebo and any anticonvulsant in reducing the number of dropouts from treatment, use of cocaine, craving and severity of dependence, depression or anxiety. Side effects were slightly more frequent in the anticonvulsant groups. No current evidence supports the clinical use of anticonvulsant medications for the treatment of cocaine dependence.
 

Quality of the evidence

The quality of the evidence was moderate for the outcomes dropout and use of cocaine, and was low for the outcomes side effects and craving. The major limitation of the trials was incomplete reporting of the methods used to protect against selection bias, randomly allocate participants to groups and conceal allocation. The evidence is current to June 2014.

 

 

Authors' conclusions: 

Although caution is needed when results from a limited number of small clinical trials are assessed, no current evidence supports the clinical use of anticonvulsant medications in the treatment of patients with cocaine dependence. Although the findings of new trials will improve the quality of study results, especially in relation to specific medications, anticonvulsants as a category cannot be considered first-, second- or third-line treatment for cocaine dependence.