Effect of Zonisamide on Cocaine Reinforcement, Craving, and Relapse

Inclusion Criteria: * Age at least 21 years old, not older than 45 years. * Evidence of cocaine dependence. * Not seeking treatment for cocaine abuse. * Able and willing to be restricted to our unit for 6-7 weeks. * Able to answer frequent questionnaires reliably and consistently. * Smoker. Exclusion Criteria: * Allergy to Sulfonamide drugs (e.g. topiramate, zonisamide, sulfamethoxazole/trimethoprim). * Diabetes, respiratory insufficiency, renal tubular acidosis or renal insufficiency, heart failure, liver insufficiency, chronic diarrhea, other chronic diseases predisposing to acidosis. * Renal insufficiency defined as serum creatine \> 1.30 mg/DL for males or \> 1.03 mg/DL for females. * History of nephrolithiasis, unexplained hematuria on screening urinalysis. * History of head injury (with loss of consciousness longer than a few minutes). * History of seizure, or use of antiepileptic medications. * HIV positive individuals who meet AIDS by Centers for Disease Control (CDC) criteria or are on antiretroviral medications. * BMI \< 19 or BMI \> 34. * Total cholesterol \> 240mg%. * Serous psychiatric illness with psychosis, dementia. * Glaucoma, family history of glaucoma, one-sided blindness. * For female participants: being pregnant, lactating or not using an effective method of contraception. * Physical dependence on any drug other than cocaine, nicotine, or caffeine.