Mr. A was a 42-year-old man with a history of cocaine addiction since the age of 17 and heroin addiction since age 28. After repeated attempts at detoxification and rehabilitation, he was able to forgo the use of cocaine, then heroin, and later methadone. During his 15 years of substance abuse treatment, he had received imipramine for depression at doses of 75–300 mg/day. During the year after his last use of methadone, Mr. A became increasingly engaged in restoring his relationship with his children and in computer training through a vocational program. The many difficulties and setbacks he faced often discouraged him; it was at these times that his cravings for cocaine returned. After a discussion about the experimental nature of gabapentin treatment, he agreed to a trial of gabapentin while continuing treatment with imipramine, 200 mg/day. His dose of gabapentin was increased to 400 mg b.i.d. over 1 week. His blood level of gabapentin at that dose was 12.4 mg/liter (>2 mg/liter is needed for seizure control). He reported that his cravings had completely disappeared within a month of reaching a dose of 800 mg/day.

Ms. B was a 31-year-old woman with a diagnosis of schizoaffective disorder and cocaine abuse. Her psychotic symptoms were well controlled with a bimonthly injection of 50 mg of fluphenazine decanoate. She required supplements of oral fluphenazine, up to 20 mg/day, to control auditory hallucinations immediately after she used crack cocaine, which she typically consumed night and day during binges lasting up to 10 days. Afterward she could be abstinent for several months. Her relapses usually coincided with returning to live with her mother in a crack-infested neighborhood, which would prompt strong cravings and vivid dreams about smoking crack. She began a course of oral gabapentin therapy, reaching a dose of 1200 mg b.i.d. At that dose, her blood level of the drug was 15.6 mg/liter. She reported a marked reduction in cravings, at times being able to live in the crack-infested neighborhood without relapsing. In the 9 months since she began gabapentin treatment, she has experienced one relapse, which consisted of smoking two crack cigarettes.