Clozapine Treatment of Dimenhydrinate Abuse

Ms. A had multiple hospitalizations for schizophrenia from the age of 20. Her first dimenhydrinate abuse was at age 29. Ms. A abused dimenhydrinate repeatedly “to get high” during an 8-year stay in the hospital. At these times, she would be loud and aggressive, with extremely poor self-care. At times, Ms. A ingested 5000 mg of dimenhydrinate, and on more than 10 occasions, she had generalized seizures secondary to overdoses. She stated, “I was relying on [dimenhydrinate] to get me through the day.” The ward staff believed that Ms. A’s dimenhydrinate abuse would eventually kill her.

We gave Ms. A clozapine when she was 35 years old. At a dose of 700 mg/day of clozapine, her blood level of the drug was 635 ng/ml. Ms. A reported a decreased urge to use dimenhydrinate while taking clozapine. She has since lived in the community, been free of seizures, and worked in a sheltered workshop for more than 3 years. Her dimenhydrinate use dropped to an average of 250 mg/day.

Mr. B explained his dimenhydrinate abuse of up to 3000 mg at a time by saying that it was a cheaper alternative to cocaine. Such ingestions were pleasant, as he reported that they made him “musical” and “creative.” He was 36 years old when we first gave him a prescription for clozapine for his schizophrenia. It was difficult to achieve a therapeutic blood level of clozapine. We then gave him fluvoxamine to increase his clozapine blood level. At a clozapine dose of 700 mg/day and a fluvoxamine dose of 25 mg/day, his blood level of clozapine increased to 441 ng/ml. His cravings for dimenhydrinate markedly decreased when clozapine had reached a therapeutic level. Mr. B has been out of hospital for 1.5 years and has continued to use dimenhydrinate at a markedly reduced level.