Cyclizine abuse among a group of opiate dependents receiving methadone.

Twenty opiate dependents receiving long-term prescriptions of oral methadone, were identified as being habitual abusers of the anti-emetic drug cyclizine. A semi-structured interview elicited the dosage of cyclizine used, its effects, the reasons for starting and persisting with abuse of cyclizine and the attitudes of the patients to it. Cyclizine was taken in large doses intravenously with methadone. The effects initially were of intense stimulation, often with hallucinations, sometimes with aggressive behaviour, and occasionally with epileptic fits. Subsequent depressive mood changes occurred often accompanied by a craving for cyclizine. Tolerance to the drug occurred but no clear cut withdrawal syndrome is apparent. It seems that dependence upon cyclizine occurs. The significance of these findings for doctors, pharmacists and for drug treatment units is discussed. The paucity of information on the pharmacology and pharmacokinetics is noted.