Cocaine abuse in methadone maintenance patients is associated with low serum methadone concentrations.

Cocaine abuse in methadone maintenance patients has emerged as a significant clinical problem. To determine if raising the daily methadone dosage is an effective way to eliminate cocaine abuse, 74 methadone maintenance patients maintained at daily dosages between 30 and 80 mg and who chronically abused cocaine were studied by a standard protocol. A total of 21 (28.4%) subjects ceased cocaine abuse when their methadone dosage was progressively raised to a maximal daily dose of 160 mg. Cocaine abuse appeared to accelerate elimination of methadone, since inadequate methadone serum concentrations (below 100 ng/ml) were found in 48 of 67 (71.6%) subjects tested 24 hours after a 100 mg oral methadone dose. Although cocaine abuse in methadone maintenance patients may respond to raising the daily methadone dosage, alternative treatments for cocaine abuse in methadone maintenance patients must be identified since cocaine abuse may lower serum methadone concentrations.