SUBJECTIVE AND OBJECTIVE SYMPTOMS IN RELATION TO PLASMA METHADONE CONCENTRATION IN METHADONE PATIENTS

Two rating scales, which were originally developed for measurements of objective and subjective signs of opiate withdrawal, were used to eva luate potential estimates (correlates) of methadone effects in relatio n to plasma methadone concentrations. Patients participating in our re gular methadone maintenance treatment project were studied during 24 h after the intake of the daily methadone dose. Methadone concentration s in plasma were compared to the subjective (estimated by the patients ) and objective (estimated by the investigator) signs of the drug effe cts before, and 2.5, 5, 9 and 24 h after intake of methadone. Some new items possibly related to rising methadone concentrations were added to the subjective scale. Results indicated that, for subjective rating s, the majority of the items investigated corresponded well with the p lasma methadone concentrations. The most significant associations were found for the following items: low psychomotor speed, alertness, runn ing nose, yawning and anxiety. For objective ratings, only the items r hinorrhea, piloerection and signs of anxiety were significantly associ ated with the methadone concentrations. These rating scales may, toget her with plasma methadone determinations, be of considerable value whe n making dose adjustments for methadone maintenance patients. Further work is, however, needed to establish concentration - effect relations hips.