Abnormal heat and pain perception in remitted heroin dependence months after detoxification from methadone-maintenance.

Patients receiving methadone maintenance therapy (MMT) for opiate dependence have altered nociception, complicating analgesic treatment. Increasing numbers of patients are choosing opiate-free treatment programs, yet data on the course of this abnormality months after detoxification from methadone is contradictory and based exclusively on cold pressor experiments. Heat and pain thresholds were measured by quantitative sensory testing (QST) in 23 subjects with heroin dependence in full, sustained remission months after detoxification from methadone and 27 healthy non-drug using controls. Self reports of pain intensity and unpleasantness were also collected. Test scores were compared across groups and correlated with measures of drug use history. There were significant differences between remitted opiate-dependent subjects and controls on the measures of heat threshold (38.83 vs. 35.96; Mann-Whitney U=177.5, p=0.006), and the measure of pain threshold (48.73 vs. 47.62; Mann-Whitney U=217.5, p=0.043). There was no correlation of any measure of drug use history with the heat or pain experience. Abstinent, formerly opioid-dependent patients continue to demonstrate abnormal noxious perception months after detoxification from methadone.