Pain perception of intravenous heroin users on maintenance therapy with levomethadone.

Compared the pain perception of 42 heroin addicts (aged 23–36 yrs) on levomethadone maintenance treatment with that of 16 healthy and drug free controls (aged 25–34 yrs). Pain perception was measured by single-blind, noninvasive pressure stimulation of the nociceptors located in the dorsal extension aponeurosis and the underlying periosteum of the middle phalanx of a digit before and respectively, 1, 2, and 4 hrs after oral routine drug administration. Measures were related to the individual levomethadone plasma levels. Under steady-state conditions, the pain perception of the patients did not differ from the controls and was not related to individual levomethadone plasma levels, although an analgesic effect in the reabsorption phase was observed. Results suggest that the individual pain perception of maintained patients is adapted to a normal response range and that even prolonged opioid consumption does not diminish dynamic analgesic responsiveness to levomethadone. (PsycInfo Database Record (c) 2022 APA, all rights reserved)