Alfentanil slightly increases the sweating threshold and markedly reduces the vasoconstriction and shivering thresholds.

Abstract

BACKGROUND: Hypothermia is common in surgical patients and victims of major trauma; it also results from environmental exposure and drug abuse. In most cases, hypothermia results largely from drug-induced inhibition of normal thermoregulatory control. Although opioids are given to a variety of patients, the thermoregulatory effects of opioids in humans remain unknown. Accordingly, the hypothesis that opioid administration impairs thermoregulatory control was tested. METHODS: Eight volunteers were studied, each on 3 days: (1) a target total plasma alfentanil concentration of 100 ng/ml, (2) control (no drug), and (3) a target alfentanil concentration of 300 ng/ml. Each day, skin and core tempe..