Acute detoxification of opioid-addicted patients with naloxone during propofol or methohexital anesthesia: A comparison of withdrawal symptoms, neuroendocrine, metabolic, and cardiovascular patterns

Objective: mu-Opioid receptor blockade during general anesthesia is a new t reatment for detoxification of opioid addicted patients. We assessed catech olamine plasma concentrations, oxygen consumption, cardiovascular variables , and withdrawal symptoms after naloxone and tested the hypothesis that var iables are influenced by the anesthetic administered during detoxification. Design: Prospective randomized clinical study. Setting: Intensive care unit of a university hospital and psychiatric ward. Patients: Twenty-five mono-opioid addicted patients with mild to moderate s ystemic disease (ASA II classification) in a methadone substitution program . Intervention: General anesthesia with either propofol (129 +/- 7 mu g.kg(-1 ).min(-1), mean +/- SEM) or methohexital (74 +/- 14 mu g.kg(-1) min(-1)), m u-opioid receptor blockade by naloxone in a stepwise fashion (increasing do ses of 0.4 mg, 0.8 mg, 1.6 mg, 3.2 mg, and 6.4 mg at 15 min intervals follo wed by 0.8 mg .hr(-1) for 24 hrs) and naltrexone 50 mg .day(-1) orally for greater than or equal to 4 wks. Clonidine was started 180 mins after the fi rst naloxone dose and its infusion rate was individually adjusted to mitiga te withdrawal symptoms during weaning and after extubation. Measurements and Main Results: During propofol and methohexital anesthesia, naloxone induced a 30-fold increase in epinephrine and a significant three -fold increase in norepinephrine plasma concentrations without a significan t difference between groups. This increase in catecholamine plasma concentr ations was associated with increased oxygen consumption and marked cardiova scular stimulation with both anesthetics, as shown by increased cardiac ind ex, heart rate, and systolic atrial pressure whereas diastolic pressure rem ained unchanged. Patients receiving propofol could be extubated significant ly earlier after discontinuation of the anesthetics. Although the maximum d egree of withdrawal symptoms (Short Opioid Withdrawal Scale) on the day aft er detoxification was similar with both anesthetics, subsequent withdrawal symptoms decreased significantly more rapidly after propofol anesthesia. Conclusions: Naloxone treatment, in opioid-addicted patients, induced a mar ked increase in catecholamine plasma concentrations, metabolism, and cardio vascular stimulation during anesthesia with both propofol and methohexital. Although both anesthetics appear suitable for detoxification treatment, th e use of propofol is associated with earlier extubation and, surprisingly, a shortened period of long-term withdrawal symptoms during detoxification.