Effects of low-dose naltrexone on analgesia produced by hydrocodone

Abstract

Purpose To assess the impact of oral naltrexone (NTX) on the analgesic effects of oral immediate-release hydrocodone (HYIR) in healthy subjects with thermally induced hyperalgesia. Methods Subjects first received a thermal discomfort test to determine hyperalgesic response and their responsiveness to opioid analgesic effects. Subjects who qualified then entered a 4-way crossover, double blind phase in which they received HYIR + NTX placebo, or HYIR + NTX 0.25, 0.5, or 1.0 mg. Results No significant differences occurred between HYIR + NTX placebo and HYIR + NTX 0.25, 0.5, or 1.0 mg in thermal discomfort scores, pain latency, or other measures of hyperalgesia. There were no significant differences among treatments or consistent dose-related trends in the subjective opioid agonist effects of HYIR measured in this study. No safety concerns were associated with any HYIR and/or NTX dose. No adverse events commonly associated with opioid use occurred with the NTX 1.0 mg dose. Conclusion No dose of NTX studied resulted in a significant decrease in HYIR-induced analgesia. There was no consistent, dose-related NTX effect on the subjective opioid agonist effects of HYIR measured in this study. Clinical Pharmacology & Therapeutics (2004) 75, P71–P71; doi: 10.1016/j.clpt.2003.11.267