Effects of naloxone on the subjective and psychomotor effects of nitrous oxide in humans.

The effects of naloxone on the mood-altering and psychomotor-impairing effects of nitrous oxide were examined in two studies. Each of the double-blind, randomized trials tested effects of three doses of naloxone or saline placebo during inhalation of 30% nitrous oxide in oxygen or 100% oxygen placebo. Experiment 1 tested a range of naloxone doses used clinically to reverse opiate-induced respiratory depression (0, 0.01, 0.1 1.0 mg/70 kg) and Experiment 2 included a dose approximately 25 times higher than that needed to reverse opiate-induced respiratory depression (0, 1.0, 3.0, 10 mg/70 kg). Nitrous oxide increased subject-rated reports of "feel drug effect," "carefree," "drunk," "sedated," and "high", and decreased psychomotor performance in both experiments. Naloxone had no effects by itself in either experiment, and, for the most part, did not significantly interact with nitrous oxide-induced changes in mood or psychomotor performance. Naloxone, in doses of 10 mg or less, does not appear to affect the subjective and psychomotor effects of nitrous oxide.