Effects of naloxone on nitrous oxide actions in healthy volunteers.
Pain December 1, 1999 James P Zacny, Aisling Conran, Helene Pardo et al.
A high dose of naloxone (30 mg/70 kg) did not reverse the pain-relieving effects of 30% nitrous oxide in a crossover trial with 14 subjects. Participants inhaled either 30% nitrous oxide or pure oxygen, then received intravenous naloxone or saline. Naloxone increased pain ratings overall and impaired mood and psychomotor performance, but it did not counteract nitrous oxide's analgesic or subjective effects. The findings question whether the opioid system mediates nitrous oxide's effects in humans.