Narcotic antagonism by naloxone. Few side-effects after a short procedure?

Twenty patients undergoing microlaryngoscopy were anaesthetised with thiopentone and nitrous oxide. Half of the patients received 1.0-1.5 mg of fentanyl during anaesthesia, the effect of which was antagonised by naloxone 0.4 mg intravenously and 0.4 mg subcutaneously. The other patients served as controls and received saline instead of fentanyl and naloxone. Fentanyl markedly reduced mean arterial pressure and the heart rate-systolic arterial pressure product during microlaryngoscopy. Conversely, there were significant increases in these measurements after naloxone had been given. However, there were no significant differences between patients given fentanyl with naloxone, and those given saline, in respect of arterial pressure, heart rate or dysrhythmia during recovery. No patient vomited, or appeared nauseated when observed afterwards in the operating room. One patient vomited several hours after naloxone.