[Effect of nalbuphine on respiration]

The respiratory depressant effects of 0.25 mg/kg nalbuphine were analyzed in detail in seven healthy volunteers by determining the CO2 response (Read's method) and the mouth occlusion pressure (Whitelaw's method) before and 10, 30 and 60 min after administration of the drug. Minute ventilation VE (PACO2 = 55 mm Hg) decreased after nalbuphine by a maximum of 36.4% (P less than 0.05). Simultaneously, the slope of the right-shifted CO2 response curve was diminished by 21.1% (NS) while the mouth occlusion pressure decreased by 36.3% (P less than 0.05), respectively. There were only slight changes in mean inspiratory flow rate. These findings demonstrate that nalbuphine does not lead to relevant impairment of central respiratory regulation or respiratory mechanics.