Effect of nitrazepam and flurazepam on the ventilatory response to carbon dioxide.

Ventilatory response to CO2 was measured before and after two different benzodiazepine hypnotics in both chronic bronchitics and patients without chest disease. Flurazepam, but not nitrazepam, produced a significant decrease in CO2 sensitivity, although there was no significant change in FEV1 or mixed venous PCO2. This is the first unequivocal evidence of central depression of respiration by a benzodiazepine and may be the mechanism by which benzodiazepines cause deterioration in patients with respiratory failure.