Double-blind comparison of the respiratory effects of parenteral lorazepam and diazepam in patients with chronic obstructive lung disease.

The effects on the respiratory function of two tranquillising drugs, lorazepam and diazepam, have been compared in 20 patients with chronic obstructive lung disease. Both drugs induce a respiratory depression (decrease in tidal volume and minute ventilation with acceleration of the respiratory frequency) with slight respiratory acidosis, but lorazepam causes no significant hypoxemia and has a shorter duration of action than diazepam. Nevertheless, if tranquillisers are indicated in such patients, they have to be used with care.