The acute effect of a single oral dose of 200 mg almitrine on gas exchange in patients with chronic obstructive bronchitis and emphysema, bronchial asthma and lung fibrosis.

We studied the acute effect of a single, oral dose of 200 mg almitrine and of placebo on arterial blood gas tensions, ventilation, gas exchange and pulmonary mechanics in 28 patients with chronic obstructive bronchitis and emphysema (COPD), 20 patients with bronchial asthma and 10 patients with interstitial lung disease. Almitrine significantly increased PaO2 in COPD, had a borderline effect in bronchial asthma and no effect in lung fibrosis. In all groups of patients almitrine significantly increased minute ventilation and decreased arterial carbon dioxide tension (PaCO2). Placebo had no effect on arterial oxygen tension (PaO2) and PaCO2 in any of the groups. Therefore, despite similar effects on ventilation, the improvement of arterial PO2 by almitrine depends on the underlying disease.