The effect of almitrine bismesylate on hypoxemia in chronic obstructive pulmonary disease.

Almitrine bismesylate was studied for its effects on hypoxemia in 67 patients with chronic obstructive lung disease in a placebo-controlled, double-blind study. Arterial Po2 rose by 11.2 mm Hg (p less than 0.05) in 21 patients receiving 100 mg twice daily and by 6.0 mm Hg (p less than 0.05) in 22 patients receiving 50 mg twice daily. Arterial Pco2 decreased by 3.8 mm Hg (p less than 0.05) in the group receiving 100 mg twice daily but was unchanged in patients receiving 50 mg twice daily. Lung function was unaltered except for a slight increase in forced mid-expiratory flow in both dosage groups (p less than 0.05). The major side effect was the unexplained worsening of dyspnea, which occurred in 4 patients (19%) receiving 100 mg twice daily, 2 (9%) receiving 50 mg twice daily group, and 1 (4%) receiving placebo. Almitrine bismesylate improves arterial blood gas values in patients with chronic obstructive lung disease, apparently by reducing intrapulmonary ventilation-perfusion mismatching, and appears to be useful in the long-term management of these patients.