Long-term effects of almitrine bismesylate on oxygenation during wakefulness and sleep in chronic obstructive pulmonary disease.

Hypoxemia in patients with chronic obstructive pulmonary disease (COPD) becomes more pronounced during sleep and can result in a number of serious consequences. Almitrine bismesylate is a peripheral chemoreceptor agonist that improves arterial oxygen tension (PaO2) in patients with COPD during wakefulness. Studies conducted for up to six months suggested the agonist may be useful in the management of nocturnal hypoxemia. In this double-blind, parallel, placebo-controlled study, patients with COPD received 50 mg of almitrine bismesylate (n = 9) or placebo (n = 11) twice a day for one year. Almitrine bismesylate increased PaO2 by 8.1 +/- 2.1 mm Hg (mean +/- SEM), decreased arterial carbon dioxide tension by 3.0 +/- 0.7 mm Hg (mean +/- SEM), and increased minute ventilation by 3.1 +/- 0.5 liters/minute (mean +/- SEM) during wakefulness. All of these changes were statistically significant. Five patients in the almitrine bismesylate group and eight patients in the placebo group completed sleep studies prior to and after 56, 180, and 360 days of almitrine bismesylate or placebo administration. Relative to placebo, almitrine bismesylate significantly increased oxygen saturation during sleep without any significant changes in the quantity or quality of sleep.