Almitrine improves oxygenation when both awake and asleep in patients with hypoxia and carbon dioxide retention caused by chronic bronchitis and emphysema.

Patients with chronic bronchitis and emphysema who are hypoxic when awake become more hypoxic during sleep, with a further rise in their preexisting pulmonary hypertension. Almitrine, a respiratory stimulant, improves arterial blood gas tensions in such patients when they are awake. We have used a double-blind, placebo-controlled, cross-over study to compare the effects of 50 mg almitrine given orally twice a day for 14 days on oxygen saturation (SaO2), respiratory movements, and sleep quality in 9 patients with hypoxic chronic bronchitis and emphysema (FEV1, 0.4 to 1.0 L; PaO2, 51 +/- (SEM) 2 mmHg; PaCO2, 49 +/- 1 mmHg). Almitrine improved arterial blood gas tensions when awake, mean PaO2 rising by 8 mmHg (p less than 0.001) and PaCO2 falling by 4 mmHg (p less than 0.01). Almitrine improved nocturnal oxygenation, mean SaO2 when awake rising from 83 +/- 4% to 89 +/- 3% (p less than 0.01), and the lowest SaO2 during sleep rising on average from 65 +/- 6% to 77 +/- 3% (p less than 0.02). The number of hypoxemic episodes (SaO2 falling by greater than or equal to 10% from the preceding stable baseline during sleep) and the time when SaO2 was below 80% (135 +/- 53 versus 46 +/- 35 min; p less than 0.01) also improved. Almitrine did not improve sleep quality. We conclude that almitrine improves arterial gas tensions when awake and reduces the frequency and severity of nocturnal hypoxemia without impairing sleep quality in patients with chronic bronchitis and emphysema who are both hypoxemic and hypercapnic when awake.(ABSTRACT TRUNCATED AT 250 WORDS)