Drug therapy of sleep-related hypoxaemia.

In patients with chronic obstructive pulmonary disease (COPD) exhibiting daytime hypoxaemia, a worsening of the latter occurs during sleep, particularly during REM sleep. The most efficient therapy of this sleep-related hypoxaemia is the nocturnal administration of O2 at a flow rate of 1.5-3 l/min. An alternative therapy, when daytime hypoxaemia is not too severe (PaO2 greater than 55 mmHg), is the use of almitrine (100 mg/day), a drug which improves daytime hypoxaemia in most COPD patients. The improvement of sleep hypoxaemia with almitrine is related to the increased daytime PaO2 and cannot be considered as a specific effect of almitrine on sleep-related respiratory events. It must be emphasized that almitrine is ineffective in about 25% of COPD patients ("nonresponders") and that almitrine can be used with conventional O2 therapy in patients with severe hypoxemia (daytime PaO2 less than 55 mmHg).