Use of calcium channel blockers in hypoxic lung disease.

COPD patients who are hypoxic develop pulmonary hypertension primarily because alveolar hypoxia induces muscular hypertrophy of pulmonary arteries. This muscular hypertrophy will regress in animals if they receive continuous oxygen therapy. Since many COPD patients refuse to use oxygen continuously, calcium channel blockers, which inhibit hypoxic pulmonary vasoconstriction, may be effective adjuvant therapy. Nifedipine lowers pulmonary vascular resistance during rest and exercise in hypoxic COPD patients.