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A rapid ascent to high altitudes causes noncardiogenic pulmonary edema in susceptible persons. This edema is related to increased pulmonary artery (PA) pressure secondary to hypoxic vasoconstriction. Treatment with nifedipine lowers PA pressure and reduces hypoxia. Hypothesizing that prophylactic nifedipine would prevent pulmonary edema, a Swiss team conducted a randomized trial in 21 mountaineers with a history of high-altitude pulmonary edema who were about to climb to 4559 meters or higher.
Ten subjects took 20 mg of slow-release nifedipine every eight hours during the climb and for the next three days at the high altitude. Pulmonary edema developed in only 1 of these subjects, as compared to 7 of the 11 subjects who took placebo. The nif…