Aspirin for prophylaxis against headache at high altitudes: randomised, double blind, placebo controlled trial

Abstract

Twenty nine volunteers with a history of headache at high altitude were randomly assigned in a double blind fashion to receive placebo (eight men, six women, mean age 38 (SD 12) years) or 320 mg aspirin (nine men, six women, mean age 38 (14) years). After examination at low altitude (600 m), subjects were transported to high altitude (3480 m) for 24 hours. We gave them three tablets, one every 4 hours, starting 1 hour before arrival at high altitude. We scored headache on a four-point scale (0=none, 1=mild, 2=moderate, 3=severe) and measured heart rate, blood pressure, and arterial oxygen saturation 1 hour before and 3, 7, 10, and 19 hours after arrival. In addition, subjects exercised for 2 minutes by stepping 60 times up and down a 24 cm step, at low altitude and within 2-5 hours after arrival at high altitude during which we continuously monitored gas exchange, heart rate, and oxygen saturation.