Indomethacin and perception of dyspnea in chronic airflow obstruction

A recent study showed that indomethacin reduces the perception of dyspnea during submaximal exercise in normal subjects (1). The purpose of this study was to determine whether indomethacin alters the perception of dyspnea in patients with chronic airflow obstruction during exercise. In a randomized double-blind crossover fashion, 11 subjects (FEV1 = 0.97 +/- 0.58 L) performed an incremental (15 W/min) cycle ergometer exercise test to exhaustion on 2 study days. Testing was performed 3 to 4 h after placebo or 50 mg of indomethacin. Perception of dyspnea was measured using the modified Borg scale. Minute ventilation, workload, and Borg scale measurements at exhaustion and during moderate exercise were determined. The data demonstrated no statistically significant differences between values obtained for minute ventilation, workload, or Borg scale measurements on placebo and indomethacin study days. Contrary to the previous findings in normal subjects, indomethacin failed to significantly alter perceived dyspnea during exercise in patients with chronic airflow limitation. This suggests that prostanoids do not play a major role in the perception of dyspnea in these patients during exercise.