The effects of indomethacin on the refractory period to hypertonic saline-induced bronchoconstriction

The purpose of this study was to determine the effect of pretreatment with indomethacin on the refractory period to hypertonic saline-induced bronchoconstriction. In a double-blind, placebo-controlled, randomized trial nine asthmatic subjects underwent two hypertonic saline challenges, 60 min apart, on a control day and after premedication with indomethacin 50 mg or matching placebo, twice daily for three days. Premedication with indomethacin did not change airway responsiveness to the initial hypertonic saline challenge. The mean maximal % fall in specific airway conductance (sGaw) was 40.3, 44.1 and 47.6% on the control, placebo and indomethacin days, respectively. Subjects were significantly less responsive to the second hypertonic challenge as compared to the initial challenge on all three study days. There was a variable effect of indomethacin pretreatment on the refractory period. Five subjects lost their refractory period after indomethacin, when the variability of the test was taken into account. This suggests that there may be contributory mechanisms to the refractory period other than the release of protective prostanoid metabolites.