Effect of a thromboxane synthetase inhibitor, ozagrel hydrochloride, on peak expiratory flow in stable asthmatics treated with beclomethasone diproprionate

Abstract

Steroid inhalation therapy is recommended for treatment of moderate to severe asthma, but it is unknown whether the therapy sufficiently suppresses production of thromboxane A₂ (TXA₂), one of the inflammatory lipid mediators. The effect of a selective orally active thromboxane synthesis inhibitor, ozagrel hydrochloride (200mg twice a day for 4 weeks), on morning and evening peak expiratory flow (PEF) was examined in 70 stable asthmatics receiving beclomethasone diproprionate (BDP) inhalation therapy (800μg/day) by a randomized, placebo-controlled, single-blinded study. Morning PEF was significantly increased from 313.5±13.1 (mean±SEM) L/min to 325.7±12.2L/min at 1 week, 335.5±12.7L/min at 2 weeks, 338.6±13.4L/min at 3 weeks, and 340.0±13.2L/min at 4 weeks in 35 patients treated with ozagrel but not in the other 35 patients treated with a placebo. The percent increase in the morning PEF was significantly greater with ozagrel than with the placebo. It is speculated that inhibition of thromboxane synthesis by medium dose of steroid inhalation therapy may be insufficient in some asthmatics.