Effect of OKY-046 (thromboxane A2 synthetase inhibitor) on exercise-induced asthma.

The influence of OKY-046, which is a thromboxane (TxA2) synthetase inhibitor, was studied in patients with exercise-induced asthma (EIA). When OKY-046 was administered to 11 patients with EIA-positive (EIA+) asthma, 7 patients showed an effect of the inhibition of airway contraction. As the mechanism of action, inhibition of TxA2 production and acceleration of PGI2 were considered, since OKY-046 has no bronchodilation action. In other words, the fact that TxA2 was a mediator of EIA had been made clear, but it was also found that it had no association as a mediator of leukotrienes (LTC4 and LTB4) in EIA.