EFFECT OF ORAL-ADMINISTRATION OF A PROSTACYCLIN ANALOG (OP-41483) ON PULMONARY-FUNCTION AND BRONCHIAL RESPONSIVENESS IN STABLE ASTHMATIC SUBJECTS

To examine whether prostacyclin has an attenuating effect on nonspecific bronchial responsiveness in asthma, we measured provocative concentration of methacholine producing a 20% fall in forced expiratory volume in 1 second (PC20-FEV1) before and after oral administration of a chemically stable prostacyclin analog (OP-41483) (200-mu-g 4 times a day for 4 days) in 8 patients with stable asthma. Neither baseline pulmonary function nor PC20-FEV1 significantly improved after the treatment. These results suggest that prostacyclin may have no direct effect on bronchial responsiveness in asthmatics. Further studies using more potent and long-lasting prostacyclin mimetic will be needed to confirm the conclusion.