DOSE-RESPONSE RELATIONSHIP OF THE H1-HISTAMINE ANTAGONIST, EBASTINE, AGAINST HISTAMINE AND METHACHOLINE-INDUCED BRONCHOCONSTRICTION IN PATIENTS WITH ASTHMA

In a double blind, randomised, placebo controlled trial in a group of extrinsic asthmatics, we have evaluated the potency and selectivity of ebastine, a new piperidine-type H1-receptor antagonist, against histamine and methacholine-induced bronchoconstriction. The median histamine PC20FEV1 value following placebo was 3.15 mg/ml (0.24-58.84). When compared with placebo, ebastine produced significant protection at 10 mg (median PC20=31.36 mg/ml, p=0.008) and 30 mg (median PC20=42.14 mg/ml, p=0.001) but there appeared to be no significant dose effect. Ebastine also produced a small shift in the methacholine concentration-response curves to the right. We conclude that ebastine is an effective antagonist of histamine-induced bronchoconstriction in the asthmatic airway with evidence of minor blockade of methacholine-induced bronchoconstriction. © 1990 Birkhäuser Verlag.