The inhibitory effect of azelastine hydrochloride on histamine- and allergen-induced bronchoconstriction in atopic asthma.
We have examined the effect of azelastine, a new H1 histamine receptor antagonist, against bronchoconstriction induced by histamine and allergen. Twelve mild, atopic asthmatics each underwent two histamine and two allergen concentration-response inhalation challenges 4 hr after treatment with either 8.8 mg of azelastine or a matched placebo. Following azelastine the dose of histamine required to provoke a 20% fall in FEV1 (PD20 histamine) rose, from a geometric mean of 0.31 mg/ml to greater than 13.2 mg/ml. Azelastine also significantly inhibited allergen-induced bronchoconstriction, the PD20 allergen rising from 9.3 cumulative breath units (c.b.u.) to greater than 47.9 c.b.u., a greater than 5-fold increase. We conclude that azelastine effectively inhibits both histamine and allergen-induced bronchoconstriction, with considerably greater potency against histamine.
Rafferty
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Immunopharmacology Group, Medicine 1, Level D, Centre Block, Southampton General Hospital, U.K.
Holgate
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D000280:Administration, Inhalation; D000284:Administration, Oral; D000328:Adult; D001249:Asthma / Q000188:drug therapy*; D001980:Bronchi / Q000187:drug effects*; D004311:Double-Blind Method; D005541:Forced Expiratory Volume; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D010793:Phthalazines / Q000494:pharmacology*; D011058:Pollen; D011724:Pyridazines / Q000494:pharmacology*; D011897:Random Allocation; D013997:Time Factors
D010793:Phthalazines; D011724:Pyridazines; D006632:Histamine; C020976:azelastine