Inhibitory effects of azelastine hydrochloride in alcohol-induced asthma

Alcohol-induced bronchoconstriction is due to high blood concentrations of acetaldehyde, a metabolic product of ethanol, which lead to the release of histamine from basophils and mast cells. We examined the inhibitory effects of azelastine hydrochloride, which inhibits histamine release and blocks H 1 receptors, in alcohol-induced asthma. Subjects were 13 Japanese asthmatic patients. We measured the change in FEV 1 after ingestion of 30 g of pure ethanol. Blood ethanol, acetaldehyde, histamine, leukotriene C4 (LTC4), and thromboxane B2 (TXB2) concentrations were also measured. Alcohol challenge test was repeated in responders after administration of azelastine for 1 week at 4 mg/day. Of 13 asthmatic patients, five (38.5%) tested positive during an ethanol challenge test, represented by a fall more than 20% in FEV 1. The responders had a high blood ethanol, and showed a rise in blood acetaldehyde and histamine concentrations, but not in LTC4 or TXB2. After azelastine treatment, there was no significant fall in FEV 1 among responders. Neither the rise in blood ethanol nor blood acetaldehyde levels were blunted by treatment with azelastine, but the rise in blood histamine was blunted by this treatment. Our results suggest that antihistamine agents may be effective against alcohol-induced asthma by both blocking H 1 receptors and inhibiting histamine release.