Inhibition of idiosyncratic reactions to aspirin in asthmatic patients by clemastine.

An H1-receptor blocking antihistamine, clemastine, taken before aspirin gave complete or partial protection against flushing, rhinorrhea, cough, and headache in ten asthmatic patients with idiosyncrasy to aspirin. In five of the ten patients aspirin-precipitated bronchoconstriction was also reduced or prevented after pretreatment with clemastine. Thus histamine appears to play a part in the production of most non-respiratory symptoms occurring after aspirin ingestion in intolerant patients with asthma. Bronchial reactions might depend partly on histamine and partly on the action of other spasmogens. It is suggested that inhibition of prostaglandins of the E series by aspirin-like drugs plays a crucial part in the release of histamine from tissue stores in aspirin-sensitive asthmatic patients. Clemastine might be of use in the treatment of acute reactions to aspirin.