Prevention of antigen-induced bronchoconstriction by lodoxamide ethyl, a new orally active antiallergic drug.

Lodoxamide ethyl, an orally active drug with pharmacologic activity similar to that of cromolyn sodium, blocks passive cutaneous anaphylaxis (PCA) in rats and antigen-induced bronchoconstriction in guinea pigs and monkeys. Its effectiveness in preventing antigen-induced airway obstruction was studied in 12 asymptomatic asthmatic adults with immediate skin test sensitivity to ragweed, Alternaria, or animal dander. The dose required to reduce the forced expiratory volume in 1 sec (FEV1) by 20% (PD20) was determined by dosimeter bronchoprovocation challenge with the appropriate antigen. At 1-wk intervals each subject received either placebo of 1, 3, or 10 mg drug in a randomized, double-blind fashion 30 min prior to starting bronchoprovocation challenge. On average, 1 mg increased the PD20 fivefold, 3 mg about sixfold, and 10 mg about 27-fold. Dose-related side effects began 10 min after drug and lasted up to 40 min. Thus the oral administration of lodoxamide ethyl was effective in preventing antigen-induced bronchoconstriction, and both the beneficial effects and side effects are dose related.