Effect of inhaled iodoxamide tromethamine in prevention of antigen-induced bronchospasm.

Lodoxamide tromethamine, a new cromolyn-like drug, was studied to determine its effectiveness and duration of action in preventing antigen-induced bronchospasm in 15 subjects with clinically stable extrinsic asthma. All subjects underwent antigen inhalation challenge 15 min after inhalation of an aerosolized solution of 0.1 mg of lodoxamide in saline or of saline solution alone (placebo) administered on separate days according to a double-blind, random-allocation protocol. Those subjects demonstrating a protective effect of lodoxamide subsequently underwent antigen inhalation challenges at various time intervals (2 to 8 hr) after lodoxamide treatment. Thirteen of 15 subjects (87%) showed a protective effect of lodoxamide administered 15 min prior to antigen challenge. Six of the 13 subjects who were protected initially remained protected 4 hr after lodoxamide treatment and one of these six subjects was also protected at 6 to 8 hr. One additional subject not protected at 4 hr was protected at 3 hr. Lodoxamide exhibited no bronchodilator activity and was not associated with any significant side effects. Further studies are warranted to compare the effectiveness of lodoxamide with that of cromolyn sodium in protection against antigen-induced bronchospasm and to evaluate the relative efficacy and safety of lodoxamide in long-term clinical trials.