ALLERGENICITY AND TOLEROGENICITY OF AMLEXANOX IN THE GUINEA-PIG

Amlexanox (AMLX), an anti-allergic agent, is available in Japan as Eli cs(R) opthalmic solution, Solfa(R) nasal douche and Solfa(R) tablets. Cases of allergic contact dermatitis induced by Elics(R) ophthalmic so lution, which contains 0.25% AMLX, were reported within a year of its introduction. We therefore examined the contact sensitizing potency of AMLX. Guinea pigs sensitized to 0.25% AMLX exhibited a strong positiv e patch test reaction. Further, AMLX-sensitized animals developed rash es following oral and systemic challenge with AMLX. This animal model reflected the clinical experience of systemic contact dermatitis due t o AMLX. The non-responsiveness induced by oral administration of AMLX to AMLX-induced animals was transient, and clinical prophylaxis by des ensitization with oral AMLX may only increase the risk of systemic con tact dermatitis. On the other hand, there have been few reports of dru g eruption from oral Solfa(R) tablets in spite of their wide use. Ther efore, we also examined the induction of tolerance by oral administrat ion of AMLX. Oral administration of AMLX before sensitization resulted in complete non-responsiveness. It seems likely that a substantial re duction in the risk of AMLX sensitization by Elics(R) may be achieved by prior oral administration of Solfa(R) tablets containing AMLX.