Effects of certain antiallergic drugs on experimental conjunctivitis in guinea pigs.

Effects of certain antiallergic drugs on experimental conjunctivitis were studied with guinea pigs. Chlorpheniramine, ketotifen and levocabastine were effective in inhibiting histamine- and antigen-induced conjunctivitis in guinea pigs. By contrast, amlexanox was only effective in inhibiting antigen-induced conjunctivitis. Topical application of antigen released 46.5 +/- 3.8% of histamine from the conjunctiva in sensitized guinea pigs. Both levocabastine and amlexanox were effective in inhibiting conjunctival histamine release induced by antigen application. Lacrimal histamine contents were also increased after challenge. The increase in the histamine content of tears was inhibited by pretreatment with levocabastine and amlexanox, but no significant effect was observed with chlorpheniramine and ketotifen. From these findings, it is concluded that certain antiallergic drugs, but not amlexanox, exhibited potent inhibition on experimental conjunctivitis in guinea pigs. In addition, it has been established that measurement of histamine in the conjunctiva and tears as well as observation of conjunctivitis syndromes are useful for evaluating the effectiveness of antiallergic drugs on various kinds of allergic conjunctivitis in clinical situations.