Effects of Ketotifen and Clemastine on Passive Transfer of Reaginic Reaction

Passive transfer (PK) tests were performed with a reaginic serum on a recipient reacting with an immediate and a more prolonged reaction when specificity challenged. Both reactions are thought to be mediated by IgE immunology. Ketotifen, a cycloheptathiophene derivative, and clemastine, given to the recipient in maximal clinical doses for 3 days, inhibited the immediate reaction. Ketotifen had a very slight effect also on the prolonged reaction. The results indicate that the in vivo effects of ketotifen in the human system are due not so much to mast cell inhibitory mechanisms, but more to post-release antihistaminic and some anti-inflammatory properties.