“…Ketotifen is a benzocycloheptathiophene derivative which is a potent antihistamine in vivo (Craps et al, 1978;Esau et al, 1984) and has been shown to act as a mast cell stabilizer in vitro (Martin & Romer, 1977). Several studies have demonstrated inhibition by ketotifen ofhistamineinduced (Craps et al, 1978) and allergen-induced (Craps et al, 1978;Palmen, 1983) bronchoconstriction, but reports of its efficacy in exerciseinduced asthma (EIA) are conflicting (Craps et al, 1978;Dorward & Patel, 1982;Petheram et al, 1981;Kennedy etal., 1980;Lilja etal., 1983). Most of these studies were performed after 3 weeks or less of treatment with ketotifen and it has been suggested that the maximum effect may not be achieved until 5 weeks after treatment has been commenced (Gobel, 1978).…”