Prophylaxis of asthma with ketotifen in children and adolescents: a review.

The therapeutic efficacy of ketotifen in the prophylactic treatment of asthmatic children and adolescents is reviewed, based on the results from 4 double-blind placebo-controlled trials involving 194 patients, 2 double-blind clemastine-controlled trials involving 86 patients, and 5 double-blind double-dummy comparative studies with disodium cromoglycate involving 136 patients. In long-term administration, oral ketotifen enabled the consumption of corticosteroids and bronchodilators to be reduced while improving the clinical symptomatology and maintaining respiratory function. Optimal results were obtained after 8 to 12 weeks. Tolerance did not develop and there was no rebound effect when treatment was interrupted. Comparative studies with clemastine, a specific H1-blocking agent, have shown that the antihistaminic properties of ketotifen are not responsible for its prophylactic action in bronchial asthma. It has been further established that a double dose, in mg/kg body weight calculated on the basis of the dose used in adults, or that the adult dose may be required in children in order to obtain optimal results. These clinical observations are in agreement with pharmacokinetic findings in children, suggesting a more rapid metabolism without alteration in the pattern of biotransformation. Comparative trials between ketotifen and disodium cromoglycate have demonstrated comparable efficacy, although this does not mean that the responder pattern is identical for the two drugs. Long-term treatment with oral ketotifen was as well tolerated in children as it was in adults. The major adverse effect was transient sedation occurring in 6% of the children at the beginning of treatment.