To determine the efficacy of ketotifen as an oral anti-asthmatic agent, experimental and therapeutic long-term trials were carried out. Four models were used in the experimental therapeutic trials and the antihislaminic agent clemastine and disodium cromoglycate were used as comparative substances. It was demonstrated that ketotifen provides protection against bronchospasm induced by allergens, histamine and exercise, but not against that induced by acetylcholine.
In the therapeutic long-term trials, the efficacy and tolerance of ketotifen were compared with that of clemastine and disodium cromoglycate for a period of 6 months. In another study ketotifen was administered for 1 year, Ketotifen proved very effective in decreasing the frequency and duration of asthmatic attacks, concomitant medication could be reduced and the patients improved subjectively. From these trials it can be concluded that ketotifen is a safe and effective oral anti-anaphylactic agent for use in the long-term treatment of bronchial asthma.