Ketotifen has anti-allergic properties and has been used similarly, to sodium chromoglycate in the prophylactic treatment of asthma. It also has the properties of an antihistamine. Ketotifen possesses marked anti-anaphylactic properties and is effective in preventing an asthmatic attacks. Ketotifen exerts as sustained inhibitory effect on histamine reactions, which can be clearly dissociated from its anti-anaphylactic properties. Experimental investigations in asthmatic subjects have shown that Ketotifen is as effective orally as a selective mast cell stabilizer administered by inhalation. Antihistamines were ineffective in those tests. The effectiveness of Ketotifen has been studied in long-term clinical trials. Asthma attacks were reduced in number, severity and duration and in some cases, the patients were completely freed from attacks. Progressive reduction of corticosteroids and/or bronchodilators was also possible. The prophylactic activity of Ketotifen may take several weeks to become fully established. Ketotifen will not abort established attacks of asthma.
Ketotifen may potentiate the effects of sedatives, hypnotics, antihistamines and alcohols. A reversible fall in the platelet count has been observed in a few patients receiving Tifen concomitantly with oral antidiabetic agents and it has been suggested that this combination should therefore be avoided.
A reversible fall in the platelet count has been observed in a few patients receiving Ketotifen concomitantly with oral antidiabetic agent and it has been suggested that this combination should therefore be avoided. Although there is no evidence of any teratogenic effect, recommendations for Ketotifen in pregnancy or when breast feeding can not be given.
Drowsiness and in isolated cases, dry mouth and slight dizziness may occur at the beginning of treatment but usually disappear spontaneously after a few days.
Although there is no evidence of any teratogenic effect, Ketotifen in pregnancy and lactation is not recommended.
It is important to continue the previous treatment for a minimum of two weeks after starting Ketotifen to avoid the possibility of exacerbation of asthma. This applies specially to systemic corticosteroids and ACTH because of the possible existence of adrenocortical insufficiency in steroid dependent patient. If inter current infection occurs, Ketotifen treatment must be supplemented by specific antimicrobial therapy. During the first day of treatment with Ketotifen, reactions may be impaired and patients should be warned not to take charge of vehicle or machinery until the effect of Ketotifen treatment on the individual is known. Patients should be advised to avoid alcoholic drinks. Ketotifen may potentiate the effects of sedatives, hypnotics, antihistamines and alcohol.
The reported features of overdosage include confusion, drowsiness, headache, bradycardia, respiratory depression etc. should be watched for. Elimination of the drug with gastric lavage or emessis is recommended. Otherwise, general supportive treatment is all that is required shall be instituted.
