<p>Ketotifen is a potent anti-allergic substance possessing a powerful and sustained non-competitive histamine (H1) receptor blocking property. Ketotifen inhibits the release of mediators (e.g histamine, leukotrienes and prostaglandins) from cells responsible for type-(I) allergic reactions. Ketotifen also stabilizes mast cells, decreases chemotaxis, activation of degranulation of eosinophils.</p>