Ketotifen is a histamine H1 receptor blocker and mast cell stabilizer used to treat mild atopic asthma and allergic conjunctivitis. Ketotifen is a benzocycloheptathiophene derivative with potent antihistaminic and mast cell stabilizing properties.
- Mechanism
- Curator reviewed · 3 references
The precise mechanism(s) through which ketotifen exerts its therapeutic effects are unclear. Ketotifen is a potent and non-competitive antagonist of H1 histamine receptors, which is likely to be a significant contributor to its anti-allergic activity. In addition, ketotifen stabilizes mast cells and has demonstrated in vitro the ability to inhibit the release of allergic and inflammatory mediators such as histamine, leukotrienes C4 and D4 (i.e. SRS-A), and platelet-activating factor (PAF).
Other in vivo observations thought to contribute to ketotifen's efficacy in asthma include the inhibition of various PAF-mediated processes (e.g. airway hyperreactivity, eosinophil and platelet accumulation in the airways), prevention of leukotriene-induced bronchoconstriction, and suppression of eosinophil priming.
- Primary indication
- Administered orally, ketotifen is indicated as an add-on medication in the chronic treatment of mild atopic asthma in children.Curator reviewed · 5 structured indications
- Formula / weight
- C19H19NOS · 309.425 g/mol (avg)
- First approval
- Canada, 1997 · United States, 1995
- Brand names
Resolves to
ZCVMWBYGMWKGHF-UHFFFAOYSA-NSMILESCN1CCC(CC1)=C1C2=C(SC=C2)C(=O)CC2=CC=CC=C12What you can answer from here — as of September 23, 2026
Which drugs share a target with Ketotifen, and which of those have an active Phase 3 trial?
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