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Ketotifen: Full Drug Profile

Medically reviewed by Dr. Otari Nergadze, Neurosurgeon | Updated: January 2026

Ketotifen - General Information

A cycloheptathiophene blocker of histamine H1 receptors and release of inflammatory mediators. It has been proposed for the treatment of asthma, rhinitis, skin allergies, and anaphylaxis. [PubChem]

 

Pharmacology of Ketotifen

Ketotifen is a fast acting non-competitive histamine antagonist. It inhibits the release of mediators from mast cells. It is a non-bronchodilator antiasthmatic drug (when taken orally).

 

Ketotifen for patients

To prevent contaminating the dropper tip and solution, care should be taken not to touch the eyelids or surrounding areas with the dropper tip of the bottle. Keep the bottle tightly closed when not in use. Patients should be advised not to wear a contact lens if their eye is red. ZADITOR™ should not be used to treat contact lens related irritation. The preservative in ZADITOR™, benzalkonium chloride, may be absorbed by soft contact lenses. Patients who wear soft contact lenses and whose eyes are not red, should be instructed to wait at least ten minutes after instilling ZADITOR™ before they insert their contact lenses.

 

Ketotifen Interactions

No information provided.

 

Ketotifen Contraindications

ZADITORTM is contraindicated in persons with a known hypersensitivity to any component of this product.

 

Additional information about Ketotifen

Ketotifen Indication

Indicated as an add-on or prophylactic oral medication in the chronic treatment of mild atopic asthmatic children. Also for the temporary prevention of itching of the eye due to allergic conjunctivitis (ophthalmic).

Mechanism Of Action
Ketotifen is a relatively selective, non-competitive histamine antagonist (H1-receptor) and mast cell stabilizer. Ketotifen inhibits the release of mediators from mast cells involved in hypersensitivity reactions. Decreased chemotaxis and activation of eosinophils has also been demonstrated. Ketotifen also inhibits cAMP phosphodiesterase. Properties of ketotifen which may contribute to its antiallergic activity and its ability to affect the underlying pathology of asthma include inhibition of the development of airway hyper-reactivity associated with activation of platelets by PAF (Platelet Activating Factor), inhibition of PAF-induced accumulation of eosinophils and platelets in the airways, suppression of the priming of eosinophils by human recombinant cytokines and antagonism of bronchoconstriction due to leukotrienes. Ketotifen inhibits of the release of allergic mediators such as histamine, leukotrienes C4 and D4(SRS-A) and PAF.
Food Interactions
Take without regard to meals.
Generic Name
Ketotifen
Synonyms
Ketotifene [INN-French]; Ketotifeno [INN-Spanish]; Ketotifenum [INN-Latin]; Ketotifene fumarate; Ketotifen Fumarate
Drug Category
Anti-Allergic Agents; Antipruritics; Histamine H1 Antagonists
Drug Type
Small Molecule; Approved
Other Brand Names containing Ketotifen
Ketotifen; Zaditor;
Absorption
Following oral administration absorption is at least 60%
Toxicity (Overdose)
Adverse reactions include headaches, conjunctival injection and rhinitis.
Protein Binding
75%
Biotransformation
Primarily hepatic. The main metabolite found in both plasma and urine is the inactive ketotifen-N-glucuronide. Nor-ketotifen, the N-demethylated metabolite, and the 10-alpha-hydroxyl derivative are the only other metabolites detectable in human urine.
Half Life
21 hours (for elimination)
Dosage Forms of Ketotifen
Tablet Oral
Chemical Formula
C19H19NOS
Organisms Affected
Humans and other mammals