Ketotifen

Ketotifen

Clinical data
Trade names	Zaditor
AHFS/Drugs.com	Micromedex Detailed Consumer Information
MedlinePlus	a604033
Pregnancy category	US: C (Risk not ruled out)
Routes of administration	Oral (tablets), ophthalmic solution
ATC code	R06AX17 (WHO) S01GX08 (WHO)
Legal status
Legal status	US: Oral — withdrawn, was ℞-only; Eye drops — over-the-counter
Pharmacokinetic data
Bioavailability	60%
Protein binding	75%
Metabolism	Hepatic
Biological half-life	12 hours
Identifiers
IUPAC name 4-(1-Methylpiperidin-4-ylidene)-4,9-dihydro-10H-benzo[4,5]cyclohepta[1,2-b]thiophen-10-one
CAS Number	34580-14-8 Y
PubChem CID	3827
IUPHAR/BPS	7206
DrugBank	DB00920 Y
ChemSpider	3695 Y
UNII	HBD503WORO
KEGG	D01332 Y
ChEMBL	CHEMBL534 Y
ECHA InfoCard	100.047.349
Chemical and physical data
Formula	C19H19NOS
Molar mass	309.426 g/mol
3D model (Jmol)	Interactive image
SMILES O=C3c1sccc1C(\c2c(cccc2)C3)=C4/CCN(C)CC4
InChI InChI=1S/C19H19NOS/c1-20-9-6-13(7-10-20)18-15-5-3-2-4-14(15)12-17(21)19-16(18)8-11-22-19/h2-5,8,11H,6-7,9-10,12H2,1H3 Y Key:ZCVMWBYGMWKGHF-UHFFFAOYSA-N Y

Ketotifen is a first-generation noncompetitive H₁-antihistamine and mast cell stabilizer. It is most commonly sold as a salt with fumaric acid, ketotifen fumarate, and is available in two forms. In its ophthalmic form, it is used to treat allergic conjunctivitis. In its oral form, it is used to prevent asthma attacks or Anaphylaxis, as well as various mast cell, allergic-type disorders.

Ketotifen relieves and prevents eye itchiness and/or irritation associated with most seasonal allergies. It starts working within minutes after administering the drops. The drug has not been studied in children under three. The mean elimination half life is 12 hours. Besides its anti-histaminic activity, it is also a functional leukotriene antagonist and a phosphodiesterase inhibitor.

"[O]ral ketotifen has been used in patients with asthma, allergic rhinitis, allergic conjunctivitis, atopic dermatitis, chronic urticaria, cold-induced urticaria, cholinergic urticaria, exercise-induced urticaria, [systemic mast cell disease including mastocytosis, MCAS, allergic and nonallergic anaphylaxis, angioedema], and food allergy in Canada, Europe, and Mexico." Now available via prescription at US compounding pharmacies: "For adults and older children with asthma or allergic disease, the recommended dose of ketotifen is 1 mg twice daily." "FDA staff did recommend more extensive evaluations for management of urticaria."

The drug may also help relieve the symptoms of irritable bowel syndrome.

Side effects include drowsiness, weight gain, dry mouth, irritability, and increased nosebleeds.

Ketotifen is marketed under many brand names worldwide.