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Ketotifen structure.svg
Systematic (IUPAC) name
Clinical data
AHFS/ Micromedex Detailed Consumer Information
MedlinePlus a604033
Pregnancy cat. C (US)
Legal status OTC (US) Oral - Prescription, Eye Drops - OTC
Routes Oral, Eye Drops
Pharmacokinetic data
Bioavailability 60%
Protein binding 75%
Metabolism Hepatic
Half-life 12 Hours
CAS number 34580-14-8 YesY
ATC code R06AX17 S01GX08
PubChem CID 3827
DrugBank DB00920
ChemSpider 3695 YesY
KEGG D01332 YesY
Chemical data
Formula C19H19NOS 
Mol. mass 309.426 g/mol
 YesY (what is this?)  (verify)

Ketotifen is a second-generation noncompetitive H1-antihistamine and mast cell stabilizer. It is most commonly sold as a salt of fumaric acid, ketotifen fumarate, and is available in two forms. In its ophthalmic form, it is used to treat allergic conjunctivitis,[1] or the itchy red eyes caused by allergies. In its oral form, it is used to prevent asthma attacks. Side effects include drowsiness, weight gain, dry mouth, irritability, and increased nosebleeds.

The drug is marketed as ophthalmic solutions under the brand names Zaditor/Zaditen (Novartis),[2] Alaway (Bausch and Lomb), Zyrtec Itchy-Eye Drops, and Claritin Eye. A generic version of Novartis' Zaditor, ketotifen fumarate ophthalmic solution, 0.025%, is available from Perrigo[clarification needed] and distributed as store brands,[citation needed] such as Eye Itch Relief from Walgreens.

General information[edit]

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.[1] The mean elimination half life is 12 hours.[3] Besides its anti-histaminic activity, it is also a functional leukotriene antagonist and a phosphodiesterase inhibitor. The drug may also help relieve the symptoms of Irritable bowel syndrome.[4]

See also[edit]


  1. ^ a b Zaditor prescribing information Novartis
  2. ^ Novartis Pharmaceuticals, Alphabetically, beginning with Z.
  3. ^ Grahnén A; Lönnebo A, Beck O, Eckernäs SA, Dahlström B, Lindström B (May 1992). "Pharmacokinetics of ketotifen after oral administration to healthy male subjects". Biopharm Drug Dispos 13 (4): 255–262. doi:10.1002/bdd.2510130404. PMID 1600111. 
  4. ^ Klooker, TK; Braak, B; Koopman, KE; Welting, O; Wouters, MM; Van Der Heide, S; Schemann, M; Bischoff, SC et al. (2010). "The mast cell stabiliser ketotifen decreases visceral hypersensitivity and improves intestinal symptoms in patients with irritable bowel syndrome". Gut 59 (9): 1213–21. doi:10.1136/gut.2010.213108. PMID 20650926. 

External links[edit]