Ketotifen is commonly found in over-the-counter allergy eye drops such as Alaway or Zaditor. In America, it is unavailable commercially as an oral therapy. Previously ketotifen has been used orally for treatment of asthma or to reduce the incidence of urticaria (hives). In the US, oral ketotifen preparations can be compounded in certified compounding pharmacies. Oral ketotifen was not withdrawn from the market for safety reasons.
Pronunciation: (kee-toe-TYE-fen)
Other Names: Zaditor, Alaway
Drug Class: Antihistamine, Mast Cell Stabilizer
Mechanism of Action: Ketotifen exhibits H1 receptor antagonizing effects and mast cell stabilization effects. Antagonizing histamine and stabilizing mast cells reduces inflammatory mediators both locally when used as an eye drop and systemically when taken orally.
Indications: As an ophthalmic preparation it is used for conjunctivitis and allergies. As an oral preparation it is used for urticaria (hives).
Drug Interactions: Do not take ketotifen with other antihistamines such as Benadryl (diphenhydramine) or Claritin (loratadine).
Consult a doctor or pharmacist before taking ketotifen with anticholinergic drugs. These are commonly found in maintenance inhalers such as Spiriva (tiotropium) or Atrovent (ipratropium).
Patients should talk to their doctor if they are taking oral diabetic agents such as glyburide and metformin because this may result in reversible thrombocytopenia.
Adverse Effects: Do not take ketotifen if you are allergic to it.
Oral ketotifen is normally well-tolerated and safe. The most common side effect is sedation, similar to other first-generation antihistamines. Other side effects may include dizziness, dry mouth, or headache.
Administration/Dosing: Usual adult dosing has been reported for oral formulations at 1 mg twice daily and 0.5 mg twice daily for pediatrics.
Special Populations:
Pregnancy – Consult your doctor or pharmacist before taking ketotifen orally if you are pregnant or plan to become pregnant.
Breastfeeding – Consult your doctor or pharmacist before taking ketotifen orally if you are breastfeeding.
Pediatric – See Administration/Dosing
References:
- Drugs.com [Internet]. Ketotifen information from Drugs.com; c1996-2018 [Updated: June 1 2018, Cited: 24 July 2018]. Available from www.drugs.com
- Sokol KC, Amar NK, Starkey J, Grant JA. Ketotifen in the management of chronic urticaria: resurrection of an old drug. Annals of allergy, asthma & immunology : official publication of the American College of Allergy, Asthma, & Immunology. 2013;111(6):433-436. doi:10.1016/j.anai.2013.10.003.
- Ketotifen. Lexi-Drugs. Lexicomp. Wolters Kluwer Health, Inc. Riverwoods, IL. Available at: http://online.lexi.com. Accessed July 24, 2018.
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