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Indications and Dosage
Ophthalmic
Allergic conjunctivitis Adult: As 0.025% soln: Instill 1 drop in the conjunctival sac of the affected eye(s) bid. Child: ≥3 yr Same as adult dose. Oral Allergic rhinitis Adult: 1 mg bid, increased up to 2 mg bid if needed. Alternatively, 0.5-1 mg at night for the 1st few days of treatment to minimise drowsiness.
Child: ≥3 yr Same as adult dose. |
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Administration
Should be taken with food.
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Contraindications
Concomitant use w/ antidiabetic agents.
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Special Precautions
Patient w/ history of epilepsy. Childn. Pregnancy and lactation.
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Adverse Reactions
Nervous: Drowsiness, dizziness, sedation, somnolence CNS stimulation (e.g. excitation, irritability, insomnia, nervousness), headache, flu-like symptoms.
GI: Dry mouth. Resp: Pharyngitis, rhinitis. Genitourinary: Cystitis. Endocrine: Wt gain. Ophthalmologic: Transient stinging, eye irritation, punctuate keratitis, corneal erosion, blurred vision, dry eye, burning sensation, conjunctivitis, circumocular rash, eye pain, mydriasis, photophobia, eye discharge, eyelid disease, eye pruritus, xerophthalmia, disease of lacrimal apparatus, conjunctival inj. Dermatologic: Rash, eczema, urticaria. |
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Ophth/PO: C
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Patient Counseling Information
This drug may cause drowsiness, somnolence and blurred vision, if affected, do not drive or operate machinery. Remove contact lenses prior to ophth admin and reinsert after 10-15 min.
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Overdosage
Symptoms: Drowsiness, confusion, nystagmus, dyspnoea, bradycardia or tachycardia, disorientation, headache, hypotension, reversible coma; hyperexcitability or convulsions (childn). Management: Symptomatic and supportive treatment. Perform gastric lavage immediately following ingestion. Admin of activated charcoal w/in approx 1 hr following ingestion. Monitor CV function. May give short acting barbiturates or benzodiazepines in case of excitation.
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Drug Interactions
May potentiate effects of sedatives, hypnotics and antihistamines.
Potentially Fatal: Reduced platelet count with oral antidiabetics. |
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Food Interaction
May potentiate effects of alcohol.
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Action
Description: Ketotifen is a histamine H1-receptor antagonist and a mast cell stabilizer. It is used in allergic conjunctivitis by interfering w/ chemokine-induced migration of eosinophils into inflamed conjunctiva.
Onset: W/in min (ophth). Pharmacokinetics: Absorption: Completely absorbed from the GI tract (oral). Minimally absorbed (ophth). Bioavailablity: Approx 50%. Time to peak plasma concentration: 2-4 hr. Distribution: Plasma protein binding: 75%. Enters breast milk. Metabolism: Undergoes hepatic first-pass metabolism; converted to inactive ketotifen-N-glucuronide metabolite. Excretion: Mainly via urine (60-70% as metabolites, 1% as unchanged drug). Elimination half-life: Biphasic: 3-5 hr (initial); approx 21 hr (terminal). |
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Chemical Structure
 Source: National Center for Biotechnology Information. PubChem Database. Ketotifen, CID=3827, https://pubchem.ncbi.nlm.nih.gov/compound/Ketotifen (accessed on Jan. 21, 2020) |
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Storage
Store below 25°C.
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ATC Classification
R06AX17 - ketotifen ; Belongs to the class of other antihistamines for systemic use.
S01GX08 - ketotifen ; Belongs to the class of other ophthalmologic antiallergics. |
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References
Alaway Soln/Drops (Bausch & Lomb Incorporated). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 04/07/2017. Alcon Laboratories Australia Pty Ltd. Zaditen 0.25 mg/ml Eye Drops Solution data sheet 15 April 2016. Medsafe. http://www.medsafe.govt.nz/. Accessed 04/07/2017. Anon. Ketotifen (Ophthalmic). Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 04/07/2017. Buckingham R (ed). Ketotifen Fumarate. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 04/07/2017. Joint Formulary Committee. Ketotifen. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 04/07/2017. McEvoy GK, Snow EK, Miller J et al (eds). Ketotifen Fumarate (EENT). AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 04/07/2017. Zaditen 0.25 mg/ml Eye Drops Solution (Laboratories Thea). MHRA. https://products.mhra.gov.uk/. Accessed 04/07/2017. Zaditen Elixir 1 mg/5mL (Alphasigma SpA). MHRA. https://products.mhra.gov.uk/. Accessed 04/07/2017. Zaditen Tablets 1 mg (Alphasigma SpA). MHRA. https://products.mhra.gov.uk/. Accessed 04/07/2017.
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