Ketotifen: Indication, Dosage, Side Effect, Precaution

Generic Medicine Info Patient Medicine Information

This information is not country-specific. Please refer to the Singapore prescribing information.

Generic Medicine Info

Indications and Dosage

Ophthalmic
Allergic conjunctivitis

Adult: As 0.025% solution or 0.25 mg/mL solution: Instil 1 drop into the conjunctival sac of the affected eye(s) bid.
Child: As 0.025% solution or 0.25 mg/mL solution: ≥3 years Same as adult dose.

Oral
Allergic conjunctivitis, Allergic rhinitis

Adult: 1 mg bid; increase to 2 mg bid if needed. Alternatively, give 0.5-1 mg at night for the 1st few days of treatment to minimise drowsiness.
Child: ≥3 years 1 mg bid.

Administration

Should be taken with food.

Contraindications

Concomitant use with oral antidiabetic agents (oral).

Special Precautions

Patient with a history of epilepsy (oral). Children. Pregnancy and lactation.

Adverse Reactions

Significant: Rarely, seizures (oral).
Eye disorders: Eye irritation or pain, punctate keratitis, punctate corneal epithelial erosion (ophthalmic).
Gastrointestinal disorders: Dry mouth.
Nervous system disorders: Dizziness, sedation.
Psychiatric disorders: Excitation, insomnia, irritability, nervousness.

Pregnancy Category (US FDA)

Ophth/PO: C

Patient Counseling Information

This drug may cause dizziness or drowsiness, if affected, do not drive or operate machinery. Remove contact lenses before administration of ophthalmic solution and reinsert them after 15 minutes.

Overdosage

Oral: Symptoms: Headache, drowsiness, confusion, disorientation, nystagmus, dyspnoea, bradycardia, tachycardia, hypotension, hyperexcitability, convulsions and coma. Management: Symptomatic treatment. Administer activated charcoal if ingestion is within approx 1 hour. May give short-acting barbiturates or benzodiazepines for excitation. Monitor CV function.

Drug Interactions

Increased risk for thrombocytopenia with oral antidiabetic agents. May potentiate the effects of sedatives, hypnotics and other antihistamines.

Food Interaction

May potentiate the effect of alcohol.

Action

Description:
Mechanism of Action: Ketotifen is a selective histamine H₁-receptor antagonist and mast cell stabiliser. It exhibits anti-inflammatory and antihistaminergic effects by inhibiting the release of mediators from cells involved in hypersensitivity reactions and reduces the chemotaxis and activation of eosinophils.
Pharmacokinetics:
Absorption: Rapidly and almost completely absorbed from the gastrointestinal tract (oral). Bioavailability: Approx 50% (oral). Time to peak plasma concentration: 2-4 hours (oral).
Distribution: Enters breast milk (oral). Plasma protein binding: Approx 75% (oral).
Metabolism: Metabolised in the liver via N-demethylation into nor-ketotifen (active metabolite); via N-glucuronidation into ketotifen-N-glucuronide (inactive metabolite); via keto-reduction into hydroxyl derivative.
Excretion: Oral: Mainly via urine (>60% as metabolites; 1% as unchanged drug). Terminal elimination half-life: Approx 21 hours.

Chemical Structure

Storage

Store below 25°C.

MIMS Class

Antihistamines & Antiallergics / Ophthalmic Decongestants, Anesthetics, Anti-Inflammatories

ATC Classification

R06AX17 - ketotifen ; Belongs to the class of other antihistamines for systemic use.
S01GX08 - ketotifen ; Belongs to the class of other ophthalmologic antiallergics.

References

Alaway Preservative Free Solution/Drops (Bausch & Lomb Incorporated). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 29/02/2024.

Alaway Solution/Drops (Bausch & Lomb Incorporated). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 29/02/2024.

Anon. Ketotifen (Ophthalmic). Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 29/02/2024.

Anon. Ketotifen (Systemic). Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 29/02/2024.

Anon. Ketotifen. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 29/02/2024.

Buckingham R (ed). Ketotifen Fumarate. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 29/02/2024.

Joint Formulary Committee. Ketotifen. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 29/02/2024.

Ketofall 0.25 mg/mL Eye Drops, Solution in Single-dose Container (Pharma Stulln GmbH). MHRA. https://products.mhra.gov.uk. Accessed 29/02/2024.

Novartis New Zealand Limited. Zaditen Eye Drops, Solution data sheet 11 August 2020. Medsafe. http://www.medsafe.govt.nz. Accessed 29/02/2024.

U-Kefen Tablets 1 mg; U-Kefen Syrup 1 mg/5 mL (Malaysian Pharmaceutical Industries Sdn. Bhd.). National PharmFaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my. Accessed 29/02/2024.

Zaditen 0.25 mg/mL, Eye Drops, Solution (Laboratoires Thea). MHRA. https://products.mhra.gov.uk. Accessed 29/02/2024.

Zaditen Elixir 1 mg/5 mL (Alfasigma S.p.A.). MHRA. https://products.mhra.gov.uk. Accessed 29/02/2024.

Zaditen Tablets 1 mg (Alfasigma S.p.A.). MHRA. https://products.mhra.gov.uk. Accessed 29/02/2024.

Disclaimer: This information is independently developed by MIMS based on Ketotifen from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2024 MIMS. All rights reserved. Powered by MIMS.com