Ketotifen

Ketotifen is a second-generation antihistamine and mast cell stabilizer, widely recognized in clinical practice for its dual mechanism of action in managing allergic conditions. Unlike conventional antihistamines that primarily block histamine receptors, ketotifen inhibits the release of inflammatory mediators from mast cells, providing a prophylactic and therapeutic approach to allergic inflammation. It is indicated for both allergic conjunctivitis and asthma prophylaxis, offering sustained control with a favorable safety profile. Available in oral and ophthalmic formulations, it serves as a cornerstone in long-term allergic management strategies.

Features

• Active ingredient: Ketotifen fumarate
• Available as oral tablets/syrup and ophthalmic solution
• Dual-action: mast cell stabilizer and H1-antihistamine
• Onset of action: within several hours; full prophylactic effect may take up to 4–12 weeks
• Half-life: approximately 21 hours
• Excretion: primarily renal

Benefits

• Provides long-term control of allergic symptoms by preventing mast cell degranulation
• Reduces ocular itching, redness, and watering in allergic conjunctivitis
• Decreases frequency and severity of asthma exacerbations in mild allergic asthma
• Minimizes reliance on rescue medications like short-acting bronchodilators
• Suitable for pediatric and adult populations (with age-specific formulations)
• Non-sedating at recommended doses for most patients

Common use

Ketotifen is primarily prescribed for the prevention and treatment of allergic conditions. Its most common applications include management of allergic conjunctivitis (via ophthalmic solution) and prophylaxis of mild allergic asthma (oral form). It is also used off-label in certain dermatological conditions like chronic urticaria and mast cell activation syndromes. In pediatric populations, it is often selected for its safety record and syrup formulation convenience.

Dosage and direction

Oral administration (asthma prophylaxis):

• Adults and children over 3 years: 1 mg twice daily, with or without food.
• Dosage may be adjusted based on response and tolerability.

Ophthalmic use (allergic conjunctivitis):

• Instill one drop into the affected eye(s) twice daily, approximately 8–12 hours apart.
• Wait at least 10 minutes before inserting contact lenses.

Always use as directed by a healthcare provider. Do not discontinue abruptly without medical advice.

Precautions

• Use with caution in patients with renal impairment; dose adjustment may be necessary.
• May cause drowsiness, especially during initial therapy; avoid driving or operating machinery until response is known.
• Not recommended during pregnancy unless potential benefit justifies potential risk (Category C).
• Exercise caution in elderly patients due to potential increased sensitivity to side effects.
• Ophthalmic solution should not be used if wearing soft contact lenses; remove before application.

Contraindications

• Hypersensitivity to ketotifen or any component of the formulation.
• Acute asthmatic attack (not a rescue medication).
• Neonates and infants under 3 years of age (for oral form).
• Active ocular infection (for ophthalmic form).

Possible side effect

Common:

• Drowsiness
• Dry mouth
• Weight gain
• Rhinitis
• Mild headache

Less common:

• Dizziness
• Nausea
• Irritability (especially in children)
• Ophthalmic: burning/stinging upon instillation

Rare:

• Thrombocytopenia
• Seizures
• Hepatitis
• Anaphylaxis (very rare)

Drug interaction

• Enhanced sedative effects with CNS depressants (e.g., benzodiazepines, opioids, alcohol).
• Potential interaction with MAO inhibitors; avoid concurrent use.
• Ketotifen may potentiate effects of anticholinergic drugs.
• No significant interaction with theophylline reported, but monitor closely when used together.

Missed dose

If a dose is missed, take it as soon as remembered. If it is near the time of the next dose, skip the missed dose and resume the regular schedule. Do not double the dose.

Overdose

Symptoms may include severe drowsiness, disorientation, tachycardia, and hypotension. Management is supportive; there is no specific antidote. Gastric lavage and activated charcoal may be considered if ingestion was recent. Seek immediate medical attention.

Storage

Store at room temperature (15–30°C). Protect from light and moisture. Keep out of reach of children. Do not freeze. Discard ophthalmic solution 28 days after opening.

Disclaimer

This information is for educational purposes and does not replace professional medical advice. Always consult a healthcare provider for diagnosis, treatment decisions, and personalized recommendations. Do not initiate or discontinue medication without medical supervision.

Reviews

“Ketotifen has been transformative for my pediatric patients with allergic asthma—it’s effective and well-tolerated.” — Dr. Elena Rostova, Allergist
“As an ophthalmologist, I find ketotifen solution provides reliable relief for seasonal allergic conjunctivitis with minimal side effects.” — Dr. Mark Higgins
“Long-term use in chronic urticaria has shown consistent reduction in symptom frequency for my patients.” — Dr. Sofia Ivanova, Dermatologist