Ketotifen Laropharm (Ketotifen Hydrogen Fumarate)

Ketotifen is an antihistamine and mast cell stabilizer used in the management of allergic and asthmatic conditions.

• Allergic rhinitis: reduces nasal congestion, itching and sneezing by blocking histamine release.
• Allergic conjunctivitis: alleviates eye itching, redness and tearing through mast cell stabilization.
• Asthma prophylaxis: helps prevent asthma attacks by decreasing airway inflammation and hyper‑responsiveness.

• Ketotifen exerts its effect by selectively antagonizing H1 histamine receptors, preventing histamine‑mediated symptoms, while simultaneously inhibiting mast cell degranulation. This dual action reduces the release of inflammatory mediators such as leukotrienes and prostaglandins, leading to decreased vascular permeability, bronchoconstriction and tissue edema associated with allergic reactions and asthma. The drug’s long half‑life supports once‑daily dosing in many patients, maintaining stable plasma concentrations.

Ketotifen may cause a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Drowsiness: feeling of sleepiness or reduced alertness.
• Dry mouth: decreased salivation leading to oral dryness.
• Headache: mild to moderate head pain.
• Fatigue: general lack of energy.
• Nausea: upset stomach or feeling of vomiting.
• Weight gain: increase in body weight with prolonged use.

Serious or Rare Side Effects

• Stevens‑Johnson syndrome: severe skin reaction with blistering and mucosal involvement.
• Hepatotoxicity: elevated liver enzymes or liver injury.
• Blood dyscrasias: rare cases of neutropenia or agranulocytosis.
• Anaphylaxis: sudden severe allergic reaction with airway compromise.
• Cardiac arrhythmia: irregular heart rhythm potentially leading to palpitations.

When prescribing or dispensing Ketotifen, consider the following precautions:

• Driving and operating machinery: avoid if drowsiness occurs.
• Hepatic impairment: use with caution; monitor liver function.
• Concomitant CNS depressants: may enhance sedative effects.
• Known hypersensitivity: discontinue if allergic reaction develops.
• Pregnancy and lactation: safety not established; weigh risks and benefits.
• Store at room temperature: keep in the original pack, protect from moisture and heat.

Ketotifen can interact with several drug classes, requiring attention to avoid adverse effects.

Major Interactions (Avoid)

• CNS depressants (e.g., benzodiazepines, barbiturates): additive sedation.
• Other antihistamines: increased risk of drowsiness.
• Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole): may raise ketotifen plasma levels.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., rifampicin, carbamazepine): may reduce effectiveness.
• Alcohol: can enhance sedative effect.
• Anticholinergic agents: may worsen dry mouth.
• Other mast cell stabilizers: potential additive therapeutic effect, monitor response.