Ketof (Ketotifen)

• Ketotifen is indicated for allergic disorders that involve histamine‑mediated inflammation.
• Allergic rhinitis: reduces nasal congestion, itching and sneezing associated with seasonal or perennial allergies.
• Allergic conjunctivitis: alleviates eye itching, redness and watery discharge caused by allergens.
• Prophylaxis of asthma symptoms: helps prevent exercise‑induced or allergen‑triggered bronchospasm in susceptible individuals.

• Ketotifen exerts its therapeutic effect by competitively blocking H1 histamine receptors on target cells, preventing histamine‑induced vasodilation and increased vascular permeability. In addition, it stabilises mast cells, inhibiting the release of inflammatory mediators such as leukotrienes, prostaglandins and cytokines. This dual action reduces both immediate and late‑phase allergic responses, contributing to symptom control. The drug’s high affinity for the H1 subtype ensures prolonged receptor occupancy, while mast‑cell stabilization occurs through inhibition of calcium influx, further dampening degranulation.

Ketotifen may cause a range of adverse reactions, which are generally classified by frequency and severity.

Common Side Effects

• Drowsiness: mild to moderate sedation, especially after the first doses.
• Dry mouth: reduced salivary flow causing a feeling of thirst.
• Headache: transient tension‑type headache.
• Nausea: occasional upset stomach.
• Weight gain: modest increase in body weight with prolonged use.

Serious or Rare Side Effects

• Hepatotoxicity: signs of liver injury such as jaundice or elevated enzymes.
• Severe allergic reaction: anaphylaxis or angioedema requiring immediate medical attention.
• Cardiac arrhythmia: rare reports of palpitations or irregular heartbeat.

When prescribing or dispensing Ketof, several precautionary measures should be observed to ensure patient safety.

• Assess patient history: evaluate for prior hypersensitivity to ketotifen or other antihistamines.
• Monitor sedation: advise patients about possible drowsiness and avoid operating machinery until tolerance is known.
• Caution in hepatic impairment: consider dose adjustment or close monitoring of liver function.
• Use during pregnancy: only if clearly needed, as safety data are limited.
• Use in lactation: weigh benefits against potential exposure to the infant through breast milk.
• Store at room temperature: keep below 25 °C, in the original container, protected from moisture and direct sunlight.

Ketotifen can interact with other medicines, altering its efficacy or safety profile.

Major Interactions (Avoid)

• Other antihistamines: additive sedation and anticholinergic effects.
• CNS depressants (e.g., benzodiazepines, opioids): increased risk of profound drowsiness.
• CYP3A4 inhibitors (e.g., ketoconazole, erythromycin): may raise ketotifen plasma concentrations.

Moderate Interactions (Monitor Closely)

• Alcohol: can potentiate sedative effects.
• Anticholinergic agents (e.g., atropine, ipratropium): may exacerbate dry mouth.
• Theophylline: possible alteration of bronchodilator response.