Kestine 20 (Ebastine)

Ebastine acts on histamine‑mediated allergic pathways, providing relief in several common allergic conditions.

• Allergic rhinitis: reduces nasal congestion, sneezing and itching associated with seasonal or perennial triggers.
• Chronic idiopathic urticaria: alleviates hives and itching by stabilizing mast cell response.
• Allergic skin symptoms: diminishes itching and swelling caused by histamine release in various dermatologic allergic reactions.

• Ebastine selectively blocks peripheral H1 histamine receptors without readily crossing the blood‑brain barrier. By antagonizing H1 receptors on mast cells, endothelial cells and sensory nerves, it prevents histamine‑induced vasodilation, increased vascular permeability, and nerve stimulation, thereby reducing symptoms such as itching, swelling, and nasal congestion associated with allergic reactions. The drug exhibits high affinity for the H1 receptor and a long plasma half‑life, allowing once‑daily dosing while minimizing central nervous system effects.

Ebastine is generally well tolerated, but some patients may experience adverse reactions.

Common Side Effects

• Headache: mild to moderate intensity.
• Dry mouth: transient sensation of oral dryness.
• Drowsiness: occasional mild sedation, less frequent than with first‑generation antihistamines.
• Nausea: mild gastrointestinal upset.
• Fatigue: feeling of reduced energy.
• Dizziness: occasional light‑headedness.

Serious or Rare Side Effects

• Angioedema: swelling of face, lips or throat requiring immediate medical attention.
• Severe skin reactions: such as Stevens‑Johnson syndrome or toxic epidermal necrolysis.
• Cardiac arrhythmias: rare QT interval prolongation leading to rhythm disturbances.
• Anaphylaxis: acute, life‑threatening allergic reaction.
• Hepatic dysfunction: elevated liver enzymes indicating possible liver injury.
• Hematologic abnormalities: rare cases of blood cell count changes.

When prescribing ebastine, several safety considerations should be observed.

• Pregnancy: use only if the potential benefit justifies the potential risk; consult a healthcare professional.
• Breastfeeding: weigh benefits against possible effects on the infant; monitor infant for adverse reactions.
• Elderly patients: monitor for increased sedation or dizziness due to age‑related pharmacokinetic changes.
• Renal or hepatic impairment: consider dose adjustment or increased monitoring in patients with reduced organ function.
• Concomitant medications: review for potential interactions, especially with CYP3A4 inhibitors.
• Store at ambient temperature: keep tablets below 25 °C in the original packaging, protected from moisture.

Ebastine may interact with other medicines, altering its efficacy or safety profile.

Major Interactions (Avoid)

• Ketoconazole: strong CYP3A4 inhibition can raise ebastine plasma levels, increasing risk of side effects.
• Ritonavir: potent CYP3A4 inhibitor may lead to excessive ebastine exposure.
• Erythromycin: CYP3A4 inhibition may elevate ebastine concentrations.

Moderate Interactions (Monitor Closely)

• First‑generation antihistamines: additive sedation when combined with ebastine.
• Alcohol: may enhance drowsiness and impair coordination.
• Theophylline: possible alteration of ebastine metabolism requiring monitoring.