Levocetirizine Krka (Levocetirizine Dihydrochloride)

• Levocetirizine, a selective H1 receptor antagonist, is indicated for several IgE‑mediated allergic disorders, helping to control symptoms by inhibiting histamine activity.
• Allergic rhinitis: reduces sneezing, itching, and nasal discharge.
• Seasonal allergic rhinitis: provides symptom relief during pollen exposure.
• Perennial allergic rhinitis: controls year‑round nasal symptoms.
• Chronic idiopathic urticaria: diminishes hives and associated itching.
• Allergic conjunctivitis: alleviates eye itching and redness.
• Allergic asthma: assists in reducing bronchial hyper‑responsiveness.
• Contact dermatitis: mitigates itching and rash from allergen exposure.

• Levocetirizine is the active R‑enantiomer of cetirizine. It binds selectively to peripheral H1 histamine receptors with high affinity, preventing histamine from activating the receptor cascade. By blocking this pathway, it reduces vascular permeability, smooth‑muscle contraction and sensory nerve stimulation that underlie the classic symptoms of allergic rhinitis and urticaria. The drug does not readily cross the blood‑brain barrier, limiting central nervous system effects.

Levocetirizine may cause adverse reactions, which are categorized by frequency.

Common Side Effects

• Drowsiness: mild sedation or sleepiness.
• Dry mouth: reduced salivation.
• Headache: transient cranial discomfort.
• Nausea: mild gastrointestinal upset.

Serious or Rare Side Effects

• Angioedema: swelling of face, lips, or throat.
• Severe rash: including Stevens‑Johnson syndrome.
• Anaphylaxis: life‑threatening allergic reaction.

Before initiating Levocetirizine therapy, consider the following precautions.

• Pregnancy: consult a healthcare professional before use.
• Breastfeeding: weigh potential benefits against possible infant exposure.
• Renal impairment: dose adjustment may be required in reduced kidney function.
• Elderly patients: monitor for increased sedation or dizziness.
• Concomitant CNS depressants: avoid additive drowsiness.
• Store at room temperature: keep in original packaging, protect from moisture and light.

Levocetirizine can interact with other medicines; awareness of major and moderate interactions helps ensure safety and optimal therapeutic outcomes.

Major Interactions (Avoid)

• Alcohol: may intensify sedation and impair coordination.
• Central nervous system depressants (e.g., benzodiazepines): additive drowsiness risk.
• Monoamine oxidase inhibitors: may increase antihistaminic effects.

Moderate Interactions (Monitor Closely)

• Ketoconazole or other strong CYP3A4 inhibitors: may increase levocetirizine plasma levels.
• Ritonavir: potential elevation of drug concentration.
• Theophylline: may enhance side‑effect profile.
• Anticholinergic agents: may worsen dry mouth.
• Antihypertensive agents: may cause mild hypotension when combined with sedatives.