Levocetirizine Glenmark Pharmaceuticals (Levocetirizine Dihydrochloride)

Levocetirizine is used to manage allergic conditions by blocking peripheral H1‑histamine receptors.

• Allergic rhinitis: reduces nasal congestion, sneezing, itching and watery discharge.
• Chronic idiopathic urticaria: alleviates hives and associated itching, improving quality of life.
• Allergic dermatitis: helps control pruritus and skin inflammation caused by histamine release.

• Levocetirizine is a selective peripheral H1‑histamine receptor antagonist. By binding with high affinity to the H1 receptors on mast cells, basophils and other target cells, it prevents histamine from triggering the cascade that leads to vasodilation, increased vascular permeability, and sensory nerve stimulation, thereby reducing the classic signs and symptoms of allergic reactions.

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

Common Side Effects

• Drowsiness: mild to moderate sleepiness, especially after the first dose.
• Headache: transient tension‑type headache.
• Dry mouth: reduced salivation causing throat discomfort.
• Fatigue: general feeling of tiredness.
• Nausea: occasional upset stomach.
• Altered taste: metallic or bitter sensation.

Serious or Rare Side Effects

• Angioedema: swelling of face, lips or tongue requiring urgent care.
• Severe skin rash: including Stevens‑Johnson syndrome.
• Anaphylaxis: rare systemic allergic reaction with respiratory compromise.
• Thrombocytopenia: low platelet count observed in isolated reports.
• Hepatic injury: elevated liver enzymes in very rare cases.
• Eosinophilic pneumonia: rare pulmonary inflammation.

Before initiating therapy, consider the following safety measures.

• Renal function assessment: dose adjustment may be needed in severe renal impairment.
• Hepatic impairment: use with caution in patients with liver disease.
• Sedation risk: avoid operating machinery or driving until individual response is known.
• Age restriction: not recommended for children under six years of age unless specifically prescribed.
• Concomitant CNS depressants: monitor for additive drowsiness when combined with alcohol or sedatives.
• Store at ambient temperature: keep below 25°C in the original packaging, protect from moisture and direct sunlight.

Levocetirizine can interact with other medicines, affecting its efficacy or safety.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir): may increase levocetirizine plasma levels.
• Other antihistamines: additive sedation and anticholinergic effects.
• Alcohol: enhances central nervous system depression.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., phenobarbital, rifampicin): may reduce drug exposure.
• Certain antidepressants (e.g., fluoxetine, paroxetine): potential for increased sedation.
• Macrolide antibiotics (e.g., erythromycin): may modestly raise levocetirizine concentrations.