Levocetirizin Glenmark (Levocetirizine Dihydrochloride)

Levocetirizine is a second‑generation H1 antihistamine that reduces allergic responses in the respiratory and cutaneous systems.

• Allergic rhinitis: alleviates nasal congestion, sneezing, itching and watery discharge.
• Seasonal allergic rhinitis: provides symptom relief during pollen exposure periods.
• Chronic idiopathic urticaria: reduces the frequency and severity of hives and associated itching.

• Levocetirizine selectively blocks peripheral H1 receptors, preventing histamine from binding to mast cells and sensory nerves. This antagonism inhibits histamine‑induced vascular permeability, edema and nerve stimulation, thereby diminishing the classic signs of allergy such as itching, swelling and rhinorrhea without readily crossing the blood‑brain barrier, which limits central sedation. The drug’s high affinity for the H1 subtype ensures prolonged receptor occupancy, contributing to once‑daily dosing in most patients.

Levocetirizine is generally well tolerated, but several adverse reactions have been reported.

Common Side Effects

• Drowsiness: mild sedation, especially at initiation.
• Fatigue: feeling of reduced energy.
• Dry mouth: decreased salivation.
• Headache: mild to moderate intensity.
• Nausea: occasional stomach upset.
• Dizziness: transient light‑headedness.
• Insomnia: difficulty falling or staying asleep.

Serious or Rare Side Effects

• Angioedema: swelling of face, lips or tongue.
• Severe skin reactions: such as Stevens‑Johnson syndrome or toxic epidermal necrolysis.
• Anaphylaxis: rapid onset of systemic allergic reaction requiring emergency care.
• Blood dyscrasias: rare cases of leukopenia or thrombocytopenia.

When prescribing levocetirizine, several precautions should be considered to ensure safe use.

• Pregnancy: use only if potential benefit justifies potential risk; consult healthcare provider.
• Breastfeeding: assess risk versus benefit as drug may be excreted in milk.
• Renal impairment: dose adjustment may be required in moderate to severe renal dysfunction.
• Elderly patients: monitor for increased sedation or confusion.
• Driving and machinery: avoid operating vehicles or hazardous equipment if drowsiness occurs.
• Store at room temperature: keep in original packaging, protect from moisture and direct sunlight.

Levocetirizine may interact with other medicines; awareness of major and moderate interactions helps prevent adverse outcomes.

Major Interactions (Avoid)

• Ketoconazole: strong CYP3A4 inhibitor that can raise levocetirizine plasma levels.
• Erythromycin: macrolide antibiotic that may increase exposure to levocetirizine.
• Ritonavir: protease inhibitor that can significantly elevate levocetirizine concentrations.

Moderate Interactions (Monitor Closely)

• Alcohol: additive central nervous system depression may enhance drowsiness.
• CNS depressants (e.g., benzodiazepines): combined effect may increase sedation.
• Theophylline: may increase hepatic clearance of levocetirizine, reducing efficacy.