Lertazin (Levocetirizine Dihydrochloride)

Levocetirizine is an antihistamine used to manage allergic conditions that involve H1‑mediated histamine release.

• Allergic rhinitis: reduces nasal congestion, sneezing, and itching associated with seasonal or perennial allergies.
• Seasonal allergic rhinitis: provides symptom control during pollen seasons.
• Chronic idiopathic urticaria: alleviates persistent hives and associated itching.

• Levocetirizine selectively antagonizes peripheral H1 histamine receptors, preventing histamine from binding and activating these receptors. By inhibiting this pathway, it reduces the vascular permeability, sensory nerve stimulation, and smooth‑muscle contraction that underlie the classic signs of allergic reactions, thereby alleviating symptoms such as itching, swelling, and nasal discharge.

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

Common Side Effects

• Drowsiness: mild to moderate sleepiness, especially at treatment initiation.
• Dry mouth: reduced salivation leading to a dry oral cavity.
• Headache: transient cranial discomfort.
• Nausea: mild gastrointestinal upset.

Serious or Rare Side Effects

• Angioedema: swelling of face, lips, or tongue requiring immediate medical attention.
• Severe skin reactions: such as Stevens‑Johnson syndrome or toxic epidermal necrolysis.
• Anaphylaxis: rare systemic allergic reaction with potential airway compromise.

Before initiating therapy, consider the following safety measures.

• Assess renal function: dose adjustment may be required in severe renal impairment.
• Use caution in hepatic disease: monitor liver enzymes if pre‑existing liver conditions exist.
• Avoid concomitant CNS depressants: may increase sedation risk.
• Monitor for hypersensitivity: discontinue if signs of rash, swelling, or difficulty breathing appear.
• Pregnancy and lactation: consult a healthcare professional before use.
• Store at ambient temperature: keep below 25 °C, retain in original packaging, and protect from moisture.

Levocetirizine may interact with other medicines; awareness of the interaction level helps manage risk.

Major Interactions (Avoid)

• Alcohol: additive sedation and impaired alertness.
• Central nervous system depressants (e.g., benzodiazepines): may cause excessive drowsiness.
• Ketoconazole or other strong CYP3A4 inhibitors: can increase levocetirizine plasma concentrations.

Moderate Interactions (Monitor Closely)

• Theophylline: may reduce antihistamine effectiveness.
• Ritonavir: may modestly raise levocetirizine levels.
• Anticholinergic agents: may exacerbate dry‑mouth side effect.