Levocetirizina Bluefish (Levocetirizine Dihydrochloride)

Levocetirizine is an H1‑receptor antagonist that reduces allergic inflammation in the upper airway and skin.

• Allergic rhinitis: alleviates sneezing, nasal itching, rhinorrhea and congestion caused by seasonal or perennial allergens.
• Chronic idiopathic urticaria: reduces the frequency and severity of hives and associated itching.
• Seasonal allergic conjunctivitis: helps control eye itching and redness when ocular symptoms accompany nasal allergy.

• Levocetirizine selectively blocks peripheral histamine H1 receptors, preventing histamine from binding to mast cells and basophils. This inhibition reduces the vascular permeability, nerve stimulation, and glandular secretion that underlie the classic symptoms of allergic reactions, thereby providing symptomatic relief without significant central nervous system penetration.

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

Common Side Effects

• Drowsiness: mild to moderate sleepiness, especially after the first dose.
• Headache: transient tension‑type headache.
• Dry mouth: reduced salivation leading to a dry oral cavity.
• Fatigue: feeling of reduced energy or mild tiredness.

Serious or Rare Side Effects

• Angioedema: swelling of the face, lips, tongue or throat requiring urgent medical attention.
• Anaphylactic reaction: severe, rapid onset allergic response.
• Severe skin reactions: such as Stevens‑Johnson syndrome or toxic epidermal necrolysis.
• Cardiac arrhythmia: rare cases of irregular heart rhythm.

Before initiating therapy, consider patient‑specific factors and monitor for potential risks.

• Renal function: adjust dose in patients with impaired renal clearance.
• Alcohol consumption: avoid or limit as it may increase drowsiness.
• Elderly patients: start with the lowest effective dose and monitor for sedation.
• Concomitant CNS depressants: use caution when combined with other sedating agents.
• Driving or machinery: advise patients to assess their alertness before operating vehicles.
• Store at ambient temperature: keep below 25 °C, retain in original packaging, protect from moisture and direct sunlight.

Levocetirizine may interact with other substances that affect the central nervous system or histamine pathways.

Major Interactions (Avoid)

• Alcohol: can potentiate sedation and impair cognition.
• Other antihistamines: additive drowsiness and anticholinergic effects.
• CNS depressants (e.g., benzodiazepines, opioids): increased risk of profound sedation.

Moderate Interactions (Monitor Closely)

• CYP3A4 inhibitors (e.g., ketoconazole, erythromycin): may raise plasma levels modestly.
• Theophylline: possible increase in theophylline concentrations.
• Ritonavir: may slightly elevate levocetirizine exposure.
• Anticholinergic drugs: monitor for enhanced dry mouth or urinary retention.