Levocetirizine Krka (Levocetirizine Dihydrochloride)

Levocetirizine acts on histamine‑mediated allergic pathways and is indicated for several common allergic conditions.

• Allergic rhinitis: reduces nasal congestion, sneezing, itching and rhinorrhea.
• Chronic idiopathic urticaria: diminishes the frequency and severity of hives and associated itching.
• Allergic conjunctivitis: helps alleviate ocular itching, redness and tearing.

• Levocetirizine is a selective antagonist of peripheral histamine H1 receptors. By binding to these receptors on mast cells, basophils and sensory nerves, it blocks the action of released histamine, thereby preventing the cascade of vascular permeability, smooth‑muscle contraction and sensory nerve activation that produce typical allergic symptoms.

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.
• Fatigue: a feeling of reduced energy or tiredness.
• Dry mouth: decreased salivation leading to a dry oral cavity.
• Headache: mild to moderate cranial pain.
• Nausea: occasional upset stomach or queasiness.
• Taste alteration: transient metallic or altered taste perception.

Serious or Rare Side Effects

• Angioedema: swelling of the face, lips, tongue or throat requiring urgent care.
• Severe skin reactions: such as Stevens‑Johnson syndrome or toxic epidermal necrolysis.
• Anaphylaxis: rare systemic allergic reaction with respiratory distress and hypotension.
• Thrombocytopenia: marked reduction in platelet count.
• Hepatic injury: abnormal liver function tests or hepatitis.

Before initiating Levocetirizine therapy, consider the following safety points.

• Renal impairment: dose adjustment may be required in patients with reduced kidney function.
• Hepatic disease: use with caution and monitor liver enzymes.
• Alcohol consumption: avoid or limit as it may increase sedation.
• Pregnancy and breastfeeding: consult a healthcare professional before use.
• Pediatric use: not recommended for children below the age specified in the local labeling.
• Store at ambient temperature: keep below 25 °C, retain in the original packaging, and protect from moisture.

Levocetirizine may interact with other medicines, altering its efficacy or safety profile.

Major Interactions (Avoid)

• Alcohol: can potentiate drowsiness and impair alertness.
• Other H1 antihistamines: additive sedation and anticholinergic effects.
• Strong CYP3A4 inhibitors (e.g., ketoconazole): may increase plasma concentrations.

Moderate Interactions (Monitor Closely)

• CYP3A4 substrates (e.g., erythromycin, ritonavir): may modestly raise levocetirizine levels.
• Theophylline: possible reduction in bronchodilator effect.
• Phenobarbital or other enzyme inducers: may lower levocetirizine exposure.