Overview
Levocetirizine is a second-generation antihistamine used for the relief of symptoms associated with allergic rhinitis and chronic idiopathic urticaria. It selectively antagonizes peripheral H1 receptors with minimal sedative effects compared to first-generation antihistamines. The medication is typically administered once daily and is available in tablet form.
Mechanism of Action
Levocetirizine is the active enantiomer of cetirizine that selectively antagonizes peripheral H1 histamine receptors. It inhibits histamine-induced wheal and flare reactions, providing relief from allergic symptoms without significant central nervous system penetration that causes sedation.
Indications
- Seasonal allergic rhinitis
- Perennial allergic rhinitis
- Chronic idiopathic urticaria
Common Doses
- 5 mg
- 2.5 mg
Dosage
Adults and children 12 years and older: 5 mg once daily. Children 6-11 years: 2.5 mg once daily. Tablets can be taken without regard to food. The 5 mg tablet is scored and can be broken for 2.5 mg dosing when needed.
Contraindications
- Hypersensitivity to levocetirizine, cetirizine, or any component of the formulation
- End-stage renal disease (CrCl <10 mL/min)
- Patients undergoing hemodialysis
Side Effects
- Somnolence
- Fatigue
- Dry mouth
- Pharyngitis
- Urinary retention
- Headache
- Nausea
- Dizziness
Interactions
- No clinically significant pharmacokinetic interactions through inhibition or induction of liver enzymes
- Additive CNS depression with alcohol and other CNS depressants
- Theoretical increased risk of QT prolongation with other QT-prolonging drugs, though clinical significance is uncertain
Counseling Points
- Take once daily, with or without food
- May cause drowsiness; avoid alcohol and other sedating medications
- Report difficulty urinating or new itching after stopping medication
- Break scored tablet for 2.5 mg dose if prescribed
- Store at room temperature