What is Levocetirizine?

Levocetirizine: An Effective Second-Generation Antihistamine

Levocetirizine is a second-generation antihistamine that is the active R-enantiomer of cetirizine dihydrochloride, available as a 5 mg tablet for the treatment of allergic conditions including allergic rhinitis and chronic idiopathic urticaria. 1, 2

Pharmacological Properties

• Levocetirizine has high bioavailability, rapid onset of action, limited distribution, and minimal hepatic metabolism, making it pharmacodynamically and pharmacokinetically favorable 2
• It demonstrates high affinity for and occupancy of the H1 receptor, providing potent and selective antihistamine activity 3
• Levocetirizine has a lower volume of distribution compared to some other second-generation antihistamines 3
• It provides 24-hour relief of allergic symptoms with once-daily dosing 1

Clinical Applications

• Levocetirizine effectively treats symptoms of allergic conditions including:
  • Seasonal and perennial allergic rhinitis 4
  • Chronic idiopathic urticaria 5
• It relieves common allergic symptoms such as:
  • Sneezing 1
  • Runny nose 1
  • Itchy nose or throat 1
  • Itchy, watery eyes 1
• Beyond its antihistamine effects, levocetirizine demonstrates anti-inflammatory properties at clinically relevant concentrations that may enhance its therapeutic benefit 2

Safety Profile

• Levocetirizine has a well-tolerated adverse effect profile compared to first-generation antihistamines 5
• As with other second-generation antihistamines, it may cause sedation, though typically less than first-generation options 6
• Caution is advised in patients with renal impairment - the dose of levocetirizine should be halved in moderate renal impairment 7
• Like cetirizine, levocetirizine should be avoided in severe renal impairment (creatinine clearance < 10 mL/min) 7

Special Populations

Pregnancy

• All antihistamines should ideally be avoided during pregnancy, especially in the first trimester 7
• If treatment is necessary during pregnancy, chlorphenamine has the longest safety record, though loratadine and cetirizine are classified as FDA Pregnancy Category B drugs 7

Pediatric Use

• Levocetirizine has been shown to be safe and effective in children aged 6-12 years 5
• The use of antihistamines in school-age children requires attention to dosage and scheduling, as sedating antihistamines may negatively affect school performance 7

Alternatives to Levocetirizine

• Other second-generation antihistamines with similar efficacy profiles include:
  • Desloratadine - non-sedating at recommended doses with the longest elimination half-life (27 hours) 6
  • Fexofenadine - completely non-sedating even at higher doses 6
  • Loratadine - non-sedating at recommended doses 6
• For patients with allergic rhinitis, intranasal antihistamines like azelastine and olopatadine may be considered as effective alternatives 6

Common Pitfalls and Considerations

• Not all second-generation antihistamines have identical side effect profiles - there are important differences in sedation potential 6
• For urticaria not responding to standard doses, increasing the dose of second-generation antihistamines above licensed recommendations may be considered when benefits outweigh risks 6
• Individual response to antihistamines varies - patients should be offered alternative options if the first is ineffective 6
• Levocetirizine should be discontinued several days before skin prick testing due to its antihistamine effects 6