A review of the evidence from comparative studies of levocetirizine and desloratadine for the symptoms of allergic rhinitis.
BACKGROUND
Levocetirizine and desloratadine are newer antihistamines indicated for the treatment of allergic rhinitis and chronic idiopathic urticaria.


OBJECTIVE
This article discusses the pharmacokinetics and pharmacodynamics of levocetirizine and desloratadine and reviews studies that have directly compared the effects of these 2 drugs in allergic rhinitis and urticaria.


METHODS
Relevant articles were identified through a search of MEDLINE from 1999 through 2004 using the main search terms levocetirizine and desloratadine.


RESULTS
Levocetirizine is absorbed rapidly and reaches a steady-state plasma concentration more quickly than does desloratadine. It is also metabolized to a lesser extent than desloratadine, has a lower V(d), and has higher specificity for histamine(1) receptors. Eight well-controlled trials were identified that directly compared the effects of levocetirizine and desloratadine in the skin and nose of healthy individuals and patients with allergic rhinitis. Drug activity was measured in terms of wheal, flare, and itch reactions; nasal symptoms or symptom scores; increases in concentrations of inflammatory markers; or facial thermography. In most of these trials, levocetirizine had a faster onset and greater consistency of effect than desloratadine. The differences in the pharmacokinetic and pharmacodynamic profiles of the 2 drugs may partially explain these clinical findings.


CONCLUSIONS
Levocetirizine may be preferred to desloratadine as a treatment option for allergic rhinitis because of its faster onset of action and greater consistency of effect. Although comparative studies in chronic idiopathic urticaria are not available, data from histamine-induced wheal and flare studies in healthy volunteers suggest that levocetirizine may be more effective in preventing itching than desloratadine.
Passalacqua
Giovanni
G
Allergy and Respiratory Diseases, Department of Internal Medicine, University of Genoa, Italy. passalacqua@unige.it
Canonica
Giorgio Walter
GW
D017332:Cetirizine / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D006633:Histamine Antagonists / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D017336:Loratadine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use; D009666:Nose / Q000187:drug effects / Q000503:physiopathology; D010879:Piperazines / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D011788:Quality of Life; D016032:Randomized Controlled Trials as Topic; D012221:Rhinitis, Allergic, Perennial / Q000188:drug therapy* / Q000503:physiopathology; D006255:Rhinitis, Allergic, Seasonal / Q000188:drug therapy* / Q000503:physiopathology; D012867:Skin / Q000187:drug effects / Q000503:physiopathology; D014581:Urticaria / Q000188:drug therapy / Q000503:physiopathology
D006633:Histamine Antagonists; D010879:Piperazines; C472067:levocetirizine; D017336:Loratadine; C121345:desloratadine; D017332:Cetirizine