Levocetirizine: from scientific evidence to a potent modern-day treatment of today's allergic patients.

Increasing evidence suggests that most of today's allergic rhinitis patients are sensitized to more than one trigger, likely due to constant exposure to increased levels of traditional and new allergens from exotic foods and pets, resulting in manifestation of the more persistent and moderate/severe symptoms. The Allergic Rhinitis and its Impact on Asthma (ARIA) initiative has consequently recommended that allergic rhinitis be classified as "intermittent" or "persistent" allergic rhinitis (IAR and PER, respectively), based on symptom duration and the impact of disease severity on the patient's quality of life. Moreover, ARIA has recommended that the efficacy of H(1)-antihistamines be investigated in patients classified according to ARIA, with the H(1)-antihistamine under investigation being evaluated long-term in terms of clinical efficacy, safety and pharmacological properties in order to fully appreciate its efficacy. Studies of levocetirizine, one of the most recent commercially available H(1)-antihistamines, indicate that this drug is among the most useful H(1)-antihistamines for the management of allergic rhinitis (IAR and PER) and chronic idiopathic urticaria because of its overall more favorable pharmacokinetic and pharmacodynamic profiles compared with other commonly used H(1)-antihistamines, as well as its high efficacy and long-term safety in children and adults. Moreover, continuous treatment with levocetirizine appears to be more effective than on-demand treatment, a property that is likely to benefit today's patients with more persistent and severe symptoms.