Dr. Holmberg is a pharmacy resident at the Carl T. Hayden Veterans Affairs Medical Center in Phoenix, Arizona.
Xyzal (levocetirizine dihydrochloride) has received FDA approval for the treatment of seasonal and perennial allergic rhinitis and uncomplicated skin manifestations of chronic idiopathic urticaria. Xyzal is approved for use in patients aged 6 and older; it offers a once-daily dosing schedule and can be taken without regard to meals.1
The American Academy of Allergy, Asthma and Immunology estimates that up to 40 million Americans are affected by allergies. Seasonal allergic rhinitis is the most common form of allergic rhinitis and results from sensitivities to seasonal pollen (trees, grass, and weeds) and mold. Allergy symptoms that last longer than 4 weeks and are triggered by allergens, such as dust mites, animal dander, and mold, are characterized as perennial allergic rhinitis. Chronic idiopathic urticaria is defined as the presence of wheals and itching that occurs daily or almost daily, lasts for at least 6 weeks, and has no known cause.2
Xyzal is an antihistamine and the active enantiomer of cetirizine. It exerts its effect through inhibition of the H1 receptors.1
Safety data for Xyzal 5 mg daily were determined by 12 randomized, placebo-controlled trials in a total of 2549 patients with either seasonal or perennial allergic rhinitis or chronic idiopathic urticaria. Trials were considered either short-term (duration of up to 6 weeks) or long-term (duration 4-6 months).1
FDA approval was based on 8 randomized, placebo-controlled trials in patients aged 12 and older using Xyzal 5 mg daily. Efficacy in the allergic rhinitis study was assessed by a significant improvement in symptoms, such as sneezing, rhinorrhea, nasal pruritus, and ocular pruritus, in the active treatment group. When evaluated for efficacy in patients with idiopathic urticaria, symptoms, such as duration of pruritus and wheal size and quantity, were found to be significantly improved in the Xyzal group.3
The recommended dose of 2.5 mg for children was not evaluated by clinical trials; instead, 2 short-term, placebo-controlled clinical trials evaluated the 5-mg daily dose in a total of 243 patients aged 6 to 12.1 The recommended dose is based on an extrapolation of pharmacokinetics in adults and children.4
Xyzal is manufactured as a 5-mg scored tablet. Because of its potentially sedating effect, doses of Xyzal should be administered in the evening. Patients aged 12 and older are recommended to use 5 mg once daily in the evening; however, some patients may experience symptom relief with a lesser dose of 2.5 mg daily. Patients aged 6 to 11 should use 2.5 mg once daily in the evening; 2.5 mg is the maximum daily dose in this age group.
In patients aged 12 and older with renal impairment, the dose of Xyzal should be adjusted according to creatinine clearance (CrCl) levels, as follows:
Xyzal is contraindicated in patients with end-stage renal impairment as defined by CrCl <10 mL/min or in patients who are undergoing hemodialysis. Patients aged 6 to 11 with renal impairment should not use Xyzal. Xyzal is contraindicated in patients with a known hypersensitivity to any of its components.
Patients are warned against using Xyzal during any activity that requires alertness, such as driving or operating heavy machinery. Patients should not use alcohol or other central nervous system depressants while taking Xyzal.1
The most commonly reported adverse effects in patients aged 12 and older included somnolence, nasopharyngitis, pharyngitis, fatigue, and dry mouth. In patients aged 6 to 11, the most common adverse events reported were pyrexia, cough, somnolence, and epistaxis.4