Posted: 06/17/2011; Pediatr Pharm. 2011;17(5) © 2011 Children's Medical Center, University of Virginia
http://www.medscape.com/viewarticle/743960_7 for full article
Desloratadine, the single active isomer of loratadine, was approved by the Food and Drug Administration (FDA) on December 21, 2001 and still requires a prescription.
Both versions are approved for pediatric use:
loratadine for children as young as 2 years of age and desloratadine for infants 6 months of age and older.
This issue of Pediatric Pharmacotherapy will provide a brief review of loratadine and desloratadine, focusing on studies supporting their use in the pediatric population.
Contraindications and Precautions
Loratadine and desloratadine are contraindicated in patients with a known sensitivity to either drug or the excipients used in the formulations available.
Hypersensitivity reactions are rare, but include rash, urticaria, pruritus, dyspnea, edema, and anaphylaxis.
Although some earlier second-generation antihistamines (astemizole, terfenadine) have been associated with prolongation of the QTc interval and a risk for torsades de pointes, multiple studies have shown no effect on ECG parameters by loratadine or desloratadine.
Drugs that inhibit the activity of CYP3A4, such as erythromycin, cimetidine, and ketoconazole, prolong the metabolism of loratadine and desloratadine. As a result, plasma concentrations may increase significantly. Administration of ketoconazole 200 mg every 12 hours produced a 307% increase in loratadine plasma concentrations, measured as the area under the concentration-time curve over 24 hours, and a 39% increase in desloratadine concentrations. In spite of the increase in plasma concentrations, studies conducted in healthy adult volunteers have not revealed a change in vital signs, electrocardiographic measurements of the QTc interval, laboratory tests, or other adverse effects.
Azithromycin and fluoxetine may also increase loratadine or desloratadine concentrations, but to a lesser degree.