Background: Levocetirizine is an antihistamine with high affinity and selectivity for H1-receptors, which exhibits an excellent benefit/risk ratio in the treatment of allergic rhinitis and urticaria. This is the first study performed with this drug in very young children.
Objective: The aim of this study was to confirm the intended regimen of levocetirizine (0.125 mg/kg twice a day) for further studies in children aged 12-24 months.
Material and methods: The pharmacokinetic/pharmacodynamic profile of levocetirizine was studied in 15 toddlers suffering from recurrent cough and other allergy-related symptoms, aged 20.7 +/- 3.7 months, and treated twice a day with 0.125 mg/kg for 90 days. A histamine-induced wheal and flare test (W&F) was performed prior to treatment. Blood was sampled at 1, 2, 4, 6, 9 and 12 hours after the first dose. Twelve hours after the evening dose on Days 3-6, and on day 90, a histamine-induced wheal and flare test was repeated and a blood sample was taken for trough value assessment.
Results: A peak plasma level of 286 +/- 68 ng/ml was observed after one hour. The elimination half-life was 4.1 +/- 0.7 hours, the apparent body clearance 1.05 +/- 0.10 ml/min/kg, and the apparent volume of distribution 0.37 +/- 0.06 l/kg. Morning trough values at Days 3-6, and at Day 90 were respectively 78 +/- 30 ng/ml and 110 +/- 86 ng/ml. The median inhibition of the wheal was 100% at Days 3-6, and Day 90. That of the flare was 99.6% at Days 3-6, and 98.9% at Day 90. The overall safety profile of this three-month open study was good.
Conclusion: This first study with levocetirizine in children aged 12-24 months shows the adequate pharmacokinetic/pharmacodynamic profile and the good safety profile of 0.125 mg/kg levocetirizine given twice a day, which can be proposed for further studies in this age group.