Objective: This study was designed to characterise the single and multiple dose pharmacokinetic profile of desloratadine, a new antihistamine, and its main metabolite, 3-hydroxy (3-OH) desloratadine, in healthy volunteers differing in sex and race.
Design: An open-label, parallel-group, single- and multiple-dose pharmacokinetic trial.
Intervention: A single 7.5mg oral tablet of desloratadine on day 1, followed by 7.5mg daily doses on days 4 to 17.
Participants: 48 healthy, nonsmoking volunteers (12 White men, 12 Black men, 12 White women, 12 Black women).
Main outcome measures: AUC(24h) and C(max) determined from serial blood samples of desloratadine and 3-OH desloratadine.
Results: There were no clinically relevant differences between men and women or Black participants and White participants for desloratadine and 3-OH desloratadine maximum plasma concentrations (C(max)) and area under the plasma concentration-time curve (AUC). Following multiple doses, the geometric mean C(max) was 5.17 microg/L in men, 5.68 microg/L in women, 5.87 microg/L in Black participants and 5.00 microg/L in White participants; the corresponding AUC from 0 to 24 hours (AUC(24h)) values were 77.9, 80.0, 90.6 and 68.8 micro g/L x h. Corresponding 3-OH desloratadine geometric mean C(max) values were 1.93, 2.79, 2.20 and 2.45 microg/L, and the AUC(24h) values were 32.1, 47.5, 37.1 and 41.1 microg/L. h.
Conclusions: Oral administration of multiple doses of desloratadine 7.5mg, a dose 50% higher than the recommended 5mg clinical dose, was well tolerated by healthy adults differing in sex and race. Comparison of the C(max) and AUC values following 14 days of treatment with desloratadine indicates that no dosage adjustment is needed on the basis of sex or race.