The pharmacokinetic profile of tacrolimus ointment 0.03% after 1 and 14 days of topical application in 53 infants (aged 3-24 months) with atopic dermatitis (AD) was determined. Patients were stratified according to the body surface area (BSA) affected (5-20%; 20-40% and >40%) and randomized to once- or twice-daily applications. The majority of blood samples (97%) contained < 1 ng/ml tacrolimus and 20% were below the lower limit of detection (0.025 ng/ml). The area under the curve (AUC) increased with increasing BSA. The mean half-life was 80 h (range 25-175 h). There were no clinically significant changes in laboratory values, and adverse events mainly comprised minor infections and local skin irritation. Thus ...