The pharmacokinetics of tacrolimus after first and repeated dosing with 0.03% ointment in infants with atopic dermatitis

Background In adults and children aged > 2 years, systemic absorption of tacrolimus from tacrolimus ointment is very low. In this study, the pharmacokinetics of tacrolimus 0.03% ointment were investigated in infants aged 3–24 months. Methods The pharmacokinetics of tacrolimus after first and repeated topical application of tacrolimus 0.03% ointment were evaluated in 53 infants (age, 3–24 month) with atopic dermatitis requiring treatment with mid‐potency topical corticosteroids. Patients were grouped according to percentage of body surface area affected (Group 1: 5–20%; Group 2: > 20–40%; Group 3: > 40%). After stratification, patients were randomized (double‐blind) to receive once‐daily or twice‐daily tacrolimus 0.03% ointment. Results Blood samples taken on days 1 and 14 (first and last application) showed minimal systemic tacrolimus exposure. Overall, 97% of blood samples assayed contained tacrolimus concentrations