Pharmacokinetics of topical calcineurin inhibitors in adult atopic dermatitis: a randomized, investigator-blind comparison.

Objective: We sought to compare pharmacokinetics of pimecrolimus cream 1% and tacrolimus ointment 0.1% in adults with extensive, moderate to severe atopic dermatitis. Secondary end points included efficacy and safety.

Methods: Patients received twice-daily treatment for 13 days. Blood concentrations of pimecrolimus and tacrolimus were measured at days 1, 5, and 13. Treatment success was defined as an Investigators' Global Assessment score of 0 (clear) or 1 (almost clear).

Results: Tacrolimus was detectable in 36% of blood samples and pimecrolimus was detectable in 12%. In patients with measurable blood drug concentrations, systemic exposure to tacrolimus (mean area under the curve(0-10h) < 9.7 ng.h/mL; n = 7) was higher than to pimecrolimus (mean area under the curve(0-10h) < 2.5 ng.h/mL; n = 2). Whole-body treatment success (day 13) was achieved in 1 of 18 (5.6%) and 2 of 19 (10.5%) patients treated with pimecrolimus and tacrolimus, respectively, and face/neck treatment success in 5 of 18 (27.8%) and 5 of 19 (26.3%) patients, respectively. Patients included in the study were adult patients with severe atopic dermatitis. The results and conclusions drawn from this study population may not be applicable for the majority of patients with atopic dermatitis who have mild to moderate disease.

Conclusion: Pimecrolimus appears to be associated with lower systemic drug exposure than tacrolimus.