Tacrolimus ointment neither blocks ultraviolet B nor affects expression of thymine dimers and p53 in human skin.

Background: There is a lack of data with regard to the interaction between ultraviolet (UV) radiation and topical calcineurin inhibitors.

Objective: We aimed to investigate (1) the UV transmission through tacrolimus ointment and (2) the impact of topical exposure to tacrolimus on the protein expression of thymine dimers (TD) and p53 in human skin.

Methods: Spectrophotometric measurements (290-400 nm) of tacrolimus ointment and the vehicle were performed.