Para-aminosalicylic acid significantly reduced tenofovir exposure in human subjects: Mismatched findings from in vitro to in vivo translational research.

Our study findings suggest that the PAS-Ca formulation significantly reduced systemic exposure to tenofovir through an unexplained mechanism, which was contrary to the initial prediction. Caution should be exercised while predicting in vivo PK profiles from in vitro data, particularly when there are potential confounders such as pharmaceutical interactions.