ABCB1 and angioedema: Because sitagliptin is a substrate of p-glycoprotein/ABCB1, which is inhibited by glecaprevir/pibrentasvir, the authors hypothesized that this drug interaction could give rise to increased serum concentrations of sitagliptin, thus inducing a more pronounced effect on DPP-IV inhibition and on the resulting mechanisms responsible for angioedema [47].