Linagliptin: Inhibits P-gp mediated transport of digoxin (w/ low potency). Increased AUC, Cmax
w/ ritonavir. Decreased steady-state AUC, Cmax
& dipeptidyl peptidase 4 inhibition at trough w/ rifampicin. Increased AUC & Cmax
of simvastatin. Metformin: Increased risk of lactic acidosis w/ acute alcohol intoxication, iodinated contrast agents, NSAIDs including selective COX II inhibitors, ACE inhibitors, AIIA & diuretics especially loop diuretics. Efficacy may be reduced w/ OCT1 inhibitors (eg, verapamil). GI absorption may be increased & efficacy w/ OCT1 inducers (eg, rifampicin). Plasma conc may be increased w/ OCT2 inhibitors (eg, cimetidine, dolutegravir, ranolazine, trimethoprim, vandetanib, isavuconazole). Efficacy & renal elimination may be altered w/ OCT1 & OCT2 inhibitors (eg, crizotinib, olaparib).