Linagliptin: Inhibits P-gp-mediated transport of digoxin w/ low potency. Increased AUC & C
max w/ ritonavir. Decreased steady-state AUC & C
max, & DPP-4 inhibition at trough w/ rifampicin. Increased plasma AUC & C
max of simvastatin. Metformin: Increased risk of lactic acidosis in alcohol intoxication; NSAIDs including selective COX-2 inhibitors, ACE inhibitors, AIIA & diuretics especially loop diuretics. May reduce efficacy w/ OCT1 inhibitors (eg, verapamil). May increase GI absorption & efficacy w/ OCT1 inducers (eg, rifampicin). May decrease renal elimination w/ OCT2 inhibitors (eg, cimetidine, dolutegravir, ranolazine, trimethoprim, vandetanib & isavuconazole). May alter efficacy & renal elimination w/ both OCT1 & OCT2 inhibitors (eg, crizotinib & olaparib).