This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pancreas, Subject name: Pharmacology
DPP-4 inhibitor that can be used in renal failure is: 
Select and explain. 
A. Linagliptin, B. Sitagliptin, C. Vildagliptin, D. Sexagliptin
A: Linagliptin
Answer: A: Linagliptin 
Explanation: DPP-4 inhibitors: Competitive and selective inhibition of DPP-4 which potentiates the action of GLP- 1 and GIP, boosts postprandial insulin release, decreases glucagon secretion and lowers meal-time as well as fasting blood glucose in type 2 diabetics. Eg.: Sitagliptin, Vildagliptin, Saxagliptin, Alogliptin, Linagliptin. Only Linagliptin is safe in renal failure. MC S/E of Gliptins: Nasopharyngitis.