This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anaesthesia
A 50 year old diabetic and hypertensive patient on amlodipine and glimepiride is posted for elective AV fistula creation for dialysis in view of acute kidney failure. What is your view as anaesthesiologist with regard to pre-operative orders 
Select and explain. 
A. Stop amlodipine but continue glimepiride, B. Continue amlodipine , stop glimepiride and switch over to insulin a day prior, C. Stop both amlodipine and glimepiride, D. Put patient on insulin and schedule surgery only after a week.
B: Continue amlodipine , stop glimepiride and switch over to insulin a day prior
Answer: B: Continue amlodipine , stop glimepiride and switch over to insulin a day prior 
Explanation: Anti hypertensive and oral hypoglycemic drugs should not be stopped. In  a major surgery insulin should be started instead of oral hypoglycemic agents.