A patient is posted for elective surgery. Which of the following drugs should be stopped on the day of surgery?

Metformin should be stopped on the day of surgery due to risk of lactic acidosis, especially if the procedure involves contrast dye or may cause hypoperfusion. Beta blockers and calcium channel blockers like amlodipine are generally continued perioperatively to maintain cardiovascular stability. Statins are also typically continued unless specifically contraindicated.