After cardiac stenting, you need to stop taking the medication for 48 hours before you can continue to take metformin to control your blood sugar. During cardiac stenting, an intravenous contrast agent is injected to assist in the visualization of the heart. A commonly used contrast agent is iodine, such as iohexol. There is a risk of lactic acidosis when iodine and metformin are used together. The contrast agent should be well hydrated during use, and it is recommended that metformin should be discontinued before and after use of the contrast agent, which is largely metabolized from the body after 48 hours. Therefore, people with normal renal function can use metformin 48 hours after the end of contrast. While patients with abnormal renal function need to review their renal function after 48 hours and have normal creatinine values before continuing to use Metformin. Cardiac stent surgery involves the use of contrast media, so diabetic patients should temporarily stop using metformin, after stopping the drug can follow the endocrinologist’s advice to use other glucose-lowering program.