Can you take Metformin while fasting I take 500mg 3 times a day I'm not diabetic but have been prescribed because of PCOS?

Answer 1

Metformin increases glucose uptake in the large muscles of the body which use glucose for energy. It also stops the natural production of glucose in the liver (an amount of glucose in your body that is independent of how much glucose you eat in your diet). I do not recommend that my patients fast while they are taking any oral anti-hyperglycemic medications.

I understand that you are not diabetic, however this medication will still act on you as if you were. Therefore, it is even more important that you consume enough glucose in your diet in a day to maintain normal blood glucose levels. While normally metformin does not cause hypoglycemia (low blood sugar) to the same extent as other agents like glipizide and glyburide, the potential for dangerously low blood sugars still exists if you fast while taking metformin.

If you are told to fast for blood work or prior to a surgery, your doctor usually will still want you to take most of your medications (there are some exceptions like Beta-blockers- a type of heart medication and Coumadin- a blood thinner, before surgeries). Your doctor should tell you which medications to stop taking and how long to stop taking them prior to your procedure whether it is a blood draw or surgery. The rest of your medications should be okay to take with just the smallest sip of plain bottled water or tap water possible. Avoid any flavored waters, juice, or sweetened tea as the sugar content may throw off certain blood test results. If you drink coffee in the mornings, avoid cream or sugar.