Metformin (Glucophage®) is a medication often prescribed for treating high blood sugar levels in people with type 2 diabetes. It works by decreasing the amount of sugar produced by the liver, limiting the amount of sugar absorbed into the blood from the diet, and making insulin receptors more sensitive (helping the body respond better to its own insulin).
As with any medicine, it is possible to develop side effects while taking metformin. Problems that were most commonly reported during clinical studies include diarrhea, nausea or vomiting, gas, and weakness.
Besides these common side effects, there are also other possible metformin problems to look out for during treatment. The drug can cause a life-threatening condition called lactic acidosis. Certain conditions may increase your risk for developing lactic acidosis (such as liver disease, congestive heart failure, or kidney failure), so let your healthcare provider know about any existing medical conditions you have before starting metformin.
(Click Metformin Side Effects and Metformin Warnings and Precautions for a more complete list of possible side effects of metformin and to find out what other potentially serious problems may occur with this medicine.)