Metformin is commonly prescribed for patients diagnosed with type 2 diabetes. It works by increasing the response of your body to insulin and decreasing the amount of glucose absorbed from the food. This drug is supposed to be taken exactly as recommended - usually two to three times a day without missing your doses. Missing doses can decrease the efficiency of your treatment. Make sure you tell your health care provider if you are using any other medications, such as acetaminophen, other nonsteroidal anti-inflammatory drugs, cyclosporine, aminoglycoside antibiotics, gold compounds, nitrates, cancer chemotherapy medications, angiotensin converting enzyme (ACE) inhibitors, sulfa antibiotics, acyclovir, HIV/AIDS meds, rifampin, propranolol, or lithium, as interactions are possible that can affect your treatment and your wellbeing. Side effects of metformin are not too common and can include the following symptoms: headache, flushing of the skin, gas, diarrhea, metallic taste in mouth, cough, runny nose, muscle pain, heartburn, bloating, constipation, stomach pain, and sneezing. There is no need to tell your doctor about them unless they change in intensity and get bothersome.