Side Effects. Drug information provided by: IBM Micromedex. Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention. Take metformin every single day and at the same time. Side effects usually lessen the longer that it’s taken. Thus, taking it daily will allow your body to get used to the medication. Unfortunately, the side effects of Metformin may require twice a day dosing to decrease the incidence and the severity of side effects. The side effects for Metformin include abdominal cramping. Metformin side effects include diabetic neuropathy, brain fog, and digestive issues. You can address them through diet, Vitamin B12, CoQ10, and exercise. Let us understand the drug Metformin in detail and study different forms of metformin, its uses and common metformin side effects along with how to deal with them. Commonly reported side effects of metformin include: lactic acidosis, diarrhea, nausea, nausea and vomiting, vomiting, and flatulence. Other side effects include: asthenia, and decreased vitamin b12 serum concentrate. Some side effects of Metformin can be more serious. One of these effects is lactic acidosis. Though the latest studies suggest this is an uncommon condition which may not be directly associated with Metformin, the risk of lactic acidosis is increased in both those with chronic kidney disease and those with liver disease. The antihyperglycemic drug Metformin, while being very effective in lowering blood glucose levels, is also associated with a host of gastrointestinal (GI) side effects that can be troubling to deal with. Have you looked into the time-release Metformin (called Glumetza)? You take your entire daily dose once in the morning, with your breakfast. It is slightly more expensive, but I've found that it really has minimal side effects because the dose is slowly released during the day. The most common side-effects of Metformin are feeling sick, diarrhea and abdominal pain. It is best to take metformin after a meal to decrease stomach side effects including diarrhea. Metformin can cause mild and serious side effects, which are the same in men and women. Here’s what you need to know about these side effects and when you should call your doctor.