Metformin helps control blood sugar and increase your body's sensitivity to insulin. The drug is available only by prescription and sold under several different brand names, including Fortamet, Glumetza, Riomet, Glucophage and Glucophage XR. Your dosage will depend on your normal diet and exercise habits -- too much metformin can lead to low blood sugar and hypoglycemia. Always follow your doctor's directions for taking your medication.
How It Works
Metformin works by limiting your liver's production of glucose and stopping your body from absorbing some of the glucose in your bloodstream. Additionally, metformin increases your body's sensitivity to insulin, allowing your pancreas to produce less insulin. Keeping blood sugar levels stable can decrease hunger and food cravings, leading to weight loss. Metformin is not an appetite suppressant, nor does it boost metabolism; to lose weight, you'll still need to pay close attention to your diet and increase your physical activity.
Standard vs. Extended Release Options
The amount of metformin you'll take depends on why you are using the medication, how often you take the medicine, other medications you might be taking and the time between doses. The National Institutes of Health explains that metformin is available as a tablet or a liquid solution. Tablets come in an extended release dose -- Glucophage XR -- or in a standard release option. Extended release pills are designed to be taken once daily, with your evening meal. Standard tablet and liquid solutions may be taken once or multiple times daily -- with meals. Metformin should be taken with food. Always follow your doctor's orders.
It's typical to start with a 500 milligram dose once daily, then increase both the amount of medication and the frequency. If you're using the extended release tablets, you may start with 1,000 milligrams, taken with your evening meal. Your dose should not exceed 2,000 milligrams daily. Standard tablets and liquid metformin can be taken once, twice or even three times daily. You may take 500 milligrams of metformin with each meal. The liquid dose of 5mL is comparable to the 500 milligram tablet.
The most common side effects of using metformin are diarrhea, indigestion, nausea, upset stomach, vomiting and headache. According to Kristi Monson, Pharm.D., diarrhea is the most common side effect, and can affect about 50 percent of people taking metformin. The extended release version seems to have fewer side effects. A rare but serious side effect of metformin is lactic acidosis, a buildup of lactic acid in your bloodstream that can potentially be fatal.