|Metformin is an "antihyperglycemic" drug, it prevents high blood sugars but does not cause hypoglycemia (low sugars). The main mechanism of action is to decrease the production of glucose by the liver. Usually if glucose levels are low, the liver produces glucose and releases it into the blood stream to provide the energy that we need to live. In the Diabetic the regulation of liver production of glucose is lost so the liver continues to manufacture glucose continuously. It makes the body more sensitive to your own insulin and improves insulin resistance. This drug also decreases the production of glucose at night by the liver so it tends to give a better blood glucose in the morning.
The medication last 12 hours in the blood so it has to given twice a day to have a 24 hr effect. It is manufactured in 500 mg (round scored) and 850 mg (oval) tablets. Side effects are usually of the stomach and intestines, there may be excess gas, cramping or loose stools. Usually the side effects are less if one starts on a low dosage and works the dosage up gradually. Dosage range is from 1000 mg to 2500 mg daily.
I suggest starting with 1/2 tab daily for a few days to see if your body tolerates the medication. After a few days try increasing to 1/2 tab twice a day for a week, then increase to 1 tab twice a day. If you have stomach or bowel distress, drop back to the previous dose level for 2 weeks, then try increasing again. The goal is to achieve Fasting glucose levels before breakfast in the morning of less than 7 mmol/L (125 mg/dl). If you have not achieved this glucose level you will probably have to increase the dose to 2 tablets twice a day. The maximum daily dose is 2500 mg (five 500 mg tabs or three 850 mg tabs). There is seldom any significant benefit in increasing the dose past 2000 mg a day.
Your physician should be contacted for any problems or unanswered questions.