Biguanide (Metformin)
Metformin’s main site of action is at the liver to reduce the excessive sugar release seen in Type 2 Diabetes. Metformin does not cause weight gain, and is usually the first choice of medication to treat Type 2 Diabetes. However, if you have kidney or liver problems, heart failure, or are very sick, your provider may need to decrease the dose of metformin or discontinue it. The main side effects of metformin are diarrhea and stomach upset or cramping. It is important to take metformin with food to reduce stomach-related side effects. A very rare side effect (less than 1 person per 100,000 patients taking metformin) is lactic acidosis (a build-up of lactic acid in your blood). The data available thus far suggests that this is an extremely rare event and often happens in situations where there is another cause of lactic acidosis such as severe illness.
Generally, the people who develop this rare side effect are the ones who shouldn’t have been taking metformin in the first place (people with kidney problems or heart failure, or alcoholism). Metformin is also called a euglycemic medication, which means it may restore the blood glucose to normal or non-diabetic levels. If you are treated with metformin alone, you should not experience low blood glucose. And if you are treated with metformin and other blood glucose normalizing (“euglycemic”) agents (such as thiazolidinediones, starch blockers, incretins or SGLT-2 inhibitors) you also should not have low blood glucose . However, hypoglycemia or low blood glucose, may develop when you take metformin together with insulin releasing pills and insulin, because they raise insulin levels and increase the risk of developing lows.
In short, metformin decreases glucose production by the liver
Side effects
The most common side effects of Metformin include:
- Diarrhea and stomach cramping
- Low blood glucose, when used in combination with insulin-releasing pills (secretagogues) and insulin