Metformin Side Effects
Although most people tolerate metformin well, there are some potential side effects of the medication. Some examples of common metformin side effects include diarrhea, nausea, and gas. Also, there are some more serious side effects of metformin that you should report immediately to your healthcare provider, such as symptoms of high blood sugar, chest pain, or signs of an allergic reaction.
As with any medicine, there are possible side effects with metformin (Glucophage®) or metformin ER (Glucophage XR®). However, not everyone who takes metformin will experience side effects. In fact, most people tolerate the drug well. When side effects do occur, in most cases they are minor and either require no treatment or can be easily treated by you or your healthcare provider.
(The metformin side effects discussed below are not a complete list of the side effects reported with this drug. Your healthcare provider can discuss a more complete list of metformin side effects with you.)
Metformin and metformin ER have been studied thoroughly in clinical trials, with many people having been evaluated. In these studies, side effects occurring in a group of people taking the drug are always documented and compared to side effects that occur in a similar group of people not taking the medicine. Based on these studies, the most common metformin side effects include:
- Diarrhea -- occurring in up to 53.2 percent of people
- Nausea or vomiting -- in up to 25.5 percent
- Gas -- in up to 12.1 percent
- Weakness -- in up to 9.2 percent
- Indigestion -- in up to 7.1 percent
- Abdominal discomfort (or stomach discomfort) -- in up to 6.4 percent
- Headache -- in up to 5.7 percent.
Generally, people have fewer side effects when taking the long-acting form (metformin ER). Common side effects for metformin ER include diarrhea (in up to 9.6 percent of people) and nausea or vomiting (in up to 6.5 percent of people).