I have just switched from Metformin to Metformin ER (extended release) and so far I am really pleased. My question is: The RX states that I should this pill with my evening meal. Does it really make any difference if I take it with breakfast (my preference) or with the evening meal?

Dr. David Erani


The extended release formulation is designed to allow for gradual absorption of the medication over a 24-hour period. It is suggested that it be taken with a meal to minimize the risk of adverse gastrointestinal effects and with the evening meal because of slower gastric emptying overnight. Also, its main effect is on fasting blood glucose levels. If you take it in the morning and it doesn’t quite last 24 hours, fasting blood glucose levels may not be well-controlled. For these reasons, extended-release metformin may be more effective when taken with the evening meal rather than the morning meal. That having been said, it would not be dangerous to take it with breakfast, and if you are doing so and getting good results, it would be hard to say that you must make a change.

May 16, 2013 at 11:18 am