How long does Metformin ER last in your system?

I am a type 2. I have a meter and have been checking sugars to figure out what to eat. I take 3 metformins at night before bed each night. Sometimes when I check it at night it is between 90 - 115 but other times it is 180 or higher. When it has been high I have not eaten anything since dinner or if I do eat it is sugar free jello or some string cheese.

I go to bed and check my sugar before breakfast and it will range from 139 - 170. Sometimes I will wait to eat to see if my sugar will come down and sometimes I will eat anyways. After two hours I check my sugar and it is 90.

Any thoughts would be great.

Metformin XR is extended release metformin. It's action should still be going strong in the morning.

I suffer from morning highs as well. As Sally notes, this is Darn Phenomenon. I found that eating in the morning "resets" things, so I always eat breakfast in the morning, even if it is just two eggs. If I don't eat, my blood sugar can remain elevated and even rise further.

Hi my A1c is 6.5. I see my Dr tomorrow morning.

Thank you for the tips Brian

I was always instructed to take metformin with a meal. Check with your pharmacist and physician concerning this issue. Good luck. Nancy

i will be the cat among the pidgeons!

The liver/brain starts the extra glucose boost starting about 3 am in the morning and keeps up the release thru to 8 to 9 am in morning.

For me a couple of issues:

Loading big doses late at night once seem useless. I have to take a 500 to 750 mg dose at 10:00pm and another dose at 12:00am midnight and that shuts down the Dawn effect and keeps liver caged from about 13:30 am thru 5:30 am on standard metformin. Satndard metformin on me has a about 2 hour lasting in the blood at peak blood dosage and cuts back excess liver glucose release.

my understanding is that ER has twice the working range of 3 to 6 hours while standard metformin has a 1 to 3 hour period. And this is not talking about residuals in the cells that last longer but have no effect on my liver.

I have watched this riot on the cgms many times as well as confirming on the caveman machine.

I have found for me taking my meal time dose one hour before a meal most beneficial while the standard recommendation is at/with meal time.

For some reason there is this belief that if you add bigger dose, body/liver will redistribute dosage over longer time period. All my testing says non,no nyet,. I have to distribute doses across/spread over the clock to get even ditribution and effect. (same for heart pills and others)

And as stated check with your Doctor/pharmacist.

Brian, Thank you for your insights…I guess not eating will actually raise BS? Sigh. I am going back to the Atkins/Dr. Bernstein way of eating…and wondering if I can take regular metformin for breakfast and lunch, but maybe have the Metformin ER - at dinner for the “Darn/Dawn” phenomenon…I will have to discuss this my MD.
Hope you are still on this forum!!