Missed Metformin Dose: What To Do?

In our latest question and answer, the pharmacist discusses what to do in the event of a missed metformin dose.

Question

If you miss your evening dose of metformin , can it be taken a few hours later or should you skip it?

Asked by Pat On Jan 09, 2019

Answered by
Medical Content Reviewed By PharmacistAnswers Staff

On Jan 10, 2019

Metformin is an antidiabetic drug used to improve glycemic control in both adults and children with Type 2 diabetes. Less commonly, it is used 'off-label' for the treatment of polycystic ovary syndrome (PCOS).

If you accidentally miss a scheduled dose, instructions are simple:

  • Take your dose as soon as you remember.
  • If it is almost time for your next dose, only take that dose and do not 'double-up' or take extra.

MedlinePlus, provided by the U.S. National Library of Medicine, specifically states:

What should I do if I forget a dose?
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

The prescribing information for Glucophage, a brand name product containing metformin, states similar instructions:

If you miss a dose of GLUCOPHAGE or GLUCOPHAGE XR, take your next dose as prescribed unless your healthcare provider tells you differently. Do not take an extra dose the next day.

Instructions for a missed dose of metformin applies to all the various formulations of the drug, including:

  • Metformin immediate-release (Glucophage)
  • Metformin extended-release (Glucophage XR, Fortamet, Glumetza)
  • Metformin liquid (Riomet)

A natural concern of missing doses of medication is whether or not you will be adversely affected.

Since metformin is used to control blood sugar, there is certainly a chance it may not be as well controlled after a missed dose. However, if you otherwise have taken the medication consistently, any change or negative effect is likely to be minimal.

This is because metformin is present in your body for long periods of time after dosing. It is distributed and accumulates in red blood cells, with a reported elimination half-life of around 17.6 hours (the elimination half-life of a drug is how long it takes for 50% of it to be eliminated from the body).

Therefore, after one missed dose, even if you only take the drug once daily, it will still have active effects in terms of regulating your blood sugar.

Answer Summary

If you miss a dose of metformin, you should take it as soon as you remember unless otherwise directed by your doctor. However, if it is almost time for your next dose, take only that dose and do not double-up or take extra doses.


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About the Pharmacist

Dr. Brian Staiger Pharm.D

Dr. Brian Staiger is a licensed pharmacist in New York State and the founder of PharmacistAnswers.com. He graduated from the University At Buffalo with a Doctor Of Pharmacy degree in 2010. He has been featured in several publications including the Huffington Post as well as a variety of health and pharmacy related blogs. Please feel free to reach out to him directly if you have any questions or want to connect! [email protected]; Office: 716-389-3076

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