Can You Crush Or Cut Metformin?

In our latest question and answer, the pharmacist discusses whether or not metformin can be cut, split or crushed.

Question

I'm diabetic and take metformin. The tablets are really large, so I'm wondering if I can crush them and take them that way.

Asked by Sammy On Jan 06, 2022

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Jan 15, 2022
Last updated Sep 22, 2022

Key points

  • Immediate-release metformin products can safely be cut, split, or crushed.
  • Metformin extended-release products (Glucophage XR, Fortamet, Glumetza, and associated generics) should not be cut, split, or crushed.
  • Crushing, cutting or splitting an extended-release metformin product will destroy the release mechanism, causing the entire dose to be released at once.

Answer

Hello and thank you for reaching out!

Being a pharmacist and having seen my fair share of metformin tablets, I certainly know how large they are, and how they can be difficult to swallow.

Whether or not you can crush or cut your metformin tablets depends on which type of metformin you are taking, as there are multiple forms.

The immediate-release metformin 500mg (and other strengths) can be cut in half without negatively affecting the medication, which may be necessary if you have difficulty swallowing large tablets or need to take 'half' doses.

Most manufacturers of metformin tablets do not make the tablet with a 'score' mark (indentation in the middle of the tablet) unfortunately, making it sometimes difficult to successfully cut precisely in half. Due to this, a pill cutter is recommended versus using a knife as designed pill cutters will provide the cleanest cut.

It is important that you take both halves of the medication as soon as possible and not store cut tablets for extended periods of time. Although metformin can be cut as mentioned above, split tablets no longer have the protective outer coating that most intact tablets have. This could make them more susceptible to moisture. Be sure to use split tablets as soon as you can and store the unused half in a moisture-resistant container.

It is important to note that only immediate-release metformin products can be cut or crushed. The extended-release metformin products cannot be.

Different Metformin Products

As mentioned, there are multiple metformin products available, and only one can be crushed or cut (immediate-release metformin).

In fact, there are five different branded metformin products (and associated generics):

  • Glucophage
  • Glucophage XR
  • Fortamet
  • Glumetza
  • Riomet

Riomet is an oral solution so that one is not applicable to this question.

Glucophage XR, Fortamet, and Glumetza are all extended-release metformin products, and, I imagine, you may be wondering why there are so many, and how they differ.

While they all contain extended-release metformin, the release mechanism for each is different:

  • Glucophage XR utilizes a 'dual hydrophilic polymer matrix'
  • Fortamet uses 'osmotic technology'
  • Glumetza uses 'gastric retention technology'

There isn't too much of a clinical difference between any of these, and going into detail about the different extended-release mechanisms isn't really the point of this answer, so the main takeaway here is that none of them can be cut or crushed.

Crushing/Cutting Metformin (Immediate-Release Only)

As mentioned, only immediate-release metformin can safely be crushed or cut.

If you are having trouble swallowing the tablets (they are large), crushing or cutting is certainly an option.

There are a number of generic manufacturers of immediate-release metformin tablets, and some have a 'score' mark, making them easier to cut. If your pharmacy stocks the scored tablets, I'd recommend requesting those.

I also want to note that if you plan on crushing immediate-release tablets, they are not flavored or sweetened, so you'll want to mix the crushed powder with some type of food (typically applesauce or pudding is recommended) and take it that way.

Why You Can't Crush Extended-Release Metformin

If you crush extended-release metformin products (e.g. Glucophage XR, Glumetza, Fortamet, and associated generics), the extended-release mechanism of the tablet will be destroyed.

Instead of releasing the drug over a long period of time as intended, the entire dose gets released at once, which negates the benefits of the tablet in the first place.

Extended-release metformin products do have an advantage over immediate-release ones as most individuals taking them report they are better tolerated in terms of side effects (less nausea, cramping, etc...). Additionally, they are generally dosed only once daily, instead of multiple times daily, making them more convenient.

I mention this just to emphasize the point that there is a reason why your doctor prescribed you the extended-release form. If you destroy the tablet, you lose the benefits of that extended-release mechanism.

As a final point here, the prescribing information for all the extended-release products warns not to crush them. The following is from the FDA-approved prescribing information for Glucophage XR:

Patients should be informed that GLUCOPHAGE XR must be swallowed whole and not crushed or chewed, and that the inactive ingredients may occasionally be eliminated in the feces as a soft mass that may resemble the original tablet.
Glucophage XR Prescribing Information

Final Words

Thanks again for reaching out to us! I hope this answer helps!

References

  • Glucophage XR Prescribing Information, AccessFDA
  • Fortamet Prescribing Information, AccessFDA
  • Glumetza Prescribing Information, AccessFDA
  • Clinical development of metformin extended-release tablets for type 2 diabetes: an overview, PubMed

About the Pharmacist

Dr. Brian Staiger, PharmD

Dr. Brian has been practicing pharmacy for over 11 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Feel free to send him an email at Hello@HelloPharmacist.com! You can also connect with Dr. Brian Staiger on LinkedIn.

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