Can You Take Miralax And Fiber At The Same Time?

In our latest question and answer, the pharmacist discusses whether or not Miralax and Benefiber can be taken at the same time.

Question

Can I give my 6-year-old daughter Miralax and Benefiber at the same time?

Asked by Mary On Jul 28, 2022

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Jul 28, 2022
Last updated Mar 29, 2024

Key points

  • There is no interaction between Miralax and fiber products. They are safe to use together.

Answer

Miralax (polyethylene glycol 3350) and fiber can be used together at the same time as there is no interaction between the two. Ideally, fiber and dietary changes are the first line of treatment for constipation but Miralax can certainly be added on if needed. 

Fiber Products

There are a variety of fiber products available over the counter including Citrucel, Metamucil, and Benefiber. All are classified as soluble fiber. These fiber products are useful for bulking up the stool as well as hastening foods through our digestive tract and are typically used as a first-line option for constipation. If you take medication, fiber should be taken at least 2 hours before or 2 hours after other medications are taken by mouth. Also, be sure to drink a good amount of water with your dose and after your dose.

Miralax

Miralax is the brand name for polyethylene glycol 3350. Polyethylene glycol is known as an osmotic laxative. It increases the fluid in the GI tract by binding water and causes this water to be retained in the stool. Polyethylene glycol is not absorbed into your body, it just moves through your GI tract. In terms of side effects, it sometimes can cause diarrhea, increase how often you go to the bathroom, and flatulence. Typically, doses of 17 grams or less don't cause too many problems.

Taking Fiber With Miralax

While both fiber products and Miralax can be taken regularly, fiber is generally considered a first-line option for constipation and can be taken daily as a supplement. Miralax can be taken daily as well, but usually only for chronic constipation. In cases where both Miralax and a fiber product (such as Benefiber) are used, the Miralax is discontinued when constipation symptoms are controlled.

If constipation remains under control with fiber and diet solely, Miralax can be used simply as needed for more severe symptoms as they come up.

References

  • Long term efficacy, safety, and tolerabilitity of low daily doses of isosmotic polyethylene glycol electrolyte balanced solution (PMF-100) in the treatment of functional chronic constipation., PubMed
  • Medical Management of Constipation, PubMed

About the Pharmacist

Dr. Brian Staiger, PharmD

Dr. Brian has been practicing pharmacy for over 13 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical, program development, and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Dr. Brian Staiger also has herbalist training and educational certificates in the field of medical ethnobotany. Feel free to send him an email at [email protected]! You can also connect with Dr. Brian Staiger on LinkedIn.

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