Will Taking Miralax Result In Getting Too Much Fiber?
In our latest question and answer, the pharmacist discusses concerns with combining Miralax and Citrucel.
Each dose of Miralax is 17 grams. If I take Citrucel and eat regular throughout the day, how do I not get too much fiber?
Dec 22, 2022- Miralax is not a fiber but an osmotic laxative that works by drawing water into your intestines, so taking it with fiber supplements like Citrucel won't cause you to get too much fiber.
- Miralax and Citrucel work differently in your body and can be safely used together to help with constipation.
- Unlike fiber supplements, Miralax does not risk causing bowel obstruction even if you take more of it.
Answer
Thanks for reaching out! Miralax isn't a fiber, so you don't have to worry about getting too much if you take it with Citrucel.
While Citrucel contains methylcellulose, which is a type of fiber and classified as a 'bulk-forming laxative', Miralax is not a fiber at all, but rather contains polyethylene glycol, an 'osmotic laxative'.
Miralax And Citrucel Work Differently
Bulk-forming laxatives, like Citrucel, absorb liquid in the gastrointestinal (GI) tract which acts to soften and increase the bulk of the stool. The increased bulk stimulates how quickly the contents of the gastrointestinal tract move, which results in an easier, and quicker passage of the stool in those with constipation.
Miralax (polyethylene glycol 3350) is an osmotic agent which stimulates the release of water and binds it in the gastrointestinal tract. It is not thought to increase how quickly things move through the GI tract although the increased water secretion can increase stool frequency.
Although these mechanisms of action look similar, there certainly are some differences:
- Miralax stimulates water secretion into the gastrointestinal tract and then binds to it
- Citrucel does not stimulate water secretion. Existing water in the GI tract mixes with Citrucel and forms a gel-like substance
- Citrucel can increase how quickly the contents of the GI tract move
Another important difference between Citrucel and Miralax is that Citrucel can sometimes, although rare, cause bowel obstruction or worsen constipation if you take too much at one time since it forms a gel-like substance, versus Miralax which just stimulates water secretion and then binds to it.
Final Words
I hope you found this helpful!
You can certainly use Miralax and Citrucel together without worrying about taking in too much fiber. In fact, we have written on the topic before of combining Miralax and fiber, which can be found here.
References & sources
Glossary — Terms in This Answer
- Methylcellulose
- A type of plant-based fiber used in laxatives like Citrucel that absorbs water and adds bulk to stool.
- Bulk-forming laxative
- A type of laxative that works by absorbing water in the intestines to soften and increase the size of stool.
- Polyethylene glycol
- An active ingredient in Miralax that draws water into the intestines to help soften stool.
- Osmotic laxative
- A type of laxative that works by pulling water into the intestines to make stool softer and easier to pass.
- Gastrointestinal tract
- The digestive system, including the stomach, small intestine, and large intestine, where food moves through the body.
- Bowel obstruction
- A blockage in the intestines that prevents normal passage of food and waste through the digestive system.
Dr. Brian Staiger, PharmD
Doctor of Pharmacy, board certified clinical pharmacist (BCPS), American Herbalist Guild, Medication Therapy Management certified
Brian Staiger, PharmD, BCPS, is a licensed pharmacist with more than 13 years of experience across retail pharmacy, clinical pharmacy, medication safety, pharmacy program development, and healthcare administration. He is the founder of HelloPharmacist.com, where he helps patients...
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