Will Taking Miralax Result In Getting Too Much Fiber?

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.