Miralax and Fecal Incompetence?

Hi all. I have IBS-C, and after an awful experience with a hemorrhoid, I've been using miralax every day for about a month now. I mix almost a full cap (right up to the line) into a large glass of water every morning. I now have a BM every day, which is really nice. Of course, it's usually watery/full on diarrhea...but that didn't bother me too much, because it was better than being constipated. That is, until today.

I've been working a lot this week, and have slipped up a few times on my diet (eating greasy foods, ranch dressing, etc.) Today, I suddenly got these terrible cramps, and, well, I was unable to make it to the toilet in time.

Is it possible that Miralax has caused my IBS-C to transition to IBS-D? Should I take a smaller dose? Has anyone else experienced this?

I use Miralax every day. What I normally take (with water) is half a cap (the advised dose) and a near full cap when I miss a day. I take it at my biggest meal, dinner.
With laxative, or any sort, you have to be careful with the amount you intake each day. Otherwise, you could face...problems like the episode you had.
I think your body doesn't like handling so much laxative that you've been taking and decided to rebel. Try to ease up a bit and see what happens.

BTW, when you find yourself having that horrible urge to go diarrhea, a need you can't delay or avoid, skip manners and run for it. Don't be afraid to look like an idiot on a mad dash to safety. I know, I've been there, and I regret nothing.