Posted 5/21/2018 12:28 AM (GMT 0)
For mine I was instructed to drink peg-lyte (sorry, no idea if that's different from Miralax) and take four dulcolax, and it started to "kick in" within 45 min- 1 hour. That said, I also had a couple loose BMs earlier that day that I suspect were a result of drinking black coffee and being in the middle of a flare, so I'm not sure if that is typical.
A friend of mine recently had a colonoscopy and she didn't start having BMs until about 2.5 hours after.