Hi there. I just found mayo connect and saw your post. I am not a doctor. I can only give you my experience with constipation. My son is 23 and has struggled his entire life with constipation and GI issues. We tried everything but nothing ever worked. We spent 2 decades trying to figure out how to get a normal BM when the only way he could go to the bathroom for years was if he was given a glycerin suppository. Sometimes it worked, sometimes we had to use multiple suppositories, sometimes he ended up impacted and we had to do an enema. About 3 years ago, we found a new GI (our old one retired). He put my son on a magnesium citrate supplement and prunelax minitabs-these are OTC. We added Miralax back in at night and only take the prunelax 4x a week (every day was too much). He does take the magnesium citrate gummy and miralax daily. He has been able to have a BM daily (sometimes twice!) without any difficulty. You can also buy liquid magnesium citrate OTC at your local Walmart, grocery store, etc. That is typically used for someone who is severely impacted and hasn't used the bathroom in days. He recommended (in the beginning before we got his dosing right with the new meds) to try having him drink half a bottle. If that didn't work in a 1/2 hour, to finish the bottle and within an hour, you'll be running for the bathroom.
Hope this helps! I know it made a HUGE difference fore my son.

Nothing works for me. I am on iron pills every other day. Take Miralax 2 times a day, eat prunes 4 a day, add chia seeds, and flax seeds to my diet, plus now eating oatmeal and either I go or don't then it just comes out when walking. Nothing helps.