Magnesium citrate
"I was plugged for more than a week. Tried Miralax, docusate, Milk of Magnesia, and fiber. Got nothing. Cause was opiates unbeknownst to me. Doctor said to try magnesium citrate.  45 min later all systems go. Been in the "oval office" off and on for a few hrs but I'll take it. I did not feel good before."