opioid-induced constipation
"My doctor gave me some samples of Movantik as well as an Rx for it.  Took first pill on an empty stomach one hour before a meal as directed.  Cramps started about an hour after taking it.  Cramps increased in intensity over the next few hours until I was experiencing the worst stomach pains of my life.  I've actually gone to the ER for stomach pain less severe than this.  Initial normal bowel movement quickly turned into total diarrhea (with the most horrible odor imaginable).  Additional side effects included intense nausea and just an overall feeling of being very sick.  These symptoms continued for an agonizing 8 to 10 hours.  I reported the side effects to my doctor and he advised against taking any more of it.  This drug is a nightmare"