Esomeprazole
"I originally took this for three months a year ago.  It worked great during the time with minimal side effects.  Went off of it with no problem and had no heartburn for quite a long time.  When I had an acid reflux episode last fall, I took it for about a week, where all these weird side effects happened.  Developed lower right back pain, joints kept cracking when moving, and the occasional stomach pain in the lower left abdomen.  Am disappointed since it was the only thing that really helped my reflux."