muscle spasm
"Been taking this for months for DDD/DJD (neck).  I notice severe pain when I don't take this nightly but still have muscle pain even when I do.  Main side effect is severe grogginess and dry mouth/hung over feeling.  I have to be in bed about 20 mins after taking it or I am walking into walls literally.  I have to drink a lot of water before bed to combat the hung over feeling.  Recently switched back to Flexeril.  Have also taken Robaxin but that didn't help much either.  I get headaches when I take Tramadol and any narcotic so I take Tylenol during the day."