Cyclobenzaprine
"I take this medication for severe abdominal pain associated with IBS. It's the best medication I have found in terms of controlling the pain, and works even better than painkillers. However, like others have noted, it makes me VERY drowsy and just gives me an "out of it" feeling even after it wears off. I would definitely not recommend taking it if you have to drive, take a test - really anything but the most basic physical and cognitive functions are impaired."