Cyclobenzaprine
"I have been in hospital for 3 weeks now.  It started out as obstructive jaundice, which they put in a stint and started me on Vidocin.  The vicodin worked great for my abdominal pain, but did nothing for the spasms I started getting in my back after being in the hospital bed for over 2 weeks.  Finally, after 2 days of intensely painful and nearly uncontrolable back spasms, they put me on Flexeril.  I'm finally able to move around and breath normally without triggering more spasms.  Thank God for Flexeril.  The pain is nearly gone.  It didn't shut it out entrirely, but it made it bearable enough that I'm finally able to move, instead of having to stay perfectly still and take shallow breaths to avoid triggering another one."