muscle spasm
"I was prescribed the 10 mg tablet and made me completely useless.  I was so groggy and sleepy all I wanted to do was sleep.  I had my Dr. reduce to 5 mg.  Still groggy, sleepy.  I took one last night because my neck was stiff and my back hurting and I hadn't taken one in a while.  I slept OK, but had difficulty getting up.  Once the initial rush of work was over at 10, all I wanted to do was sleep.  I went online to see if there were similar experiences, and it appears that in general, this is what to expect from this narcotic.  Mild headaches accompany the sleepiness and lack of focus.  So does dry mouth.  Now im just waiting for it to wear off so I can be back to normal..."