muscle spasm
"My doctor just prescribed 10mg (cyclobenzaprine) 2X daily, due to disc protrusion in my C6-7 and muscle spasms in my neck and shoulders.  I have been taking it for a couple days now and it works great for the pain, however it does make me extremely drowsy! The night before last I took one at bedtime and it knocked me out cold and I slept great, but it made me very fatigued the next day.  Luckily it was my day off so I spent it in bed, but my spasms came back in the early afternoon, so I took another one.  Again, out cold!  Slept all day and decided not to take another one last night because I was still very drowsy.  I will reduce my dosage to 5mg around 6pm and see how that works.  Definitely not taking during the day unless in severe pain!"