Zolpidem
"I had trouble functioning during the day because I couldn't fall asleep until 1 or 2 am, then had to get up at 6 am.  My doctor prescribed 10 mg Ambien (not CR) but because I'm small I decided to cut one in half the first night.  I was able to sleep soundly almost immediately after my head hit the pillow and I slept all night.  That was about three years ago and I am still taking my half pill per night and sleeping well.   I have occasional times (maybe once every two months) that I don't sleep well with them, but I don't blame the pill for that.  Follow the directions, if you don't it isn't the fault of the drug, it's your own fault."