I used to take Unisom. It's in tablet form and is scored in the middle so you can cut it in half. I would recommend starting with half. They help you fall asleep, but may not necessarily KEEP you asleep.
I don't take them anymore cuz they started either making me really groggy the next day or giving me a headache. I could probably take 1/4 but I'm fine with just letting things be the way they are, it's a little weird but nobody's complaining, so far.

... Good luck.
Laura