Trazodone is an older class of anti-depressant known as an SARI. It has a pretty short half life, so I've used it on an as-needed basis before bed. It really works well.
Fluoxetine has a very long half life, so it's not something you use right before bed. It takes about two weeks to build up enough that I notice a difference, but that difference is very noticeable. It does not make me sleepy. Its main effect is that it keeps me asleep, which is what I have the most trouble with.
I've heard it can cause insomnia in some people, especially in the first couple of weeks, but that's not the case with me.
If you do take it, 5-10mg/day is enough to get maximum benefit. No study out there supports the insane 20-40mg doses that doctors hand out these days.