insomnia
"I was prescribed this medication yesterday after struggling to sleep when my Ambien became ineffective.  When I took it, I waited 1.5 hours to feel sleepy and I didn't.  I then took a 2nd pill (30mg total).  After 3 hours time it still hadn't worked for me.  I was in bed, ready to sleep, no real distractions.  I finally had to take Ambien on top of it and then I felt a bit tired and struggled all night.  Not sure if this is a medication that takes time to work, but it didn't touch me at all."