What is Ambien CR?

Ambien CR, or zolpidem tartrate extended-release, is a prescription sleep aid that works on two levels in your body to fight insomnia. The first of the two layers of the pill gets into your system quickly so you fall asleep with less trouble. The second layer is a controlled-release formula that keeps working through the night to help you to stay asleep or go back to sleep more easily if you should wake up. Ambien CR, which falls into the drug class of sedative/hypnotic, works in the brain to let you sleep by reducing the activity in the brain.