Ambien is a famous brand name for the generic drug Zolpidem. It is preferably used to treat disorders like – insomnia. This drug comes in extended and release forms that help a person fall asleep quickly. The extended-release version of Ambien is available by the name Ambien CR, and the immediate-release version is Ambien IR. The method of taking both drugs is different. Also, the way it will work in your body is not the same.