Ambien may be purchased online since it can be used to help you fall asleep faster or, in its extended-release (ER) version, to help you stay asleep. Ambien CR is Ambien’s extended-release formulation. It is a non-narcotic sedative-hypnotic that has been particularly designed to aid in sleep maintenance and inducing sleep. Ambien CR pills are made up of two layers: a fast-dissolving outer layer to promote sleep and a slow-dissolving second layer to keep you asleep. Depending on your symptoms and complaints, the doctor will choose which version of the Ambien medicine is best for you.