Ambien (zolpidem) is a prescription medication used to treat insomnia by helping individuals fall asleep faster. It belongs to a class of drugs called sedative-hypnotics, which work by affecting GABA receptors in the brain to produce a calming effect. Ambien is available in immediate-release (IR) and extended-release (ER or CR) formulations. The IR version helps initiate sleep quickly, while the ER version has a second layer that aids in maintaining sleep.