Ambien, also known by its generic name zolpidem, is a prescription medication used to treat insomnia or difficulty sleeping. It belongs to a class of drugs called sedative-hypnotics and works by affecting certain neurotransmitters in the brain to produce a calming effect. Ambien is typically prescribed for short-term use, generally for a few weeks or less, to help people with insomnia initiate and maintain sleep. It comes in immediate-release tablets, as well as an extended-release version called Ambien CR (controlled release), which has a dual-layer design to help individuals fall asleep and stay asleep.