Ambien is a prescription medication primarily used to treat insomnia, a common sleep disorder characterized by difficulty falling asleep or staying asleep. Ambien belongs to a class of drugs known as sedative-hypnotics. It works by affecting certain chemicals in the brain to help initiate sleep and maintain sleep throughout the night. Ambien is available in different formulations, including immediate-release tablets, extended-release tablets (Ambien CR), and sublingual tablets (Edluar).