Ambien is the brand name for zolpidem tartrate, a prescription medication primarily used for the short-term treatment of insomnia, a sleep disorder characterized by difficulty falling asleep or staying asleep. It belongs to a class of drugs known as sedative-hypnotics, which act on the brain to slow down activity and promote sleep. Ambien was first approved by the U.S. Food and Drug Administration (FDA) in 1992 and quickly became one of the most commonly prescribed sleep medications worldwide. Ambien is available in several formulations. The immediate-release form helps individuals fall asleep quickly, usually within 15 to 30 minutes. The extended-release form, sold under the brand name Ambien CR, has two layers—one that dissolves quickly to induce sleep and another that releases more slowly to help maintain sleep throughout the night. Other related products include Edluar (a sublingual tablet) and Intermezzo, which is designed for people who wake up in the middle of the night and have difficulty returning to sleep.