Ambien is a brand name for the drug zolpidem, which is commonly prescribed to treat insomnia, a sleep disorder characterized by difficulty falling asleep or staying asleep. Zolpidem belongs to a class of medications called sedative-hypnotics, which work by slowing down brain activity to help induce sleep. While Ambien can be effective for many people in helping them get to sleep, it's important to use it exactly as prescribed by a healthcare professional, as it can be habit-forming and may cause dependence if misused.