Ambien is a brand name for the drug zolpidem, which is a sedative-hypnotic medication. It is commonly prescribed to treat insomnia, a sleep disorder characterized by difficulty falling asleep or staying asleep. Ambien works by enhancing the effects of a neurotransmitter called gamma-aminobutyric acid (GABA) in the brain, which helps to calm and slow down brain activity, allowing for better sleep. It is typically taken orally, and its effects can start within 30 minutes of ingestion.