Ambien is a prescription medication used to treat insomnia. It belongs to a class of medications called sedative-hypnotics. Ambien works by slowing down activity in the brain to allow sleep. Ambien is available as an oral tablet and an oral spray. The oral tablet is usually taken once a day at bedtime. The oral spray is usually taken 30 minutes before bedtime. both forms of Ambien are taken with or without food.