Insomnia, or poor sleep, is fairly common but it does not usually last for long. It may mean that you have difficulty getting off to sleep, or you may wake up for long periods during the night, or you may wake up too early in the morning. Zopiclone belongs to a class of medicines commonly called Z drugs. It works by acting on the way messages are sent in your brain, which help you to sleep. It reduces the time it takes for you to fall asleep and increases the length of time you spend sleeping.