Lunesta is used to treat insomnia. Symptoms include trouble falling asleep or waking up often during the night. Lunesta's effects typically begin within 30 minutes, helping to reduce the time it takes to fall asleep and increasing the total time spent sleeping. Lunesta carries a Boxed Warning for Complex Sleep Behaviors. Complex Sleep Behaviors have caused serious injury and death. After taking Lunesta pills, you may get up out of bed while still not fully awake and engage in an activity that you are not aware of complex sleep behaviors. The next morning, you may not remember that you did anything during the night. These activities may occur with Lunesta, whether or not you drink alcohol or take other medicines that make you sleepy.