Lunesta is a prescription medication used to treat insomnia, helping individuals fall asleep and stay asleep. Its active ingredient, eszopiclone, belongs to a class of drugs known as sedative-hypnotics. Lunesta is typically taken shortly before bedtime and is effective for both short-term and long-term use, depending on a doctor's recommendation. Common side effects of Lunesta may include drowsiness, dizziness, and a bitter taste in the mouth. It is important to follow the prescribed dosage and consult a healthcare provider if any unusual symptoms occur. Patients should also avoid alcohol while taking Lunesta, as it can increase the risk of side effects.