Hi, Lunesta contains eszopiclone which belongs to the group of medications known as sedative-hypnotics is used in the treatment of certain sleep problems like insomnia. Similarly, Lunesta generic 2 mg also contains eszopiclone that is used for same purposes. But, this medication may cause feeling of constant tickle in the bladder and frequent urge to urinate which are less common side effects of this medication. Frequent urge to urinate, may interrupt someone s decent sleep. This medication also can cause painful or difficult urination. If someone experiences these side effects during taking this medication, then he or she should inform his or her prescribing doctor and his or her doctor may stop this medication and choose another medication for him or her. Again, Flexeril contains cyclobenzaprine that is a muscle relaxant is used short term to treat muscle spasms from musculoskeletal conditions. But, using eszopiclone like Lunesta together with cyclobenzaprine like Flexeril may increase side effects such as drowsiness, dizziness, confusion, impairment in thinking, judgement or motor coordination, difficulty concentrating etc. Again, Percocet contains both oxycodone and acetaminophen or paracetamol, in where oxycodone is an opioid pain reliever and acetaminophen or paracetamol is a non opioid pain reliever. But, using Lunesta together with Percocet may cause central nervous system depression that can lead to serious side effects such as respiratory distress, coma or even death. Take care. Hope I have answered your questions. Let me know if I can assist you further. Regards, Dr. Zubayer Alam, General And Family Physician