Hydrocodone M365 is a prescription pain medication containing hydrocodone and acetaminophen. The 5 mg/325 mg combination is intended for the management of pain severe enough to require an opioid when alternative treatment options are inadequate. Hydrocodone is an opioid analgesic, while acetaminophen provides additional pain-relieving effects. Because this medication carries important risks, including addiction, misuse, overdose, and potentially life-threatening breathing problems, it should be used only under appropriate medical supervision and exactly as prescribed. Patients should also be aware that excessive acetaminophen can cause serious liver injury. Discuss your medical history, current medications, and any concerns with a qualified healthcare professional before treatment.