Opioid and acetaminophen combinations are used to treat moderate to severe pain, such as pain from surgery, injury, or chronic conditions like arthritis. These medications work by combining an opioid, which changes how your brain responds to pain, with acetaminophen (Tylenol), which reduces fever and relieves pain. Most of these medications are taken orally, but some may come in other forms. Examples include hydrocodone/acetaminophen, oxycodone/acetaminophen (Percocet), and tramadol/acetaminophen.