Tylenol (acetaminophen) and regular NyQuil should not be taken together because NyQuil already contains acetaminophen, and combining them increases the risk of liver damage from an acetaminophen overdose. In adults, the usual absolute maximum daily acetaminophen dose is about 4,000 mg, and staying well below that is safer, especially if there is any liver disease or regular alcohol use.
Why it is a problem
- Most NyQuil formulations contain acetaminophen along with other ingredients, so taking Tylenol adds extra acetaminophen on top of what is already in NyQuil.
- Too much acetaminophen can cause serious liver injury, which may not cause symptoms right away but can be life‑threatening.
What to do instead
- Use either NyQuil alone or Tylenol alone for pain/fever, not both together, and carefully follow the dosing directions on the package.
- If you already took them together once and your total acetaminophen dose in 24 hours is still under 4,000 mg and you have no liver disease or heavy alcohol use, serious harm is unlikely, but you should not keep combining them.
When to seek help
- Get urgent medical help or contact poison control if you took more than the labeled dose or feel nausea, vomiting, upper right abdominal pain, confusion, or yellowing of the skin or eyes after taking these medicines.
- If you need both a nighttime cold medicine and pain control, ask a doctor or pharmacist to help choose products that do not duplicate acetaminophen.
