I took Sudafed at 9:30 pm, is it OK to take NyQuil at 3:00 am?

Hello Patient9260, it depends on what kind of Sudafed you took, there are many formulations of Sudafed. Many kinds of cold medications contain acetaminophen(Tylenol) too much Tylenol can cause liver damage. I believe you can take up to 4000 mg of acetaminophen in one day and be safe. Also be sure the Nyquil does not contain the same ingredients as in the Sudafed or you could get a double dose. but if you took the Sudafed at 9:30 and the Nyquil at 3 am that's about 6 and a half hours, you should be fine.