I've been dealing with a blaring headache most of the day and called the pharmacist about whether or not I could take Tylenol with Coumadin (I'm on 2mg) and she told me to check with my Doctor. I can't wait until Monday to deal with this. Will one 350 mg pill make a difference in INR levels?
It shouldn't make much, if any, difference. Although studies that looked at mixing acetaminophen (Tylenol) and an anti-coagulant like Coumadin are conflicting, it is generally thought that as long as you don't take high doses for an extended period of time, it's not a problem.
Here is a link to the Drug Interaction Checker that explains the possible interactions: Drug Interactions Between Coumadin and Tylenol
Not a great link, not a well sourced article.
Generally the issue is if you take greater than 2 grams per day of Tylenol.