#acetaminophen

Acetaminophen/paracetamol has a hard stop upper dose limit, above which it becomes extremely toxic.

That limit is 4g (8 “extra strength” (500mg) tablets) in 24 hours (about 2 tablets every 6 hours).

A single dose of 22 extra strength tablets can kill you.

Taking 12 or more tablets per day for more than a week can also kill you (this is about 3 tablets every 6 hours).

Symptoms of overdose take up to 24 hours to manifest, and are fairly difficult to distinguish from other problems. They include abdominal pain (especially right upper quadrant), nausea, malaise, and confusion.

The antidote (n-acetylcystine) must be given within 8hours of ingestion in order to be useful.

After 10 hours the only thing that will work is a liver transplant.

You might think “why would I ever accidentally take so much?”

Well, acetaminophen is in almost everything in the cold/flu/pain aisle. Migraine combos like Excedrin, cold and flu combos like NyQuil, basically anything that says “non-aspirin pain relief”, and anything that’s branded as a fever reducer. It’s all probably acetaminophen/paracetamol.