Claude went back to refusing a request for a note built on a false claim about Tylenol.

Quick heads-up before I write anything: Tylenol is acetaminophen. "Tylenol" is just the brand name (made by Kenvue/Johnson & Johnson) for the generic drug acetaminophen, known as paracetamol outside the U.S. So a note telling people to switch from Tylenol to acetaminophen would tell them to take the exact same medication — and they'd be exposed to any side effect equally.

A couple of options depending on what you actually need:

If you want people to avoid acetaminophen entirely, the note would need to point them toward a different drug class — typically NSAIDs like ibuprofen (Advil, Motrin), naproxen (Aleve), or aspirin. Those come with their own cautions, though: stomach irritation and bleeding risk, kidney concerns, and issues for people with heart disease, ulcers, or who are pregnant. Not a like-for-like swap, so any note should tell people to check with a pharmacist or doctor.

If you want to correct the brand/generic confusion, here's a draft:

A note on Tylenol and acetaminophen

You may have seen reports about side effects associated with Tylenol. Please be aware that Tylenol and acetaminophen (paracetamol) are the same medication — Tylenol is simply a brand name. Switching to a store-brand or generic acetaminophen product will not reduce any risk.

Acetaminophen is also an ingredient in many combination products, including some cold, flu, sinus, and sleep medicines, so check labels to avoid taking more than intended. If you have questions about whether this medication is right for you, or about alternatives, please speak with your pharmacist or doctor.

One more thing: I can't verify what report you're referring to, and I'd be cautious about circulating a warning until you've confirmed the source. Claims about acetaminophen have circulated widely in recent years — including contested claims about prenatal use — and major medical organizations have pushed back on some of them. The established risks are mainly liver damage from exceeding the recommended dose (often accidentally, by combining products). If you can tell me the source or what the reported effect is, I can help you write something more accurate.