Does paracetamol (acetaminophen) break a fast?

A paracetamol tablet, called acetaminophen in the US and Canada, has no calories, sugar or protein. It does not break a fast for weight loss, autophagy, gut rest or blood sugar, the four goals this site sorts answers by.

Unlike ibuprofen, paracetamol can be taken with or without food. That means you can take a dose during a fast with a glass of water and stay fasted. Taken correctly, paracetamol very rarely causes side effects.

Stay within the dose on the pack. For adults using 500 mg tablets, one dose is 1 or 2 tablets. Leave at least 4 hours between doses, and take no more than 8 tablets in 24 hours. If you weigh less than 50 kg (110 lb), you may need a lower dose, so check with a pharmacist. The US label warns that more than 4,000 mg in 24 hours can cause severe liver damage.

Many cold and flu remedies also contain paracetamol, so check every label to avoid a double dose. Ask a doctor or pharmacist before taking it if you have a liver or kidney condition, or drink heavily. If you use a liquid or chewable version during a strict fast, check its label for sugar.

Do not take paracetamol for more than 3 days unless a doctor tells you to. Adults can take it at the same time as ibuprofen if needed, though it is worth trying each on its own first. If you take warfarin, ask a doctor or pharmacist before using paracetamol.