Paracetamol (Acetaminophen) Toxicity Calculator for Dogs & Cats
Paracetamol (acetaminophen) dose in mg/kg and what to expect in cats and dogs, with the antidote dose of N-acetylcysteine.
Results are calculated in your browser. Always double-check before administering and use your clinical judgement.
How it is calculated
Dose (mg/kg) = total mg ÷ body weight (kg).
Cats: toxicosis generally occurs at 40–50 mg/kg, but some cats showed signs at 10 mg/kg. Dogs: acute signs are not seen unless the dose exceeds 100 mg/kg; methaemoglobinaemia has been reported above 200 mg/kg. Antidote: N-acetylcysteine, 140 mg/kg loading dose of a 5% solution (IV or PO), then 70 mg/kg PO every 6 hours for five to seven additional treatments [1].
Worked example
250 mg in a 4 kg cat = 62.5 mg/kg.
Frequently asked questions
How much paracetamol is toxic to a cat?
Toxicosis generally occurs at 40–50 mg/kg, though some cats have shown clinical signs at 10 mg/kg [1].
What is the antidote for paracetamol poisoning?
N-acetylcysteine: a loading dose of 140 mg/kg of a 5% solution IV or PO, followed by 70 mg/kg PO every 6 hours for five to seven additional treatments [1].
More toxicology calculators
References
For veterinary professionals. Information supports — never replaces — clinical judgement; always check the current product label and local regulations.