Tylenol Overdose
Assess acetaminophen (Tylenol) overdose risk instantly. Enter weight and amount ingested to check toxicity level, mg/kg ratio, and NAC treatment recommendations.
About This Calculator
The Tylenol Overdose Risk Assessment Calculator helps evaluate the severity of an acute acetaminophen (Tylenol/paracetamol) overdose. By entering your body weight and the estimated total dose ingested, the calculator determines whether you have crossed the hepatotoxic threshold of 150 mg/kg and provides a risk level with N-acetylcysteine (NAC) treatment recommendations.
Acetaminophen is the active ingredient in Tylenol and over 600 other over-the-counter and prescription medications. Accidental overdose is a leading cause of acute liver failure in the US, UK, and India. The Rumack-Matthew nomogram is the standard clinical tool used by emergency physicians to assess toxicity risk, and this calculator applies the same mg/kg threshold methodology to provide an immediate risk assessment.
The calculator uses established medical guidelines: a single acute ingestion of more than 150 mg/kg is potentially hepatotoxic and warrants NAC therapy. Doses exceeding 200 mg/kg are considered high risk, and above 250 mg/kg the risk of severe liver injury is substantial. Time since ingestion is tracked because NAC is most effective within 8 hours of overdose.
Regional Notes
India: Paracetamol (the local name for acetaminophen) is widely available without prescription. Common formulations include 500 mg and 650 mg tablets. Poison control centers: AIIMS New Delhi (011-26589391) and the National Poisons Information Centre (1800-116-116).
US: Tylenol brands include Regular Strength (325 mg), Extra Strength (500 mg), and Arthritis (650 mg). The FDA has limited adult Extra Strength to 3,000 mg/day from all sources. Poison Control: 1-800-222-1222.
UK: Paracetamol is sold as Panadol and own-brand products. The MHRA limits pack sizes to 32 tablets (16 for pharmacy sales) to limit overdose risk. NHS: call 111 for urgent advice or 999 for emergency.
Frequently Asked Questions
What is a Tylenol (acetaminophen) overdose?
A Tylenol overdose occurs when someone takes more than the recommended dose of acetaminophen. Single doses exceeding 150 mg per kg of body weight can cause liver damage. Early treatment with N-acetylcysteine (NAC) can prevent serious liver injury.
What is the toxic dose of Tylenol?
A single dose of more than 150 mg per kg of body weight (or more than 7,500 mg total in adults) is considered potentially hepatotoxic. Doses above 200 mg/kg are high risk, and above 250 mg/kg indicate severe risk requiring urgent medical intervention.
How is acetaminophen overdose treated?
The antidote for acetaminophen overdose is N-acetylcysteine (NAC), which is most effective when given within 8 hours of ingestion. Treatment may also include activated charcoal if given within 1-2 hours and supportive care in a hospital setting.
How does the Rumack-Matthew nomogram work?
The Rumack-Matthew nomogram plots serum acetaminophen levels against time since ingestion to determine toxicity risk. A level above the treatment line (starting at 150 mcg/mL at 4 hours) indicates need for NAC therapy. This calculator provides an initial risk assessment based on reported ingested dose.
When should someone seek medical help after Tylenol overdose?
Anyone who suspects a Tylenol overdose should seek emergency medical care immediately, even if symptoms are not yet present. Early treatment with NAC within 8 hours is crucial for preventing liver damage. Call poison control or visit the nearest emergency room.
What are the symptoms of Tylenol overdose?
Symptoms progress in stages: Stage 1 (0-24 hours): nausea, vomiting, sweating, pallor. Stage 2 (24-72 hours): right upper quadrant pain, elevated liver enzymes. Stage 3 (72-96 hours): liver failure, jaundice, coagulopathy. Some patients may be asymptomatic initially.