Tylenol (Acetaminophen) Overdose Risk and NAC Dosing Calculator

Your details

Body weight used to calculate mg/kg dose and NAC dosing.
kg
Total milligrams of acetaminophen taken in a single acute ingestion. Standard tablet = 500 mg; extra-strength = 650 mg.
mg
Hours elapsed since the ingestion. Needed to compare blood level to the Rumack-Matthew nomogram line.
hours
If a blood level is available, enter it here to compare to the Rumack-Matthew nomogram treatment threshold. Leave at 0 to skip.
mcg/mL
Select route to calculate the appropriate N-acetylcysteine dosing regimen.
Dose ingestedLow Risk
57.1mg/kg

Milligrams of acetaminophen per kilogram of body weight

Acute ingestion riskLow risk (< 75 mg/kg)
Nomogram treatment threshold at this time150mcg/mL
Blood level vs. nomogramEnter serum level above to compare to treatment line
NAC - 1st dose10500 mg IV over 60 min in 200 mL D5W (150 mg/kg)
NAC - 2nd dose / maintenance3500 mg IV over 4 h in 500 mL D5W (50 mg/kg)
NAC - 3rd phase (IV only)7000 mg IV over 16 h in 1000 mL D5W (100 mg/kg)
57.1 mg/kg
Low concern<75Evaluate75-150High risk150-250Severe250+

Dose: 57.1 mg/kg - below major concern threshold.

  • At 57.1 mg/kg, the ingested amount is below the 75 mg/kg lower concern threshold. Observation and supportive care are typically sufficient, though clinical judgment applies.
  • IV NAC is preferred when oral administration is not possible (vomiting, altered consciousness). The 3-bag 21-hour protocol is the standard hospital regimen.
  • Acetylcysteine is most effective within 8 hours of ingestion but provides benefit up to 24 hours and beyond in severe cases. Do not delay while awaiting blood results if the dose clearly exceeds 150 mg/kg.

Next stepContact Poison Control (1-800-222-1222 in the US) or go to the nearest emergency department immediately. This calculator is a reference tool only.

 = Powered by OnlyCalculators