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Patient handout

Acetaminophen (paracetamol) overdose

PRODUCTION

1. Your condition

This handout is for acetaminophen (paracetamol) overdose. Your care team identified this based on: reported ingestion of acetaminophen / paracetamol.

Other reasons your team may use this plan: detectable serum acetaminophen level; unexplained alt elevation in poly-substance/intentional ingestion; intentional overdose / suicide attempt.

2. Your medications

Take these medications exactly as prescribed. Do not stop or change a dose without talking to your provider.

MedicationStarting doseHowWhenWhat it does
acetylcysteine150 mg/kg (max 110 kg → 16,500 mg)IVover 60 minutes (Prescott load)Prescott regimen — Prescott Lancet 1979; modified to 60-min infusion (originally 15 min) to reduce anaphylactoid reactions

Plan: APAP antidote — N-acetylcysteine (Prescott IV 21-h vs PO 72-h)

3. Your action plan

Use these zones to know what to do based on how you feel.

GREEN — Recovery — labs normalising, NAC complete
If you have:
  • ALT trending downward — AASLD 2023 (Stravitz)
  • INR <2.0 — ACMT 2023
  • No encephalopathy — AASLD 2023 (Stravitz)
  • Tolerating PO — NICE 2024
Do this:
  • Avoid all acetaminophen-containing products for at least 2 weeks — NICE 2024
  • Read all labels — many combination cold/flu products contain acetaminophen — NICE 2024
  • Hard cap of 3 g/day acetaminophen in healthy adults; 2 g/day if regular alcohol use or chronic liver disease — Heard NEJM 2008
  • Avoid alcohol while on any acetaminophen for at least 4 weeks — AASLD 2023 (Stravitz)
  • Follow primary-care visit within 1 week — NICE 2024
YELLOW — Caution — return precautions
If you have:
  • New nausea/vomiting — NICE 2024
  • Right-upper-quadrant pain — NICE 2024
  • Yellow skin or eyes — NICE 2024
  • Confusion — AASLD 2023 (Stravitz)
  • Dark urine — NICE 2024
Do this:
  • Return to ED immediately — NICE 2024
  • Do not take any acetaminophen — NICE 2024
  • Bring all medication bottles — NICE 2024
RED — Crisis — psych safety + suicide prevention
If you have:
  • Recurrent suicidal thoughts — NICE 2024
  • Plan to repeat overdose — NICE 2024
  • Worsening depression — NICE 2024
Do this:
  • Call 988 (Suicide & Crisis Lifeline) — NICE 2024
  • Go to nearest ED — NICE 2024
  • Do not stay alone — contact emergency contact / family — NICE 2024
  • Confirm follow-up with psychiatry within 7 days — NICE 2024

4. When to seek emergency care

Call 911 or go to the nearest emergency room right away if you have:

  • 4-h+ APAP level above the 150 mg/L (US) / 100 mg/L (UK) treatment line on Rumack-Matthew nomogram — Rumack-Matthew 1975
  • Time since ingestion >8 h, unknown timing, or staggered ingestion — nomogram does not apply — ACMT 2023
  • Arterial pH <7.3 after fluid resuscitation (KCC single-criterion threshold) — O'Grady 1989 KCC(life-threatening)
  • INR >6.5 (PT >100s) AND creatinine >300 µmol/L AND grade III/IV HE — O'Grady 1989 KCC(life-threatening)
  • Lactate >3.5 mmol/L after fluid resuscitation (refined KCC) — Bernal 2002
  • Reported ingestion >30 g (or >500 mg/kg in pediatric) — NICE 2024
  • Pregnant patient with APAP overdose at any level above treatment line or with unknown timing — Heard NEJM 2008

5. Follow-up

Psychiatry safety plan, hepatology if injury, PCP med review, social work, poison-prevention education, child protection if pediatric

6. Sources

Guideline: 2023 AASLD Practice Guidance on Acute Liver Failure + 2023 ACMT NAC Duration + 2024 UK NPIS/RCEM Paracetamol Guideline + 2014/2023 EXTRIP APAP + Kings College Criteria (O'Brien 1989)

  1. pubmed.ncbi.nlm.nih.gov/26957510
  2. pubmed.ncbi.nlm.nih.gov/30992913