What is the treatment guideline for a 14-year-old patient who has taken an overdose of 24 Dolo (paracetamol) tablets, is stable, but complains of stomach ache?

Immediate IV NAC Administration is Indicated

For this 14-year-old patient who ingested 24 Dolo (paracetamol) tablets, you must initiate intravenous N-acetylcysteine (NAC) immediately, regardless of timing or acetaminophen levels, given the potentially hepatotoxic dose and presence of symptoms. 1, 2, 3

Dose Assessment and Risk Stratification

• 24 tablets of standard Dolo (500mg each) = 12 grams total, which exceeds the hepatotoxic threshold of 10g/day and represents a dose >150 mg/kg for most 14-year-olds 2, 4
• This ingestion places the patient at high risk for severe hepatotoxicity, with mortality risk directly correlating to treatment delay 1, 2
• The stomach ache may represent early gastrointestinal symptoms or evolving hepatotoxicity 2

Immediate Management Algorithm

Step 1: Start IV NAC Without Delay

Do not wait for acetaminophen levels or laboratory results before initiating NAC 1, 2, 3

• If timing of ingestion is unknown or >8 hours has passed: administer loading dose immediately 3
• If acetaminophen concentration cannot be obtained within 8 hours: administer loading dose immediately and continue full 21-hour protocol 3
• The critical window is 0-8 hours post-ingestion where NAC provides maximal hepatoprotection (only 2.9% develop severe hepatotoxicity when treated within 8 hours vs 26.4% when started 10-24 hours later) 1, 2

Step 2: IV NAC Dosing Protocol (21-Hour Regimen)

Standard three-bag IV protocol 1, 2, 3:

• Loading dose: 150 mg/kg IV over 15 minutes 1, 3
• Second dose: 50 mg/kg IV over 4 hours 1, 3
• Third dose: 100 mg/kg IV over 16 hours (total 21-hour protocol) 1, 3
• Total dose: 300 mg/kg over 21 hours 3

Step 3: Urgent Laboratory Assessment

Obtain immediately (do not delay NAC for these results) 2, 3:

• Acetaminophen level (if ≥4 hours post-ingestion; levels drawn <4 hours are unreliable) 2, 3
• AST, ALT (baseline and repeat every 12-24 hours for first 72 hours) 2, 4, 3
• INR/PT (coagulopathy is red flag for liver failure) 2, 4
• Bilirubin, creatinine, BUN 3
• Blood glucose, electrolytes 3

Step 4: Consider Activated Charcoal (Time-Dependent)

• If patient presents within 4 hours of ingestion, give activated charcoal 1g/kg orally just prior to starting NAC 1, 2
• Do not delay NAC administration even if activated charcoal is given 1
• Charcoal is ineffective if >4 hours have passed since ingestion 2

Critical Red Flags Requiring Extended NAC Beyond 21 Hours

Continue or restart NAC immediately if any of the following develop 1, 2:

• Any elevation in AST or ALT above normal 1, 2
• Rising transaminases (even if initially normal) 1, 2
• Any coagulopathy (INR >1.5) 2, 4
• Detectable acetaminophen level at end of 21-hour protocol 1, 2
• AST/ALT >1000 IU/L (severe hepatotoxicity—continue NAC until transaminases declining and INR normalizes) 1, 2

Special Considerations for This Case

Why IV Route is Preferred Over Oral

• IV NAC is superior for established or evolving hepatotoxicity 1
• The 21-hour IV protocol may be too short for some patients; monitor closely and extend if red flags develop 1, 5
• Oral NAC (72-hour protocol) is equally effective but less practical in acute presentations with potential vomiting 1, 5

Rumack-Matthew Nomogram Limitations

• The nomogram does NOT apply if timing is uncertain or if this represents repeated supratherapeutic ingestion over >24 hours 2, 4, 3
• For single acute ingestion with known timing: plot acetaminophen level drawn 4-24 hours post-ingestion on nomogram 2, 3
• If level plots above "possible toxicity" line: continue full 21-hour NAC protocol 2, 3
• However, given the 12g dose, treat regardless of nomogram placement 2

Critical Pitfalls to Avoid

1. Do not delay NAC while awaiting acetaminophen levels—efficacy is time-dependent, and low/absent levels do not rule out toxicity if ingestion was remote 1, 2

2. Do not stop NAC prematurely at 21 hours if any red flags are present (elevated transaminases, detectable acetaminophen, coagulopathy) 1, 2

3. Do not rely solely on patient stability—hepatotoxicity may not manifest clinically for 24-72 hours, but hepatocellular injury begins within hours 2, 6

4. Do not assume stomach ache is benign—monitor closely for evolving hepatotoxicity with serial liver function tests 2, 4

Monitoring and Disposition

• Admit for observation with serial AST/ALT/INR every 12-24 hours for minimum 72 hours 2, 4
• ICU-level care required if: AST/ALT >1000 IU/L, any coagulopathy, altered mental status, or signs of acute liver failure 1, 2
• Contact transplant center immediately if severe hepatotoxicity develops (AST/ALT >3500 IU/L, INR >1.5, encephalopathy) 2, 4

Evidence for Late NAC Administration

Even if >24 hours have passed since ingestion, NAC still provides significant benefit and reduces mortality from 80% to 52% in fulminant hepatic failure 1, 2, 7, 8. Late NAC administration (even 72+ hours post-ingestion) has successfully reversed hepatic failure in case reports 7, 8.