Paracetamol poisoning is a common medical emergency caused by overdose of paracetamol (acetaminophen). If not treated early, it can lead to serious liver damage, hepatic failure, and death. This article provides easy notes for MBBS students, nursing students, and exam preparation.
What is Paracetamol Poisoning?
Paracetamol toxicity usually occurs after ingestion of a high dose of medicine intentionally or accidentally. Toxic metabolites damage liver cells when glutathione stores become depleted.
Toxic Dose of Paracetamol
| Age Group | Approx Toxic Dose |
|---|---|
| Adults | More than 10–15 g single overdose |
| Children | Usually weight-based assessment required |
Risk increases in: chronic alcohol use, malnutrition, starvation, liver disease, enzyme-inducing drugs.
How Does Toxicity Occur?
Normally paracetamol is metabolized safely in the liver. In overdose, toxic metabolite NAPQI accumulates and depletes glutathione, causing hepatic necrosis.
Symptoms of Paracetamol Poisoning
| Time After Overdose | Common Findings |
|---|---|
| 0–24 hours | Nausea, vomiting, sweating, may be asymptomatic |
| 24–72 hours | Right upper abdominal pain, rising liver enzymes |
| 72–96 hours | Liver failure, jaundice, coagulopathy |
| 4+ days | Recovery or worsening hepatic failure |
Diagnosis
- History of overdose
- Serum paracetamol level (after 4 hours)
- Liver function tests
- INR/PT
- Renal function tests
- Blood sugar
Management of Paracetamol Poisoning
1. Initial Stabilization
- Assess airway, breathing, circulation
- Monitor vitals
- IV access
2. Activated Charcoal
If patient presents within 1 hour of large ingestion, activated charcoal may help reduce absorption.
3. Antidote: N-Acetylcysteine (NAC)
NAC is the main treatment. It replenishes glutathione and protects the liver.
NAC Dose (General IV Protocol)
| Step | Dose |
|---|---|
| Loading | 150 mg/kg IV |
| Second infusion | 50 mg/kg over next few hours |
| Third infusion | 100 mg/kg over remaining period |
Always follow your hospital protocol or latest guidelines.
Methionine
Methionine may be used as an oral alternative when NAC is unavailable in selected cases.
Complications
- Acute liver failure
- Renal failure
- Hypoglycemia
- Encephalopathy
- Metabolic acidosis
- Death in severe untreated cases
When to Refer to Specialist Liver Centre?
- INR rising significantly
- Acidosis
- Oliguria or rising creatinine
- Altered consciousness
- Hypoglycemia
Liver Transplant Consideration
Severe hepatic failure with poor prognostic signs may require urgent liver transplant evaluation.
Quick Revision Summary
Frequently Asked Questions (FAQ)
N-Acetylcysteine (NAC).
As early as possible, ideally within 8 hours.
Yes, severe overdose can cause acute liver failure.
Yes, if given early after ingestion.
Conclusion
Paracetamol poisoning is a time-sensitive emergency. Prompt recognition, serum level testing, and NAC treatment are essential to prevent liver damage and save lives.
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