Paracetamol poisoning
Paracetamol poisoning happens when someone takes too much paracetamol[1] ‒ a common drug for relieving pain ‒ within a short time.[2] The poisoning tends to happen in three phases.[3]
Phases
First phase
The first phase begins within hours of someone overdosing on paracetamol.[4][5] Symptoms include nausea, vomiting, sweating, and a pale look,[4][5] though some patients do not show symptoms.[4][5]
Second phase
The second phase occurs within 24 and 72 hours of the overdose when liver damage happens.[4][5] The damage is typically found in liver cells that metabolize the paracetamol.[4][5]
Liver biopsy tends to show coagulative necrosis in zone 3 of the liver acinus, around the central venules, as these hepatocytes have higher concentrations of cytochrome P450 enzymes compared to zone 1 hepatocytes around the acinus' portal venule.[6]
The liver damage is often not noticed until right upper quadrant abdominal pain occurs,[7] while the international normalized ratio (INR) and the liver transaminases ALT and AST rise to abnormal levels.[7][8]
Pathophysiology
This can happen when the sulfate and glucuronide pathways, and the cytochrome P450 enzyme system, are saturated with toxic reactive intermediates from the metabolized paracetamol ‒ especially N-acetyl-p-benzoquinone imine (NAPQI).[9]
The lack of glutathione to detoxify the excess NAPQI allows it to damage liver cells massively,[9] causing liver failure.[9] Acute kidney failure may also occur due to either hepatorenal syndrome or multiple organ dysfunction syndrome.[8][9]
Third phase
The third phase follows at 3 to 5 days, marked by massive liver cell deaths and fulminant liver failure,[3] along with sepsis, brain swelling, kidney failure, and multiple organ failure that cause death.[3]
Treatment
Paracetamol poisoning can be treated by activated[10] charcoal.[11] The antidote acetylcysteine is sometimes given.[11] A liver transplant may be required if the liver damage is huge.[11] Liver failure is rare when early treatment is given.[11] Death occurs in 0.1% of the treated cases.[11]
Paracetamol Poisoning Media
Awareness poster on acetaminophen abuse
Acetylcysteine is the antidote for paracetamol toxicity.
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Related pages
References
- ↑ Also called Panadol or Tylenol in some countries.
- ↑ Paracetamol Indications, Uses, Dosage, Drugs Interactions, Side effects. medicaldialogues.in (May 31, 2023). Retrieved 8 November 2024.
- ↑ 3.0 3.1 3.2 Acetaminophen poisoning and toxicity. Pediatrics 55 (6) (1975). p. 871–76. doi:10.1542/peds.55.6.871.
- ↑ 4.0 4.1 4.2 4.3 4.4 Severe metabolic acidosis early in paracetamol poisoning. British Medical Journal (Clinical Research Ed.) 285 (6345) (September 1982). p. 851–2. doi:10.1136/bmj.285.6345.851.
- ↑ 5.0 5.1 5.2 5.3 5.4 Early metabolic acidosis and coma after acetaminophen ingestion. Annals of Emergency Medicine 33 (4) (April 1999). p. 452–6. doi:10.1016/S0196-0644(99)70312-4.
- ↑ LiverTox: Clinical and Research Information on Drug-Induced Liver Injury (4 May 2019)National Institute of Diabetes and Digestive and Kidney Diseases. Retrieved 19 November 2023.
- ↑ 7.0 7.1 Heard KJ. Acetylcysteine for Acetaminophen Poisoning. The New England Journal of Medicine 359 (3) (July 2008). p. 285–92. doi:10.1056/NEJMct0708278.
- ↑ 8.0 8.1 Nephrotoxicity after acute severe acetaminophen poisoning in adolescents. Journal of Toxicology: Clinical Toxicology 39 (5) (2001). p. 441–5. doi:10.1081/CLT-100105413.
- ↑ 9.0 9.1 9.2 9.3 * Evidence that acetaminophen and N-hydroxyacetaminophen form a common arylating intermediate, N-acetyl-p-benzoquinoneimine. Molecular Pharmacology 18 (3) (November 1980). p. 536–42. Retrieved 2025-04-19.
- Comparison of N-acetylcysteine and methylene blue, alone or in combination, for treatment of acetaminophen toxicosis in cats. American Journal of Veterinary Research 56 (11) (November 1995). p. 1529–33. doi:10.2460/ajvr.1995.56.11.1529.
- Richardson, JA. Management of acetaminophen and ibuprofen toxicoses in dogs and cats. Journal of Veterinary Emergency and Critical Care 10 (4) (July–September 2000). p. 285–291. doi:10.1111/j.1476-4431.2000.tb00013.x.
- ↑ Activated Charcoal - Uses, Side Effects, and More. WebMD. Retrieved April 17, 2025.
- ↑ 11.0 11.1 11.2 11.3 11.4 Ferri, Fred F.. Ferri's Clinical Advisor 2017 E-Book: 5 Books in 1 (in en) (2016)Elsevier Health Sciences. p. 11. ISBN 978-0-323-44838-3. Retrieved 6 July 2017.
