Paracetamol poisoning
Paracetamol poisoning happens when someone takes too much paracetamol ‒ a common drug for relieving pain ‒ within a short time. The poisoning tends to happen in three phases.
Phases
First phase
The first phase begins within hours of someone overdosing on paracetamol. Symptoms include nausea, vomiting, sweating, and a pale look, though some patients do not show symptoms.
Second phase
The second phase occurs within 24 and 72 hours of the overdose when liver damage happens. The damage is typically found in liver cells that metabolize the paracetamol.
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.
The liver damage is often not noticed until right upper quadrant abdominal pain occurs, while the international normalized ratio (INR) and the liver transaminases ALT and AST rise to abnormal levels.
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).
The lack of glutathione to detoxify the excess NAPQI allows it to damage liver cells massively, causing liver failure. Acute kidney failure may also occur due to either hepatorenal syndrome or multiple organ dysfunction syndrome.
Third phase
The third phase follows at 3 to 5 days, marked by massive liver cell deaths and fulminant liver failure, along with sepsis, brain swelling, kidney failure, and multiple organ failure that cause death.
Treatment
Paracetamol poisoning can be treated by activated charcoal. The antidote acetylcysteine is sometimes given. A liver transplant may be required if the liver damage is huge. Liver failure is rare when early treatment is given. Death occurs in 0.1% of the treated cases.
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.
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- ↑ "Acute Hepatic Necrosis". LiverTox: Clinical and Research Information on Drug-Induced Liver Injury (Internet). National Institute of Diabetes and Digestive and Kidney Diseases. 4 May 2019. PMID 31689035. Retrieved 19 November 2023.
- 1 2 Heard KJ (July 2008). "Acetylcysteine for Acetaminophen Poisoning". The New England Journal of Medicine. 359 (3): 285–92. doi:10.1056/NEJMct0708278. PMC 2637612. PMID 18635433.
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- Rumbeiha WK, Lin YS, Oehme FW (November 1995). "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): 1529–33. doi:10.2460/ajvr.1995.56.11.1529. PMID 8585668.
- Richardson, JA (July–September 2000). "Management of acetaminophen and ibuprofen toxicoses in dogs and cats" (PDF). Journal of Veterinary Emergency and Critical Care. 10 (4): 285–291. doi:10.1111/j.1476-4431.2000.tb00013.x. Archived from the original (PDF) on November 22, 2008.
- ↑ "Activated Charcoal - Uses, Side Effects, and More". WebMD. Retrieved April 17, 2025.
- 1 2 3 4 5 Ferri, Fred F. (2016). Ferri's Clinical Advisor 2017 E-Book: 5 Books in 1. Elsevier Health Sciences. p. 11. ISBN 978-0-323-44838-3. Archived from the original on September 10, 2017. Retrieved July 6, 2017.
