paracetamol(redirected from Acetamanophen)
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An antipyretic and analgesic, with potency similar to that of aspirin.
paracetamolAn over-the-counter analgesic used for headaches, muscle or joint pain, and fever, which lacks anti-inflammatory activity.
≥ 300 mg/L
Overdose can cause fatal liver failure. Up to 10% of hospitalisations for overdose and 40% of acute hepatic failure are linked to paracetamol overdose, which is more often accidental—e.g., children, alcoholics—than suicidal. Doses of > 150 mg/kg/24 hours cause acute liver failure.
Clinical stage of paracetamol toxicity
1. 1–24 hours—Non-specific.
2. 24–48 hours—Right upper quadrant pain, tenderness with elevated liver enzymes.
3. 72–96 hours—Marked increase in liver enzymes; fulminant hepatic failure, coagulopathy, acidosis.
4. 4–14 days—Liver recuperates or patient dies.
Pathogenesis of paracetamol overdose
90% is metabolised in the liver to non-toxic glucuronide and sulphate conjugates; 5% is oxidised by cytochrome p450 to NAPQI, which covalently binds to hepatocyte macromolecules, leading to hepatocyte death; 5% is excreted unchanged in urine.