Symptoms and treatment for overdosage and antidote(s): 650 mg tab: Symptoms of paracetamol overdosage sometimes occur 6 to 14 hours after ingestion and persist for 24 hours. Diarrhoea, pallor, nausea, vomiting, anorexia (loss of appetite), abdominal pain and unusual increased sweating.
Liver damage may become apparent 12 to 48 hours after ingestion. Abnormalities of glucose metabolism and metabolic acidosis may occur. In severe poisoning, hepatic failure may progress to encephalopathy, coma and death. Acute renal failure with acute tubular necrosis may develop even in the absence of severe liver damage. Cardiac arrhythmias have been reported.
Prompt treatment is essential in the management of paracetamol overdosage. Any patient who has ingested about 7.5 g more of paracetamol in the preceding 4 hours should undergo gastric lavage. The plasma or serum-paracetamol concentration should be determined as soon as possible, but no sooner than 4 hours after ingestion. Generally treatment is required if the paracetamol concentration is higher than a line (the 200 line) drawn on semi -log/linear paper joining the points 200 mg per litre (1.32 mmol per litre) at 4 hours and 30 mg per litre (0.20 mmol per litre) at 15 hours. Acetylcysteine is given either intravenously or by mouth and tends to be preferred to methionine, which is given by mouth.
500 mg tab & oral susp: Empty stomach via induction of an emesis or gastric lavage. Activated charcoal may interfere with absorption of orally administered acetylcysteine (antidote used to protect against acetaminophen induced hepatotoxicity) and decrease its efficacy. Although activated charcoal is recommended if ingestion of other substances in addition to acetaminophen is confirmed or suspected, its removal by gastric lavage may be advisable before the antidote is given.