Acidosis is the most important single indicator of probable mortality and the need for transplantation. A mortality rate of 95% without transplant was reported in patients who had a documented pH less than 7.30. Other indicators of poor prognosis include chronic kidney disease (stage 3 or worse), hepatic encephalopathy, a markedly elevated prothrombin time, or an elevated blood lactic acid level (lactic acidosis). One study has shown that a factor V level less than 10% of normal indicated a poor prognosis (91% mortality), whereas a ratio of factor VIII to factor V of less than 30 indicated a good prognosis (100% survival). Patients with a poor prognosis are usually identified for likely liver transplantation. Patients that do not die are expected to fully recover and have a normal life expectancy and quality of life. Epidemiology
Many over-the-counter and prescription-only medications contain paracetamol. Because of its wide availability paired with comparably high toxicity, (compared to ibuprofen and aspirin) there is a much higher potential for overdose. Paracetamol toxicity is one of the most common causes of poisoning worldwide. In the United States, the United Kingdom, Australia, and New Zealand, paracetamol is the most common cause of drug overdoses. Additionally, in both the United States and the United Kingdom it is the most common cause of acute liver failure.In England and Wales an estimated 41,200 cases of paracetamol poisoning occurred in 1989 to 1990, with a mortality of 0.40%.
If repeated doses of charcoal are indicated because of another ingested drug, then subsequent doses of charcoal and acetylcysteine should be staggered.Intravenous acetylcysteine is given as a continuous infusion over 20 hours for a total dose 300 mg/kg. Recommended administration involves infusion of a 150 mg/kg loading dose over 15 to 60 minutes, followed by a 50 mg/kg infusion over four hours; the last 100 mg/kg are infused over the remaining 16 hours of the protocol. Intravenous acetylcysteine has the advantage of shortening hospital stay, increasing both doctor and patient convenience, and allowing administration of activated charcoal to reduce absorption of both the paracetamol and any co-ingested drugs without concerns about interference with oral acetylcysteine. Intravenous dosing varies with weight, specifically in children. For patients less than 20 kg, the loading dose is 150 mg/kg in 3 mL/kg diluent, administered over 60 minutes; the second dose is 50 mg/kg in 7 mL/kg diluent over 4 hours; and the third and final dose is 100 mg/kg in 14 mL/kg diluent over 16 hours.The most common adverse effect to acetylcysteine treatment is an anaphylactoid reaction, usually manifested by rash, wheeze, or mild hypotension. May cause infertility or death. Adverse reactions are more common in people treated with IV acetylcysteine, occurring in up to 20% of patients. Anaphylactoid reactions are more likely to occur with the first infusion (the loading dose).