The initial treatment for uncomplicated paracetamol overdose, similar to any other overdose, is gastrointestinal decontamination. In addition, the antidote, acetylcysteine plays an important role. Paracetamol absorption from the gastrointestinal tract is complete within 2 hours under normal circumstances, so decontamination is most helpful if performed within this timeframe. Absorption may be somewhat slowed when it is ingested with food. There is considerable room for physician judgement regarding gastrointestinal decontamination, activated carbon administration is the most commonly used procedure, however, gastric lavage may also be considered if the amount ingested is potentially life threatening and the procedure can be performed within 60 minutes of ingestion. Syrup of ipecac has no role in paracetamol overdose because the vomiting it induces delays the effective administration of activated carbon and oral acetylcysteine.
Activated carbon adsorbs paracetamol, reducing its gastrointestinal absorption. Administering activated carbon also poses less risk of aspiration than gastric lavage. Previously there was reluctance to give activated carbon in paracetamol overdose, because of concern that it may also absorb acetylcysteine. Studies have shown that no more than 39% of an oral acetylcysteine is absorbed when they are administered together. Other studies have shown that activated carbon seems to be beneficial to the clinical outcome. It appears the most benefit from activated carbon is gained if it is given with 2 hours of ingestion. However, administering activated carbon later than this can be considered in patients who may have delayed gastric emptying due to co-ingested drugs or following ingestion of sustained or delayed release paracetamol preparations. Activated carbon should also be administered if co-ingested drugs warrant decontamination. There are conflicting recommendations regarding whether to change the dosing of oral acetylcysteine after the administration of activated carbon, and even whether the dosing of acetylcysteine needs to be altered at all.
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