The drug dose should be calculated using their current weight. Their toxic dose (mg/kg) should be calculated using their booking or pre-pregnancy weight.

Pregnancy - patients who are pregnant can be treated using this protocol.

For this group a weight of 110kg should be used to calculate their toxic dose (mg/kg) and their drug dose.

Low weight - patients 110kg can be treated using this protocol.

Use the NHSGGC Acetylcysteine Prescribing and Administration Chart which is located in all Emergency Departments and Medical Receiving areas.

Therapeutic excess paracetamol overdose (ingested total overdose in >1 hour time period no self-harm intent).

Staggered overdoses (ingested total overdose in >1 hour time period in the context of self-harm).

≥75mg/kg of paracetamol over a period of 24 hours (ingested total overdose in ≤1 hour time period).

Patients who have ingested (any of the following):.

Therapeutic excess (any of the following):.

Self-harm - all patients (irrespective of reported ingested dose or timing, clinical judgement required if historical).

Patient should undergo a further hospital medical assessment if: The standard local protocol is acetylcysteine IV in two infusions with the option to extending depending on biochemical criteria. In some scenarios the paracetamol level can be plotted against a single treatment line on the paracetamol treatment nomogram. Management of a patient suffering from a paracetamol overdose is dependent on the presentation scenario and time from ingestion. It may also be effective up to and possibly beyond 24 hours. It has near 100% efficacy in preventing paracetamol-induced hepatotoxicity if given within the first 8 hours from ingestion of overdose. A cetylcysteine IV (N-acetylcysteine, Parvolex ®, NAC) is the treatment of choice. In overdose the potential risk of a patient having significant liver damage is directly proportional to the amount of paracetamol ingested.

TOXBASE (password required) should continue to be used as a clinical decision support resource in conjunction with the National Poisons Information Service (NPIS, 03). While the MHRA has not yet approved its use, TOXBASE now lists the regime as a recognised treatment period. The same dose of N-acetylcysteine is administered in this regime but over a 12-hour ( not 21-hour) treatment period.

This guideline reflects the local NHSGGC policy on acetylcysteine use in adult paracetamol overdoses and is based on the Scottish and Newcastle Anti-emetic Pre-treatment for Paracetamol Poisoning (SNAP) regime.

Antidote for acetaminophen toxicity