| To obtain emergency consultation with a medical toxicologist, in the United States, call 1-800-222-1222 for the nearest regional poison control center. Contact information for poison control centers around the world is available at the WHO website and in the UpToDate topic on regional poison control centers (society guideline links). |
| Clinical presentation |
| Nausea and vomiting are common early symptoms. |
| Patients that subsequently develop liver injury and death may be asymptomatic for hours after an acute ingestion. |
| Diagnostic evaluation |
| In all patients with suspected acetaminophen poisoning, obtain the following: serum acetaminophen concentration, aminotransferases (AST, ALT), PT/INR, and basic chemistry panel (electrolytes, BUN, creatinine). |
| In all patients with a suspected intentional overdose, obtain serum salicylate concentration, fingerstick glucose, ECG, and qualitative pregnancy test in females of childbearing age. |
| Treatment |
| Secure airway, breathing, and circulation as necessary. |
| Give activated charcoal (AC) 50 g to all adult patients presenting within 4 hours of ingestion unless contraindicated; AC may be useful for co-ingestants or extended-release formulation beyond 4 hours. Pediatric AC: 1 g/kg (maximum 50 g). |
Treat with acetylcysteine if: - Serum acetaminophen concentration drawn at 4 to 24 hours after an acute ingestion is above the treatment line on the Revised Rumack-Matthew nomogram.
- Serum acetaminophen concentration is unavailable or will not return within 8 hours of time of ingestion and suspected ingestion of >150 mg/kg (7.5 g total dose regardless of weight) of acetaminophen.
- Reliable history with repeated supratherapeutic ingestion (ie, multiple ingestions during a period greater than 24 hours) and a serum acetaminophen concentrations ≥ 20 mcg/mL (132 micromol/L) or AST/ALT is elevated (unless the elevation is patient's baseline value).
- Unreliable history (eg, time of ingestion is unknown) and serum acetaminophen concentration >10 mcg/mL (66 micromol/L) or AST/ALT is elevated (unless the elevation is patient's baseline value).
- There is evidence of any liver injury with a history of acetaminophen ingestion.
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Oral dosing of acetylcysteine: - Oral dosing is acceptable for non-pregnant patients with a functional gastrointestinal tract and no evidence of hepatic failure.
- Dose 140 mg/kg loading dose (maximum 15 g) followed by 70 mg/kg (maximum 7.5 g per dose) every 4 hours until stopping criteria are met.
- If vomiting occurs within 1 hour of NAC dosing, a full NAC dose should be repeated as rapidly as possible.
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IV dosing of acetylcysteine: - Many protocols exist. Whichever is chosen should deliver at least 300 mg/kg acetylcysteine during the first 20 to 24 hours of treatment.
- One common protocol is the following: 150 mg/kg loading dose (maximum 15 g) over 60 minutes followed by 50 mg/kg (maximum 5 g) infused over 4 hours, then 100 mg/kg (maximum 10 g) infused over the remaining 16 hours. This should be followed by a continuous IV infusion at 6.25 mg/kg per hour until stopping criteria are met. Patients weighing <40 kg: Use a reduced diluent volume (refer to UpToDate content on intravenous acetylcysteine dilution in children).
- IV dosing is acceptable in all cases of acetaminophen toxicity but should be used instead of oral dosing in patients unable to tolerate oral acetylcysteine (eg, intractable vomiting), patients with a medical condition precluding administration of oral acetylcysteine (eg, corrosive ingestion, gastrointestinal bleed), patients with hepatic failure, and pregnant patients.
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| All of the following criteria should be met to stop acetylcysteine treatment: INR is <2, AST/ALT are normal or have decreased 25 to 50% from the peak, serum acetaminophen concentration <10 mcg/mL (66 micromol/L), and the patient is clinically well. |
