From the Guidelines
A Tylenol (acetaminophen) overdose requires immediate intervention as it can cause severe hepatotoxicity, and as a paramedic, your pre-hospital treatment options should prioritize administering activated charcoal and providing supportive care to minimize morbidity and mortality. As a paramedic, you should expect to see patients initially presenting with nausea, vomiting, abdominal pain, and malaise within the first 24 hours. Later signs include right upper quadrant pain, jaundice, and altered mental status indicating liver damage.
Pre-Hospital Treatment Options
Your pre-hospital treatment options include:
- Administering activated charcoal (1 g/kg orally) if the ingestion occurred within 1-2 hours and the patient is alert with intact airway reflexes 1
- Providing supportive care including IV access, fluid resuscitation with normal saline for hypotension, antiemetics such as ondansetron 4 mg IV for vomiting, and cardiac monitoring
- Obtaining information about the amount ingested, time of ingestion, and any co-ingestants
Definitive Treatment
The definitive treatment is N-acetylcysteine (NAC), but this is typically initiated at the hospital after serum acetaminophen levels are obtained. Transport the patient promptly to an appropriate facility, as NAC is most effective when started within 8 hours of ingestion 1. Acetaminophen toxicity occurs because the liver's detoxification pathways become saturated, leading to the formation of a toxic metabolite (NAPQI) that depletes glutathione and causes hepatocellular necrosis.
Key Considerations
It is essential to note that the Rumack-Matthew nomogram can be used to determine the risk of hepatotoxicity, and NAC should be administered to patients with possible or probable risk for hepatotoxicity, ideally within 8 to 10 hours postingestion 1. Additionally, NAC may still be of value 48 hours or more after ingestion, and it can be given orally or intravenously 1.
From the FDA Drug Label
DOSAGE AND ADMINISTRATION General Regardless of the quantity of acetaminophen reported to have been ingested, administer acetylcysteine solution immediately if 24 hours or less have elapsed from the reported time of ingestion of an overdose of acetaminophen. The stomach should be emptied promptly by lavage or by inducing emesis with syrup of ipecac. Draw blood for predetoxification acetaminophen plasma assay and baseline SGOT, SGPT, bilirubin, prothrombin time, creatinine, BUN, blood sugar and electrolytes. Administer the loading dose of acetylcysteine, 140 mg per kg of body weight.
As a paramedic, in the case of a Tylenol overdose, you can expect to:
- Administer acetylcysteine solution immediately if 24 hours or less have elapsed from the reported time of ingestion
- Empty the stomach promptly by lavage or by inducing emesis with syrup of ipecac
- Draw blood for predetoxification acetaminophen plasma assay and baseline tests
- Administer the loading dose of acetylcysteine, 140 mg per kg of body weight 2 Pre-hospital treatment options include:
- Inducing emesis with syrup of ipecac
- Administering activated charcoal (if indicated)
- Maintaining fluid and electrolyte balance based on clinical evaluation of state of hydration and serum electrolytes 2
From the Research
Tylenol Overdose Expectations
- A Tylenol overdose can lead to serious hepatotoxicity, with most adults requiring an ingestion of about 12g or more acetaminophen before being at risk of serious liver injury 3.
- Peak serum transaminase activities usually occur 48-96 hours after acute ingestion, and it is possible for patients to present in liver failure days after ingestion with undetectable serum acetaminophen concentrations 3.
- Patients who have chronically ingested excessive acetaminophen doses and develop hepatotoxicity usually present with liver failure, and renal failure is more common in this population 3.
Pre-Hospital Treatment Options
- Activated charcoal can be considered if local poison center policies support its prehospital use, a toxic dose of acetaminophen has been taken, and fewer than 2 hours have elapsed since the ingestion 4.
- However, the use of activated charcoal more than four hours after acetaminophen overdose may still provide additional patient benefit over N-acetylcysteine (NAC) therapy alone, as it was associated with reduced incidence of liver injury in one study 5.
- N-acetylcysteine (NAC) is the specific antidote available for serious overdoses of acetaminophen, and its main mechanism of action is to maintain intracellular glutathione stores to detoxify the electrophilic acetaminophen metabolite 3.
- The concomitant use of activated charcoal and NAC is not recommended until further studies are completed, as one study found that activated charcoal may adsorb and inactivate NAC 6.
Patient Referral Criteria
- Any patient with stated or suspected self-harm or who is the recipient of a potentially malicious administration of acetaminophen should be referred to an emergency department immediately, regardless of the amount ingested 4.
- Patients less than 6 years of age should be referred to an emergency department if the estimated acute ingestion amount is unknown or is 200 mg/kg or more, while patients 6 years of age or older should be referred if they have ingested at least 10g or 200 mg/kg (whichever is lower) or when the amount ingested is unknown 4.
- Patients referred to an emergency department should arrive in time to have a stat serum acetaminophen concentration determined at 4 hours after ingestion or as soon as possible thereafter 4.