Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

Acetaminophen Poisoning

(Paracetamol Poisoning; Acetaminophen Overdose; Paracetamol Overdose)
by Krisha McCoy, MS
Definition

Acetaminophen poisoning is an overdose of the over-the-counter (OTC) pain medicine acetaminophen (eg, Tylenol). These drugs are usually safe when used as recommended and the maximum daily dose is not exceeded.

Patients with chronic diseases (especially liver disease) need to be especially careful not to exceed the maximum daily dose. Acetaminophen poisoning may occur as a result of one large dose or chronic overdoses. This is a potentially serious condition that requires care from your doctor.

Causes

An overdose of acetaminophen can result from:

  • Accidental overdose (eg, unsupervised children, altered judgment regarding appropriate acetaminophen intake, or when abusing alcohol)
  • Combining medicines that contain acetaminophen (Acetaminophen is found in more combination products than any other drug; examples include acetaminophen and codeine, as well as acetaminophen and aspirin.)
  • Intentional overdose (eg, suicide attempt)

People who already have liver damage can have acetaminophen poisoning even if they take the recommended dose. Acetaminophen poisoning can also happen if acetaminophen is taken along with other substances that harm the liver, like alcohol.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

The following factors increase your chance of developing acetaminophen poisoning:

  • Age: 15-24 years or older than 40 years (People over 40 are more likely to have severe effects.)
  • Gender: female
  • Suicidal behavior
Symptoms

Symptoms include:

  • Symptoms of liver failure:
    • Abdominal pain (especially in the upper right portion of the abdomen)
    • Anorexia
    • Confusion, stupor
    • Excessive sweating
    • Jaundice
    • Malaise
    • Nausea
    • Pale skin
    • Vomiting
  • Excessive sweating
  • Nausea
  • Pale skin
  • Vomiting

Diagnosis

Your doctor will ask about your symptoms and medical history and perform a physical exam. Tests may include the following:

  • Blood tests—to determine the level of acetaminophen in your blood and to determine liver function (eg, liver enzyme tests, coagulation tests)
  • Rumack-Matthew nomogram—an assessment to determine the effect on the liver. The test measures blood levels of acetaminophen relative to the time since ingestion of the medicine.
Treatment

Talk with your doctor about the best treatment plan for you. Treatment options include:

Monitoring

For children who have relatively low levels of acetaminophen in their blood, monitoring at home may be recommended.

Activated Charcoal

Your doctor may recommend activated charcoal. This can help prevent acetaminophen from absorbing in the gastrointestinal tract. It is taken by mouth.

N-acetylcysteine

In most cases, N-acetylcysteine, an amino acid, will be given by mouth or IV (through the vein) as an antidote.

If you are diagnosed with acetaminophen poisoning, follow your doctor's instructions .

Prevention

To help reduce your chances of getting acetaminophen poisoning, take the following steps:

  • Avoid heavy alcohol intake. Do not drink alcohol if you are taking medicines that contain acetaminophen.
  • Do not substitute sustained-release acetaminophen for immediate-release without adjusting the dosing interval.
  • Follow your doctor's or the package directions regarding dosing and duration of therapy when taking acetaminophen. Always ask your doctor if you have questions.
  • When taking combination medicines (eg, cold medicines), read the label to determine if acetaminophen is an ingredient. Avoid taking multiple medicines at once that contain acetaminophen.

Last reviewed: September 2011 by Lawrence Frisch, MD, MPH.

RESOURCES:
CANADIAN RESOURCES:
References:
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