Show Notes

0:35 – Hidden acetaminophen toxicity in OTC products

3:24 – Pharmacokinetics and toxicokinetics

6:06 – Clinical Course

9:22 – The antidote – NAC

11:02 – The Rumack-Matthew Nomogram

17:36 – Treatment protocols

22:34 – Monitoring and Lab Work

23:23 – Considerations when treating pediatric patients

23:57 – IV APAP overdose, fomepizole

25:42 – Take Home Points

Acetaminophen vs. Tylenol:

The importance of recognizing that acetaminophen is found in many products beyond Tylenol.
Common medications containing acetaminophen, such as Excedrin, Fioricet, Percocet, Dayquil/Nyquil, and others.
The risk of unintentional overdose due to combination products.

Prevalence of Acetaminophen Toxicity:

Widespread availability and under-recognition contribute to its prevalence.
The potential for unintentional overdose when taking multiple medications containing acetaminophen.

Pharmacokinetics and Metabolism:

Pathophysiology of Liver Injury:

How excessive NAPQI leads to hepatocyte death, especially in zone III of the liver.
The difference between therapeutic dosing and overdose metabolism.

Clinical Stages of Acetaminophen Toxicity:

Antidote – N-Acetylcysteine (NAC):

The Rumack-Matthew Nomogram:

Treatment Protocols:

Monitoring and Laboratory Work:

Special Considerations:

Take-Home Points:

Comprehensive Medication History: Always inquire about all medications taken to assess for potential acetaminophen exposure.
Early Recognition and Treatment: Due to often silent initial stages, maintain a high index of suspicion and measure acetaminophen levels promptly.
Understanding Metabolism and Toxicity: Recognize how overdose alters metabolism, leading to toxic NAPQI accumulation.
N-Acetylcysteine Efficacy: NAC is most effective when administered early but remains beneficial even in advanced stages.
Proper Use of the Nomogram: Utilize the Rumack-Matthew Nomogram appropriately for acute ingestions and consult toxicology when in doubt.
Monitoring and Continuing Care: Be vigilant in monitoring laboratory values and prepared to extend NAC therapy as needed.
Consultation and Resources: Engage with poison control centers and utilize available resources for complex cases.

Resources Mentioned

Rumack-Matthew Nomogram

Rumack-Matthew Nomogram, credit: MDCalc

King’s College Criteria

King’s College Criteria for Acetaminophen Toxicity
Use this tool to assess the need for liver transplant evaluation in cases of acetaminophen-induced hepatic failure. Includes criteria for pH, INR, creatinine, and more.

Poison Control Center (available 24/7 for consultation): 1-800-222-1222

Goldfrank’s Toxicologic Emergencies, 9th Edition was consulted for information on the pharmacokinetics and clinical presentation of acetaminophen toxicity.
For more details, see: Nelson, L. S., Howland, M. A., Lewin, N. A., Smith, S. W., Goldfrank, L. R., & Hoffman, R. S. (Eds.). (2011). Goldfrank’s toxicologic emergencies (9th ed.). McGraw-Hill Education.