Allergy-Associates

Acute liver injury caused by accidental or intentional acetaminophen overdose is well known.  If ingested all at once, 30 acetaminophens are lethal by causing acute liver failure. 

One of the metabolites of acetaminophen is N-acctyl-p-benzoquinone imine (NAPQI) which is produced by the liver enzyme system P-450.  Glutathione stores in the liver detoxify this otherwise harmful metabolite.  Acute overdose can deplete the glutathione stores in the liver and this will cause the liver cells to die. 

New research published in the journal Hepatology indicates that acute liver injury can occur from “normal” doses of acetaminophen in the right (wrong) setting.  Eighty-nine hospital cases of acute liver injury in an academic medical center were caused by doses of acetaminophen of 3,000 to 4,000 mg a day (4,000 mg is the largest recommended dose) when combined with either fasting for 24 hours or excess alcohol intake or both.  The authors of the article suggested people who fast periodically or who use alcohol liberally be aware of this potential pitfall.  Fasting depletes the liver of resources as the liver is a source for energy supplies when no calories are consumed.  Excess alcohol monopolizes the liver’s metabolism and makes it difficult to handle the breakdown of medicines. 

Harvard researchers at Boston Children’s Hospital recently finished a detailed study of the use of acetaminophen in asthmatic children. The outcome allows for a sigh of relief.

In 2000 British researchers questioned whether acetaminophen use led to exacerbation of wheezing in children. The concern arose because when children are sick with respiratory infections, this common, over -the-counter drug is frequently used to treat fever. So, the question arose: was it the illness itself or, perhaps, the acetaminophen that caused worsening of asthma?

One reason acetaminophen was a suspect is because it is known to temporarily reduce glutathione in the lungs – a natural compound that has anti-oxidant properties. Because of these concerns, many pediatricians in the U.S. and the U.K. were shying away from the use of acetaminophen in asthmatics. It was for this reason that Harvard undertook a randomized prospective study.

Their results were very reassuring. They found no increased risk of worsening asthma in the acetaminophen group versus the “control group.” Thus, they concluded it is safe to use, and that it’s the infection that worsens the asthma, not the popular drug.