Alcohol Warning: If you consume 3 or more alcoholic drinks everyday, ask your doctor whether you should take acetaminophen and asprin or other pain relievers/fever reducers. Acetaminophen and asprin may cause liver damage and stomach bleeding.

What the bottle doesn’t tell you is what “liver damage” is and that all it takes is one night of drinking and the recommended therapeutic dose of acetaminophen to treat that headache the next morning for “liver damage’ to occur. In fact, taking acetaminophen hours after alcohol consumption has stopped is worse than taking it during or directly after consumption. The process all begins with an enzyme found in the liver called cytochrome P450 2EI, or CYP2E1 for short.

CYP2E1 helps break down a certain class of chemicals called xenobiotics (meaning “foreign to life”), and is the first step in the break down of acetaminophen. When CYP2E1 works to break down acetaminophen, a new compound is formed called N-acetyl-p-benzoquinoneimine (NAPQI for short). Normally, NAPQI interacts with an antioxidant called glutathione (GSH for short), which turns NAPQI into a non-toxic metabolite that is excreted harmlessly from the body.

Alcohol, a substrate for CYP2E1, increases the amount of the enzyme in the liver which also increases acetaminophen metabolism. As little as one bottle of wine (or 6 twelve-ounce cans of beer) has been found to increase the CYP2E1 levels sufficiently enough to increase acetaminophen metabolism by 22 percent.  While this may sound like a good thing, it is actually very bad if you are a liver cell. Faster acetaminophen metabolism means that it is broken down to NAPQI faster. If there is enough of the antioxidant GSH, NAPQI is still broken down and excreted. However, if there is not enough GSH present, the NAPQI instead interacts with proteins in liver cells and causes those cells to die.

The liver is one of the few internal organs of humans that has the capacity to regenerate, however frequent liver damage can result in loss of liver function and ultimately death. In fact, thousands of people in the United States die each year from using over the counter and prescription Non-Steroidal Anti-Inflammatory Drugs (Unnecessary Prescribing of NSAIDs). So, next time you wake up with a headache from a few drinks the night before, think twice before you run to the medicine cabinet and down a few pills. Try to avoid any acetaminophen containing pain relievers, or, better yet, just sleep it off… given the chance, your body will take care of itself!

Resources:

American Gastroenterological Association

National Institute on Alcohol Abuse and Alcoholism:
Alcohol Alert No. 27 & Alcohol Alert No. 35

Stryer, Lubert, Jeremy M. Berg, and John L. Tymoczko. Biochemistry. Boston: W. H. Freeman & Company, 2002.