Acetaminophen and Your Liver

Acetaminophen (the main ingredient in Tylenol) is the most widely used pain reliever and fever suppressant in the United States. Each year, Americans consume an estimated 8 billion tablets of acetaminophen (an average of 29 tablets per person). The overwhelming popularity of this drug indicates that the general public views it as being safe and non-toxic. Not so.
Liver Damage
Acetaminophen is known in the medical community for its ability to cause life-threatening liver damage if taken in high doses. Misuse of acetaminophen is responsible for 40 – 50% of all cases of acute liver failure in both the United States and the United Kingdom, and the mortality in these cases is as high as 20%.
Lack of Awareness
The problem with acetaminophen, other than the risk of liver damage, is an apparent lack of awareness of this side effect in the general population. Clinical studies show that as many as 50% of toxic acetaminophen ingestions are not suicide attempts, but rather occur in people who ingest large doses of the drug to relieve pain.
What You Need to Know
The most important measure for preventing acetaminophen-induced liver injury is to limit the daily intake of acetaminophen to a maximum of 4 grams (equivalent to 12 regular-strength tablets, 8 extra-strength tablets, or 4 extended-release tablets). Acetaminophen almost never produces liver damage when the quantity ingested at one time is less than 7 grams, so limiting the total daily dose to 4 grams should eliminate the risk for liver damage. Further restrictions are recommended if alcoholism, HIV infection, and therapy with dilantin (an anticonvulsant) is present. These conditions show an increased susceptibility to acetaminophen-induced liver damage, and the total daily dose of the drug should be less than 4 grams, or a suitable alternative drug should be used.
Look for Acetaminophen in Cold Remedies
It is also important to check for acetaminophen in any drug preparation advertised as a cold remedy or pain reliever. At least 200 drug products contain acetaminophen, and excessive use of these preparations could result in a toxic ingestion. When reviewing the contents of a drug preparation, be aware that acetaminophen is often listed by the abbreviation APAP.
What To Do Following An Overdose
If a toxic ingestion of acetaminophen does occur, immediate medical attention in an emergency room can be life-saving. There is an effective antidote for acetaminophen poisoning, but it must be given within 24 hours of drug ingestion.