By Simeon Margolis, M.D., Ph.D.
About a month ago, the U.S. Food and Drug Administration (FDA) said that many over-the-counter (OTC) painkillers that contain acetaminophen will have to carry new warnings about potential dangers of liver damage.
The FDA had previously recommended that adults and children 12 years and age or older should not exceed 4,000 mg of acetaminophen in a 24-hour period. People with severe arthritis, for example, can fairly easily exceed this daily amount if they take 2 extra-strength Tylenols every 4 to 6 hours and also use other OTC products that contain acetaminophen. (Regular Tylenol tablets contain 325 mg of acetaminophen; Extra-Strength Tylenol contains 500 mg.)
In recent years, many consumers have settled on acetaminophen as their favorite pain reliever because so much concern and anxiety have been swirling around other popular pain killers for dealing with arthritis, headaches, and menstrual pain. Since Tylenol does not cause GI bleeding, many people consider acetaminophen to be far safer than other painkillers. And yet, studies have now revealed that high doses of acetaminophen can cause severe liver damage and even death.
Gastrointestinal bleeding can be a serious side effect of the non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, naproxen (Aleve®), ibuprofen (Advil®, Motrin®), and Excedrin®. When a newer group of NSAIDs, termed COX-2 inhibitors, were developed, researchers expected fewer bleeding complications from them; however, follow-up studies showed that the COX-2 inhibitors were associated with a significantly greater number of heart attacks and strokes. These deadly side effects led the manufacturers of two of the COX-2 inhibitors—rofecoxib (Vioxx®) and valdecoxib (Bextra®)—to remove them from the market.
Some uncertainties remain about the heart and stroke risks of the remaining COX-2 inhibitor, celecoxib (Celebrex®). All of these grave worries concerning the old and newer pain-relieving NSAIDs further persuaded people to return to their old stand-by, acetaminophen.
To help people avoid damaging their liver with acetaminophen, the FDA's report calls for a maximum adult daily dose of 3,250 mg (some experts believe this amount is too high) and a single dose no greater than 650 mg. And since the combination of alcohol and acetaminophen is even more toxic to the liver, people who consume more than 3 alcoholic drinks a day should limit their acetaminophen intake even further.
In addition to watching their intake of acetaminophen itself, consumers need to know they still might exceed a safe dose if they take any of the many other OTC products, including remedies for colds, headaches, and fevers, that contain acetaminophen.