Monday, August 10, 2009


Pain reliever acetaminophen is safe if used properly

Acetaminophen, known commonly as the brand name Tylenol and by its chemical abbreviation APAP, is the most widely used medication in the country.

Although considered the safest pain reliever available, it is also the most common cause of liver failure and accidental overdoses kill more than 100 Americans each year.

These two facts are why the FDA recently convened a special panel to take another look at acetaminophen’s safety.

When can acetaminophen become dangerous? It is based on how the liver removes it from our bodies. Acetaminophen is metabolized in our liver to harmless substances that are eliminated in urine.

A single step in the process produces a toxic metabolite that in usual situations is quickly inactivated by a compound called glutathione. In an overdose situation, the body can run out of glutathione. When this occurs, the toxic metabolite begins to accumulate and liver damage can occur in just a few hours.

The question is then how much is too much? For healthy adults, the standard recommendation has always been a maximum of 1000mg per dose and a daily total of no more than 4000mg is considered safe.

Elderly persons, those with liver disease, and those whom consume alcohol on a chronic basis should take less and discuss this issue with their physician. Taking more than 4000mg per day happens all too often – usually the culprit is not keeping track of how much is in the many combination products being used.

Besides being sold over-the-counter (OTC) as a pain reliever and fever reducer in tablets, capsules, and liquids all on its own, acetaminophen is available as an active ingredient in many combination products.

Vicodin, Percocet, Darvocet, Excedrin, Vicks DayQuill, Contac Sever Cold and Flu, and TheraFlu Flu and Sore Throat are just a few of over 50 prescription and OTC products available that contain acetaminophen as just one of its ingredients.

Sometimes acetaminophen is clearly listed in the ingredient chart, other times it is “hidden” as “APAP.” Problems arise when a person uses multiple products at the same time and fails to pay attention to the total amount of acetaminophen they are receiving, an easy thing to overlook when you don’t feel well.

The FDA advisory panel has suggested a number of measures that could help decrease the risk of accidental overdoses.

The recommended amount for a single dose and total daily doses maybe lowered, extra strength tablets (500mg each) may become prescription only, and combination products may not be allowed to be produced any longer.

Each of these recommendations has pros and cons and the FDA has yet to act upon them. In fact they it may choose to not make any changes at all.

How can you protect yourself and your loved ones now?

Remember that acetaminophen is still the safest pain reliever for healthy adults and should continue to be used for mild to moderate pain.

The most important thing is to check each of your medications that you are using for pain or fever relief for the amount of acetaminophen or APAP that is contained in each dose. Add up the amounts and be sure to intake no more than 1000mg in any 6-hour period or 4000mg in 24 hours. Pay special attention when using multiple pain or cough and cold products at the same time.

Staying below these limits will help ensure your safety.

Michael Smith is a pharmacist and Clinical Coordinator in the Department of Pharmacy Services at The William W. Backus Hospital. This column should not replace advice or instruction from your personal physician. If you want to comment on this column or others, go to the Healthy Living blog at or e-mail Smith and all of the Healthy Living columnists at

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