Accidental acetaminophen overdose is common

Accidental acetaminophen overdose is common

The Medicine Cabinet: Ask the Harvard Experts

By Howard LeWine, M.D.

Q: A friend was recently hospitalized with liver damage. The doctors told her it was caused by the acetaminophen in the over-the-counter medicines she was taking for back pain. I always thought of Tylenol as a safe drug. Now I am scared to use it. Your thoughts, please.

A: In general, acetaminophen is a safe drug, as long as you don’t take too much.

Acetaminophen helps ease pain and reduces fever. It doesn’t dampen inflammation like the NSAIDs ibuprofen or naproxen can. But acetaminophen has the benefits of being easier on the stomach and no risk of increased heart problems.

I suspect that your friend unknowingly took more than the recommended daily dose of acetaminophen. More than 600 products contain acetaminophen, and inadvertently combining them can nudge you into the red zone.

People don’t realize that these doses all add up, and before you know it you’ve exceeded the recommended dose of acetaminophen.

The body breaks down most of the acetaminophen in a normal dose and eliminates it in the urine. But some of the drug is converted into a byproduct that is toxic to the liver. If you take too much — all at once or over a period of days — more toxin can build up than the body can handle.

For the average healthy adult, the generally recommended maximum daily dose is no more than 4,000 milligrams (mg) from all sources. But in some people, doses close to the 4,000 mg daily limit for adults could still be toxic to the liver. It’s safest to take only what you need, and to not exceed 3,000 mg a day whenever possible, especially if you have a small body.

Here are some general precautions for avoiding an accidental overdose of acetaminophen:

–Cold and flu remedies count. When you reach for an over-the-counter cough, cold or flu product, take a look at the label. Does it contain acetaminophen?

–Add up the amount in all your pills. Carefully examine the individual ingredients in all your medications, both prescription and over-the-counter drugs. Add up the total amount of acetaminophen.

–Easy on the alcohol. Drinking alcohol causes the liver to convert more of the acetaminophen you take into toxic byproducts.

–Know if your medications interact. Ask your doctor or pharmacist if any of your prescription medications could interact badly with acetaminophen.

(Howard LeWine, M.D., is an internist at Brigham and Women’s Hospital in Boston and assistant professor at Harvard Medical School. For additional consumer health information, please visit