As of Friday, April 11, 2014
DEAR DOCTOR K: As I’ve entered my 50s, I find myself reaching for Tylenol more often for my aches and pains. Should I be aware of any safety precautions?
DEAR READER: Acetaminophen is the active ingredient in Tylenol and several other over-the-counter medications. As with all medications, you should use it cautiously. But if you stick to the guidelines, there’s little need to worry.
Acetaminophen controls pain and fever; it is an important drug for controlling chronic pain. But taking too much acetaminophen can damage the liver. In extreme cases, this liver damage can require a liver transplant, or even cause death.
For the average healthy adult, the recommended maximum dose is no more than 4,000 milligrams (mg) per day from all sources. Some of my patients who regularly take between 3,000 mg and 4,000 mg have had abnormalities of the liver that show up on blood tests. I think their livers are particularly sensitive to acetaminophen. So I recommend that all my patients try to stay below 3,000 mg per day. If they need more than that for adequate pain relief, I monitor their liver tests carefully.
There are many pills available over-the-counter that contain acetaminophen — more than 600 products. This includes many pain pills and sleep-aid pills. For any non-prescription medicines that you take regularly, be sure to check the bottle to see if it contains acetaminophen, and how much. The combination of these pills plus regular acetaminophen pills can nudge you into the red zone.
If you have concerns, ask your doctor how much acetaminophen you should be able to tolerate safely. And check with your doctor if you need to take acetaminophen regularly for chronic pain.
Here are some general precautions for avoiding an accidental overdose:
— Cold and flu remedies count. When you reach for an over-the-counter cough, cold or flu product, look at the label. Does it contain acetaminophen?
— Know the dose of your pills. Acetaminophen pills available over the counter may contain 325, 500 or 650 mg of the drug. On my website, AskDoctorK.com, I’ve put a table showing how often and how much you can safely take of each dose.
— Stick to recommended doses. Don’t be tempted to take more than the recommended dose. Take only as much as you need. Try not to exceed 3,000 mg a day if possible.
— Go 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 if any of your prescription medications could interact badly with acNon-prescription medicines available over the counter are generally safe when taken as directed on the bottle. But that doesn’t mean that they’re safe in any amount.
About 10 years ago, the sister of a close colleague was having terrible back pain and took 8,000 mg per day of acetaminophen for several days. It caused liver failure, from which she died. Respect the directions on all over-the-counter medicines. They are there for a reason.
Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.S