Acetaminophen, sold under the brand name Tylenol and also
included in more than 200 over-the-counter cold and flu remedies and other
medications, is the most widely used painkiller in the United States. Up to
100 million Americans take acetaminophen every year.
Overdoses (both intentional and accidental) of
acetaminophen are the leading cause of acute liver failure in the United
States.
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While most people assume Tylenol and other
over-the-counter medications that contain acetaminophen are harmless, the
drugs are actually surrounded by a growing controversy as to their safety --
even when taken at the recommended dosages.
Liver Damage Possible Even at Recommended Doses
It's well known that overdosing on Tylenol (which is
commonly done accidentally, as we discuss below) can harm the liver. However,
a study published in the Journal of the American Medical Association
found that even at recommended doses, the drug shows signs of causing organ
damage.
Out of 106 patients in the study, 41 of them (39 percent)
who took acetaminophen alone (Extra Strength Tylenol) or in combination with
another drug had their liver enzymes increase to more than three times the
normal upper limit. It is at this threshold (when liver enzymes increase to
three times the normal level) that doctors typically become concerned about
potential liver damage.
Further, another 27 patients had enzyme levels increase
more than five times normal, and eight patients had levels that increased
eight times the normal enzyme level. Their enzyme levels continued to
increase for up to four days after the acetaminophen was stopped, and their
enzyme levels did not return to normal for as long as 11 days, researchers
said.
"This study shows that even taking the amount on the
package can be a problem for some people," said Dr. William M. Lee of
the University of Texas Southwestern Medical School, who was not involved in
the study.
Long-Term Tylenol Use May Damage the Kidneys
A study published in the Archives of Internal Medicine
found that 10 percent of women who took acetaminophen over an 11-year period
had a 30 percent decline in kidney filtration function.
The more acetaminophen taken, the greater the damaging
effects. Among women who took between 1,500 and 9,000 tablets during the
study, risk of kidney impairment increased 64 percent. Those who took more
than 9,000 tablets had an even greater risk.
Further, an article in Life Extension magazine points out
that several studies have shown that regular use of acetaminophen may double
your risk of kidney cancer.
Accidental and Intentional Overdosing Common
Acetaminophen overdose is the leading cause of acute liver
failure in the United States. While some of these stem from intentional
overdoses (England has placed restrictions on the number of acetaminophen
pills that can be sold at one time due to suicide concerns), many are
accidental.
In fact, each year more than 56,000 people visit an
emergency room because of acetaminophen overdoses, and 100 people die from
unintentionally taking too much.
Check how much acetaminophen is in every drug you take
(both prescription and over-the-counter) by reading the label. Add up the
amounts to make sure you are not exceeding the maximum daily recommended
dose of 4,000 milligrams.
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When taken at the highest recommended dose, experts say
acetaminophen is generally safe, but acknowledge that the margin of error is
very small.
According to Lee, the maximum dose of many acetaminophen
medications, including Extra Strength Tylenol, is set too high. In the case
of Extra Strength Tylenol, the maximum dose is two 500-milligram pills every
six hours, or 4 grams a day.
If a person inadvertently takes an extra pill, an extra
dose, or a different medication that may also contain acetaminophen (it's
also in the prescription narcotics Vicodin, Percocet, and others), they can
easily surpass the upper limit and put themselves at risk of liver damage,
liver failure and even death.
"Just a doubling of the maximum daily dose can be
enough to kill," says Dr. Anne Larson of the University of Washington
Medical Center. And " ... if two is good, 10 is better in some patients'
minds," she says.
Adding to the problem is the sheer number of products
available that contain acetaminophen.
"You can take a prescription med that has
acetaminophen in it, and a cough syrup that has acetaminophen in it, and then
if you take an Extra-Strength Tylenol, you can have 4 grams of
acetaminophen," says Matthew Grissinger, a pharmacist and
medication-safety analyst for the Institute for Safe Medication Practices.
"There's too much choice out there. It's out of hand."
Acetaminophen Safety Tips
If you use Tylenol, over-the-counter cold and flu remedies
or any other drugs that may contain acetaminophen, be sure to follow these
safety tips:
·
Make sure you don't exceed the
maximum daily recommended amount, which is no more than 4,000 milligrams of
acetaminophen a day, or eight extra-strength pills (and to be safe you may
want to stay well under it).
·
Read the labels on all the drugs you
are taking, even if you're not sure it contains acetaminophen. Add up the
amount of acetaminophen to be sure you're under 4,000 milligrams a day.
·
If you are in a vulnerable population
-- which includes those who regularly use alcohol, have hepatitis or other
liver disease, or have kidney disease -- you should discuss acetaminophen use
with your doctor. You will likely need to limit your use to no more than
2,000 to 3,000 milligrams a day.
·
Follow dosage information for
children carefully, as overdose can occur quickly.
·
Be aware that some products
containing acetaminophen also contain aspartame,
which can be dangerous in those with phenylketonuria.
Recommended Reading
The
Five Most Dangerous Medicine Mistakes that Way Too Many People Make
Aspirin:
What are the Benefits, What are the Risks?
Sources
eMedicine.com
Daily News Central
NewsTarget.com
Life
Extension Magazine
CBS News
Baxter Bulletin
Seattle Post-Intelligencer
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