Study Links Common Painkiller with Kidney Damage
BOSTON (AP) _ Some doctors are warning that long-term, daily use of a common aspirin substitute may triple the usual risk of kidney damage, but the maker of Tylenol disputed the finding.
″I don’t want people to panic and say, ’My kids shouldn’t have Tylenol,‴ said Dr. Saulo Klahr, president of the National Kidney Foundation. ″But at the same time, it’s important for people not to take this drug daily.″
Klahr said acetaminophen, the main ingredient in Tylenol, Anacin-3, Datril and other brands, may accumulate in the kidneys and cause chemical damage. A related painkiller, called phenacetin, was taken off the market six years ago because of concern about kidney damage and bladder cancer.
Some experts also have worried that prolonged daily use of ibuprofen, another common painkiller, may harm the kidneys. The drug was released for non-prescription sales in 1985 and was not included in the study of acetaminophen.
The study, published in today’s New England Journal of Medicine, found no sign that aspirin is bad for the kidneys. However, it can cause stomach irritation and bleeding and perhaps a rare childhood disorder called Reye’s syndrome.
The new research found that acetaminophen is safe when used occasionally. And while it raises the possibility that overuse harms the kidneys, it does not prove this.
″Acetaminophen is not necessarily risk free,″ said Dr. Dale P. Sandler, who directed the National Institute of Environmental Health Science study.
″This study does not demonstrate any effect for acetaminophen when taken as directed, which is when needed for symptoms, but when symptoms persist, you should seek medical advice.″
In a Journal editorial, Drs. William M. Bennett of Oregon Health Sciences University and Marc E. DeBroe of the University of Antwerp in Belgium cautioned that ″this finding should be considered tentative until it is confirmed by other studies.″
Dr. Vardamen M. Buckalew Jr. of Bowman Gray School of Medicine, a co-author of the study, commented: ″I would be swayed toward believing there is a cause and effect relationship between heavy acetaminophen ingestion and renal (kidney) disease. But I would agree with anyone who says we need to do more work.″
The study compared 554 people in North Carolina who had newly diagnosed kidney disease with 516 randomly chosen adults. It found the people who took the medicine daily for an extended period had three times the risk of kidney disease than occasional users.
Acetaminophen accounts for 37 percent of the nation’s $2.5 billion annual over-the-counter sales of pain pills, according to the consulting firm Kline & Co. Aspirin represents about 43 percent and ibuprofen 20 percent.
According to Kline, 71 percent of the acetaminophen sold in the United States is Tylenol, which is made by Johnson & Johnson.
A spokesman for the company said the study was flawed, in part because it often relied on relatives of kidney patients to determine their use of acetaminophen and other painkillers.
″The study in question provides no basis to suggest that the use of acetaminophen is associated with kidney disease,″ spokesman Edwin C. Watson said in a statement.
At Whitehall Laboratories, which makes Anacin-3, spokeswoman Carol Emerling said, ″The article says it deserves further scrutiny from the scientific community, and we will be interested in following the results of that further scrutiny.″
High blood pressure and diabetes are major underlying causes of kidney disease. Sandler said that even if acetaminophen does prove harmful, it is probably less significant than those causes.
″How much kidney disease is explained by this?″ Sandler said. ″A small but not inconsequential amount. The importance is knowing that there is a risk that is preventable, whereas there is not much we can do about kidney disease associated with diabetes.″