TUESDAY, July 17, 2001 (HealthDayNews) -- Typical doses of over-the-counter painkillers like Tylenol, Advil and aspirin don't appear to damage the kidneys, Boston scientists say.
People who take three to four tablets a week, or even somewhat more, don't appear to be risking kidney failure, says the largest study yet to examine the issue. Historically, long-term consumption of over-the-counter painkillers have been linked to cases of chronic kidney disease and kidney failure, but those people had other risk factors, like an immune disease or a bout of recent drinking, say the researchers.Other experts, however, are cautious about the findings.
"This is a study that is somewhat reassuring about moderate-to-mild usage of analgesics, but other studies will have more to say about heavier consumption," says Dr. William Henrich, chairman of the department of medicine at the University of Maryland School of Medicine in Baltimore, and a spokesman for the National Kidney Foundation. He also is leading a government-sponsored study of the issue, and those results should be out within a year or so.
Henrich says the Boston research has a few important caveats. It didn't look at the effects of high doses of the medicines, such as several pills a day, which may be more dangerous than moderate amounts. And it didn't include women, who appear to make up the bulk of patients with kidney complications arising from use of the painkillers.
A report on the study, which was sponsored in part by Tylenol maker McNeil Consumer Healthcare of Fort Washington, Pa., appears in this week's Journal of the American Medical Association.
Dr. Kathryn Rexrode, a researcher at Brigham and Women's Hospital in Boston, and her colleagues compared analgesic intake and kidney problems in more than 11,000 male doctors. The subjects, ages 40 to 84, were asked to guess how many painkillers they'd taken over the prior 14 years. The doctors also gave blood samples that were tested for high levels of a protein called creatinine, which would indicate the kidneys aren't working well.
Four percent, or 460, of the men had elevated creatinine, and about 11 percent, or 1,258, showed signs of trouble clearing the protein from their blood, a more precise indicator of kidney damage than simply measuring amounts.
Yet neither marker reflected painkiller intake, regardless of how much the men had taken, the researchers say. Men who said they took fewer than one pill a year, or essentially none, had the same kidney function as those who reported taking three to four tablets a week or more. And older men did not appear to have more risk of kidney damage with increasing consumption of analgesics.
"People who have been taking these medications in the usual dosages had no increased risk for kidney dysfunction," Rexrode says.
Rexrode says the study didn't look at other health problems associated with over-the-counter painkillers, such as ulcers and gastric bleeding. Non-steroidal anti-inflammatory medications, or NSAIDs like aspirin, are estimated to cause 7,600 deaths and some 76,000 hospitalizations a year from gastrointestinal complications.
What To Do
While occasional use of over-the-counter painkillers won't harm your kidneys, don't overdo it, Henrich says. "I think that consumers think that anything you can buy in a drug store or grocery store is safe and can be taken with impunity. My own belief is that that's not true. It's good advice for consumers not to take these medicines for a long period of time or in high doses without their physician knowing about it."
To learn more about the effects of analgesics on the kidneys, check the National Institutes of Health.
For more about the kidneys, try the National Kidney Foundation.