Low-dose aspirin affects kidneys

Many people take a low dose of aspirin daily to help ward off heart trouble, but there could be a down side to it. Low-dose aspirin therapy may adversely affect the kidneys in elderly patients.Although low-dose aspirin is used by many elderly patients, monitoring of kidney function is currently not recommended as a routine. Researchers at the Tel Aviv Medical Center, Israel recently reported transitory retention of uric acid and creatinine that are signs of kidney impairment caused by aspirin at doses of 75 to 325 milligrams per day.To investigate further, they examined the effects of 100 mg of aspirin taken daily for two weeks by 83 stable geriatric patients (who averaged 81 years of age), and compared them with 40 similar control patients. The researchers collected blood samples, and examined 24-hour urine collections for creatinine and uric acid, at baseline and weekly for 5 weeks.

Urinary excretion of creatinine decreased in 60 (72 percent) of patients and excretion of uric acid decreased in 54 (65 percent) after 2 weeks of aspirin therapy. Average clearance of uric acid also decreased in these patients. The deterioration in kidney function was significantly greater (and more prevalent) in the aspirin-treated group than in the 40 control patients.They found that kidney function improved after aspirin was stopped, but even three weeks later 48 percent of the patients still had some residual impairment. Physicians are well aware of the possible adverse effects of non-steroidal anti-inflammatory drugs and high-dose aspirin on the kidneys. More attention should be paid to the effects of low dose aspirin, especially in the elderly.

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