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Effects of COX-2 Inhibitors, a New Class of Anti-Inflammatory Drugs, on Kidney Function in Older Patients
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What is the problem and what is known about it so far?
Nonsteroidal anti-inflammatory drugs (NSAIDs) are useful in treating many painful conditions, including headaches and arthritis. Unfortunately, NSAIDs occasionally produce serious side effects, including stomach ulcers and kidney problems, particularly in older persons. A new type of NSAID, called cyclooxygenase-2 (COX-2) inhibitors, affects some important body processes less than do earlier NSAIDs (COX-1/COX-2 inhibitors). This suggests that COX-2 inhibitors (for example, rofecoxib) may cause fewer side effects in patients than COX-1/COX-2 inhibitors (for example, ibuprofen and indomethacin). However, some studies in animals suggest that COX-2 inhibitors also can cause kidney problems.
Why did the researchers do this particular study?
To see if the COX-2 inhibitor rofecoxib affects kidney function.
Who was studied?
The study had two parts. In the first, researchers enrolled 16 patients 60 to 80 years of age; in the second, they enrolled 71 patients 65 to 80 years of age. All study patients had kidneys that worked normally for their age.
How was the study done?
In the first part of the study, the researchers randomly assigned patients to receive a single dose of rofecoxib, 250 mg; indomethacin, 75 mg; or placebo. In the second part, patients received 12.5 mg or 25 mg of rofecoxib daily (the usual doses given for arthritis); indomethacin 50 mg; or placebo, three times a day for 5 days. The placebos looked exactly like the other drugs but contained no active ingredient. The researchers then used special tests to measure how well the kidneys of all study participants were working. Because salt intake can affect these tests, all patients ate a low-salt diet during the study.
What did the researchers find?
Fifteen of 16 patients completed the first part of the study, and 60 of 71 patients completed the second part. Patients in both parts of the study had reversible decreases in kidney function with the COX-2 inhibitor (rofecoxib) that were similar to those with the COX-1 inhibitor (indomethacin).
What were the limitations of the study?
Study patients took the drugs at doses and in patterns that differ somewhat from the way patients might use these drugs in real life. Because the study included only persons older than 60 years of age, it is unknown whether the same kidney effects would occur in younger people. Study participants took the drugs for a short time, whereas real patients often use them for long periods. The study does not tell us whether the short-term kidney effects would progress to serious kidney failure if treatment with NSAIDs were given long-term.
What are the implications of the study?
The COX-2 inhibitors affect kidney function in much the same way as COX-1/COX-2 inhibitors. Doctors must be on the lookout for potential kidney side effects when they prescribe COX-2 inhibitors, particularly in older patients.
Article and Author Information
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The summary below is from the full report titled “Effect of Cyclooxygenase-2 Inhibition on Renal Function in Elderly Persons Receiving a Low-Salt Diet. A Randomized, Controlled Trial.” It is in the 4 July 2000 issue of Annals of Internal Medicine (volume 133, pages 1-9). The authors are S.K. Swan, D.W. Rudy, K.C. Lasseter, C.F. Ryan, K.L. Buechel, L.J. Lambrecht, M.B. Pinto, S.C. Dilzer, O. Obrda, K.J. Sundblad, C.P. Gumbs, D.L. Ebel, H. Quan, P.J. Larson, J.I. Schwartz, T.A. Musliner, B.J. Gertz, D.C. Brater, and S.-L. Yao.
- Copyright ©2004 by the American College of Physicians
