Over-the-counter analgesics, such as aspirin, acetaminophen, ibuprofen, ketoprofen, and naproxen, are usually safe when taken as directed. However, if taken in excess or over too long a period of time, they can harm the kidneys. Products in which two or more painkillers are combined may be especially harmful to kidneys when used to excess.
The National Kidney Foundation recommends that these products be used only under a doctor’s supervision in people with kidney disease, heart disease, high blood pressure, or liver disease; in people over 65; or in people taking diuretics. Their effects can be monitored through a simple blood test called the serum creatinine test, which can be used to estimate a person’s glomerular filtration rate (GFR). Sometimes a urine test is used to check for protein in the urine (a sign of kidney damage as well as diseases such as diabetic nephropathy). The National Kidney Foundation offers other tips for the safe use of analgesics:
• Do not use them for more than 10 days for pain or more than 3 days for fever. If these conditions persist beyond those periods, see your doctor.
• Avoid prolonged use of products that contain mixtures of painkillers.
• If you are taking analgesics, be sure to drink six to eight glasses of fluid a day.
• If you are taking analgesics, avoid drinking alcohol.
• If you have kidney disease, consult your doctor before using an analgesic.
• Make sure your doctor knows about all the drugs you are taking, including over-the-counter products and dietary supplements.
• Make sure you read the warning label before using any over-the-counter analgesic.