An analgesic (AN-ul-JEE-zik) is any medicine intended to kill pain. Over-the-counter analgesics (medicines bought without a prescription) include aspirin, acetaminophen, ibuprofen, naproxen sodium, and others. These drugs present no danger for most people when taken in the recommended dosage. But some conditions make taking even these common painkillers dangerous for the kidneys. Also, taking one or a combination of these drugs regularly over a long period of time may increase the risk for kidney problems. Most drugs that can cause kidney damage are the ones that are excreted only through the kidneys.
Case reports have attributed incidents of acute kidney failure to the use of painkillers, including aspirin, ibuprofen, and naproxen. The patients in these reports had risk factors such as systemic lupus erythematosus, advanced age, chronic renal conditions, or a recent binge of alcohol consumption. These cases involved a single dose in some instances and never more than 10 days of analgesic use. Acute kidney failure requires emergency dialysis to clean the blood. But normal kidney function often returns after the emergency is over.
If you have hyperkalemia, you have too much potassium in your blood. The body needs a delicate balance of potassium to help the heart and other muscles work properly. But too much potassium in your blood can lead to dangerous, and possibly deadly, changes in heart rhythm.
A different kind of problem can result from taking painkillers every day for several years. Analgesic nephropathy is a chronic kidney disease that gradually leads to end-stage renal disease and the permanent need for dialysis or a kidney transplant to restore renal function.
The painkillers that combine two or more analgesics (for example, aspirin and acetaminophen together) with caffeine or codeine are most likely to damage the kidneys. These mixtures are often sold as powders. Single analgesics (e.g., aspirin alone) have not been found to cause kidney damage.
Patients with conditions that put them at risk for acute kidney failure should check with their doctors before taking any medicine. People who take painkillers on a regular basis should check with their doctors to make sure they are not hurting their kidneys. The doctor may be able to recommend a safer alternative.