Analgesic nephropathy refers to kidney damage caused by regular, long-term use of pain medicines. Short-term, occasional use of these medicines does not seem to cause kidney damage.

What is going on in the body?

Pain medicines may cause kidney damage when a person takes more than 6 to 8 pills every day for several years. This kind of long-term use of pain relievers can occur in people with chronic headaches, back pain, or other chronic pain syndromes.

These medicines cause kidney damage in two different ways. The first way is called chronic interstitial nephritis. In this disorder, inflammatory cells cause scarring and result in damaged, shrunken kidneys. The second way is called papillary necrosis. In this case, the inner kidney dies and sloughs off, leaving a damaged kidney. The damage due to these pain medicines occurs slowly, over many years. It is usually not diagnosed until severe damage has occurred.

What are the causes and risks of the disease?

Analgesic nephropathy is caused by long-term, regular use of pain medicines. These medicines include acetaminophen, aspirin, and nonsteroidal anti-inflammatory drugs, or NSAIDs. Ibuprofen and naproxen are examples of NSAIDs. Those with chronic pain are more likely to use these medicines in a way that causes kidney damage. Medicines that combine two or more analgesics together with caffeine or codeine are most likely to cause damage. These medicines are often sold as powders containing acetaminophen and aspirin with caffeine.