Analgesic nephropathy: kidney damage from long-term painkiller use

The kidneys filter waste from the blood and are exposed to high concentrations of the medicines you take. MedlinePlus describes analgesic nephropathy as damage within the internal structures of the kidney, caused by overexposure to mixtures of medicines, particularly over-the-counter pain relievers. In the UK the same kinds of products are sold in pharmacies and supermarkets, which makes it easy to take them regularly without thinking about the total amount.

The damage can be temporary or long term. MedlinePlus states that the damage to the kidney may be acute and temporary, or chronic and long term, and that complications can include acute and chronic kidney failure, inflammation in the spaces between the kidney tubules (interstitial nephritis) and death of tissue where the collecting ducts enter the kidney (renal papillary necrosis). It also lists ongoing urinary tract infections, high blood pressure and, less often, cancer of the kidney or ureter.

MedlinePlus says the condition is caused by long-term use of analgesics, particularly over-the-counter medicines that contain paracetamol (called acetaminophen in the US) and NSAIDs such as aspirin, ibuprofen or naproxen. It frequently occurs as a result of self-medicating for chronic pain, for example headache or arthritis. The NHS includes long-term, regular use of NSAIDs among the causes of chronic kidney disease, alongside high blood pressure, diabetes and blockages to urine flow.

• Use of over-the-counter analgesics that contain more than one active ingredient.

• Taking 6 or more pills a day for 3 years, which MedlinePlus lists as a risk factor.

• Chronic headaches, painful periods, backache or musculoskeletal pain that lead to regular self-treatment.

• Emotional or behavioural changes and a history of dependent behaviours, such as smoking, alcohol use or excessive use of tranquillisers, which MedlinePlus also lists.

• Existing kidney disease, high blood pressure or diabetes, which the NHS identifies as common causes of chronic kidney disease, so that regular painkiller use on top of them deserves particular care.

MedlinePlus says there may be no symptoms in the beginning. As the kidneys are injured, symptoms of kidney disease develop. The NHS makes the same point about chronic kidney disease in general: there are usually no symptoms in the early stages, and it may only be found if a blood or urine test is done for another reason.

• Fatigue and weakness.

• Increased urinary frequency or urgency, or decreased urine output.

• Blood in the urine.

• Flank or back pain.

• Swelling throughout the body, especially the lower legs.

• Nausea and vomiting, easy bruising or bleeding.

• Decreased alertness, drowsiness or confusion, and numbness, especially in the legs, in more advanced disease.

There is no single test. MedlinePlus says the provider will examine you and ask about symptoms, and may find high blood pressure, swelling in the lower legs or abnormal heart and lung sounds. Tests that may be done include blood tests for creatinine and urea, a complete blood count, urinalysis, a kidney ultrasound, a CT scan of the kidney and a toxicology screen.

The NHS says chronic kidney disease can be diagnosed with blood and urine tests, which look for high levels of certain substances that show the kidneys are not working properly, and that the results are used to give the stage of the disease. A clear and honest account of every medicine you take, including products bought without a prescription, is one of the most important parts of the assessment.

MedlinePlus says the primary goals of treatment are to prevent further damage to the kidneys and to treat kidney failure. The provider may tell you to stop all suspect painkillers, particularly over-the-counter medicines. If kidney failure develops, diet changes and fluid restriction may be suggested, and eventually dialysis or a kidney transplant may be needed. Counselling may help you develop alternative methods of controlling chronic pain.

The NHS says chronic kidney disease has no cure but treatment can relieve symptoms and stop it getting worse, with lifestyle changes, medicines to control blood pressure and cholesterol, regular check-ups, and dialysis or transplant in advanced disease. It adds that most people with CKD can control their condition with medicine and regular check-ups, and that it only progresses to kidney failure in around 2 in 100 people with the condition. Outcomes depend on how much damage has been done before the cause is recognised, which is why early identification matters.

MedlinePlus says to follow the provider's instructions when using medicines, including those bought over the counter, and not to take more than the recommended dose without asking. In practice that means a few habits.

• Read the active ingredients on every product, because some cold, flu and headache remedies contain more than one pain-relieving ingredient.

• If you need pain relief on most days, treat that as a reason to see a GP rather than a routine to continue. Regular daily use is exactly the pattern linked to this condition.

• Tell a pharmacist or GP if you have kidney disease, high blood pressure or diabetes before using anti-inflammatory painkillers regularly.

• Ask about non-drug and alternative approaches to chronic pain, such as physiotherapy or pain management support.

MedlinePlus advises contacting a provider if you have symptoms of analgesic nephropathy, especially if you have been using painkillers for a long time, if there is blood or solid material in your urine, or if the amount of urine has decreased. The NHS advises seeing a GP for persistent or worrying symptoms that you think could be caused by kidney disease, and lists tiredness, swollen ankles, feet or hands, shortness of breath, feeling sick and blood in the pee as possible later symptoms.