- An analgesic is any medicine intended to relieve pain (any painkiller).
- Painkillers present no danger for the majority of people when taken at the recommended dosage.
- Analgesic use is linked to two different forms of kidney damage: acute renal failure and analgesic nephropathy.
- Analgesic nephropathy can result from taking painkillers every day for several years.
- Analgesic nephropathy is a chronic kidney disease that over a number of years gradually leads to irreversible kidney failure and the permanent need for dialysis or a kidney transplant to restore kidney function.
- An estimated four out of every 100 000 people will develop analgesic nephropathy. It is most common in women over 30.
What is analgesic nephropathy?
Analgesic nephropathy is a chronic kidney disease that over a number of years gradually leads to irreversible kidney failure and the permanent need for dialysis, or a kidney transplant to restore kidney function. It is caused by the excessive long-term use of painkillers (analgesics).
It is estimated that about four out of every 100 000 people will develop analgesic nephropathy. Women over 30 years of age are at the highest risk.
What causes analgesic nephropathy?
Analgesic nephropathy is caused by the excessive long-term use of painkillers (analgesics). Over-the-counter (OTC) painkillers that contain phenacetin or acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin or ibuprofen are thought to be particularly high risk.
Excessive use has been described as roughly three pills per day for six years.
Additional factors associated with an increased risk include:
- chronic headache, backache, or musculoskeletal pain
- a history of dependent behaviours
- painful menstrual periods
What are the symptoms of analgesic nephropathy?
Possible symptoms can include:
- increased urinary frequency or urgency
- blood in the urine
- decreased urine output
- flank or back pain
- decreased alertness
- numbness of extremities
- easy bruising and bleeding
It is also possible that no symptoms will be present.
How is a diagnosis made?
A diagnosis is made using a medical history, physical examination, urine and blood tests, and in some cases X-rays.
How is it treated?
The aim of treatment is to prevent any further kidney damage and to treat the existing damage.
Further damage can usually be limited by stopping the use of the painkiller that is causing the kidney failure. Counselling or behaviour modifications may be required to find non-pharmaceutical ways of handling chronic pain.
Depending on the extent of the kidney damage, you may be advised to change your diet, limit your fluid in-take, or take medications to avoid anaemia and bone problems caused by kidney disease.
Your doctor will monitor your kidney function with regular urine and blood tests.
In severe cases, dialysis or a kidney transplant may be necessary.
What is the prognosis?
Kidney damage may be acute and temporary or chronic and long-term. In severe cases, dialysis or a kidney transplant may be necessary.
Possible complications may include:
- urinary tract infections
- interstitial nephritis
- renal failure
- tissue death
- transitional cell carcinoma of the kidney or ureter
When to call your doctor
Call your doctor when you experience any of the symptoms of analgesic nephropathy, especially if you have been using painkillers over a long and sustained period of time.
Also call your doctor if you have blood or solid material in your urine, or a decrease in urinary output.
How can it be prevented?
Use medications strictly in accordance with your doctor's advice. In the case of over-the-counter painkillers, do not exceed the recommended dosage on the pack.