Analgesic nephropathy is a renal disease characterized by papillary necrosis and chronic interstitial nephritis, and caused by the long-term consumption of analgesic agents . According to one definition, analgesic nephropathy results from the use of combination agents that contain two or more analgesics agents and usually codeine or caffeine . However, many believe that analgesic nephropathy may result from ingestion of any single analgesic agent that is taken long term . The use of phenacetin, which is no longer available, was particularly associated with analgesic nephropathy .
The manifestations, diagnosis, differential diagnosis, and prognosis of analgesic nephropathy are reviewed here. The epidemiology, risk factors, and the associations with urinary tract malignancy and atherosclerotic cardiovascular disease are discussed separately. (See "Analgesic-related chronic kidney disease", section on 'Chronic kidney disease associated with individual analgesic agents' and "Urinary tract malignancy and atherosclerotic disease in patients with chronic analgesic abuse".)
Analgesic nephropathy used to be one of the more common causes of chronic kidney disease (CKD), particularly in Australia and parts of Europe and the United States, but there was a marked decline in prevalence in the 1990s , which may have been related to the withdrawal of phenacetin from the market and to legislation that made combined analgesics available only by prescription [5-7]. The prevalence of analgesic nephropathy since the withdrawal of phenacetin is uncertain since a positive diagnosis is rarely made. The epidemiology of analgesic nephropathy and the role of phenacetin are discussed elsewhere. (See "Analgesic-related chronic kidney disease", section on 'Chronic kidney disease associated with individual analgesic agents'.)
Clinical manifestations — Most patients who present with classic analgesic nephropathy are >45 years of age . Usually, patients have no symptoms, and the disease is incidentally detected by laboratory studies that are performed for an unrelated problem and show an elevated creatinine or abnormal urinalysis.
Most patients have no symptoms referable to the urinary tract, although flank pain or hematuria from a sloughed or obstructing papilla may occur. Some patients (more commonly women) report a history of urinary tract infections . In the studies cited above, a history of repeated urinary tract infection was present in up to 60 percent of patients [1,9-13].