Found in the renal pelvis, ureter, and capillaries supplying the nephrons, capillary sclerosis is thought to lead to renal papillary necrosis and, in turn, chronic interstitial nephritis.How phenacetin and other analgesics lead to this damage is incompletely understood. It is currently thought that the kidney toxicities of NSAIDs and the antipyretics phenacetin and paracetamol may combine to give rise to analgesic nephropathy. A committee of investigators reported in 2000 that there was insufficient evidence to suggest that non-phenacetin analgesics by themselves are associated with analgesic nephropathy. Aspirin and NSAIDs
Proper kidney function depends upon adequate blood flow to the kidney. Kidney blood flow is a complex, tightly regulated process that relies on a number of hormones and other small molecules, such as prostaglandins. Under normal circumstances, prostaglandin E2 (PGE2) produced by the kidney is necessary to support adequate blood flow to the kidney. Like all prostaglandins, PGE2 synthesis depends upon the cyclooxygenases.Aspirin and other NSAIDs are inhibitors of the cyclooxygenases. In the kidney, this inhibition results in decreased PGE2 concentration causing a reduction in blood flow. Because blood flow to the kidney first reaches the renal cortex (outside) and then the renal medulla (inside), the deeper structures of the kidney are most sensitive to decreased blood flow. Thus the innermost structures of the kidney, known as the renal papillae, are especially dependent on prostaglandin synthesis to maintain adequate blood flow.
In Stage 5 chronic kidney disease patients renal replacement therapy may become necessary. History
Analgesics are a class of medications widely used in the treatment of pain. They include aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs), as well as the antipyretics paracetamol (known as acetaminophen in the United States) and phenacetin. Introduced in the late 19th century, phenacetin was once a common component of mixed analgesics in parts of Europe, Australia, and the United States. These analgesics contained aspirin or other NSAIDs combined with phenacetin, paracetamol, or salicylamide, and caffeine or codeine.In the 1950s, Spühler and Zollinger reported an association between kidney injury and the chronic use of phenacetin. They noted that chronic users of phenacetin had an increased risk of developing specific kidney injuries, namely renal papillary necrosis and chronic interstitial nephritis. This condition was dubbed analgesic nephropathy and was attributed to phenacetin, although no absolute causative role was demonstrated. With further reports of the increased risk of kidney injury with prolonged and excessive phenacetin use, however, phenacetin was banned in several countries between the 1960s and 1980s.As the use of phenacetin declined, so too did the prevalence of analgesic nephropathy as a cause of end-stage kidney disease. Data from Switzerland, for example, demonstrated a decline in the prevalence of analgesic nephropathy among people with end-stage kidney disease, from 28% in 1981 to 12% in 1990.