Analgesic nephropathy in the United Kingdom: Incidence, clinical features and pathogenesis.

Phenacetin came into use in 1887, just 10 years after the first case of renal papillary necrosis was reportedl 2 but the association between the excessive use of phenacetin-containing analgesics and the development of renal damage was not recognised until 1953,3 since when there has been gradual recognition that excessive analgesic consumption is a major cause of chronic renal disease in many parts of the world. The initial emphasis on phenacetin has given way to the realisation that many analgesic mixtures are nephrotoxic. Such mixtures are readily available to the public and are widely advertised, not just for pain relief, but as tonics and general panaceas. Despite restrictions on the sale of phenacetin and its major metabolite paracetamol in several countries, abuse of analgesic mixtures has continued and there is no definite evidence that the incidence of analgesic nephropathy is declining. Renal damage in analgesic nephropathy is due to a combination of renal papillary necrosis and chronic interstitial nephritis. In many cases the disease runs a rapidly progressive course with death from renal failure within a few years of the initial presentation. This paper is based on a study carried out in Nottingham, and outlines the major features of analgesic nephropathy in the United Kingdom. The clinical features of analgesic nephropathy are now widely recognised yet many patients have already developed severe renal failure by the time the history of analgesic abuse is obtained.4 5 Unless the association with a high analgesic consumption is recognised, the renal damage is often attributed to bacterial infection and the condition labelled "pyelonephritis." Several studies have shown, however, that bacterial urinary tract infection in the adult rarely leads to end-stage renal failure,5 6 and Heptinstall has emphasised that the small, scarred kidney often labelled "chronic pyelonephritis" is the end result of many different pathological processes; in many cases the original disease cannot be determined.7 Early diagnosis of analgesic nephropathy is important since complete withdrawal of analgesics before significant renal damage has occurred will result in improvement in renal function.