Summary: Oral administration of single large doses of phenylbutazone (400 mg/kg) and indomethacin (75 mg/kg) to female Wistar rats resulted in the development of patchy renal papillary necrosis in 19% and 21% of kidneys respectively. The lesions were seen as early as 2 hours after drug administration. The appearances of the necrotic areas suggested a toxic aetiology, although in some animals, some contribution by haemorrhagic shock could not be excluded because with both drugs, many animals developed massive gastro-intestinal haemorrhage.
Most rats receiving phenylbutazone developed acute gastric erosions with a peculiar distribution, similar to that reported in man for this drug. Although many rats receiving indomethacin suffered from gastro-intestinal haemorrhage, only a few developed gastric ulcers.
(C) 1974 Royal College of Pathologists of Australasia