Subchronic toxicity study of pirprofen (Rengasi) was performed in rats. This included the effect of the drug on the serum aminotransferases (S.G.0.T. & S.C.P.T.) and prostaglandin F2, in addition to, the histopathological effects on the tissues of the different organs. The study revealed that, pirprofen has an adverse effect on the hepatocellular functions in the form of an increase in aminotransferases activity and hepatocellular degeneration. It, also, produced inhibition of prostaglandin F2 synthesis. Degenerative changes occured in the tubules of the kidneys, as well as congestion of their blood vessels and oedema in the interstitial tissue. The gastric mucosa showed moderate congestion of the blood vessels. At the end of the study which continued for three weeks, the gastric mucosa of some rats revealed superficial
erosions and tiny ulcerations; while one rat displayed evidence of perforation of the stomach. Though we can recommend the short term medication period to avoid all the previous side effects appeared