ABSTRACT
As a result of the scale of the Covid 19 pandemic that launched from China in December 2019 and to limit its spread, several treatments were used to control this virus, including, hydroxychloroquine, favipiravir, lopinavir, remidesivir, tocilizumab, and anakinra. Favipiravir is an antiviral drug that works by inhibiting RNA-dependent RNA polymerase, favipiravir inhibited viral genome replication, which was most noticeable in the middle of the viral proliferation period. Favipiravir was found to have antiviral activity, Purine nucleosides or purine bases inhibit favipiravir, meaning that it competes with purine nucleosides rather than pyrimidine nucleosides, In a time-of-drugaddition test, to treat a variety of RNA viruses (influenza, West Nile, yellow fever, flaviviruses, arenaviruses, bunyaviruses and alphaviruses). Here, we show for the first time the histologycal effect of favipiravir on the liver and kidneys using albino rats, using light microscopy, where the optical microscopic revealed that normal doses in liver showed hepatic cords arranged, normal central vein and mild sinusoildal infiltration of mono nuclear leukocytes mainly lymphocytes, the hepatocytes showed mild granular cytoplasm while double doses showed little hemorrhagic foci and disarrangement of hepatic cords. The magnified sections revealed few of hepatocytes showed mild cloudy swelling associated with little figures of cellular necrosis. As for kidneys, the optical microscopic observations showed multiple foci of hemorrhage, the magnified section revealed congestion of glomerular capillary tuft and few of renal tubules showed mild granular or vacular degeneration. On the other hand, sections of renal medulla revealed normal appearance for normal doses while renal cortex and medulla were showed marked interstitial nephritis, which characterized by interstitial thickening due to infiltration of mono nuclear leukocytes and the renal tubules showed sever vacular degeneration and necrosis for double doses. These results can guide the safe use of favipiravir and reduce the risks to tissue the liver and kidney by using double doses.