Peripoal fibrosis is caused by?

Methotrexate. This drug is a well-established cause of hepatic fibrosis and cirrhosis. These complications are best recognized following long-term use of the agent in inflammatory disorders such as psoriasis and rheumatoid ahritis, although cases have also followed administration for neoplastic diseases. The risk of liver damage depends largely on the dose, duration, and timing of therapy. In prospective studies, up to 25% of patients receiving a cumulative dose of 1.5 to 2 grams over five years have developed fibrosis or cirrhosis. The risk appears to be lessened by weekly, as opposed to daily, administration of the drug, and exacerbated by concomitant obesity or alcohol abuse. Methotrexate-induced hepatotoxicity is often clinically silent and, even in advanced disease, can exhibit an indolent clinical course. Evidence of poal hypeension or liver failure can nonetheless develop in some cirrhotic cases and may lead to death or the necessity for liver transplantation.