Abstract

Background: The first report, written by Sidney Farber in 1948, detailed his success in the use of methotrexate (MTX) for the treatment of leukemia in children. The drug was used for the first time in 1951 for the treatment of rheumatoid arthritis and psoriasis. MTX classical antifolate, also known as amethopterin, is 4-amino-4- dcoxy-Na-methyl folic acid. The correlation between toxic reactions and the pharmacokinetics of MTX discloses certain time- and concentration-dependent relationships that appear to determine which target tissue is at risk for toxicity, whether toxicity will occur and the severity of MTX toxicity. A high dose of MTX (HDMTX) is defined as more than 500 mg/m2 or if given intravenously.
Case Presentation: HDMTX can cause significant toxicity, including myelosuppression, mucositis, hepatotoxicity and, in severe cases, may cause multiorgan failure.
Conclusion: An early understanding of the causes and risk factors for MTX toxicity may be beneficial in reducing the occurrence of MTX toxicity in the Taif region.

Key words: Methotrexte, toxicity, high dose, hepatotoxicity, rheumatoid arthritis.