​Pharmacology - Methotrexate

​Pharmacology - Methotrexate
Methotrexate Action Interferes with purine synthesis and the production of thymidylate and consequently with DNA synthesis.

Mode of Action
Competitively inhibits dihydrofolate reductase (DHFR).

Clinical Use
Given orally, i.v., i.m., or intrathecally; taken up into cells by the folate transport system.High-dose regimens should be followed by ‘rescue’ with folinic acid – a type of tetrahydrofolate – to limit harmful e†ects on the bone marrow and GIT mucosa.Acute lymphoblastic leukemia in children; choriocarcinoma; tumors of head, neck breast & lung.

Adverse Reactions
Myelosupression, GIT disturbances, mucositis and sometimes pneumonitis.