Methotrexate

Methotrexate

Write Short Note On Methotrexate.
Or
Write In Brief On Uses And Adverse Effects Of Methotrexate.
Answer:

Methotrexate is an antimetabolite and is a folate antagonist. The drug has anti-neoplastic, immunosuppressive, and anti-inflammatory effects.

Methotrexate Mechanism Of Action

Methotrexate competitively inhibits the dihydrofolate reductase enzyme and prevents the conversion of dihydrofolic acid to Tetrahydrofolic acid and depletes intracellular tetrahydrofolic acid. Tetrahydrofolic acid is very necessary for the synthesis of purines and thymidylate which in turn are very necessary for the synthesis of DNA and RNA.

Methotrexate Dosage, Administration, and Guidelines

Read And Learn More: Pharmacology Question And Answers

Methotrexate Phamacokinetics

Methotrexate is well absorbed in oral administration. It can also be administered IM, IV, or intrathecally. Drug bound to plasma proteins and poorly crosses the blood-brain barrier. Most of the drug is excreted unchanged in the urine.

Methotrexate Uses

As an anti-cancer drug in the treatment of:

• Choriocarcinoma is the choice of drug.
• In acute leukemia
• In Burkitts lymphoma
• In breast cancer
• In non-Hodgkin’s lymphoma
• In osteosarcoma
• In head and neck cancer

Due to its anti-inflammatory and immunosuppressive effects, it is also used in the treatment of

• Psoriasis
• Rheumatoid arthritis
• Inflammatory bowel disease
• In organ transplantation
• In ectopic pregnancy.

Methotrexate: Uses, Mechanism of Action, and Side Effects

Methotrexate Adverse Effects

• Megaloblastic anemia
• Hepatotoxicity on chronic administration
• Bone marrow suppression: It manifests as leucopenia, agranulocytosis, thrombocytopenia, and aplastic anemia. In these patients infection and bleeding are common.
• Immunosuppression: Decreased count of lymphocytes causes immunosuppression and patients are prone to opportunistic infections.
• GIT manifestations: Nausea, vomiting, diarrhea
• Alopecia due to damage of hair follicles.
• Presence of dermatitis and skin rashes
• Gonads: Oligozoospermia and infertility in males; amenorrhea and infertility in females.
• Pregnancy: It produces teratogenic effects.
• Hyperuricemia: Gout and urate stones can occur in the urinary tract because of excessive cell destruction.
• Hepatic fibrosis.

Methotrexate for Rheumatoid Arthritis and Cancer Treatment

Methotrexate Drug Interactions

• Salicylates/Sulphonamides/Tetracycline: Displace methotrexate bound to plasma protein and increase its free form in plasma causing toxicity.
• NSAIDs and sulphonamides potentiate methotrexate toxicity by interfering with its excretion.