Antimetabolites

Question 1

Methotrexate

Answer 1

• Folate antagonist.
• Used in ALL, Choriocarcinoma, Burkitts lymphoma, Breast cancer. AI disease in low doses.
• AE: BM suppression, stomatitis, Nephrotoxicity, Hepatic fibrosis, Pneumonitis, Erythema etc.
• NB, teratogenic.

Question 2

6-Mercaptopurine

Answer 2

• Purine analogue, blocks their biosynthesis + is incorporated into DNA to give nonfunctional DNA.
• Used in ALL maintenance.
• AE: BM suppression, Hepatotoxicity

Question 3

Azathioprine

Answer 3

• Purine analogues. Prodrug -> 6-MP.

- Mainly as immunosuppression for RA.

Question 4

5-Fluorouracil

Answer 4

• Pyrimidine analogue (uracil), inhibits thymidine synthase to inhibit DNA synth.
• IV due to severe GIT toxicity. Crosses BBB.
• used in Solid tumors
• AE: GIT tox, Myelosuppression, neurotox

Question 5

Cytosine arabinose (cytarabine)

Answer 5

• Inhib DNA polymerase.
• Acute leukemias.
• Myelosuppression, GIT disturbances