Heme and Oncology II

Question 1

Methotrexate (mechanism, use, toxicity)

Answer 1

Inhibits dihydrofolate reductase, inhibiting DNA synthesis; cancer, ectopic pregnancy; myelosuppression, macrovesicular fatty change in liver

Question 2

5-fluorouracil (mechanism, use, toxicity)

Answer 2

Pyrimidine analog that is activated and inhibits thymidylate synthase, inhibiting DNA synthesis; myelosuppression, photosensitivity

Question 3

Cytarabine (mechanism, use, toxicity)

Answer 3

Pyrimidine analog that inhibits DNA polymerase; leukopenia, thrombocytopenia, megaloblastic anemia

Question 4

Azathioprine, 6-mercaptopurine, 6-thioguanine (mechanism, use, toxicity)

Answer 4

Purine analogs that are activated by HGPRT and inhibit purine synthesis; toxicity is increased with allopurinol, causes bone marrow, GI, and liver toxicity

Question 5

Dactinomycin (actinomycin D) (mechanism, use, toxicity)

Answer 5

DNA intercalator; used for childhood tumors; myelosuppression

Question 6

Doxorubicin (Adriamycin), daunorubicin (mechanism, use, toxicity)

Answer 6

Generates free radicals that cause DNA strand breaks; dilated cardiomyopathy(Dexrazoxone, an iron chelator, prevents this), myelosuppression, alopecia

Question 7

Bleomycin (mechanism, use, toxicity)

Answer 7

Generates free radicals that cause DNA strand breaks; pulmonary fibrosis with minimal myelosuppression

Question 8

Cyclophosphamide, ifosfamide (mechanism, use, toxicity)

Answer 8

Crosslinks DNA (must be activated by liver); myelosuppression, hemhorragic cystitis (can be minimized with mesna)

Question 9

Carmustine, lomustine, semustine, streptozocin (mechanism, use, toxicity)

Answer 9

Used to treat CNS tumors-Can cross blood brain barrier

Question 10

Busulfan (mechanism, use, toxicity)

Answer 10

Alkylates DNA; pulmonary fibrosis, hyperpigmentation

Question 11

Vincristine, vinblastine (mechanism, use, toxicity)

Answer 11

Block microtubule polymerization; vincristine causes neurotoxicity, vinblastine causes bone marrow suppression

Question 12

Paclitaxel, other taxols (mechanism, use, toxicity)

Answer 12

Blocks microtubule breakdown; myelosuppression, alopecia