Onc 6 - Cancer Drugs Part 1

Question 1

What is the mechanism of action of methotrexate?

Answer 1

Folic acid analog.

Question 2

What are the uses of methotrexate?

Answer 2

Cancer drug (Leukemia {ALL,AML} Lymphoma, Breast, Sarcoma). Uterine pathologies (Choriocarcinoma, Hydatidiform mole, ectopic pregnancy). Immunosuppression (Rheumatoid arthritis, Psoriasis).

Question 3

What is the side effect of Methotrexate?

Answer 3

It causes myelosuppression (reversible w/ Leucovorin). Causes Fibrotic lung disease. Teratogenic.

Question 4

What are the uses of 5-Fluorouracil?

Answer 4

Actinic keratosis. Basal cell skin cancer. Pancreatic cancer. Colon cancer.

Question 5

What are the side effects of 5-fluorouracil?

Answer 5

Myelosuppression (not reversible w/ leucovorin, if given too much, use uridine as rescue agent). Can cause photosensitivity in topical use.

Question 6

How does 6-Mercaptopurine work?

Answer 6

An antimetabolite that works in the S phase, it is a purine analog that inhibits purine synthesis by inhibiting the enzyme PRPP

Question 7

What are the side effects of 6-Mercaptopurine?

Answer 7

Metabolized by xanthine oxidase, therefore increased toxicity w/ allopurinol. Causes myelosuppression and hepatotoxicity.

Question 8

What is Cytarabine?

Answer 8

It is a Pyrimidine analog that inhibits DNA polymerase.

Question 9

What is an Alkylating agent? How does it work?

Answer 9

Attaches an alkyl group to DNA: it crosslinks DNA strands so the cells can’t divide.

Question 10

What is cyclophosphamide? What is it use for?

Answer 10

It is an alkylating agent that attaches to guanine residues on DNA. It is used to treat cancer, OL as immunosuppression (lupus nephritis, polyarteritis nodosa)

Question 11

What are the side effects of cyclophosphamide?

Answer 11

Hemorrhagic cystitis (due to toxic metabolite acrolein but can be prevented if given w/ mesna). Also increase risk of TCC of bladder. It requires bioactivation in liver.

Question 12

Ifosfamide shares many attributes and properties with Cyclophosphamide. However, in what cancer is Ifosfamide mostly used?

Answer 12

Used in testicular cancer. It cannot be used as OL immunosuppressant like cyclophosphamide.

Question 13

What are the Nitrogen mustards? What are three examples and in what cancers can be used?

Answer 13

Thy are the Nitrosoureas, they are alkylating agents and they all end in -mustine. Carmustine, Lomustine, Semustine. They are used in brain tumors because they can cross the blood-brain barrier. However, they can also cause CNS toxicity.

Question 14

What is the unique side effect of Busulfan?

Answer 14

Pulmonary fibrosis.

Question 15

What are two examples of Anthracyclines? How do they work? What is the unique side effect and what can we give to avoid it?

Answer 15

Doxorubicin and Daunorubicin. They work by generating free radicals and intercalate DNA. They can cause cardiotoxicity that leads to Dilated cardiomyopathy and heart failure. Give Dexrazoxane to prevent cardiotoxicity.

Question 16

Why is heart especially susceptible to free radical damage?

Answer 16

Because the heart muscles are relatively deficient in superoxidase dismutase.

Question 17

How does Dactinomycin work? In what three cancers is it specially used?

Answer 17

Wilms tumor. Ewing sarcoma. Rhabdomyosarcoma.

Question 18

How does Bleomycin work and what is the unique side effect? In what particular cancer is it used?

Answer 18

It works by generating free radicals. It can cause pulmonary fibrosis. Used in combination with other anti-neoplastic drugs in testicular cancer.

Question 19

What three anti-neoplastic drugs can cause pulmonary fibrosis?

Answer 19

Busulfan. Bleomycin. Methotrexate.

Question 20

How does the mechanism of action of methotrexate differ from 5-fluorouracil?

Answer 20

Methotrexate is a folic acid analog and inhibits dihydrofolate reductase. 5-fluorouracil is a pyrimidine analog and inhibits thymidylate synthase.

Question 21

How does the body metabolize 6-mercaptopurine?

Answer 21

Xanthine oxidase.

Question 22

Which anticancer drug is also often used in rheumatoid diseases as well as ectopic pregnancies?

Answer 22

Methotrexate.

Question 23

Which anticancer drug fits the following description: Alkylate DNA, can cause pulmonary fibrosis.

Answer 23

Busulfan.

Question 24

Which anticancer drug fits the following description: Intercalates DNA, can cause pulmonary fibrosis.

Answer 24

Bleomycin.

Question 25

Which anticancer drug fits the following description: blocks purine synthesis, metabolized by xanthine oxidase.

Answer 25

6-mercaptopurine (6-MP).

Question 26

Which anticancer drug fits the following description: a Nitrogen mustard, alkylates DNA (electrophile that binds DNA).

Answer 26

Nitrosoureas.

Question 27

Which anticancer drug fits the following description: a Folic acid analog that inhibits Dihydrofolate reductase.

Answer 27

Methotrexate.

Question 28

Which anticancer drug fits the following description: Intercalates DNA, produces oxygen free radicals, is cardiotoxic.

Answer 28

Doxorubicin. Daunorubicin.

Question 29

Which anticancer drug fits the following description: DNA alkylating agents used in brain cancer?

Answer 29

Nitrosoureas.

Question 30

Which anticancer drug fits the following description: Applied topically for AKs and basal cell carcinoma?

Answer 30

5-fluorouracil.

Question 31

Which anticancer drug fits the following description: tx for childhood tumors (Ewing sarcoma, Wilms tumor, rhabdomyosarcoma).

Answer 31

Dactinomycin.

Question 32

Which anticancer drug fits the following description: Side effect of hemorrhagic cystitis.

Answer 32

Cyclophosphamide. Ifosfamide.