Chemo drugs

Question 1

What are the 5 main classes of chemo drugs?

Answer 1

Alkylating agents 
Antimetabolites
Cytotoxic antibiotics 
Microtubule inhibitors 
Steroid hormones and antagonists

Question 2

How do alkylating agents work?

Answer 2

Form covalent bonds with DNA to interfere with transcription and replication.

• 1 DNA strand: stops transcription
• Both DNA strands: stops replication

Question 3

What are examples of alkylating agents?

Answer 3

Cysplatin - cancer. Targets purine nucleotides

Cyclophosphamide - cancer.

Melphalan - multiple myeloma

Busulphan

Question 4

How do antimetabolites work?

Answer 4

Interfere with nucleotide or DNA synthesis.

Question 5

What are examples of antimetabolites?

Answer 5

Antifolates: methotrexate - inhibits dihydrofolate reductase enzyme.

Fluoro-uracil - inhibits thymidine formation

Mercaptopurine - converted to nucleotides and disrupts purine synthesis

Cytabarine - nucleotide analogue which inhibits DNA polymerases.

Question 6

How do cytotoxic antibiotics work?

Answer 6

Direct action on DNA as intercalators.

Question 7

What are examples of cytotoxic antibiotics?

Answer 7

Dactinomycin

Doxorubicin

Question 8

What are examples of microtubule inhibitors?

Answer 8

Vincristine

Question 9

How do steroid hormones work?

Answer 9

Work on tumours which are responsive to hormones, making them regress.

Question 10

What are examples of steroid hormones?

Answer 10

Prednisone - synthetic adrenocortical steroid hormone which is converted to prednisolone to suppress lymphocyte growth

Tamoxifen - oestrogen receptor antagonist