Topoisomerase Inhibitors

Question 1

What do topoisomerase enzymes regulate?

Answer 1

The winding states of DNA

Question 2

When does the winding of DNA occur?

Answer 2

During DNA replications and transcription into mRNA

Question 3

What is the first step for topoisomerase enzymes?

Answer 3

Act as molecular scissors and cuts the DNA phosphate backbone

Question 4

What is the second step for the topoisomerase enzymes?

Answer 4

DNA strands pass through the nick or cut in the DNA phosphate backbone

Question 5

What is the third step for the topoisomerase enzymes?

Answer 5

Acts as molecular glue and reseals the DNA phosphate backbone

Question 6

What step do the topoisomerase inhibitors prevent?

Answer 6

Step 3

Question 7

What is the bacterial type II of topoisomerase called?

Answer 7

DNA gyrase

Question 8

What is the MOA for irinotecan?

Answer 8

Topoisomerase I Inhibitor

Question 9

What is a unique concern with irinotecan?

Answer 9

IICS (irinotecan-induced choline this syndrome)

Question 10

If caught early enough, what would you treat the ADR caused by irinotecan with?

Answer 10

Atropine

Question 11

What is the boxed warning for irinotecan?

Answer 11

Diarrhea

Question 12

If caught later, what would you treat the ADR caused by irinotecan with?

Answer 12

Loperamide

Question 13

What is a distant cousin of morphine?

Answer 13

Loperamide

Question 14

What does the gene UGT1A1 code for?

Answer 14

UGT Enzyme

Question 15

What does the UGT enzyme do?

Answer 15

Inactivate/detoxify irinotecan drug phase II drug metabolism

Question 16

Patients with a mutated and dysfunctional UGT enzyme are at an increase risk of what two things?

Answer 16

1. Diarrhea
2. Neutropenia

Question 17

Topoisomerase II inhibitors that act at the G2 phase

Answer 17

Epipodophylltoxins

Question 18

Etoposide IV

Answer 18

TOPSAR

Question 19

What is an ADR of etoposide IV?

Answer 19

Infusion rate related hypotension

Question 20

When should you infuse etoposide?

Answer 20

Over 30-60 minutes

Question 21

What concentration should you dilute etoposide to?

Answer 21

< 0.4 mg/mL

Question 22

What must you avoid when using etoposide?

Answer 22

DEHP as a plasticizer

Question 23

When is etopophos used?

Answer 23

If the concentration needs to be > 0.4 mg/mL

Question 24

What patients is etopophos useful in?

Answer 24

Ones with fluid retention

Question 25

True or false: etopophos does not have concern when using DEHP as a plasticizer

Answer 25

True