Topoisomerase Inhibitors Flashcards
What do topoisomerase enzymes regulate?
The winding states of DNA
When does the winding of DNA occur?
During DNA replications and transcription into mRNA
What is the first step for topoisomerase enzymes?
Act as molecular scissors and cuts the DNA phosphate backbone
What is the second step for the topoisomerase enzymes?
DNA strands pass through the nick or cut in the DNA phosphate backbone
What is the third step for the topoisomerase enzymes?
Acts as molecular glue and reseals the DNA phosphate backbone
What step do the topoisomerase inhibitors prevent?
Step 3
What is the bacterial type II of topoisomerase called?
DNA gyrase
What is the MOA for irinotecan?
Topoisomerase I Inhibitor
What is a unique concern with irinotecan?
IICS (irinotecan-induced choline this syndrome)
If caught early enough, what would you treat the ADR caused by irinotecan with?
Atropine
What is the boxed warning for irinotecan?
Diarrhea
If caught later, what would you treat the ADR caused by irinotecan with?
Loperamide
What is a distant cousin of morphine?
Loperamide
What does the gene UGT1A1 code for?
UGT Enzyme
What does the UGT enzyme do?
Inactivate/detoxify irinotecan drug phase II drug metabolism
Patients with a mutated and dysfunctional UGT enzyme are at an increase risk of what two things?
- Diarrhea
- Neutropenia
Topoisomerase II inhibitors that act at the G2 phase
Epipodophylltoxins
Etoposide IV
TOPSAR
What is an ADR of etoposide IV?
Infusion rate related hypotension
When should you infuse etoposide?
Over 30-60 minutes
What concentration should you dilute etoposide to?
< 0.4 mg/mL
What must you avoid when using etoposide?
DEHP as a plasticizer
When is etopophos used?
If the concentration needs to be > 0.4 mg/mL
What patients is etopophos useful in?
Ones with fluid retention
True or false: etopophos does not have concern when using DEHP as a plasticizer
True
