Topoisomerase inhibitors — Flashcards

Flashcard 1: Which Topoisomerases do Fluoroquinolones inhibit?_____

Answer: II and IV

Flashcard 2: Which enzyme is inhibited by teniposide?_____

Answer: topoisomerase II

Flashcard 3: Which enzyme is inhibited by topotecan?_____

Answer: topoisomerase I

Flashcard 4: Irinotecan and topotecan can result in _____-suppression

Answer: myelo

Flashcard 5: Which topoisomerase I inhibitor is indicated in ovarian and small cell lung cancer?_____

Answer: topotecan

Flashcard 6: Which enzyme is inhibited by etoposide?_____

Answer: topoisomerase II

Flashcard 7: Mechanism and indication of Anastrozole?

Answer: Aromatase inhibitor used in postmenopausal breast cancer

Extra: Mechanism: Competitively inhibits aromatase, decreasing estrogen synthesis. Indication: ER-positive breast cancer in postmenopausal women. Examples of other aromatase inhibitors: Letrozole, Exemestane.

Flashcard 8: Mechanism of action of Exemestane:

Answer: Irreversible (Steroidal) Aromatase Inhibitor

Extra: Mechanism: Irreversible inhibition of the enzyme aromatase. Indication: Breast cancer in postmenopausal women. Note: Exemestane is a steroidal inhibitor, unlike Anastrozole and Letrozole which are non-steroidal (reversible).

Flashcard 9: alkylating agents

Answer: absence of digits (and multiple varied anomalies)

Flashcard 10: Teratogenic effect of folate antagonists?

Answer: Neural tube defects (NTDs)

Extra: Folate antagonists (e.g., Methotrexate, Aminopterin) interfere with DNA synthesis and are potent teratogens. Maternal use, especially during the first trimester (organogenesis), is strongly associated with neural tube defects. Low folate levels in general are a risk factor, which is why folic acid supplementation is recommended preconceptionally.