NAPLEX (North American Pharmacist Licensure Examination) Practice Exam

What is the primary action of platinum-based chemotherapy compounds?

1. Inhibit microtubule function

2. Cross link DNA

3. Block coiling and uncoiling of DNA

4. Inhibit pyrimidine synthesis

The correct answer is: Cross link DNA

Platinum-based chemotherapy compounds, such as cisplatin and carboplatin, work by binding to the DNA strands in cancer cells and forming cross-links between the strands. This prevents the cancer cells from being able to divide and grow, ultimately leading to their death. Option A is incorrect because microtubules are not directly involved in the mechanism of platinum-based chemotherapy. Option C is incorrect because it describes the action of topoisomerase inhibitors, not platinum-based compounds. Option D is incorrect because it describes the action of antimetabolites, not platinum-based compounds.