Which anticancer drug acts by inhibiting ribonucleotide reductase, thereby blocking conversion of ribonucleotides to deoxyribonucleotides required for DNA synthesis?

• A Pentostatin
• B Fludarabine
• C Gemcitabine
• D Hydroxyurea ✓

Explanation

Hydroxyurea specifically inhibits ribonucleotide reductase, depleting deoxyribonucleotide pools and arresting cells in S phase. It is used in myeloproliferative disorders such as chronic myeloid leukemia and polycythemia vera, and as a radiosensitizer. Fludarabine, gemcitabine and pentostatin are purine antimetabolites that act after intracellular phosphorylation to inhibit DNA polymerase, DNA chain extension or adenosine deaminase respectively.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.