Which chemotherapeutic agent exerts cytotoxicity primarily by forming covalent crosslinks between DNA strands during all phases of the cell cycle?
- A Methotrexate
- B Cyclophosphamide ✓
- C Vincristine
- D Paclitaxel
Correct answer: B. Cyclophosphamide
Explanation
Cyclophosphamide is an alkylating agent whose activated metabolite phosphoramide mustard forms covalent crosslinks between DNA strands, damaging DNA in a cell cycle nonspecific manner; haemorrhagic cystitis from acrolein is mitigated with mesna. Methotrexate inhibits dihydrofolate reductase and acts in S phase, vincristine blocks tubulin polymerisation in M phase, and paclitaxel stabilises microtubules also in M phase.
Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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