Which antitumor drug is not an alkylating agent? (LQ)
Alkylating agents are electrophile molecules that react with electron rich atoms to form covalent bonD.
Examples: Cyclophosphamide, Ifosfamide
i. Cisplatin, Carboplatin and oxiliplatin
Mech. of action: These agents form reactive intermediates that covalently modify bases in DNA. In addition they can activate apoptosis.
Major site of action within DNA is N7 portion of guanine. Common toxicities: Myelosuppression, alopecia, gonadal dysfunction, pulmonary fibrosis, mucositis, second neoplasm (esp. leukemia)
5-FU is an antimetabolite:
- It is a pyrimidine antagonist
- Converted in body to 5-fdUMP which inhibits thymidylate synthetase, resulting in inhibition of DNA synthesis through: "thymine less death"
- In addition it gets incorporated into RNA causing single stranded break.
- Toxicity: Mucositis, Diarrhea, Myelosuppression, Hand foot syndrome.