Cell Cycle Specific Cytotoxic Drugs MCQs

Option A: Ciprofloxacin is fluoroquinolone class of antibiotic, which inhibits DNA replication by inhibiting bacterial DNA topoisomerase and DNA gyrase. Certain drugs bind to microtubules and thus interfere with their assembly or disassembly. These include colchicine, Vinblastine, Griseofulvin & paclitaxel. Option B: colchicine which is used for treatment of acute gouty arthritis Option C: Vinblastine is a vinca alkaloid used for treating certain types of cancer Option D: Griseofulvin is an antifungal agent Paclitaxel (Taxol) is effective against ovarian cancer. Reference: Harper's illustrated biochemistry 32nd edition CH 51 PN 625

Explanation: Etoposide is a chemotherapy drug that targets topoisomerase II in eukaryotic cells. Etoposide stabilizes the topoisomerase II-DNA complex after it has introduced a double-strand break, preventing the enzyme from re-ligating the DNA. This results in DNA breaks, which interfere with DNA replication and lead to cell death. Etoposide is widely used in the treatment of various cancers, such as lung cancer, testicular cancer, and lymphomas, making this the correct answer.

Explanation: Epirubicin is an anthracycline known for cardiotoxicity , which can worsen pre-existing heart failure. It is contraindicated in patients with heart failure . Adverse Effects of Epirubicin: Cardiomyopathy Alopecia Anemia Amenorrhea Leukopenia Diarrhea Explanation of Other Options: Methotrexate (Option A): Folate antagonist Not significantly cardiotoxic. Cyclophosphamide (Option C): Alkylating agent Some cardiovascular effects but not strongly cardiotoxic. Can be used cautiously. Cisplatin (Option D): Nephrotoxic primarilyC ardiotoxicity risk is lower. Can be used with monitoring.

Ans. is `b ' i.e., Cisplatin o Cisplatin is the most common culprit causing chemotherapy induced nausea and vomiting, therefore cisplatin is given as slow i.v. infusion(never bolus) to prevent vomiting.

Ans. is 'd' i.e., Increased production of dihydrofolate reductase Methotrexate resistance o Methotrexate resistance may be due to any of the following mechanism :? i) Defective transport into cells ii) Production of altered form of DHFR that have decreased affinity for methotrexate iii) Increased concentrations of intracellular DHFR through gene amplification or altered gene regulation iv) Decreased ability to synthesize methotrexate polyglutamates v) Increased expression of a drug efflux transporter, of the MRP (multidrug resistance protein) class

Oprelvekin (IL-11) stimulates platelet production and decreases the number of platelet transfusions required by patients undergoing bone marrow suppression therapy for cancer. Reference: Basic & Clinical Pharmacology, Fourteenth Edition By Bertram G. Katzung Pg no. 843-44

Ans. is 'a' i.e., Inhibits mitotic spindle Vinca alkaloids (vincristine) inhibit mitotic spindles by preventing polymerization of tubulin