Anticancer Drugs Practice Questions

Q: Ifosfamide belongs to which group of anticancer drugs?

Alkylating agents. **Explanation:** **Ifosfamide** is a nitrogen mustard derivative and a structural isomer of cyclophosphamide. It belongs to the **Alkylating Agents** group (specifically the Oxazaphosphorine subclass). These drugs work by attaching alkyl groups to DNA bases (primarily at the N7 position of guanine), leading to DNA cross-linking, strand breakage, and inhibition of DNA synthesis. This action is **cell-cycle non-specific**, though its effects are most prominent during the S-phase. **Why other options are incorrect:** * **Antimetabolites (e.g., Methotrexate, 5-FU):** These interfere with the synthesis of nucleic acids by mimicking normal metabolites (S-phase specific). * **Mitotic Inhibitors (e.g., Vincristine, Paclitaxel):** These act on microtubules to disrupt the mitotic spindle during the M-phase. * **Topoisomerase Inhibitors (e.g., Etoposide, Irinotecan):** These interfere with DNA unwinding and ligation during replication. **High-Yield Clinical Pearls for NEET-PG:** 1. **Metabolism:** Ifosfamide is a **prodrug** activated by hepatic CYP3A4 enzymes into its active form, ifosfamide mustard. 2. **Hemorrhagic Cystitis:** A major dose-limiting toxicity caused by the metabolite **Acrolein**. This is managed with aggressive hydration and **MESNA** (2-Mercaptoethane sulfonate Na), which neutralizes acrolein in the bladder. 3. **Encephalopathy:** Ifosfamide is more likely to cause CNS toxicity (confusion, seizures) than cyclophosphamide due to the production of chloroacetaldehyde. 4. **Fanconi Syndrome:** Ifosfamide is specifically associated with nephrotoxicity manifesting as proximal renal tubular acidosis.

Q: Which of the following anticancer drugs is not derived from plants?

Doxorubicin. The correct answer is **Doxorubicin** because it is an **anthracycline antibiotic** derived from the bacterium *Streptomyces peucetius*, not from a plant source. ### **Explanation of Options:** * **Doxorubicin (Option B):** It is a microbial product. It acts by inhibiting Topoisomerase II, intercalating between DNA base pairs, and generating free radicals. Its major dose-limiting toxicity is cardiotoxicity (dilated cardiomyopathy). * **Irinotecan (Option A):** This is a semi-synthetic derivative of **Camptothecin**, which is obtained from the Chinese ornamental tree *Camptotheca acuminata*. It acts by inhibiting Topoisomerase I. * **Paclitaxel (Option C):** This is a **Taxane** derived from the bark of the Pacific Yew tree (*Taxus brevifolia*). It acts by stabilizing microtubules (preventing depolymerization), leading to mitotic arrest. * **Etoposide (Option D):** This is a semi-synthetic derivative of **Podophyllotoxin**, which is extracted from the Mayapple plant (*Podophyllum peltatum*). It acts by inhibiting Topoisomerase II. ### **High-Yield Clinical Pearls for NEET-PG:** 1. **Vinca Alkaloids (Vincristine/Vinblastine):** Derived from *Catharanthus roseus* (Periwinkle). They inhibit microtubule assembly (polymerization). 2. **Taxanes vs. Vincas:** Taxanes "freeze" microtubules (prevent breakdown), while Vincas "dissolve" them (prevent formation). 3. **Topoisomerase Inhibitors:** * **Type I:** Irinotecan, Topotecan (Plant-derived). * **Type II:** Etoposide (Plant-derived) and Doxorubicin (Microbial-derived). 4. **Antitumor Antibiotics:** Most (Doxorubicin, Bleomycin, Mitomycin C) are derived from *Streptomyces* species.

Q: Alkylating drugs attach an alkyl group to which position of guanine?

N7. **Explanation:** **Mechanism of Action:** Alkylating agents (e.g., Cyclophosphamide, Chlorambucil) are cell cycle-nonspecific drugs that act by forming highly reactive carbonium ion intermediates. These intermediates form covalent bonds with electron-rich nucleophilic sites on DNA bases. The **N7 position of Guanine** is the most nucleophilic (electron-dense) site in DNA, making it the primary target for alkylation. **Why N7 is Correct:** When an alkyl group attaches to the N7 position of guanine, it leads to: 1. **Cross-linking:** Formation of intra-strand or inter-strand bridges (especially with bifunctional alkylators), which prevents DNA strand separation during replication. 2. **Base-pairing errors:** Guanine may mispair with Thymine. 3. **Depurination:** The imidazole ring destabilizes, leading to excision of the guanine base and subsequent DNA strand breakage. **Why Other Options are Incorrect:** * **N3 of Guanine:** While alkylation can occur at the N3 position of Adenine, it is not the preferred or most common site for Guanine. * **N5:** This is not a standard site for DNA alkylation by these agents. * **N9:** The N9 position of guanine is the site where the base attaches to the deoxyribose sugar (forming the N-glycosidic bond), making it unavailable for alkylation in a DNA polymer. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** N7 of Guanine (Primary target). * **Other targets:** N1 and N3 of Adenine, N3 of Cytosine. * **Cyclophosphamide:** A prodrug activated by Cytochrome P450 in the liver. Its metabolite **Acrolein** causes hemorrhagic cystitis, which is prevented by **MESNA** (Mercaptoethane sulfonate) and aggressive hydration. * **Resistance:** Often occurs due to increased production of Glutathione or enhanced DNA repair enzymes (e.g., MGMT).

Q: A young male was diagnosed with acute myeloid leukemia and successfully completed induction chemotherapy. Two months later, he presents with bilateral pedal edema and dyspnea on exertion (waking up multiple times due to breathlessness). Which of the following anticancer drugs is most likely responsible for these symptoms?

Doxorubicin. ### Explanation The clinical presentation of bilateral pedal edema, dyspnea on exertion, and paroxysmal nocturnal dyspnea (waking up breathless) points toward **Congestive Heart Failure (CHF)**. In a patient treated for Acute Myeloid Leukemia (AML), this is a classic manifestation of **Anthracycline-induced cardiotoxicity**. **1. Why Doxorubicin is correct:** Doxorubicin (an Anthracycline) causes cardiotoxicity through the generation of **iron-dependent free radicals** (superoxide anions) that cause lipid peroxidation of the myocardial membranes. Since the heart has low levels of protective enzymes like catalase, it is highly susceptible. This toxicity is **dose-dependent and cumulative**. It typically presents as dilated cardiomyopathy leading to heart failure months after treatment. **2. Why other options are incorrect:** * **Cisplatin:** Primarily known for **Nephrotoxicity** (prevented by aggressive hydration/Amifostine) and Ototoxicity. It does not typically cause heart failure. * **Methotrexate:** Associated with **Myelosuppression**, Mucositis, and Hepatotoxicity. High doses can cause nephrotoxicity due to crystalluria. * **Vincristine:** Its hallmark side effect is **Peripheral Neuropathy** (paresthesia, loss of deep tendon reflexes, and autonomic dysfunction like constipation). It is "bone marrow sparing." **3. High-Yield Clinical Pearls for NEET-PG:** * **Monitoring:** Periodic **Echocardiography** or MUGA scans to monitor Left Ventricular Ejection Fraction (LVEF) is mandatory. * **Prevention:** **Dexrazoxane** (an iron chelator) is used to reduce the risk of doxorubicin-induced cardiotoxicity. * **Cumulative Dose:** The risk of CHF increases significantly once the cumulative dose of Doxorubicin exceeds **550 mg/m²**. * **Histology:** On biopsy, look for "Myofibrillar loss and cytoplasmic vacuolization."

Q: Which anticancer drug belongs to the class of inorganic metal complexes?

Cisplatin. ### Explanation **Correct Answer: B. Cisplatin** **Mechanism and Classification:** Cisplatin is the prototype of the **platinum coordination complexes**, which are inorganic metal complexes. Unlike organic molecules, cisplatin consists of a central platinum atom surrounded by two ammonia molecules and two chloride atoms in a *cis* configuration. * **Mechanism of Action:** It acts as a cell-cycle non-specific alkylating-like agent. Inside the cell, chloride ions are displaced by water, forming a reactive species that binds to DNA (primarily at the N7 position of guanine). This creates **intrastrand cross-links**, leading to DNA bending, inhibition of replication, and apoptosis. **Analysis of Incorrect Options:** * **A. Dacarbazine:** An organic alkylating agent belonging to the **Triazene** group. It is a prodrug activated in the liver to MTIC, used primarily in melanoma and Hodgkin lymphoma. * **C. Methotrexate:** A classic **Antimetabolite**. It is a folate analogue that inhibits the enzyme dihydrofolate reductase (DHFR), thereby arresting DNA synthesis. * **D. Vincristine:** A **Vinca Alkaloid** derived from the periwinkle plant (*Catharanthus roseus*). It is a microtubule inhibitor that binds to tubulin and prevents polymerization (M-phase specific). **High-Yield Clinical Pearls for NEET-PG:** * **Toxicity Profile:** Cisplatin is notorious for "the three Ns": **N**ephrotoxicity (prevented by aggressive hydration and Amifostine), **N**eurotoxicity (peripheral neuropathy), and severe **N**ausea/vomiting (highly emetogenic). It is also **Ototoxic**. * **Indications:** It is the cornerstone of treatment for solid tumors, especially testicular, ovarian, and lung cancers. * **Resistance:** Often occurs due to increased DNA repair or increased intracellular levels of glutathione.

Q: Which of the following is associated with neutropenia?

Methotrexate. **Explanation:** **1. Why Methotrexate is the Correct Answer:** Methotrexate (MTX) is a folate antimetabolite that inhibits the enzyme **dihydrofolate reductase (DHFR)**. This inhibition prevents the conversion of dihydrofolate to tetrahydrofolate, which is essential for DNA synthesis (thymidylate synthesis). Because it acts on rapidly dividing cells, the bone marrow is highly susceptible. **Myelosuppression**, specifically **neutropenia**, is the dose-limiting toxicity of Methotrexate. This can be mitigated by "Leucovorin rescue" (folinic acid), which bypasses the inhibited DHFR enzyme. **2. Analysis of Incorrect Options:** * **Doxorubicin:** While it can cause myelosuppression, its most characteristic and high-yield side effect is **cardiotoxicity** (dilated cardiomyopathy) due to free radical generation. * **Vinblastine:** Although Vinblastine is more bone-marrow toxic than Vincristine ("Blast the marrow"), it is not the primary answer when compared to the systemic antimetabolic effect of Methotrexate in many standardized contexts. However, in clinical practice, many of these drugs cause neutropenia; the question focuses on the classic association with antimetabolites. * **Cisplatin:** The hallmark toxicities of Cisplatin are **nephrotoxicity** and **ototoxicity**. It is considered relatively "bone marrow sparing" compared to other cytotoxic agents. **3. NEET-PG High-Yield Pearls:** * **Mnemonic for Vinca Alkaloids:** **V**in**b**lastine **B**lasts the **B**one marrow; **V**incristine **C**onstricts the **C**ranials (Neurotoxicity/Peripheral neuropathy). * **Methotrexate Toxicity:** Always remember the triad of Myelosuppression, Mucositis, and Hepatotoxicity (cirrhosis with long-term use). * **Antidote:** **Glucarpidase** can be used for methotrexate toxicity in patients with renal failure. * **Cisplatin:** Prevent nephrotoxicity with aggressive hydration and **Amifostine** (a cytoprotective agent).

Q: A female patient with a mechanical heart valve who is taking warfarin informs you that she hopes to get pregnant in the near future. What advice do you give her regarding her antithrombotic medication during the anticipated pregnancy?

Replace warfarin with heparin.. ### Explanation **1. Why the correct answer is right:** Warfarin is a small, lipid-soluble molecule that easily crosses the placenta. It is highly **teratogenic**, especially during the first trimester (6th–9th week), leading to **Fetal Warfarin Syndrome** (characterized by nasal hypoplasia, stippled epiphyses, and CNS defects). In contrast, **Heparin** (both Unfractionated Heparin and LMWH) is a large, polar molecule that **does not cross the placenta** and is therefore safe for the fetus. For patients with mechanical heart valves, anticoagulation must be maintained throughout pregnancy to prevent valve thrombosis, making heparin the safest substitute. **2. Why the incorrect options are wrong:** * **Option A:** Continuing warfarin until the third trimester exposes the fetus to the highest risk of malformations in the first trimester and intracranial hemorrhage during labor in the third trimester. * **Option B:** Aspirin at analgesic doses is not a substitute for anticoagulation in mechanical valves and can cause premature closure of the *ductus arteriosus*. * **Option C:** Discontinuing all medications is life-threatening for the mother, as pregnancy is a hypercoagulable state; a mechanical valve without anticoagulation will almost certainly thrombose. **3. Clinical Pearls for NEET-PG:** * **Fetal Warfarin Syndrome:** Look for keywords like "Chondrodysplasia punctata" or "stippled epiphyses." * **LMWH vs. UFH:** LMWH (e.g., Enoxaparin) is generally preferred in pregnancy due to a lower risk of Heparin-Induced Thrombocytopenia (HIT) and osteoporosis, but it requires monitoring of **Factor Xa levels**. * **The "Switch":** Common practice involves switching to Heparin before conception or as soon as pregnancy is confirmed, though some guidelines allow warfarin between 13–36 weeks if the dose is low (<5mg/day). However, for MCQ purposes, **Heparin is the drug of choice in pregnancy.**

Q: Which of the following is a monoclonal antibody against IL-5?

Mepolizumab. **Explanation:** **Mepolizumab** is a humanized monoclonal antibody that directly binds to and inhibits **Interleukin-5 (IL-5)**. IL-5 is the primary cytokine responsible for the growth, activation, and survival of eosinophils. By neutralizing IL-5, mepolizumab reduces eosinophilic inflammation, making it a key treatment for **severe eosinophilic asthma** and Hypereosinophilic Syndrome. **Analysis of Incorrect Options:** * **A. Omalizumab:** This is a monoclonal antibody against **IgE**. It prevents IgE from binding to mast cells and basophils, used primarily in severe allergic asthma. * **C. Tocilizumab:** This is an **IL-6 receptor antagonist**. It is used in Rheumatoid Arthritis, Giant Cell Arteritis, and was notably used in managing the "cytokine storm" in severe COVID-19. * **D. Alemtuzumab:** This is a monoclonal antibody against **CD52**, found on mature lymphocytes. It is used in the treatment of Chronic Lymphocytic Leukemia (CLL) and Multiple Sclerosis. **High-Yield NEET-PG Pearls:** 1. **IL-5 Inhibitors:** Remember the "mabs" for eosinophilic asthma: **Mepolizumab** and **Reslizumab** (bind to IL-5) and **Benralizumab** (binds to the IL-5 receptor). 2. **Dupilumab:** Often confused with these, it targets the **IL-4 receptor alpha subunit** (inhibiting both IL-4 and IL-13) and is used for atopic dermatitis and asthma. 3. **Suffix Clue:** "-li-" in Mepo**li**zumab stands for "limbic/immune system," while "-tu-" in Toci**tu**zumab (though often shortened) or Rituximab refers to "tumor."

Q: Ifosfamide belongs to which group of anticancer drugs?

Alkylating agents. **Explanation:** **Ifosfamide** is a nitrogen mustard derivative and a structural isomer of cyclophosphamide. It belongs to the **Alkylating Agents** group (specifically the Oxazaphosphorine subclass). These drugs work by attaching alkyl groups to DNA bases (primarily at the N7 position of guanine), leading to DNA cross-linking, strand breakage, and inhibition of DNA synthesis. Like cyclophosphamide, ifosfamide is a **prodrug** that requires hepatic activation by the Cytochrome P450 system (CYP3A4 and CYP2B6) to form its active metabolite, ifosfamide mustard. **Why other options are incorrect:** * **Antimetabolites (e.g., Methotrexate, 5-FU):** These interfere with metabolic pathways (like folic acid or pyrimidine synthesis) and are S-phase specific. * **Mitotic Inhibitors (e.g., Vincristine, Paclitaxel):** These target microtubules during the M-phase of the cell cycle. * **Topoisomerase Inhibitors (e.g., Etoposide, Irinotecan):** These inhibit enzymes responsible for DNA winding/unwinding. **High-Yield Clinical Pearls for NEET-PG:** 1. **Hemorrhagic Cystitis:** Ifosfamide produces **Acrolein**, a toxic metabolite that causes bladder irritation. This risk is significantly higher with ifosfamide than with cyclophosphamide. 2. **Mesna (2-Mercaptoethane sulfonate):** Always co-administered with ifosfamide to neutralize acrolein in the bladder and prevent hemorrhagic cystitis. 3. **Encephalopathy:** Ifosfamide can cause CNS toxicity (confusion, seizures) due to the production of **chloroacetaldehyde**. This is a unique side effect compared to cyclophosphamide. 4. **Cell Cycle Non-Specific (CCNS):** Like most alkylating agents, ifosfamide acts throughout the cell cycle.

Question 1

Ifosfamide belongs to which group of anticancer drugs?

Accepted Answer

Alkylating agents

Answer

Antimetabolites

Answer

Mitotic inhibitors

Answer

Topoisomerase inhibitors

Question 2

Which of the following anticancer drugs is not derived from plants?

Accepted Answer

Doxorubicin

Answer

Irinotecan

Answer

Paclitaxel

Answer

Etoposide

Question 3

Alkylating drugs attach an alkyl group to which position of guanine?

Accepted Answer

N7

Answer

N3

Answer

N5

Answer

N9

Question 4

A young male was diagnosed with acute myeloid leukemia and successfully completed induction chemotherapy. Two months later, he presents with bilateral pedal edema and dyspnea on exertion (waking up multiple times due to breathlessness). Which of the following anticancer drugs is most likely responsible for these symptoms?

Accepted Answer

Doxorubicin

Answer

Cisplatin

Answer

Methotrexate

Answer

Vincristine

Question 5

Which of the following statements is true regarding intravenous administration of chemotherapy?

Accepted Answer

Problems of wound healing should be anticipated if systemic 5-FU therapy is begun less than 2 weeks postoperatively.

Answer

Subcutaneous extravasation of carmustine (BCNU) or 5-fluorouracil (5-FU) usually causes ulceration.

Answer

Extravasation of doxorubicin rarely causes serious ulceration because the agent binds quickly to tissue nucleic acid.

Answer

Serious and progressive ulceration can be expected following extravasation of vincristine or vinblastine.

Question 6

Which anticancer drug belongs to the class of inorganic metal complexes?

Accepted Answer

Cisplatin

Answer

Dacarbazine

Answer

Methotrexate

Answer

Vincristine

Question 7

Which of the following is associated with neutropenia?

Accepted Answer

Methotrexate

Answer

Doxorubicin

Answer

Vinblastine

Answer

Cisplatin

Question 8

A female patient with a mechanical heart valve who is taking warfarin informs you that she hopes to get pregnant in the near future. What advice do you give her regarding her antithrombotic medication during the anticipated pregnancy?

Accepted Answer

Replace warfarin with heparin.

Answer

Continue with warfarin until the third trimester.

Answer

Replace warfarin with aspirin at analgesic doses.

Answer

Discontinue all medications that affect the blood.

Question 9

Which of the following is a monoclonal antibody against IL-5?

Accepted Answer

Mepolizumab

Answer

Omalizumab

Answer

Tocilizumab

Answer

Alemtuzumab

Question 10

Ifosfamide belongs to which group of anticancer drugs?

Accepted Answer

Alkylating agents

Answer

Antimetabolites

Answer

Mitotic inhibitors

Answer

Topoisomerase inhibitors

Anticancer Drugs — MCQs

Anticancer Drugs — MCQs

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