UPSC-CMS 2019 — Pharmacology

Q: All of the following are hormonal agents used in treatment of cancer EXCEPT:

Irinotecan. ***Irinotecan*** - **Irinotecan** is a **chemotherapeutic agent** that acts as a **topoisomerase I inhibitor**, interfering with DNA replication and repair. - It works through a **cytotoxic mechanism** directly killing cancer cells, rather than modulating hormonal pathways. *Cabergoline* - **Cabergoline** is a **dopamine agonist** primarily used to treat **prolactinomas**, which are prolactin-producing pituitary tumors. - While it treats a tumor, its mechanism is **hormonal modulation** by reducing prolactin secretion, not direct cytotoxicity. *Anastrozole* - **Anastrozole** is an **aromatase inhibitor** used in estrogen receptor-positive breast cancer. - It works by **blocking the conversion of androgens to estrogens**, thereby reducing estrogen levels that fuel cancer growth. *Leuprolide* - **Leuprolide** is a **GnRH agonist** used in prostate cancer, breast cancer, and other hormone-sensitive conditions. - It initially stimulates, then continuously downregulates, the **pituitary gland's production of LH and FSH**, leading to reduced testosterone or estrogen levels. [Practice more Pharmacology PYQs on OnCourse]

Q: Which of the following are the vaccines for prevention of cervical cancer? 1. Cervarix 2. Gardasil 3. T-dap 4. Influenza Select the correct answer using the code given below:

1 and 2. ***Option A: 1 and 2 (Cervarix and Gardasil)*** - Both are **HPV vaccines** that prevent cervical cancer by targeting oncogenic human papillomavirus types - **Cervarix**: Bivalent vaccine protecting against HPV-16 and HPV-18 (responsible for ~70% of cervical cancers) - **Gardasil**: Quadrivalent vaccine (Gardasil-4) protecting against HPV-6, 11, 16, and 18; Nonavalent version (Gardasil-9) covers additional high-risk HPV types (31, 33, 45, 52, 58) - **Clinical significance**: Persistent HPV infection is the primary cause of cervical cancer; vaccination is primary prevention *Option B: 1 and 3* - While Cervarix is correct, **T-dap vaccine** (tetanus, diphtheria, acellular pertussis) is a bacterial vaccine with no role in cervical cancer prevention - T-dap targets entirely different pathogens and has no effect on HPV infection *Option C: 2 and 3* - Gardasil is correct for cervical cancer prevention, but **T-dap** is unrelated to HPV or cervical cancer - Mixing a correct HPV vaccine with an unrelated bacterial vaccine makes this option incorrect *Option D: 2 and 4* - Gardasil is correct, but **influenza vaccine** targets influenza virus to prevent seasonal flu, not HPV-related malignancies - Influenza vaccine has no protective effect against cervical cancer [Practice more Pharmacology PYQs on OnCourse]

Q: Which one of the following drugs does NOT interfere with efficacy of oral contraceptive pills and increase the failure rates?

Ranitidine. ***Ranitidine*** - **Ranitidine** is an H2 receptor antagonist that reduces stomach acid and does not interact with the **cytochrome P450 enzyme system**, which metabolizes oral contraceptives. - This means it does not significantly alter the **pharmacokinetics** of oral contraceptive pills, ensuring their efficacy is maintained. *Barbiturates* - **Barbiturates** are potent inducers of the **hepatic cytochrome P450 enzyme system**, specifically CYP3A4. - This induction accelerates the metabolism of estrogen and progestin components of oral contraceptives, leading to **lower serum levels** and reduced contraceptive efficacy. *Rifampicin* - **Rifampicin** is a strong inducer of the **hepatic cytochrome P450 enzyme system**, particularly CYP3A4, which is responsible for metabolizing steroid hormones. - This accelerated metabolism significantly reduces the serum concentrations of oral contraceptive hormones, thereby **decreasing their effectiveness** and increasing the risk of unintended pregnancy. *Ampicillin* - **Ampicillin**, and other broad-spectrum antibiotics, can theoretically interfere with oral contraceptive efficacy by disrupting the **enterohepatic recirculation** of estrogens. - This disruption leads to a decrease in the reabsorption of estrogen metabolites from the gut, resulting in **lower circulating estrogen levels** and potentially reduced contraceptive protection. [Practice more Pharmacology PYQs on OnCourse]

Q: Which one of the following antihypertensive drugs is NOT safe during pregnancy?

ACE-inhibitors. ***ACE-inhibitors*** - **ACE inhibitors** (e.g., enalapril, lisinopril) are **contraindicated** in pregnancy due to their association with severe fetal abnormalities, including **renal agenesis**, **oligohydramnios**, and **fetal death** [1], [2]. - They should be discontinued as soon as pregnancy is confirmed or suspected due to their known **teratogenic effects** [1], [2].*Labetalol* - **Labetalol**, a combined alpha- and beta-blocker, is considered one of the **first-line agents** for managing hypertension in pregnancy. - It has a good safety profile for both the mother and the fetus and is commonly used in conditions like **preeclampsia**.*Nifedipine* - **Nifedipine**, a calcium channel blocker, is also a **safe and effective** option for treating hypertension during pregnancy. - It is frequently used for managing **chronic hypertension** and **preeclampsia** due to its rapid onset of action and tolerability.*Alpha-methyl dopa* - **Alpha-methyl dopa** (methyldopa) is considered one of the **safest and most extensively studied** antihypertensive medications for use in pregnancy. - It is often the **first-choice agent** for chronic hypertension during pregnancy due to its long-standing track record of safety for the fetus. [Practice more Pharmacology PYQs on OnCourse]

Q: The drug of choice for chemoprophylaxis to health care personnel and close contacts of suspected or confirmed case of pandemic influenza A (H1N1) is:

Oseltamivir. ***Oseltamivir*** - **Oseltamivir** is the recommended drug for chemoprophylaxis against pandemic influenza A (H1N1) for healthcare personnel and close contacts [1, 2]. - This recommendation is based on its effectiveness against the **neuraminidase** of the H1N1 virus, preventing viral release and spread. *Ribavirin* - **Ribavirin** is an antiviral agent used for conditions like chronic hepatitis C and RSV, but it is not recommended for influenza chemoprophylaxis. - Its mechanism of action and efficacy profile do not make it a primary choice for preventing H1N1 infection. *Amantadine* - **Amantadine** targets the M2 ion channel of influenza A viruses, but many H1N1 strains, including the pandemic strain, developed **resistance** to this drug [1]. - Due to widespread resistance, **amantadine** and rimantadine are no longer recommended for routine influenza treatment or prophylaxis [1]. *Zanamivir* - **Zanamivir** is another **neuraminidase inhibitor** effective against influenza A and B, but it is administered via inhalation. - While effective, **oseltamivir** is generally preferred for chemoprophylaxis due to its oral administration, making it more convenient for widespread use [2]. [Practice more Pharmacology PYQs on OnCourse]

6 Previous Year Questions with Answers & Explanations

Questions

All Subjects Anatomy (1)Anesthesiology (1)Biochemistry (3)Community Medicine (28)ENT (1)Internal Medicine (10)Microbiology (1)Obstetrics and Gynecology (37)Ophthalmology (2)Orthopaedics (1)Pathology (5)Pediatrics (3)Pharmacology (6)Physiology (2)Radiology (2)Surgery (16)

All of the following are hormonal agents used in treatment of cancer EXCEPT:

Which of the following are the vaccines for prevention of cervical cancer? 1. Cervarix 2. Gardasil 3. T-dap 4. Influenza Select the correct answer using the code given below:

Which one of the following drugs does NOT interfere with efficacy of oral contraceptive pills and increase the failure rates?

Which one of the following antihypertensive drugs is NOT safe during pregnancy?

The drug of choice for chemoprophylaxis to health care personnel and close contacts of suspected or confirmed case of pandemic influenza A (H1N1) is:

All of the following drugs are effective for treatment of hookworm infection in single dose EXCEPT:

UPSC-CMS 2019 - Pharmacology UPSC-CMS Practice Questions and MCQs

Question 1: All of the following are hormonal agents used in treatment of cancer EXCEPT:

A. Cabergoline
B. Leuprolide
C. Irinotecan (Correct Answer)
D. Anastrozole

Explanation: ***Irinotecan*** - **Irinotecan** is a **chemotherapeutic agent** that acts as a **topoisomerase I inhibitor**, interfering with DNA replication and repair. - It works through a **cytotoxic mechanism** directly killing cancer cells, rather than modulating hormonal pathways. *Cabergoline* - **Cabergoline** is a **dopamine agonist** primarily used to treat **prolactinomas**, which are prolactin-producing pituitary tumors. - While it treats a tumor, its mechanism is **hormonal modulation** by reducing prolactin secretion, not direct cytotoxicity. *Anastrozole* - **Anastrozole** is an **aromatase inhibitor** used in estrogen receptor-positive breast cancer. - It works by **blocking the conversion of androgens to estrogens**, thereby reducing estrogen levels that fuel cancer growth. *Leuprolide* - **Leuprolide** is a **GnRH agonist** used in prostate cancer, breast cancer, and other hormone-sensitive conditions. - It initially stimulates, then continuously downregulates, the **pituitary gland's production of LH and FSH**, leading to reduced testosterone or estrogen levels.

Question 2: Which of the following are the vaccines for prevention of cervical cancer? 1. Cervarix 2. Gardasil 3. T-dap 4. Influenza Select the correct answer using the code given below:

A. 1 and 2 (Correct Answer)
B. 1 and 3
C. 2 and 3
D. 2 and 4

Explanation: ***Option A: 1 and 2 (Cervarix and Gardasil)*** - Both are **HPV vaccines** that prevent cervical cancer by targeting oncogenic human papillomavirus types - **Cervarix**: Bivalent vaccine protecting against HPV-16 and HPV-18 (responsible for ~70% of cervical cancers) - **Gardasil**: Quadrivalent vaccine (Gardasil-4) protecting against HPV-6, 11, 16, and 18; Nonavalent version (Gardasil-9) covers additional high-risk HPV types (31, 33, 45, 52, 58) - **Clinical significance**: Persistent HPV infection is the primary cause of cervical cancer; vaccination is primary prevention *Option B: 1 and 3* - While Cervarix is correct, **T-dap vaccine** (tetanus, diphtheria, acellular pertussis) is a bacterial vaccine with no role in cervical cancer prevention - T-dap targets entirely different pathogens and has no effect on HPV infection *Option C: 2 and 3* - Gardasil is correct for cervical cancer prevention, but **T-dap** is unrelated to HPV or cervical cancer - Mixing a correct HPV vaccine with an unrelated bacterial vaccine makes this option incorrect *Option D: 2 and 4* - Gardasil is correct, but **influenza vaccine** targets influenza virus to prevent seasonal flu, not HPV-related malignancies - Influenza vaccine has no protective effect against cervical cancer

Question 3: Which one of the following drugs does NOT interfere with efficacy of oral contraceptive pills and increase the failure rates?

A. Barbiturates
B. Rifampicin
C. Ranitidine (Correct Answer)
D. Ampicillin

Explanation: ***Ranitidine*** - **Ranitidine** is an H2 receptor antagonist that reduces stomach acid and does not interact with the **cytochrome P450 enzyme system**, which metabolizes oral contraceptives. - This means it does not significantly alter the **pharmacokinetics** of oral contraceptive pills, ensuring their efficacy is maintained. *Barbiturates* - **Barbiturates** are potent inducers of the **hepatic cytochrome P450 enzyme system**, specifically CYP3A4. - This induction accelerates the metabolism of estrogen and progestin components of oral contraceptives, leading to **lower serum levels** and reduced contraceptive efficacy. *Rifampicin* - **Rifampicin** is a strong inducer of the **hepatic cytochrome P450 enzyme system**, particularly CYP3A4, which is responsible for metabolizing steroid hormones. - This accelerated metabolism significantly reduces the serum concentrations of oral contraceptive hormones, thereby **decreasing their effectiveness** and increasing the risk of unintended pregnancy. *Ampicillin* - **Ampicillin**, and other broad-spectrum antibiotics, can theoretically interfere with oral contraceptive efficacy by disrupting the **enterohepatic recirculation** of estrogens. - This disruption leads to a decrease in the reabsorption of estrogen metabolites from the gut, resulting in **lower circulating estrogen levels** and potentially reduced contraceptive protection.

Question 4: Which one of the following antihypertensive drugs is NOT safe during pregnancy?

A. Labetalol
B. ACE-inhibitors (Correct Answer)
C. Nifedipine
D. Alpha-methyl dopa

Explanation: ***ACE-inhibitors*** - **ACE inhibitors** (e.g., enalapril, lisinopril) are **contraindicated** in pregnancy due to their association with severe fetal abnormalities, including **renal agenesis**, **oligohydramnios**, and **fetal death** [1], [2]. - They should be discontinued as soon as pregnancy is confirmed or suspected due to their known **teratogenic effects** [1], [2].*Labetalol* - **Labetalol**, a combined alpha- and beta-blocker, is considered one of the **first-line agents** for managing hypertension in pregnancy. - It has a good safety profile for both the mother and the fetus and is commonly used in conditions like **preeclampsia**.*Nifedipine* - **Nifedipine**, a calcium channel blocker, is also a **safe and effective** option for treating hypertension during pregnancy. - It is frequently used for managing **chronic hypertension** and **preeclampsia** due to its rapid onset of action and tolerability.*Alpha-methyl dopa* - **Alpha-methyl dopa** (methyldopa) is considered one of the **safest and most extensively studied** antihypertensive medications for use in pregnancy. - It is often the **first-choice agent** for chronic hypertension during pregnancy due to its long-standing track record of safety for the fetus.

Question 5: The drug of choice for chemoprophylaxis to health care personnel and close contacts of suspected or confirmed case of pandemic influenza A (H1N1) is:

A. Ribavirin
B. Oseltamivir (Correct Answer)
C. Amantadine
D. Zanamivir

Explanation: ***Oseltamivir*** - **Oseltamivir** is the recommended drug for chemoprophylaxis against pandemic influenza A (H1N1) for healthcare personnel and close contacts [1, 2]. - This recommendation is based on its effectiveness against the **neuraminidase** of the H1N1 virus, preventing viral release and spread. *Ribavirin* - **Ribavirin** is an antiviral agent used for conditions like chronic hepatitis C and RSV, but it is not recommended for influenza chemoprophylaxis. - Its mechanism of action and efficacy profile do not make it a primary choice for preventing H1N1 infection. *Amantadine* - **Amantadine** targets the M2 ion channel of influenza A viruses, but many H1N1 strains, including the pandemic strain, developed **resistance** to this drug [1]. - Due to widespread resistance, **amantadine** and rimantadine are no longer recommended for routine influenza treatment or prophylaxis [1]. *Zanamivir* - **Zanamivir** is another **neuraminidase inhibitor** effective against influenza A and B, but it is administered via inhalation. - While effective, **oseltamivir** is generally preferred for chemoprophylaxis due to its oral administration, making it more convenient for widespread use [2].

Question 6: All of the following drugs are effective for treatment of hookworm infection in single dose EXCEPT:

A. Albendazole
B. Levamisole
C. Pyrantel
D. Piperazine (Correct Answer)

Explanation: ***Piperazine*** - **Piperazine** is primarily effective against **Ascaris lumbricoides** and **Enterobius vermicularis**, acting as a depolarizing neuromuscular blocker. - It is **not effective** against hookworm infections and is therefore unsuitable for treating the human reservoir of hookworms. *Albendazole* - **Albendazole** is a broad-spectrum anthelminthic highly effective against hookworm infections, including **Necator americanus** and **Ancylostoma duodenale**. - A **single dose** is often sufficient due to its effectiveness in eliminating adult worms and reducing egg excretion. *Levamisole* - **Levamisole** is an anthelminthic that can be effective against hookworm species, working as a **ganglionic stimulant** causing paralysis of the worms. - A **single dose** regimen is typically adequate for hookworm treatment. *Pyrantel* - **Pyrantel pamoate** is effective against hookworms by causing **neuromuscular blockade**, leading to expulsion of the worms. - It is often given as a **single dose** for effective treatment of hookworm infections.