INI-CET 2021 - Pharmacology PYQs Practice Questions

Q: Identify the correct 'organism-drug to which it is intrinsically resistant' pair.

Candida krusei - Fluconazole. ***Candida krusei - Fluconazole*** - **Candida krusei** is intrinsically resistant to **fluconazole** due to reduced affinity of its target enzyme, **lanosterol 14-alpha demethylase**, for the drug. - This resistance is a natural characteristic of the species, meaning it is inherent and not acquired through exposure. *Aspergillus fumigatus - Micafungin* - **Aspergillus fumigatus** is generally susceptible to **micafungin**, an **echinocandin drug** that targets fungal cell wall synthesis. - While resistance can develop, it is not an intrinsic characteristic of *A. fumigatus* to micafungin. *Candida albicans - Amphotericin B* - **Candida albicans** is typically susceptible to **amphotericin B**, a polyene antifungal that binds to ergosterol in the fungal cell membrane. - Intrinsic resistance to amphotericin B in *C. albicans* is rare, though acquired resistance can occur. *Aspergillus niger - Voriconazole* - **Aspergillus niger** is usually susceptible to **voriconazole**, a broad-spectrum triazole antifungal. - There is no known intrinsic resistance of *A. niger* to voriconazole. [Practice more Pharmacology PYQs on OnCourse]

Q: What is the mechanism of action of local anesthetics?

Block sodium channels. ***Block sodium channels*** - Local anesthetics work by **reversibly binding** to the alpha subunit of **voltage-gated sodium channels** on the neuronal membrane. - This binding prevents the influx of sodium ions, thereby inhibiting the **depolarization** of the neuron and **propagation of action potentials**. *Block chloride channels* - **Chloride channels** are primarily involved in **hyperpolarization** or stabilization of the resting membrane potential, and their blockade is not the primary mechanism of local anesthesia. - Drugs like **benzodiazepines** modulate GABA-gated chloride channels for their anxiolytic and sedative effects. *Block calcium channels* - **Calcium channels** are important for neurotransmitter release and muscle contraction, but their blockade is not the way local anesthetics exert their effects. - **Calcium channel blockers** are used in cardiovascular medicine (e.g., diltiazem, verapamil) to reduce heart rate and blood pressure. *Block potassium channels* - **Potassium channels** are crucial for repolarization of the neuronal membrane and maintaining the resting potential. - While some toxins block potassium channels, it is not the principal mechanism by which **local anesthetics** achieve their nerve blocking effect. [Practice more Pharmacology PYQs on OnCourse]

Q: Which of the following is not used to treat PCOD?

Tamoxifen. ***Tamoxifen*** - **Tamoxifen** is a selective estrogen receptor modulator (SERM) primarily used in the treatment of **estrogen receptor-positive breast cancer**. - While other SERMs like clomiphene citrate are used in PCOD for ovulation induction, tamoxifen is not a standard treatment for **PCOD** itself. *OCP* - **Oral contraceptive pills (OCPs)** are a common first-line treatment for managing various symptoms of PCOD, such as **menstrual irregularities** and **hirsutism**. - They work by suppressing ovarian androgen production and providing regular withdrawal bleeds. *Metformin* - **Metformin** is an insulin-sensitizing agent often used in PCOD, especially in women with **insulin resistance** or impaired glucose tolerance. - It helps improve **menstrual regularity** and can facilitate ovulation in some patients by reducing insulin levels. *Clomiphene citrate* - **Clomiphene citrate** is a selective estrogen receptor modulator (SERM) commonly used as an **ovulation induction agent** in women with PCOD who are trying to conceive. - It works by blocking estrogen receptors in the hypothalamus, leading to increased release of **gonadotropins** (FSH and LH). [Practice more Pharmacology PYQs on OnCourse]

Q: Hepatitis B subunit vaccine contains which of the following antigens?

HbsAg. ***HbsAg*** - The Hepatitis B vaccine is a **subunit vaccine** that contains recombinant **hepatitis B surface antigen (HBsAg)**. - This antigen is highly immunogenic and elicits a protective antibody response (anti-HBs) that neutralizes the virus. *HbeAg* - **HBeAg** indicates active viral replication and high infectivity, but it is not the antigen used in the vaccine. - While important for diagnostic purposes, antibodies to HBeAg (anti-HBe) indicate reduced viral replication. *HbcAg* - **HBcAg (hepatitis B core antigen)** is an internal component of the virion and is not found in the subunit vaccine. - Antibodies to HBcAg (anti-HBc) indicate past or current infection but do not confer protective immunity. *HBV DNA* - **HBV DNA** represents the viral genetic material and is a marker of active viral replication and infectivity. - It is not an antigen and therefore not included in a subunit vaccine designed to induce an immune response to viral proteins. [Practice more Pharmacology PYQs on OnCourse]

Question 1

Identify the correct 'organism-drug to which it is intrinsically resistant' pair.

Accepted Answer

Candida krusei - Fluconazole

Answer

Candida albicans - Amphotericin B

Answer

Aspergillus fumigatus - Micafungin

Answer

Aspergillus niger - Voriconazole

Question 2

What is the mechanism of action of local anesthetics?

Accepted Answer

Block sodium channels

Answer

Block chloride channels

Answer

Block calcium channels

Answer

Block potassium channels

Question 3

Which of the following is not used to treat PCOD?

Accepted Answer

Tamoxifen

Answer

OCP

Answer

Metformin

Answer

Clomiphene citrate

Question 4

Which of the following is true regarding nicotine substitution therapy?

Accepted Answer

There should be a 15-minute gap between nicotine gum and coffee/soda/acidic food as they decrease its absorption

Answer

Preferably given by gastrointestinal route.

Answer

Varenicline comes with a black box warning of cardiovascular death

Answer

Nicotine chewing gum is better for constant use as it gives 25% higher blood level than lozenges

Question 5

Hepatitis B subunit vaccine contains which of the following antigens?

Accepted Answer

HbsAg

Answer

HbeAg

Answer

HbcAg

Answer

HBV DNA

Question 6

Which of the following is false about the selection of essential drugs?

Accepted Answer

Fixed drug combination is preferred over single drugs

Answer

Cost to benefit has to be considered

Answer

An adequate safety profile needs to be established

Answer

Disease prevalence is considered

Question 7

A patient who was diagnosed with epilepsy was put on retigabine TDS. Now phenytoin is being added. Which of the following changes should be made to retigabine?

Accepted Answer

Increase the dose

Answer

Stop the drug

Answer

Stop retigabine and start on carbamazepine

Answer

Decrease the dose

Question 8

A patient with history of ischemic stroke was started on clopidogrel. However, she had another attack of stroke after 6 months. Which of the following is likely to be responsible for the failure of clopidogrel in this patient?

Accepted Answer

Downregulation of CYP2C19

Answer

Upregulation of CYP1A1

Answer

Downregulation of CYP2E1

Answer

Downregulation of CYP2D6

Question 9

Nivolumab is used as checkpoint inhibitor in

Accepted Answer

Hodgkin's lymphoma

Answer

Medulloblastoma

Answer

Retinoblastoma

Answer

Pleuropulmonary blastoma

Question 10

Antimicrobial combinations are used in all except

Accepted Answer

Gonorrhea

Answer

Intra abdominal infections

Answer

Malaria

Answer

Tuberculosis

INI-CET 2021 — Pharmacology