INI-CET 2021 - Pharmacology PYQs Practice Questions

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

Fixed drug combination is preferred over single drugs. ***Fixed drug combination is preferred over single drugs*** - The statement that **fixed-drug combinations (FDCs)** are preferred over single drugs for essential drug selection is false. Generally, **single drugs are preferred** to allow for individual dose adjustments and minimize potential adverse effects from unnecessary components. - FDCs are only considered essential when they offer specific advantages, such as **improved adherence** (e.g., in tuberculosis treatment) or a **synergistic effect** not achievable with individual drugs. *Cost to benefit has to be considered* - This statement is true; the **cost-effectiveness** and **cost-benefit ratio** are crucial factors in selecting essential drugs. - Essential drugs aim to provide the most public health benefit at an **affordable cost**, ensuring access for a broad population. *An adequate safety profile needs to be established* - This statement is true; essential drugs must have a **well-established safety profile** with acceptable risks. - The benefits of the drug must significantly outweigh its potential harms, with minimal serious **adverse reactions**. *Disease prevalence is considered* - This statement is true; essential drugs are selected based on their ability to address the **most prevalent diseases** and health needs of a population. - Prioritizing drugs for common conditions ensures that public health resources are effectively allocated to where they are most needed. [Practice more Pharmacology PYQs on OnCourse]

Q: 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?

Increase the dose. ***Increase the dose*** - **Phenytoin** is a potent **enzyme inducer** that induces hepatic enzymes including **UGT (glucuronidation) enzymes**. - **Retigabine** is primarily metabolized by **N-acetylation and glucuronidation** (not significantly by CYP450 enzymes). - Phenytoin induces UGT enzymes, which **increases retigabine metabolism and clearance**, leading to **decreased plasma concentrations**. - To maintain therapeutic levels and seizure control, the **dose of retigabine needs to be increased** when co-administered with phenytoin. *Stop the drug* - There is no clinical indication to completely **stop retigabine** simply because phenytoin is being added, as both can be used concurrently with dose adjustment. - Doing so might lead to a **loss of seizure control** if retigabine was providing effective seizure management. *Stop retigabine and start on carbamazepine* - This is an unnecessary and unindicated change; there is no medical reason to **switch from retigabine to carbamazepine** due to phenytoin addition. - Like phenytoin, **carbamazepine is also a strong enzyme inducer**, so similar drug interactions would occur. *Decrease the dose* - **Decreasing the dose** would be appropriate if phenytoin were an enzyme inhibitor, leading to higher retigabine levels. - Since phenytoin is an **enzyme inducer**, decreasing the dose would further reduce retigabine's therapeutic concentration, potentially leading to **breakthrough seizures**. [Practice more Pharmacology PYQs on OnCourse]

Question 1

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 2

Which of the following is not used to treat PCOD?

Accepted Answer

Tamoxifen

Answer

OCP

Answer

Metformin

Answer

Clomiphene citrate

Question 3

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 4

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 5

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 6

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 7

An HIV positive woman on ART was prescribed ergotamine for a migraine attack 4 days back. She presented with complaints that she is unable to feel her legs from the mid - thigh to her toes, for the past two days. The angiography image is given below. What is the likely diagnosis?

Accepted Answer

Ergotism

Answer

Polyradicular neuropathy

Answer

Atherosclerosis

Answer

Vasculitis

Question 8

Nivolumab is used as checkpoint inhibitor in

Accepted Answer

Hodgkin's lymphoma

Answer

Medulloblastoma

Answer

Retinoblastoma

Answer

Pleuropulmonary blastoma

Question 9

Antimicrobial combinations are used in all except

Accepted Answer

Gonorrhea

Answer

Intra abdominal infections

Answer

Malaria

Answer

Tuberculosis

Question 10

What would happen to the half-life and plasma concentration of a drug which follows first-order kinetics, if the dose is doubled?

Accepted Answer

Half - life remains the same and plasma concentration doubles

Answer

Half - life and plasma concentration remains the same

Answer

Half - life doubles and plasma concentration remains the same

Answer

Half - life and plasma concentration doubles

INI-CET 2021 — Pharmacology