INI-CET 2026 - Pharmacology PYQs Practice Questions

Q: Calculate the Therapeutic Index of the given drug from the dose-response curve below:

4. ***4*** - The **Therapeutic Index (TI)** is calculated as the ratio of the **Lethal Dose (LD50)** to the **Effective Dose (ED50)**, represented by the formula **TI = LD50 / ED50**. - Given the typical interpretation of such graphs in pharmacology exams, if the ED50 is at 25mg and the LD50 is at 100mg, the calculation 100/25 yields a **Therapeutic Index of 4**. *0.25* - This value represents the **reciprocal** of the correct answer (ED50/LD50), which is incorrect terminology. - A value less than 1 would imply that the **effective dose** is higher than the **lethal dose**, which would make the drug impossible to use safely. *0.75* - This value is not derived from the standard ratio of **LD50** over **ED50** in typical dose-response curve assessments. - It does not correctly reflect the **margin of safety** associated with the drug's therapeutic window. *2* - This result would be obtained if the ratio between the **lethal** and **effective doses** was 2:1. - This likely reflects a misreading of the **x-axis intercepts** for potency or toxicity on the provided graph. [Practice more Pharmacology PYQs on OnCourse]

Q: What is the mechanism of action of Resmetirom?

Stimulation of Thyroid Hormone Receptor-beta. ***Stimulation of Thyroid Hormone Receptor-beta*** - Resmetirom is a first-in-class, oral, liver-directed **selective thyroid hormone receptor-beta (THR-β) agonist**. - By stimulating this receptor specifically in the liver, it helps reduce **hepatic lipotoxicity**, downregulate **fibrogenesis**, and improve lipid metabolism, making it indicated for **non-alcoholic steatohepatitis (NASH)** with liver fibrosis. *Blockage at NPC1L1 transporter* - This mechanism describes **Ezetimibe**, a drug used to treat **hypercholesterolemia** by inhibiting cholesterol absorption in the small intestine. - It does not target liver fibrosis or NASH directly through thyroid hormone pathways. *Activation of PPAR-γ* - This is the mechanism of **Thiazolidinediones** (e.g., Pioglitazone), which are insulin-sensitizing agents. - While used in diabetes and sometimes studied in NASH, they work by enhancing insulin sensitivity rather than selectively agonizing hepatic THR-β. *Blockage of Acetyl Co-A carboxylase* - Inhibitors of acetyl-CoA carboxylase (ACC), such as Firsocostat, were investigated for NASH to reduce **de novo lipogenesis**. - They function by inhibiting the rate-limiting step in fatty acid synthesis, distinct from thyroid receptor modulation. [Practice more Pharmacology PYQs on OnCourse]

Q: What is the mechanism of action of Pretomanid under the BPaLM regimen?

Inhibition of mycolic acid synthesis. ***Inhibition of mycolic acid synthesis*** - Pretomanid is a **nitroimidazooxazine** that acts as a prodrug, which is activated by the mycobacterial deazaflavin-dependent nitroreductase enzyme (Ddn). - Once activated, it interferes with **mycolic acid synthesis** and also generates reactive nitrogen species that lead to the inhibition of cellular respiration and ATP depletion in both actively replicating and dormant **Mycobacterium tuberculosis**. *Inhibition of ATP synthase* - This mechanism is specific to **bedaquiline**, another component of the BPaLM regimen, which targets the proton pump of the mycobacterial ATP synthase. - Inhibition of this enzyme leads to the rapid depletion of intracellular ATP, resulting in bacteriostasis and eventual cell death. *Inhibition of RNA polymerase* - This is the primary mechanism of action for **rifamycins** (such as Rifampicin), which bind to the beta unit of RNA polymerase. - By preventing transcription, Rifampicin effectively halts bacterial protein synthesis. *Inhibition of arabinoglycan synthesis* - This mechanism is characteristic of **ethambutol**, which inhibits the arabinosyl transferase enzymes involved in cell wall synthesis. - Disruption of arabinoglycan synthesis weakens the mycobacterial cell wall, making the organism more susceptible to other antibiotics. [Practice more Pharmacology PYQs on OnCourse]

Q: Identify the type of elimination kinetics represented in the given graph:

First-order kinetics. ***First-order kinetics*** - This process is characterized by the elimination of a **constant fraction** of the drug per unit time, resulting in an **exponential decay** curve on a linear plot. - The rate of elimination is directly **proportional to the plasma concentration** of the drug, meaning faster elimination occurs when drug levels are higher. *Zero-order kinetics* - This involves the elimination of a **constant amount** of drug per unit time, regardless of the plasma concentration. - It typically results in a **linear decline** in plasma concentration over time, often seen when elimination pathways are **saturated**. *Nonlinear kinetics* - This term usually refers to situations where the rate of elimination does not change proportionally with dose, often because the metabolic enzyme systems are **saturated**. - While both zero-order and Michaelis-Menten kinetics are forms of nonlinear elimination, the term is too broad to describe a standard decay curve specifically. *Saturation kinetics* - This describes a state where the capacity of an enzyme or transport system is fully utilized and the system reaches its **maximum velocity (Vmax)**. - When a system becomes saturated at therapeutic levels, it shifts from first-order to **zero-order elimination**. [Practice more Pharmacology PYQs on OnCourse]

Question 1

Calculate the Therapeutic Index of the given drug
from the dose-response curve below:

Accepted Answer

4

Answer

0.25

Answer

0.75

Answer

2

Question 2

What is the mechanism of action of Resmetirom?

Accepted Answer

Stimulation of Thyroid Hormone Receptor-beta

Answer

Blockage at NPC1L1 transporter

Answer

Activation of PPAR-γ

Answer

Blockage of Acetyl Co-A carboxylase

Question 3

What is the mechanism of action of Pretomanid under the BPaLM regimen?

Accepted Answer

Inhibition of mycolic acid synthesis

Answer

Inhibition of ATP synthase

Answer

Inhibition of RNA polymerase

Answer

Inhibition of arabinoglycan synthesis

Question 4

Identify the type of elimination kinetics represented in the given
graph:

Accepted Answer

First-order kinetics

Answer

Zero-order kinetics

Answer

Nonlinear kinetics

Answer

Saturation kinetics

Question 5

A 45-year-old chronic smoker is being counselled for smoking cessation therapy. Which of the
following statements regarding nicotine replacement and pharmacotherapy is correct?

Accepted Answer

Acidic beverages should be avoided 15 minutes before using nicotine gum to maximize absorption

Answer

Nicotine patch provides superior efficacy compared to nicotine gum

Answer

Bupropion is associated with more adverse effects than Varenicline

Answer

Varenicline carries a black box warning for cardiovascular toxicity

Question 6

Lamotrigine is most effective in which of the following seizure types?

Accepted Answer

Tonic-clonic seizures

Answer

Absence seizures

Answer

Atonic seizures

Answer

Myoclonic seizures

Question 7

Unlike other calcium channel blockers, Cilnidipine does not cause reflex tachycardia. What is
the reason for this?

Accepted Answer

It additionally blocks N-type calcium channels

Answer

It additionally blocks T-type calcium channels

Answer

It additionally blocks C-type calcium channels

Answer

It additionally blocks sodium channels

Question 8

A patient is diagnosed with invasive mucormycosis following COVID-19 infection. Which of the
following antifungal agents has NO activity against Mucor species and should be avoided?

Accepted Answer

Voriconazole

Answer

Isavuconazole

Answer

Posaconazole

Answer

Liposomal Amphotericin B

Question 9

Regarding ESBL-producing organisms and their treatment, which of the following statements
are correct?
1. 1st generation cephalosporins such as Cefazolin retain activity against ESBL producers, unlike
3rd generation
2. Carbapenems have proven clinical efficacy against ESBL-producing organisms
3. The beta-lactamase enzyme responsible for ESBL resistance is encoded on transferable
plasmids
4. Piperacillin-Tazobactam is a reliable and effective alternative to Carbapenems

Accepted Answer

2, 3 and 4 only

Answer

1, 2 and 4 only

Answer

1, 2 and 3 only

Answer

1, 2, 3 and 4 all

Question 10

Which of the following statements is correct regarding Ticagrelor?

Accepted Answer

It exerts its antiplatelet effect by directly blocking the P2Y12 ADP receptor

Answer

It is associated with reduced risk of intracranial bleeding compared to Clopidogrel

Answer

It requires hepatic enzymatic activation to produce its active metabolite

Answer

Its antiplatelet action is irreversible and persists until new platelets are formed

INI-CET 2026 — Pharmacology