INI-CET 2026 - Pharmacology Practice Questions

Q: Match the following antibiotic with its most commonly associated organism: 1. Streptomycin a. Streptococcal pharyngitis 2. Amoxicillin b. H. pylori 3. Doxycycline c. Mycobacterium tuberculosis 4. Clarithromycin d. Chlamydia trachomatis

1-c, 2-a, 3-d, 4-b. ***1-c, 2-a, 3-d, 4-b*** - **Streptomycin** is a classic second-line agent used specifically for the treatment of **Mycobacterium tuberculosis**. - **Amoxicillin** is a first-line penicillin antibiotic frequently used to treat **Streptococcal pharyngitis** caused by Group A Streptococcus. - **Doxycycline** is the preferred treatment for **Chlamydia trachomatis** infections, an obligate intracellular bacteria. - **Clarithromycin** is a key component in the triple therapy regimen used to eradicate **H. pylori** in peptic ulcer disease. *1-c, 2-b, 3-d, 4-a* - While correctly matching **Streptomycin** and **Doxycycline**, it incorrectly assigns **Amoxicillin** to **H. pylori** (which requires a specific macrolide or nitroimidazole combination) and **Clarithromycin** to **Streptococcal pharyngitis**. - **Clarithromycin** is not the standard first-line treatment for uncomplicated **pharyngitis** unless the patient has a severe penicillin allergy. *1-a, 2-c, 3-b, 4-d* - This pairing is incorrect as **Streptomycin** is essential for **Mycobacterial** infections, not **Streptococcal pharyngitis**. - **Doxycycline** is not indicated for **H. pylori**, and **Amoxicillin** is not the drug of choice for **Mycobacterium tuberculosis**. *1-d, 2-a, 3-c, 4-b* - This option incorrectly lists **Streptomycin** as the treatment for **Chlamydia**, while it is primarily an anti-tuberculosis agent. - It also suggests **Doxycycline** treats **Mycobacterium tuberculosis**, which is not clinically standard for TB therapy.

Q: Which of the following is correctly matched (Anti-aging compound - Molecular pathway)?

Metformin - AMPK pathway. ***Metformin - AMPK pathway*** - **Metformin** is a well-studied geroprotector that functions primarily by activating **AMP-activated protein kinase (AMPK)**. - Activation of the **AMPK pathway** mimics the metabolic state of caloric restriction, leading to improved cellular energy homeostasis and insulin sensitivity. *Resveratrol - mTOR inhibition* - **Resveratrol** is primarily known as a **SIRT1 activator**, rather than a direct inhibitor of the **mTOR pathway**. - While it may indirectly influence downstream signaling, its primary recognized mechanism in the context of anti-aging is the modulation of **sirtuins**. *Caloric restriction - Sirtuin (SIRT-1)* - While **caloric restriction** does activate **SIRT1**, the provided pairing is often considered contextually ambiguous or broader in literature compared to the direct pharmacological pathway linkage of metformin and AMPK. - In many standardized formats, this is sometimes presented as a distractor based on the specific primary molecular targets being tested; however, the metformin-AMPK link is the most definitive primary mechanism of action in pharmacology curricula. *Rapamycin - IGF-1/Insulin pathway* - **Rapamycin** acts specifically as a potent inhibitor of the **mTOR complex 1 (mTORC1)**. - While mTOR signaling is downstream of the **IGF-1/Insulin pathway**, characterizing Rapamycin as an IGF-1/Insulin pathway modulator is inaccurate; it is fundamentally an **mTOR inhibitor**.

Q: All the following are ligand-gated ion channels EXCEPT:

H2 receptor. ***H2 receptor*** - The **H2 receptor** is a classic example of a **G-protein coupled receptor (GPCR)**, specifically linked via **Gs protein** to adenylate cyclase, not a ligand-gated ion channel. - It mediates gastric acid secretion through the activation of **cAMP** secondary messenger pathways rather than direct ion flux. *5-HT3 receptor* - The **5-HT3 receptor** is a unique serotonin receptor that functions as a **ligand-gated ion channel** (ionotropic). - It is permeable to cations like **Na+**, **K+**, and **Ca2+**, leading to rapid depolarization. *GABA-A receptor* - The **GABA-A receptor** is a well-known **ligand-gated ion channel** that allows the influx of **chloride ions** (Cl-). - Upon binding GABA, it induces an **inhibitory postsynaptic potential (IPSP)**, leading to neuronal hyperpolarization. *Nicotinic receptor* - The **nicotinic acetylcholine receptor (nAChR)** is the prototypical ligand-gated ion channel found at the **neuromuscular junction**. - It opens a non-selective cation channel upon the binding of **acetylcholine**, triggering muscle fiber depolarization.

Q: A wound swab reveals gram-positive cocci in clusters, catalase-positive, sensitive to Cefoxitin and Oxacillin. What is the drug of choice?

Cloxacillin. ***Cloxacillin*** - The organism identified is a **Methicillin-Sensitive Staphylococcus aureus (MSSA)**, as indicated by the **positive sensitivity to Cefoxitin and Oxacillin**, which are used to test for methicillin resistance. - **Cloxacillin** (or other penicillinase-resistant penicillins like Nafcillin or Oxacillin) is the drug of choice for MSSA due to superior efficacy compared to broader-spectrum alternatives. *Ceftriaxone* - This is a **third-generation cephalosporin** that lacks robust activity against MSSA compared to anti-staphylococcal penicillins. - It is not the preferred agent for **staphylococcal infections** unless there is a specific contraindication to penicillins or in specialized clinical contexts. *Vancomycin* - This drug is indicated as the first-line treatment for **Methicillin-Resistant Staphylococcus aureus (MRSA)**. - It has a slower bactericidal effect compared to **beta-lactams** and is reserved for cases of penicillin allergy or resistant strains. *Amoxicillin/Clavulanate* - While this combination is effective against many beta-lactamase-producing bacteria, it is not the gold-standard treatment for **severe S. aureus infections**. - It is typically utilized for polymicrobial infections or oral step-down therapy rather than preferred IV treatment for MSSA.

Q: Which of the following drug-receptor target pairings are correctly matched? 1. Trastuzumab - HER2 receptor 2. Sunitinib - HER1 (EGFR) 3. Gefitinib - HER1 (EGFR)

1 and 3 are correct. ***1 and 3 are correct*** - **Trastuzumab** is a monoclonal antibody specifically designed to bind to the extracellular domain of the **HER2 receptor** (human epidermal growth factor receptor 2), inhibiting downstream signaling in HER2-positive cancers such as breast cancer. - **Gefitinib** is a tyrosine kinase inhibitor that specifically targets the intracellular domain of **HER1 (EGFR)**, making it effective in non-small cell lung cancer with specific EGFR mutations. *Only 1 is correct* - This option is incorrect because it fails to acknowledge that **Gefitinib** is also a correctly matched pair for **HER1 (EGFR)** inhibition. - It overlooks the significant role of tyrosine kinase inhibitors in modern targeted oncology therapies. *2 and 3 are correct* - This is incorrect because **Sunitinib** does not target **HER1 (EGFR)**; rather, it is a multi-targeted receptor tyrosine kinase inhibitor predominantly targeting **VEGFR** (vascular endothelial growth factor receptor) and **PDGFR** (platelet-derived growth factor receptor). - Its primary clinical indication is for renal cell carcinoma and gastrointestinal stromal tumors, differing mechanistically from EGFR-targeted therapies. *All are correct* - This option is incorrect because the inclusion of **Sunitinib** as a **HER1 (EGFR)** inhibitor is pharmacologically inaccurate. - Sunitinib is an anti-angiogenic agent targeting growth factor receptors related to vascular proliferation rather than the EGFR family.

Q: A novel anti-aging compound induces autophagy by inhibiting EP300 histone acetyltransferase, leading to deacetylation of autophagy-related proteins. Which known anti-aging agent works by the same mechanism?

Spermidine. ***Spermidine*** - Spermidine is a naturally occurring polyamine that functions as an **epigenetic modulator** by inhibiting **EP300 histone acetyltransferase**. - This inhibition leads to the **deacetylation** of autophagy-related proteins, which effectively **induces autophagy** and promotes cellular longevity. *Rapamycin* - Rapamycin acts by inhibiting the **mechanistic target of rapamycin (mTOR)** pathway, a highly conserved nutrient-sensing kinase. - Its primary mode of action on autophagy is through the inhibition of mTORC1 rather than modulating histone acetylation. *Metformin* - Metformin exerts its effects primarily by activating **AMP-activated protein kinase (AMPK)**, which regulates cellular metabolism and energy homeostasis. - While it can indirectly upregulate autophagy, it does not function by inhibiting histone acetyltransferases like EP300. *Resveratrol* - Resveratrol functions primarily as an activator of **Sirtuin 1 (SIRT1)**, an NAD+-dependent protein deacetylase. - It promotes longevity through the activation of deacetylases, distinct from the direct inhibition of acetyltransferase activity found with spermidine.

Question 1

Match the following antibiotic with its most commonly associated organism:

1. Streptomycin a. Streptococcal pharyngitis

2. Amoxicillin b. H. pylori

3. Doxycycline c. Mycobacterium tuberculosis

4. Clarithromycin d. Chlamydia trachomatis

Accepted Answer

1-c, 2-a, 3-d, 4-b

Answer

1-c, 2-b, 3-d, 4-a

Answer

1-a, 2-c, 3-b, 4-d

Answer

1-d, 2-a, 3-c, 4-b

Question 2

Which of the following is correctly matched (Anti-aging compound - Molecular pathway)?

Accepted Answer

Metformin - AMPK pathway

Answer

Resveratrol - mTOR inhibition

Answer

Caloric restriction - Sirtuin (SIRT-1)

Answer

Rapamycin - IGF-1/Insulin pathway

Question 3

All the following are ligand-gated ion channels EXCEPT:

Accepted Answer

H2 receptor

Answer

5-HT3 receptor

Answer

GABA-A receptor

Answer

Nicotinic receptor

Question 4

A wound swab reveals gram-positive cocci in clusters, catalase-positive, sensitive to Cefoxitin
and Oxacillin. What is the drug of choice?

Accepted Answer

Cloxacillin

Answer

Ceftriaxone

Answer

Vancomycin

Answer

Amoxicillin/Clavulanate

Question 5

Which of the following drug-receptor target pairings are correctly matched? 1. Trastuzumab -
HER2 receptor 2. Sunitinib - HER1 (EGFR) 3. Gefitinib - HER1 (EGFR)

Accepted Answer

1 and 3 are correct

Answer

Only 1 is correct

Answer

2 and 3 are correct

Answer

All are correct

Question 6

A novel anti-aging compound induces autophagy by inhibiting EP300 histone acetyltransferase,
leading to deacetylation of autophagy-related proteins. Which known anti-aging agent works by the
same mechanism?

Accepted Answer

Spermidine

Answer

Rapamycin

Answer

Metformin

Answer

Resveratrol

INI-CET 2026 — Pharmacology