INI-CET 2022 - Pharmacology Practice Questions

Q: A man was brought to the emergency room after poisoning with an unknown substance. Muscarinic poisoning was suspected and he was treated for the same. What is the possible presenting feature which led to the diagnosis?

Bradycardia. ***Bradycardia*** - Muscarinic poisoning stimulates **parasympathetic nervous system** activity, leading to a decrease in heart rate. - This **bradycardia** is a classic sign of excessive muscarinic receptor activation, as seen with organophosphate or carbamate poisoning [1, 2].*Diuresis* - While muscarinic receptor activation can increase bladder detrusor contraction (leading to urinary urgency and frequency) [1, 2], **diuresis** (increased urine production) is not a primary or direct presenting feature of muscarinic poisoning. - Instead, the focus is on incontinence rather than simply increased urine output.*Mydriasis* - **Mydriasis** (pupil dilation) is associated with **anticholinergic poisoning**, which blocks muscarinic receptors. - Muscarinic poisoning, conversely, causes **miosis** (pupil constriction) due to excessive stimulation of muscarinic receptors in the iris sphincter muscle.*Muscle fasciculations* - **Muscle fasciculations** are a characteristic sign of **nicotinic receptor overstimulation**, not muscarinic [1, 3]. - While both nicotinic and muscarinic receptors are activated in organophosphate poisoning, fasciculations point to the **nicotinic effects** at the neuromuscular junction [1, 3].

Q: Match the following antiarrhythmic drugs with their mechanism of action: | Mechanism of action | Drug | | :-- | :-- | | 1. Na+ channel blocker | A. Quinidine | | 2. K+ channel blocker | B. Digoxin | | 3. Na+K+ ATPase inhibitor | C. Esmolol | | 4. Beta-blocker | D. Ibutilide |

1-A, 2-D, 3-B, 4-C. ***1-A, 2-D, 3-B, 4-C*** - **Quinidine** is a Class IA antiarrhythmic drug that primarily blocks **sodium channels**, prolonging the action potential duration and refractoriness. - **Ibutilide** is a Class III antiarrhythmic drug that blocks **potassium channels**, leading to delayed repolarization and increased effective refractory period. - **Digoxin** inhibits the **Na+/K+ ATPase pump**, increasing intracellular calcium and affecting AV nodal conduction. - **Esmolol** is a **beta-blocker** (Class II antiarrhythmic) that reduces heart rate and contractility by blocking β1-adrenergic receptors. *1-A, 2-C, 3-D, 4-B* - This option incorrectly matches **Esmolol** (a beta-blocker) with **K+ channel blocker** and **Ibutilide** (K+ channel blocker) with **Na+K+ ATPase inhibitor**. - It also incorrectly matches **Digoxin** (Na+K+ ATPase inhibitor) with **beta-blocker**. *1-D, 2-C, 3-A, 4-B* - This option incorrectly matches **Ibutilide** (K+ channel blocker) with **Na+ channel blocker** and incorrectly matches **Quinidine** (Na+ channel blocker) with **Na+K+ ATPase inhibitor**. - It also incorrectly matches **Digoxin** (Na+K+ ATPase inhibitor) with **beta-blocker**. *1-D, 2-B, 3-A, 4-C* - This option incorrectly matches **Ibutilide** (K+ channel blocker) with **Na+ channel blocker** and **Digoxin** (Na+K+ ATPase inhibitor) with **K+ channel blocker**. - It also incorrectly matches **Quinidine** (Na+ channel blocker) with **Na+K+ ATPase inhibitor**.

Q: Match the following drugs with the targets of their actions: Drugs: A. Trastuzumab B. Infliximab C. Sirolimus D. Imatinib Targets: 1. BCR-ABL tyrosine kinase 2. mTOR 3. TNF alpha 4. HER2/neu

A-4, B-3, C-2, D-1. ***Correct Answer: A-4, B-3, C-2, D-1*** - **Trastuzumab** (Herceptin) is a **monoclonal antibody** that targets the **HER2/neu receptor (4)** [1], [2], commonly overexpressed in certain breast cancers and gastric cancers. - **Infliximab** is another **monoclonal antibody** that specifically targets and neutralizes **TNF-alpha (3)**, an inflammatory cytokine, making it useful in treating autoimmune diseases like rheumatoid arthritis and Crohn's disease. - **Sirolimus** is an **immunosuppressant** drug that inhibits the mammalian target of rapamycin (**mTOR (2)**), a protein kinase involved in cell growth and proliferation, used in transplant medicine and as an anticancer agent. - **Imatinib** is a **tyrosine kinase inhibitor** that primarily targets the **BCR-ABL fusion protein (1)** [1], [2], which is characteristic of chronic myeloid leukemia. *Incorrect: A-2, B-3, C-1, D-4* - This option incorrectly matches Trastuzumab with mTOR and Sirolimus with BCR-ABL, which are not their primary targets. - Trastuzumab targets HER2/neu [1], [2], and Sirolimus targets mTOR. *Incorrect: A-3, B-4, C-2, D-1* - This option incorrectly matches Trastuzumab with TNF-alpha and Infliximab with HER2/neu. - Infliximab targets TNF-alpha, and Trastuzumab targets HER2/neu [1], [2]. *Incorrect: A-4, B-3, C-1, D-2* - This option incorrectly matches Sirolimus with BCR-ABL and Imatinib with mTOR. - Sirolimus inhibits mTOR, and Imatinib inhibits BCR-ABL [1], [2].

Question 1

A man was brought to the emergency room after poisoning with an unknown substance.
Muscarinic poisoning was suspected and he was treated for the same. What is the possible presenting feature which led to the diagnosis?

Accepted Answer

Bradycardia

Answer

Diuresis

Answer

Mydriasis

Answer

Muscle fasciculations

Question 2

Which of the following statements is correct regarding the given graph?

Accepted Answer

Drug 1 represents agonist and drug 4 represents inverse agonist

Answer

Drug 1 represents agonist and drug 2 represents inverse agonist

Answer

Drug 3 represents agonist and drug 4 represents inverse agonist

Answer

Drug 2 represents partial agonist and drug 3 represents inverse agonist

Question 3

Match the following antiarrhythmic drugs with their mechanism of action:

Accepted Answer

1-A, 2-D, 3-B, 4-C

Answer

1-D, 2-B, 3-A, 4-C

Answer

1-A, 2-C, 3-D, 4-B

Answer

1-D, 2-C, 3-A, 4-B

Question 4

Match the following drugs with the targets of their actions:

Drugs:
A. Trastuzumab
B. Infliximab  
C. Sirolimus
D. Imatinib

Targets:
1. BCR-ABL tyrosine kinase
2. mTOR
3. TNF alpha
4. HER2/neu

Accepted Answer

A-4, B-3, C-2, D-1

Answer

A-2, B-3, C-1, D-4

Answer

A-3, B-4, C-2, D-1

Answer

A-4, B-3, C-1, D-2

INI-CET 2022 — Pharmacology