NEET-PG 2015 - Pharmacology Practice Questions

Q: Which of the following methods can reduce flushing caused by niacin?

All of the options. ***All of the options*** - **All three methods** (tachyphylaxis, laropiprant, and premedication with aspirin) are effective strategies for reducing niacin-induced flushing. - This demonstrates that multiple pharmacological and physiological approaches can mitigate this common side effect of niacin therapy. **Why each method works:** **Tachyphylaxis:** - Refers to the rapid decrease in response to a drug after repeated administration - With continued niacin use, tolerance develops and flushing intensity decreases over time - This is a natural adaptive response, though not an immediate solution for initial flushing episodes **Laropiprant:** - A selective antagonist of the **prostaglandin D2 receptor 1 (DP1)** - Specifically developed to reduce niacin-induced flushing by blocking prostaglandin D2-mediated vasodilation - Was marketed in combination with niacin (though later withdrawn due to other safety concerns) **Premedication with aspirin:** - **Aspirin** or other NSAIDs taken approximately 30 minutes before niacin administration - Reduces flushing by inhibiting **prostaglandin synthesis**, particularly prostaglandin D2 - Prostaglandins are key mediators of the cutaneous vasodilation that causes flushing

Q: Which of the following drugs can lead to pemphigus?

Penicillamine. ***Penicillamine*** - **Penicillamine** is a well-known drug that can induce **pemphigus**, often through mechanisms involving alterations in **desmosome structure** or function. - The drug's sulfhydryl groups are thought to interfere with the integrity of **desmoglein proteins**, leading to blister formation. *Isoniazid* - **Isoniazid** is a first-line antituberculosis drug primarily associated with **hepatotoxicity** and **peripheral neuropathy**. - It is not typically implicated in the development of **pemphigus**. *Carbamazepine* - **Carbamazepine** is an anticonvulsant that can cause various cutaneous reactions, most notably **Stevens-Johnson syndrome (SJS)** and **toxic epidermal necrolysis (TEN)**. - While it can cause severe skin reactions, **pemphigus** is not a common side effect of carbamazepine. *Furosemide* - **Furosemide** is a loop diuretic that can cause **photosensitivity**, rashes, and rarely, severe skin reactions like **erythema multiforme**. - It is not recognized as a drug that induces **pemphigus**.

Q: Which of the following drugs is an alpha 2 agonist?

Apraclonidine. ***Apraclonidine*** - **Apraclonidine** is a synthetic **alpha-2 adrenergic agonist** that reduces aqueous humor production and increases uveoscleral outflow, thereby lowering intraocular pressure. - It is primarily used for the short-term treatment of **open-angle glaucoma** or ocular hypertension. *Timolol* - **Timolol** is a **non-selective beta-adrenergic blocker** that reduces aqueous humor production, leading to a decrease in intraocular pressure. - It does not act on alpha-2 receptors, distinguishing it from apraclonidine. *PG analogues* - **Prostaglandin analogues** (PG analogues) such as latanoprost, bimatoprost, and travoprost are primarily used to treat glaucoma by **increasing uveoscleral outflow** of aqueous humor. - They act on **prostaglandin F2α receptors**, not alpha-2 adrenergic receptors. *Verapamil* - **Verapamil** is a **calcium channel blocker** primarily used to treat hypertension, angina, and arrhythmias. - It acts by blocking calcium channels in vascular smooth muscle and the heart, and does not have significant alpha-2 adrenergic agonist activity.

Q: Which of the following typical antipsychotic drugs is least commonly used in depot form?

Chlorpromazine. ***Chlorpromazine*** - Chlorpromazine is a **typical antipsychotic** that is **NOT available in depot form** for clinical use. - It is available only in **oral** and **short-acting injectable** formulations, making it the **least commonly used in depot form** among the options listed. - Its high sedative properties, orthostatic hypotension risk, and pharmacokinetic profile make it unsuitable for long-acting depot formulation. *Haloperidol* - **Haloperidol decanoate** is one of the **most widely used depot formulations** of typical antipsychotics. - Administered intramuscularly every **3-4 weeks**, it is highly effective for **long-term maintenance treatment** in schizophrenia. - Its favorable pharmacokinetic profile makes it ideal for depot preparation. *Fluphenazine* - **Fluphenazine decanoate** and **fluphenazine enanthate** are **well-established depot preparations** with decades of clinical use. - These formulations allow for dosing every **2-4 weeks**, significantly improving **medication adherence** in chronic psychotic disorders. - Fluphenazine depot is a first-line option for long-acting injectable antipsychotic therapy. *Trifluoperazine* - Trifluoperazine is primarily available and used as an **oral medication** for maintenance therapy. - While some limited depot formulations have been reported in older literature, they are **not commonly used in clinical practice**. - However, it is still more available in depot form than chlorpromazine, which has essentially **no depot use**.

Q: What is the mechanism of action of duloxetine?

Inhibition of both serotonin and norepinephrine reuptake. ***Inhibition of both serotonin and norepinephrine reuptake*** - **Duloxetine** is a **serotonin-norepinephrine reuptake inhibitor (SNRI)**, meaning it blocks the reuptake of both neurotransmitters, increasing their concentrations in the synaptic cleft [2]. - This dual action contributes to its efficacy in treating **depression**, **anxiety disorders**, and **neuropathic pain** [2], [3]. *Selective serotonin reuptake inhibition* - This describes the mechanism of **SSRIs (Selective Serotonin Reuptake Inhibitors)**, such as fluoxetine or sertraline, which primarily target serotonin [1]. - Duloxetine's mechanism is broader, affecting both serotonin and norepinephrine [2]. *Selective norepinephrine reuptake inhibition* - This mechanism is characteristic of medications like **atomoxetine**, used for ADHD, which primarily targets norepinephrine. - Duloxetine has a dual action, not selective to norepinephrine alone. *No effect on neurotransmitter reuptake* - Medications with no effect on neurotransmitter reuptake would not typically be effective as antidepressants or treatments for neuropathic pain. - Duloxetine's therapeutic effects are directly linked to its inhibition of reuptake for both serotonin and norepinephrine [2], [4].

Q: Which of the following is the only clinically available depolarizing muscle relaxant?

Suxamethonium. ***Suxamethonium*** - **Suxamethonium** (also known as succinylcholine) is currently the **only depolarizing neuromuscular blocker** available for clinical use. - It works by mimicking acetylcholine, binding to and activating nicotinic acetylcholine receptors at the **neuromuscular junction**, causing initial muscle fasciculations followed by relaxation. *Decamethonium* - **Decamethonium** is a depolarizing neuromuscular blocker but is **no longer clinically available** due to its prolonged action and side effects. - It also acts by opening nicotinic acetylcholine receptor channels, leading to depolarization and muscle paralysis. *Mivacurium* - **Mivacurium** is a **nondepolarizing neuromuscular blocker**, meaning it acts as a competitive antagonist at the acetylcholine receptor. - It is known for its **short duration of action** due to rapid hydrolysis by plasma cholinesterases but is not depolarizing. *None of the options* - This option is incorrect because suxamethonium is indeed a clinically available depolarizing muscle relaxant. - The question specifically asks for the *only* clinically available one, which suxamethonium fulfills.

Q: Which of the following statements about flumazenil is correct?

Can be used in benzodiazepine overdose. ***Can be used in benzodiazepine overdose*** - **Flumazenil** is a **competitive antagonist** at the **GABA-A receptor**, specifically designed to reverse the effects of **benzodiazepines**. - It binds to the same receptor site as benzodiazepines, effectively blocking their sedative and anxiolytic actions, making it useful in emergent overdose situations. *Can be used in barbiturate poisoning* - **Flumazenil** is **ineffective** in **barbiturate overdose** because barbiturates bind to a different site on the GABA-A receptor than benzodiazepines. - Barbiturates enhance **GABAergic activity** through a distinct mechanism, which flumazenil does not antagonize. *Specific antidote for opiate overdose* - The **specific antidote for opiate overdose** is **naloxone**, which acts as an opioid receptor antagonist. - **Flumazenil** has **no affinity** for opioid receptors and thus no role in reversing opiate toxicity. *None of the options* - This option is incorrect because **flumazenil** is indeed used for **benzodiazepine overdose**, as described above. - Its specific mechanism of action targets benzodiazepine-induced central nervous system depression.

Q: Which of the following actions is NOT associated with tricyclic antidepressants?

MAO inhibition. ***MAO inhibition*** - Tricyclic antidepressants (TCAs) primarily exert their effects by inhibiting the reuptake of **norepinephrine** and **serotonin**, not by inhibiting monoamine oxidase (MAO). - **MAO inhibitors** are a distinct class of antidepressants with a different mechanism of action and side effect profile. *Anticholinergic action* - Many TCAs have significant **anticholinergic effects**, blocking muscarinic receptors and leading to side effects like dry mouth, constipation, and blurred vision. - These effects contribute to the **adverse event profile** of TCAs, especially in elderly patients. *Block 5-HT or NE reuptake* - The primary mechanism of action of TCAs involves the **inhibition of serotonin (5-HT)** and **norepinephrine (NE) reuptake** into presynaptic neurons. - This action increases the concentration of these neurotransmitters in the **synaptic cleft**, thereby potentiating their effects. *Causes sedation* - TCAs frequently cause **sedation**, particularly the more histaminergic ones (e.g., amitriptyline, doxepin), due to their **histamine H1 receptor antagonism**. - This side effect can be beneficial for patients with insomnia but can be problematic for daytime functioning.

Q: Modafinil is primarily used for the treatment of which of the following conditions?

Narcolepsy. ***Narcolepsy*** - **Modafinil** is a **eugeroic** (wakefulness-promoting agent) specifically approved and widely used for the treatment of excessive daytime sleepiness associated with **narcolepsy**. - Its mechanism involves increasing **dopamine** and **norepinephrine** levels, and modulating **orexin** pathways, promoting alertness without significant psychomotor stimulation. *Sexual dysfunction* - While sometimes explored off-label for certain types of sexual dysfunction, **modafinil** is not a primary or approved treatment for this condition. - Primary treatments for sexual dysfunction often involve specific medications like **PDE5 inhibitors** or hormone therapy, depending on the cause. *Depression* - **Modafinil** is not a primary antidepressant, although it can be used as an **adjunctive therapy** in some cases to combat residual fatigue or hypersomnia associated with depression. - Standard treatment for depression involves **selective serotonin reuptake inhibitors (SSRIs)**, **serotonin-norepinephrine reuptake inhibitors (SNRIs)**, or other classes of antidepressants. *Anxiety* - **Modafinil** is a stimulant-like drug and can sometimes **exacerbate anxiety** in susceptible individuals due to its catecholaminergic effects. - Primary treatments for anxiety disorders include **selective serotonin reuptake inhibitors (SSRIs)**, **benzodiazepines** (for acute relief), and psychotherapy.

Question 1

Which of the following methods can reduce flushing caused by niacin?

Accepted Answer

All of the options

Answer

Tachyphylaxis

Answer

Laropiprant

Answer

Premedication with aspirin

Question 2

Which of the following drugs can lead to pemphigus?

Accepted Answer

Penicillamine

Answer

Carbamazepine

Answer

Isoniazid

Answer

Furosemide

Question 3

A patient undergoing a minor surgical procedure is given lignocaine injection. Assertion: Local anaesthetics act by blocking nerve conduction. Reason: Small fibers and non-myelinated fibers are blocked more easily than large myelinated fibers.

Accepted Answer

Both Assertion and Reason are true, and Reason is not the correct explanation for Assertion

Answer

Assertion is false, but Reason is true

Answer

Both Assertion and Reason are true, and Reason is the correct explanation for Assertion

Answer

Assertion is true, but Reason is false

Question 4

Which of the following drugs is an alpha 2 agonist?

Accepted Answer

Apraclonidine

Answer

Timolol

Answer

PG analogues

Answer

Verapamil

Question 5

Which of the following typical antipsychotic drugs is least commonly used in depot form?

Accepted Answer

Chlorpromazine

Answer

Haloperidol

Answer

Fluphenazine

Answer

Trifluoperazine

Question 6

What is the mechanism of action of duloxetine?

Accepted Answer

Inhibition of both serotonin and norepinephrine reuptake

Answer

Selective serotonin reuptake inhibition

Answer

Selective norepinephrine reuptake inhibition

Answer

No effect on neurotransmitter reuptake

Question 7

Which of the following is the only clinically available depolarizing muscle relaxant?

Accepted Answer

Suxamethonium

Answer

Decamethonium

Answer

Mivacurium

Answer

None of the options

Question 8

Which of the following statements about flumazenil is correct?

Accepted Answer

Can be used in benzodiazepine overdose

Answer

Can be used in barbiturate poisoning

Answer

Specific antidote for opiate overdose

Answer

None of the options

Question 9

Which of the following actions is NOT associated with tricyclic antidepressants?

Accepted Answer

MAO inhibition

Answer

Block 5-HT or NE reuptake

Answer

Anticholinergic action

Answer

Causes sedation

Question 10

Modafinil is primarily used for the treatment of which of the following conditions?

Accepted Answer

Narcolepsy

Answer

Sexual dysfunction

Answer

Depression

Answer

Anxiety

NEET-PG 2015 — Pharmacology