NEET-PG 2019 - Pharmacology Practice Questions

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 fluoroquinolone has the maximum bioavailability?

Levofloxacin. ***Levofloxacin*** - **Levofloxacin** exhibits high oral bioavailability, approximately 99%, meaning nearly all of the administered dose reaches systemic circulation [1]. - This high bioavailability allows for seamless transition from intravenous to oral administration without significant changes in drug exposure [1]. *Moxifloxacin* - **Moxifloxacin** has a high bioavailability of approximately 90%, which is slightly lower than levofloxacin's almost complete absorption [1]. - While excellent, it is not the absolute highest among fluoroquinolones. *Gatifloxacin* - **Gatifloxacin** has good oral bioavailability, around 96%, but it is still generally considered slightly less than that of levofloxacin [1]. - This difference, though small, makes levofloxacin the one with the highest overall bioavailability. *Ciprofloxacin* - **Ciprofloxacin** has the lowest oral bioavailability among the listed fluoroquinolones, ranging from 70% to 80% [1]. - Its absorption can be significantly impaired by co-administration with multivalent cations, leading to reduced systemic concentrations.

Q: A drug with high plasma protein binding property has which of the following properties?

Lower volume of distribution. ***Lower volume of distribution*** - Drugs with high plasma protein binding are largely confined to the **vascular compartment** as they bind to proteins (e.g., albumin, alpha-1-acid glycoprotein), making them less available to distribute into tissues. - This confinement within the plasma compartment results in a **smaller apparent volume of distribution**. *Less drug interaction* - High plasma protein binding actually increases the potential for **drug-drug interactions** through displacement. - If a second drug displaces the first from its binding sites, it can increase the **free fraction** and potentially lead to toxicity. *Reduced renal clearance* - While highly protein-bound drugs are generally not easily filtered by the glomeruli, their primary route of elimination is often through **hepatic metabolism** or **active tubular secretion**, rather than reduced renal elimination. - Many highly protein-bound drugs still undergo significant renal excretion via **active secretion**, if they are substrates for active transporters. *Less tubular secretion* - Plasma protein binding does not inherently reduce tubular secretion; in some cases, the drug-protein complex can dissociate rapidly at the secretory sites, allowing for efficient secretion of the **free drug**. - In fact, many drugs that undergo significant tubular secretion are also highly protein-bound, as protein binding helps **maintain a concentration gradient** for and delivery of the drug to the secretion transporters.

Q: Which among the following is most probable reason for preference of Cisatracurium over atracurium?

Decreased histamine release. ***Decreased histamine release*** - **Cisatracurium** is preferred over atracurium primarily due to its significantly **lower potential for histamine release**, which can cause undesirable side effects like **hypotension**, **tachycardia**, and **bronchospasm**. - This reduced histamine release contributes to a **more stable hemodynamic profile** and **fewer allergic-type reactions**, especially in critically ill or hemodynamically unstable patients. *Increased histamine release* - This is incorrect because **atracurium** is known to cause **more histamine release** compared to cisatracurium, which is why cisatracurium is often preferred. - Increased histamine release is an **undesirable effect** that can lead to adverse cardiovascular and respiratory reactions. *Decreased CNS toxicity* - While both drugs are **quaternary ammonium compounds** and do not readily cross the blood-brain barrier, **CNS toxicity** is not a primary concern or differentiating factor between atracurium and cisatracurium in clinical practice. - The potential for CNS effects from their metabolites (like **laudanosine**) is generally low with standard dosing, and **cisatracurium produces less laudanosine**. *Due to elimination by non-specific plasma esterases* - Both cisatracurium and atracurium are eliminated primarily by **Hofmann elimination** and **non-specific plasma esterases**. This is a shared characteristic, not a reason for cisatracurium's preference over atracurium. - **Hofmann elimination** is a non-enzymatic chemical degradation process that occurs at physiological pH and temperature, making their elimination **independent of renal or hepatic function**.

Q: What is the drug of choice (DOC) for smoking cessation?

Varenicline. ***Varenicline*** - **Varenicline** is a **partial nicotinic receptor agonist** that reduces both the cravings for nicotine and the pleasurable effects of smoking. - It is considered a **first-line agent** for smoking cessation due to its effectiveness in increasing abstinence rates. *Acamprosate* - **Acamprosate** is a medication used to maintain abstinence from **alcohol dependence** by modulating GABA and glutamate neurotransmission. - It is **not indicated** for smoking cessation and has no direct mechanism of action related to nicotine addiction. *Thalidomide* - **Thalidomide** is an **immunomodulatory drug** with anti-angiogenic and anti-inflammatory properties, primarily used in conditions like **multiple myeloma** and **leprosy**. - It has **severe teratogenic effects** and is not used for smoking cessation due to its complex mechanism and significant side effect profile. *Tryptophan* - **Tryptophan** is an **essential amino acid** that serves as a precursor to **serotonin**, a neurotransmitter involved in mood regulation and sleep. - While it can impact mood, it is **not an approved or effective treatment** for directly addressing nicotine dependence or cravings.

Q: MgSO4 has no role in the prevention of...

Bradycardia. ***Bradycardia*** - Magnesium sulfate has **no role in preventing bradycardia**; in fact, it can **cause or worsen bradycardia** as a significant side effect. - MgSO4 acts as a **calcium channel blocker** and CNS depressant, which can lead to cardiac conduction depression and bradycardia. - Its administration requires careful monitoring for cardiorespiratory depression, including bradycardia. *Seizures in severe pre-eclampsia* - Magnesium sulfate is the **drug of choice** for prevention of eclamptic seizures in women with severe pre-eclampsia (Magpie Trial). - It acts as a **CNS depressant** by reducing acetylcholine release at the neuromuscular junction and inhibiting neuronal excitability. - Clear established role in seizure prophylaxis. *Recurrent seizures in eclampsia* - Magnesium sulfate is the **gold standard** for treatment of active eclamptic seizures and prevention of their recurrence. - Its **anticonvulsant properties** make it the first-line agent in managing this life-threatening complication of pregnancy. - Superior to other anticonvulsants like diazepam or phenytoin in this context. *Respiratory Distress Syndrome (RDS) in premature baby* - **Antenatal corticosteroids** (betamethasone/dexamethasone), NOT magnesium sulfate, are used for **prevention of RDS** in premature babies. - While MgSO4 given antenatally does provide **neuroprotection** and reduces risk of cerebral palsy in preterm infants, this is distinct from RDS prevention. - MgSO4 has no established role in preventing respiratory distress syndrome itself.

Q: MOA of Teduglutide in short bowel syndrome?

GLP-2 analog. ***GLP-2 analog*** - Teduglutide is a **glucagon-like peptide-2 (GLP-2) analog** that binds to and activates GLP-2 receptors. - This activation promotes **intestinal adaptation** by enhancing mucosal growth, increasing nutrient absorption, and improving fluid balance in patients with short bowel syndrome. *5-HT1A receptor antagonist* - 5-HT1A receptor antagonists are primarily used in conditions related to **serotonin pathways**, such as anxiety or depression. - They do not have a direct mechanism to address the **malabsorption** issues seen in short bowel syndrome. *GLP-1 receptor agonist* - GLP-1 receptor agonists are primarily used in the management of **type 2 diabetes** to enhance insulin secretion and reduce glucagon levels. - While GLP-1 and GLP-2 are related, GLP-1 does not have the same direct **trophic and restorative effects** on the intestinal mucosa as GLP-2. *C-peptide analog* - C-peptide is a byproduct of **insulin production** and its analogs have been studied for potential effects on diabetic neuropathy or nephropathy, but not for intestinal adaptation. - It does not play a direct role in regulating **intestinal growth** or nutrient absorption in the context of short bowel syndrome.

Q: What is the primary mechanism by which colchicine exerts its anti-inflammatory effects in acute gout?

Acts by inhibiting neutrophil migration. ***Acts by inhibiting neutrophil migration*** - Colchicine primarily functions by **disrupting microtubule formation** in neutrophils, which impairs their chemotaxis and migration to sites of inflammation. - This inhibition of neutrophil activity is crucial in dampening the **inflammatory response** triggered by uric acid crystals in acute gout. *Acts primarily as a uricosuric agent* - While other medications like **probenecid** are uricosuric and increase uric acid excretion, colchicine does not have this primary mechanism of action. - Its main anti-inflammatory effect is independent of uric acid metabolism or excretion. *Is the first-line treatment for chronic gout management* - Colchicine is effective for **acute gout attacks** and as a prophylactic against attacks during initiation of urate-lowering therapy. - However, **allopurinol** and **febuxostat** are the first-line treatments for chronic gout because they reduce uric acid production. *Has no effect on microtubule function* - This statement is incorrect; colchicine's entire mechanism of action is dependent on its ability to **bind to tubulin** and inhibit microtubule polymerization. - This disruption of microtubules is responsible for its anti-inflammatory effects and also its common side effects.

Q: What is the recommended dose of diphtheria antitoxin for adults?

20000 to 50000 IU. ***20000 to 50000 IU*** - For adults with **diphtheria**, the recommended dose of **diphtheria antitoxin (DAT)** in the range of 20,000 to 50,000 IU is appropriate for **pharyngeal or laryngeal diphtheria** of moderate severity (typically disease present for 48-72 hours). - This dosage aims to neutralize the **diphtheria toxin** circulating in the bloodstream and prevent further tissue damage. - **Note:** More severe or extensive disease (>3 days duration or with bull neck) may require higher doses (80,000-120,000 IU). *1000 to 2000 IU* - This dosage is **too low** for therapeutic treatment of diphtheria in adults. - Such a low dose would be insufficient to neutralize the substantial amount of **toxin** produced during an active infection, regardless of disease severity. *10000 to 20000 IU* - This dose is **suboptimal** for most forms of diphtheria in adults. - Even for **mild cutaneous diphtheria**, doses typically start at 20,000 IU or higher. - For respiratory diphtheria, this range would be inadequate to effectively counteract the toxin. *None of the options* - This is incorrect because **20,000 to 50,000 IU** is a recognized and recommended range for diphtheria antitoxin in adult treatment of moderate pharyngeal/laryngeal disease. - Diphtheria antitoxin is a crucial and **specific treatment** for diphtheria, and evidence-based dosage ranges exist based on disease severity and location.

Question 1

Imipenem, a newer antibiotic with a broad antibacterial spectrum, is co-administered with cilastatin. What is the primary reason for this combination?

Accepted Answer

Cilastatin prevents the degradation of imipenem by inhibiting an enzyme in the kidneys.

Answer

Cilastatin enhances the gastrointestinal absorption of imipenem.

Answer

Cilastatin inhibits the beta-lactamase enzyme that degrades imipenem.

Answer

The combination of antibiotics is synergistic against Pseudomonas species.

Question 2

Which of the following drugs is an alpha 2 agonist?

Accepted Answer

Apraclonidine

Answer

Timolol

Answer

PG analogues

Answer

Verapamil

Question 3

Which fluoroquinolone has the maximum bioavailability?

Accepted Answer

Levofloxacin

Answer

Gatifloxacin

Answer

Ciprofloxacin

Answer

Moxifloxacin

Question 4

A drug with high plasma protein binding property has which of the following properties?

Accepted Answer

Lower volume of distribution

Answer

Reduced renal clearance

Answer

Less drug interaction

Answer

Less tubular secretion

Question 5

Which among the following is most probable reason for preference of Cisatracurium over atracurium?

Accepted Answer

Decreased histamine release

Answer

Increased histamine release

Answer

Decreased CNS toxicity

Answer

Due to elimination by non-specific plasma esterases

Question 6

What is the drug of choice (DOC) for smoking cessation?

Accepted Answer

Varenicline

Answer

Acamprosate

Answer

Thalidomide

Answer

Tryptophan

Question 7

MgSO4 has no role in the prevention of...

Accepted Answer

Bradycardia

Answer

Seizures in severe pre-eclampsia

Answer

Recurrent seizures in eclampsia

Answer

Respiratory Distress Syndrome (RDS) in premature baby

Question 8

MOA of Teduglutide in short bowel syndrome?

Accepted Answer

GLP-2 analog

Answer

5-HT1A receptor antagonist

Answer

GLP-1 receptor agonist

Answer

C-peptide analog

Question 9

What is the primary mechanism by which colchicine exerts its anti-inflammatory effects in acute gout?

Accepted Answer

Acts by inhibiting neutrophil migration

Answer

Acts primarily as a uricosuric agent

Answer

Is the first-line treatment for chronic gout management

Answer

Has no effect on microtubule function

Question 10

What is the recommended dose of diphtheria antitoxin for adults?

Accepted Answer

20000 to 50000 IU

Answer

1000 to 2000 IU

Answer

10000 to 20000 IU

Answer

None of the options

NEET-PG 2019 — Pharmacology