NEET-PG 2019 - Pharmacology Practice Questions

Q: DOC for prophylaxis against Diphtheria is:-

Erythromycin. ***Erythromycin*** - **Erythromycin** is the drug of choice for prophylaxis and treatment of diphtheria, especially in individuals exposed to a confirmed case. - It works by inhibiting protein synthesis in *Corynebacterium diphtheriae*, preventing bacterial multiplication and toxin production. *Cloxacillin* - **Cloxacillin** is a narrow-spectrum penicillinase-resistant penicillin primarily used for treating staphylococcal infections. - It is not effective against *Corynebacterium diphtheriae* and therefore not used for diphtheria prophylaxis. *Rifampicin* - **Rifampicin** is an antibiotic commonly used for tuberculosis and prophylaxis against meningococcal disease. - It does not have significant activity against *Corynebacterium diphtheriae* and is not indicated for diphtheria prevention. *Ciprofloxacin* - **Ciprofloxacin** is a fluoroquinolone antibiotic with a broad spectrum of activity against many bacterial infections. - While it can be used for some respiratory infections, it is not the recommended antibiotic for diphtheria prophylaxis.

Q: Tolvaptan is used for:-

SIADH. ***SIADH*** - **Tolvaptan** is a **vasopressin V2 receptor antagonist** that promotes water excretion without affecting sodium, making it ideal for treating **euvolemic and hypervolemic hyponatremia** associated with SIADH. - In **syndrome of inappropriate antidiuretic hormone secretion (SIADH)**, there is excessive **ADH** leading to water retention and dilutional hyponatremia; tolvaptan effectively counters this by blocking vasopressin's action. *Von Willebrand disease* - This is a **bleeding disorder** caused by a deficiency or dysfunction of **von Willebrand factor**, treated with **desmopressin** or factor replacement, not tolvaptan. - Tolvaptan has no role in coagulation pathways or the management of bleeding disorders. *Central DI* - **Central diabetes insipidus (DI)** results from reduced **ADH production** by the hypothalamus or posterior pituitary, leading to excessive water loss. - It is treated with **desmopressin** (synthetic ADH) to replace the deficient hormone, which is the opposite effect of tolvaptan. *Catecholamine resistant Shock* - **Catecholamine-resistant shock** is characterized by persistent hypotension despite high doses of **vasopressors**. - Treatment often involves agents like **vasopressin** (not tolvaptan) or corticosteroids to improve vascular tone, as tolvaptan would worsen the hypotension by promoting diuresis.

Q: Agent used for eliciting diagnostic differentiation of Myasthenia Gravis from Cholinergic crisis is:-

Edrophonium. ***Edrophonium*** - **Edrophonium** is a **short-acting acetylcholinesterase inhibitor** (duration 5-10 minutes) used in the **Tensilon test** to differentiate myasthenic crisis from cholinergic crisis - In **myasthenic crisis**, edrophonium temporarily improves muscle strength due to increased acetylcholine at the neuromuscular junction - In **cholinergic crisis**, it worsens weakness or shows no improvement - The rapid onset and short duration allow clear observation of transient response, making it ideal for diagnostic differentiation *Neostigmine* - **Neostigmine** is a longer-acting acetylcholinesterase inhibitor (duration 2-4 hours) used for chronic management of myasthenia gravis - Its prolonged effect makes it unsuitable for rapid diagnostic differentiation in acute crisis situations - The extended duration would make it difficult to observe transient changes and could worsen a cholinergic crisis for a prolonged period *Ecothiophate* - **Ecothiophate** is an irreversible acetylcholinesterase inhibitor used primarily in ophthalmology for glaucoma - Its irreversible action and prolonged effect (days to weeks) make it completely inappropriate for crisis differentiation - Would severely exacerbate cholinergic symptoms with sustained effect that cannot be reversed *Ambenonium* - **Ambenonium** is another long-acting acetylcholinesterase inhibitor (duration 3-8 hours) used for chronic treatment of myasthenia gravis - Similar to neostigmine, its extended duration makes it unsuitable for acute diagnostic challenge - The rapid onset and offset required for the Tensilon test cannot be achieved with this agent

Q: Cisatracurium is better than atracurium because:-

Less histamine release. ***Less histamine release*** - **Cisatracurium** causes significantly less **histamine release** compared to atracurium, reducing the risk of **hypotension** and **bronchospasm**. [1] - This makes cisatracurium a safer choice for patients with **cardiovascular instability** or **asthma**. *No active metabolites* - While cisatracurium produces **laudanosine** as a metabolite, this is also true for **atracurium**. - The difference lies in the **concentration** of laudanosine and its potential for central nervous system toxicity, which is generally lower with cisatracurium. *Shorter half-life* - **Cisatracurium** generally has a **slightly longer half-life** than atracurium, but both are characterized by a relatively rapid onset and offset of action. - Their elimination primarily occurs via **Hoffman elimination** and **ester hydrolysis**, independent of renal or hepatic function. *Better neuromuscular blockade* - Both **cisatracurium** and **atracurium** are effective **neuromuscular blockers** when administered at appropriate doses. - The "better" aspect for cisatracurium relates more to its **improved safety profile** (less histamine release) rather than a significantly superior blockade efficacy. [1]

Q: Wrong statement about SGLT (sodium-glucose linked transporter):

SGLT2 inhibitors worsen heart failure. ***SGLT2 inhibitors worsen heart failure*** - This statement is incorrect because **SGLT2 inhibitors** have been shown to **improve outcomes in heart failure**, reducing hospitalizations and cardiovascular mortality, even in patients without diabetes. - Their beneficial effects in heart failure are attributed to mechanisms such as **osmotic diuresis**, natriuresis, improved cardiac energetics, and reduced preload and afterload. - Landmark trials like **DAPA-HF** and **EMPEROR-Reduced** demonstrated significant benefits in heart failure with reduced ejection fraction (HFrEF). *SGLT2 inhibitors produce weight loss* - **SGLT2 inhibitors** cause **glucosuria** (excretion of glucose in the urine), leading to a loss of calories and subsequent modest weight loss (2-3 kg). - This effect is a common and beneficial side effect, contributing to improved metabolic profiles in patients with type 2 diabetes. *SGLT1 is present in the intestine and kidneys* - **SGLT1** is the primary transporter responsible for glucose absorption in the **small intestine** and is also found in the **kidneys' S3 segment** of the proximal tubule. - In the kidneys, it plays a minor role in glucose reabsorption compared to SGLT2, but it is critical for dietary glucose absorption. *SGLT1 has low capacity and high affinity* - **SGLT1** is characterized by its **high affinity** for glucose (Km ~0.4 mM), allowing it to efficiently reabsorb glucose even at low concentrations. - However, it has a **lower capacity** compared to SGLT2, meaning it reabsorbs a smaller absolute amount of glucose despite its strong binding.

Q: Oral factor Xa inhibitor is:

Rivaroxaban. ***Rivaroxaban*** - **Rivaroxaban** is a direct oral anticoagulant (DOAC) that specifically inhibits **factor Xa**, preventing thrombin generation and clot formation. - It is administered **orally** and is widely used for preventing and treating venous thromboembolism and stroke in atrial fibrillation. *Bivalirudin* - **Bivalirudin** is a **direct thrombin inhibitor** (DTI), not a factor Xa inhibitor. - It is administered **intravenously**, primarily used in percutaneous coronary interventions. *Dabigatran* - **Dabigatran** is an **oral direct thrombin inhibitor** (DTI), which directly inhibits thrombin (factor IIa). - It does not inhibit factor Xa; its mechanism of action is distinct from that of factor Xa inhibitors. *Fondaparinux* - **Fondaparinux** is an **indirect factor Xa inhibitor** that requires antithrombin for its anticoagulant activity. - It is administered **subcutaneously**, distinguishing it from oral factor Xa inhibitors like rivaroxaban.

Question 1

DOC for prophylaxis against Diphtheria is:-

Accepted Answer

Erythromycin

Answer

Cloxacillin

Answer

Rifampicin

Answer

Ciprofloxacin

Question 2

Which of the following statements is not true about tamoxifen?

Accepted Answer

Tamoxifen is useful in post-menopausal and aromatase inhibitors in premenopausal patients.

Answer

It can cause endometrial carcinoma.

Answer

It is used for visceral metastasis.

Answer

Dose is 20 mg for 5 years.

Question 3

Tolvaptan is used for:-

Accepted Answer

SIADH

Answer

Von Willebrand disease

Answer

Central DI

Answer

Catecholamine resistant Shock

Question 4

Agent used for eliciting diagnostic differentiation of Myasthenia Gravis from Cholinergic crisis is:-

Accepted Answer

Edrophonium

Answer

Neostigmine

Answer

Ecothiophate

Answer

Ambenonium

Question 5

Cisatracurium is better than atracurium because:-

Accepted Answer

Less histamine release

Answer

No active metabolites

Answer

Shorter half-life

Answer

Better neuromuscular blockade

Question 6

Wrong statement about SGLT (sodium-glucose linked transporter):

Accepted Answer

SGLT2 inhibitors worsen heart failure

Answer

SGLT2 inhibitors produce weight loss

Answer

SGLT1 is present in the intestine and kidneys

Answer

SGLT1 has low capacity and high affinity

Question 7

Oral factor Xa inhibitor is:

Accepted Answer

Rivaroxaban

Answer

Bivalirudin

Answer

Dabigatran

Answer

Fondaparinux

NEET-PG 2019 — Pharmacology