NEET-PG 2018 - Pharmacology Practice Questions

Q: Coagulation testing is needed for:

Lepirudin (direct thrombin inhibitor). ***Lepirudin (direct thrombin inhibitor)*** - **Lepirudin**, being a direct thrombin inhibitor, necessitates **coagulation testing** (such as aPTT) to monitor its anticoagulant effect and adjust dosing, especially in patients with renal impairment. - Its narrow therapeutic window and potential for bleeding complications require careful monitoring to ensure patient safety and drug efficacy, as it lacks a specific antidote. *Dabigatran (oral anticoagulant)* - **Dabigatran** is a **direct oral anticoagulant (DOAC)** that typically does not require routine coagulation monitoring due to its predictable pharmacokinetic and pharmacodynamic profiles. - While specific tests can assess its effect in emergencies, they are not part of standard management, distinguishing it from drugs requiring regular monitoring. *Enoxaparin (low molecular weight heparin)* - **Enoxaparin**, a **low molecular weight heparin (LMWH)**, usually does not require routine coagulation monitoring in most patients due to its predictable dose-response relationship. - Monitoring with anti-Xa levels may be considered in specific populations, such as those with renal insufficiency, extremes of weight, or in pediatric and pregnant patients. *Fondaparinux (synthetic pentasaccharide)* - **Fondaparinux** is a synthetic pentasaccharide that **does not require routine coagulation monitoring** as its anticoagulant effect is highly predictable and dose-dependent. - Its action is mediated through selective inhibition of **Factor Xa**, and standard coagulation tests like aPTT or PT are not sensitive to its effects.

Q: Amphotericin B acts on:-

Cell membrane. ***Cell membrane*** Amphotericin B primarily targets the **ergosterol** in the fungal **cell membrane** [1]. It binds to **ergosterol**, forming pores and disrupting the membrane's integrity, leading to leakage of cellular contents and ultimately cell death [1]. *Cytoplasm* The cytoplasm is the internal fluid of the cell where many metabolic processes occur, but it is **not the primary target** of amphotericin B's fungicidal action. While cytoplasmic contents leak out due to membrane damage, the drug does not directly act on cytoplasmic components to exert its effect. *Nucleus* The nucleus contains the genetic material of the fungal cell, but amphotericin B does **not directly interact with nuclear components** or DNA. Damage to the cell membrane is the primary mechanism, with nuclear function only indirectly affected by overall cellular disruption. *Cell wall* Fungal cell walls are composed of **chitin and glucans**, but amphotericin B **does not target these components**. Its action is distinct from drugs that inhibit cell wall synthesis, such as echinocandins.

Q: Drug which lacks intrinsic activity against anaerobes is:-

Aminoglycosides. ***Aminoglycosides*** - Aminoglycosides require an **oxygen-dependent transport system** to enter bacterial cells and exert their effects. - Due to the **anaerobic environment**, this transport system is inactive, rendering aminoglycosides ineffective against anaerobic bacteria. *Beta lactams* - Many beta-lactam antibiotics, especially certain **cephalosporins (e.g., cefoxitin, cefotetan)** and **carbapenems (e.g., imipenem, meropenem)**, have significant activity against anaerobes. - They inhibit **cell wall synthesis** and are a common choice for infections involving anaerobes. *Metronidazole* - **Metronidazole** is a potent and widely used antibiotic specifically effective against a broad spectrum of **anaerobic bacteria** and protozoa. - It acts by forming **cytotoxic reduced products** that disrupt bacterial DNA synthesis in anaerobic conditions. *Chloramphenicol* - **Chloramphenicol** is a broad-spectrum antibiotic that is highly effective against both aerobic and **anaerobic bacteria**. - It works by binding to the **50S ribosomal subunit**, thereby inhibiting bacterial protein synthesis.

Q: All are false about tigecycline, except:-

It is a broad spectrum antimicrobial. ***It is a broad spectrum antimicrobial*** - **Tigecycline** is known for its wide spectrum of activity, effective against a variety of gram-positive, gram-negative, and anaerobic bacteria. - It is particularly useful in treating infections caused by **multidrug-resistant (MDR)** organisms, including MRSA and VRE. *90% pseudomonas strains are sensitive* - Tigecycline generally has **poor activity** against *Pseudomonas aeruginosa*, and its use is specifically cautioned against for such infections. - **Many *Pseudomonas* strains are intrinsically resistant** to tigecycline, making it an unreliable choice for treating these infections. *It is bactericidal drug* - Tigecycline is a **bacteriostatic** antibiotic, meaning it inhibits bacterial growth rather than directly killing bacteria. - It achieves its effect by binding to the **30S ribosomal subunit**, thereby blocking protein synthesis. *Dose reduction is required in renal failure* - **Tigecycline** is primarily eliminated via **biliary and fecal excretion**, with only a small portion excreted renally. - Therefore, **dose adjustments are generally not required** in patients with renal impairment, but caution is usually advised in severe hepatic impairment.

Q: What is the mechanism of action of colchicine in acute gout?

Inhibition of leukocyte migration and phagocytosis. ***Inhibition of leukocyte migration and phagocytosis*** - Colchicine primarily exerts its anti-inflammatory effect in acute gout by **binding to tubulin**, which inhibits microtubule polymerization. - This action disrupts essential cellular functions in inflammatory cells, particularly **neutrophils**, thereby reducing their migration to inflamed sites and their ability to phagocytose uric acid crystals. *Renal disease involving interstitial tissues* - This option describes a potential complication or manifestation of gout, such as **urate nephropathy**, rather than the mechanism of action of colchicine. - Colchicine does not directly target or treat pre-existing renal interstitial tissue disease as its primary mechanism for acute gout relief. *Uric acid nephrolithiasis* - This condition involves the formation of **kidney stones from uric acid** and is a consequence of chronic hyperuricemia. - Colchicine is not used to acutely treat or prevent the formation of uric acid kidney stones; its role is in managing the inflammatory arthritis of gout. *Deficiency of enzyme Xanthine oxidase* - **Xanthine oxidase** is an enzyme involved in the production of uric acid, and its inhibition (e.g., by allopurinol or febuxostat) is a strategy to lower uric acid levels in the blood. - Colchicine does not affect xanthine oxidase activity; it works downstream by modulating the inflammatory response to uric acid crystals.

Q: Choice of drug for management of the parasitic infection shown below is:

Triclabendazole. ***Triclabendazole*** - The image displays an adult **Fasciola hepatica** (liver fluke), characterized by its **leaf-like shape** and the prominent **anterior cone** terminating in an oral sucker. - **Triclabendazole** is the drug of choice for treating **fascioliasis**, as it effectively kills both immature and mature forms of Fasciola hepatica. *Albendazole* - **Albendazole** is primarily used to treat a wide range of **intestinal nematode infections** (e.g., Ascaris, hookworm, whipworm) and some **cestode infections** (e.g., neurocysticercosis, echinococcosis). - It has **limited efficacy** against trematodes like Fasciola hepatica. *Praziquantel* - **Praziquantel** is a broad-spectrum antihelminthic drug effective against most **trematodes (flukes)**, including schistosomes and other liver flukes (e.g., Clonorchis, Opisthorchis), and **cestodes (tapeworms)**. - However, it is **ineffective against Fasciola hepatica**, making it unsuitable for this specific infection. *Niclosamide* - **Niclosamide** is an oral anthelmintic primarily used to treat **tapeworm infections (cestodiasis)**, including Taenia species and Hymenolepis nana. - It is **not effective against trematodes** like Fasciola hepatica.

Q: Best drug for the condition shown below is: (NEET Jan 2018)

Doxycycline. ***Correct: Doxycycline*** - The image shows a **tick embedded in the skin** with surrounding erythema, indicative of a **tick bite** and potential **Lyme disease** or other tick-borne infections. - **Doxycycline** is the **drug of choice** for early Lyme disease (caused by *Borrelia burgdorferi*) and many other common tick-borne illnesses like Rickettsial infections (e.g., Rocky Mountain Spotted Fever) and Anaplasmosis. *Incorrect: Ivermectin* - **Ivermectin** is primarily used to treat **parasitic worm infections** like onchocerciasis, strongyloidiasis, and scabies. - It is **not effective** against bacterial infections transmitted by ticks. *Incorrect: Sulphonamides* - **Sulphonamides** are a class of **antibiotics** effective against various bacterial infections, but they are generally **not the first-line treatment** for tick-borne diseases. - For tick-borne illnesses, **doxycycline** typically has broader and more effective coverage. *Incorrect: Penicillin* - **Penicillin** is an **antibiotic** primarily effective against a range of gram-positive and some gram-negative bacteria, and spirochetes like *Treponema pallidum*. - While it has some activity against *Borrelia burgdorferi* (Lyme disease), **doxycycline is preferred** for early-stage Lyme disease and is specifically active against other common tick-borne pathogens where penicillin is not.

Question 1

Coagulation testing is needed for:

Accepted Answer

Lepirudin (direct thrombin inhibitor)

Answer

Dabigatran (oral anticoagulant)

Answer

Enoxaparin (low molecular weight heparin)

Answer

Fondaparinux (synthetic pentasaccharide)

Question 2

Amphotericin B acts on:-

Accepted Answer

Cell membrane

Answer

Cytoplasm

Answer

Nucleus

Answer

Cell wall

Question 3

Drug which lacks intrinsic activity against anaerobes is:-

Accepted Answer

Aminoglycosides

Answer

Beta lactams

Answer

Metronidazole

Answer

Chloramphenicol

Question 4

All are false about tigecycline, except:-

Accepted Answer

It is a broad spectrum antimicrobial

Answer

90% pseudomonas strains are sensitive

Answer

It is bactericidal drug

Answer

Dose reduction is required in renal failure

Question 5

What is the mechanism of action of colchicine in acute gout?

Accepted Answer

Inhibition of leukocyte migration and phagocytosis

Answer

Renal disease involving interstitial tissues

Answer

Uric acid nephrolithiasis

Answer

Deficiency of enzyme Xanthine oxidase

Question 6

Choice of drug for management of the parasitic infection shown below is:

Accepted Answer

Triclabendazole

Answer

Albendazole

Answer

Praziquantel

Answer

Niclosamide

Question 7

Best drug for the condition shown below is: (NEET Jan 2018)

Accepted Answer

Doxycycline

Answer

Ivermectin

Answer

Sulphonamides

Answer

Penicillin

NEET-PG 2018 — Pharmacology