NEET-PG 2018 - Pharmacology Practice Questions

Q: Maximum increase in prolactin level is caused by:-

Risperidone (Potent D2 receptor antagonist). ***Risperidone (Potent D2 receptor antagonist)*** - Risperidone is a **potent D2 receptor antagonist**, meaning it blocks dopamine's action at these receptors. Since dopamine inhibits prolactin release, blocking D2 receptors leads to a significant increase in **prolactin levels**. - Its high affinity for D2 receptors in the **tuberoinfundibular pathway** is a primary reason for its pronounced effect on prolactin. *Olanzapine (Primarily blocks 5HT2 receptors)* - While olanzapine can cause some prolactin elevation, its primary mechanism involves **5HT2 receptor blockade**, with less potent D2 antagonism compared to risperidone. - The degree of **hyperprolactinemia** associated with olanzapine is generally milder than that seen with risperidone. *Aripiprazole (D2 partial agonist)* - Aripiprazole is a **D2 partial agonist**, meaning it acts as an antagonist when dopamine levels are high and an agonist when dopamine levels are low, effectively stabilizing dopamine activity. - Due to its partial agonism, aripiprazole typically has a **low risk of hyperprolactinemia** and can even normalize elevated prolactin levels caused by other antipsychotics. *Clozapine (Primarily blocks 5HT2 receptors)* - Clozapine primarily blocks **5HT2 receptors** and has relatively weak D2 receptor antagonism, especially transient D2 blockade. - It generally causes **minimal to no prolactin elevation** and is considered a prolactin-sparing antipsychotic.

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.

Question 1

Maximum increase in prolactin level is caused by:-

Accepted Answer

Risperidone (Potent D2 receptor antagonist)

Answer

Olanzapine (Primarily blocks 5HT2 receptors)

Answer

Aripiprazole (D2 partial agonist)

Answer

Clozapine (Primarily blocks 5HT2 receptors)

Question 2

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 3

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

Accepted Answer

Triclabendazole

Answer

Albendazole

Answer

Praziquantel

Answer

Niclosamide

NEET-PG 2018 — Pharmacology