NEET-PG 2015 - Pharmacology Practice Questions

Q: What is the treatment for extrapyramidal side effects induced by Haloperidol?

Anticholinergic drugs. ***Anticholinergic drugs (effective treatment)*** - **Anticholinergic medications**, such as **benztropine** or **diphenhydramine**, are the primary treatment for **acute extrapyramidal symptoms (EPS)** like dystonia and parkinsonism induced by antipsychotics like haloperidol. - They work by **blocking muscarinic acetylcholine receptors**, helping to restore the balance between dopamine and acetylcholine in the basal ganglia. *Benzodiazepines (used for anxiety and muscle relaxation)* - While benzodiazepines can offer some relief for **akathisia** (a form of EPS characterized by restlessness) due to their sedative and muscle relaxant properties, they are **not the first-line treatment for other acute EPS** such as dystonia or parkinsonism. - They primarily enhance **GABAergic transmission** and are effective for anxiety and seizure control rather than direct antagonism of EPS mechanisms. *Barbiturates (used as sedative-hypnotic drugs)* - **Barbiturates** are strong central nervous system depressants used for sedation, anesthesia, and seizure control, but are **not indicated for the treatment of EPS**. - Their significant **sedative and addictive potential**, along with a narrow therapeutic index, makes them unsuitable for this purpose. *SSRIs (used for depression and anxiety)* - **SSRIs (Selective Serotonin Reuptake Inhibitors)** are antidepressants that work by increasing serotonin levels in the brain and are used to treat depression, anxiety, and obsessive-compulsive disorder. - They **do not have a direct role** in ameliorating dopamine-acetylcholine imbalance responsible for haloperidol-induced EPS.

Q: Mechanism of action of thiazides is by -

Inhibiting Na+/Cl- symporter in DCT. **Inhibiting Na+/Cl- symporter in DCT** - Thiazide diuretics primarily act on the **distal convoluted tubule (DCT)** of the nephron [2]. - They inhibit the **Na+/Cl- symporter** (NCC channel) on the apical membrane, preventing reabsorption of sodium and chloride ions [1], [2]. *Inhibiting Na+K+2CI- in descending limb of loop of henle* - The descending limb of the loop of Henle is permeable to water but largely impermeable to solutes; there is no significant Na+K+2Cl- symporter activity here. - This mechanism describes the action of loop diuretics, but they act on the **ascending** limb, not the descending limb. *Inhibiting Na+K+2Cl- in ascending limb of loop of henle* - This mechanism describes the action of **loop diuretics** (e.g., furosemide, bumetanide) [3]. - Loop diuretics inhibit the **Na+K+2Cl- cotransporter (NKCC2)** in the thick ascending limb of the loop of Henle, leading to significant diuresis [3]. *Inhibiting Na+/Cl- symporter in PCT* - The **proximal convoluted tubule (PCT)** is primarily responsible for reabsorbing most of the filtered sodium, chloride, bicarbonate, and other solutes. - While sodium is reabsorbed in the PCT, it's mainly through Na+/H+ exchangers and other mechanisms, not a specific Na+/Cl- symporter that is targeted by thiazides [2].

Q: Which of the following drugs can cause hypertrophic pyloric stenosis?

Erythromycin. ***Erythromycin*** - **Erythromycin** use in infants, particularly during the first few weeks of life, has been associated with an increased risk of developing **hypertrophic pyloric stenosis**. - The mechanism is believed to involve the drug's properties as a **motilin receptor agonist**, which may affect the development or function of the pyloric sphincter. *Nifedipine* - **Nifedipine** is a calcium channel blocker primarily used for cardiovascular conditions like hypertension and angina. - It works by relaxing smooth muscles and is not linked to the development of **pyloric stenosis**. *Vancomycin* - **Vancomycin** is an antibiotic used for severe bacterial infections, particularly against Gram-positive bacteria. - It is not associated with the development of **hypertrophic pyloric stenosis**. *Phenylpropanolamine* - **Phenylpropanolamine** is a sympathomimetic drug previously used as a decongestant and anorectic. - It primarily affects alpha-adrenergic receptors and has no established link to **pyloric stenosis**.

Question 1

What is the treatment for extrapyramidal side effects induced by Haloperidol?

Accepted Answer

Anticholinergic drugs

Answer

Barbiturates

Answer

SSRIs

Answer

Benzodiazepines

Question 2

Mechanism of action of thiazides is by -

Accepted Answer

Inhibiting Na+/Cl- symporter in DCT

Answer

Inhibiting Na+K+2Cl- in ascending limb of loop of henle

Answer

Inhibiting Na+/Cl- symporter in PCT

Answer

Inhibiting Na+K+2Cl- in descending limb of loop of henle

Question 3

Which of the following drugs can cause hypertrophic pyloric stenosis?

Accepted Answer

Erythromycin

Answer

Nifedipine

Answer

Vancomycin

Answer

Phenyl propanolamine

NEET-PG 2015 — Pharmacology