NEET-PG 2013 - Pharmacology Practice Questions

Q: Which of the following is NOT a beta-2 agonist?

Ketotifen. ***Ketotifen*** - **Ketotifen** is an **oral anti-allergic drug** that acts as a **mast cell stabilizer** and **H1-antihistamine**, not a beta-2 agonist. - It is used for **prophylactic treatment** of asthma and allergic conditions, working through different mechanisms than bronchodilators. *Terbutaline* - **Terbutaline** is a **short-acting beta-2 agonist (SABA)** used for bronchodilation in asthma and COPD [2]. - Available in **oral, inhaled, and injectable forms** for rapid relief of bronchospasm. *Salbutamol* - **Salbutamol** (also known as albuterol) is a **short-acting beta-2 agonist (SABA)** and the most widely used rescue inhaler for asthma [1], [2]. - Provides **rapid bronchodilation** by stimulating beta-2 receptors in airway smooth muscles [3]. *Bambuterol* - **Bambuterol** is a **long-acting beta-2 agonist (LABA)** that is a prodrug of **terbutaline**. - It is slowly converted to the active form in the body, providing **sustained bronchodilation** for maintenance therapy.

Q: Which of the following is NOT a function of Prostaglandin E1 (PGE1)?

Plays a role in initiating puberty. ***Plays a role in initiating puberty*** - **Prostaglandin E1 (PGE1)** is primarily involved in smooth muscle relaxation, vasodilation, and inflammation, and does not have a direct role in initiating **puberty**. - The initiation of puberty is mainly controlled by the **hypothalamic-pituitary-gonadal (HPG) axis** and surge of **gonadotropin-releasing hormone (GnRH)**. *Used in the management of erectile dysfunction* - **PGE1 formulations** (alprostadil) are used as a topical or intracavernosal injection to treat **erectile dysfunction** by inducing vasodilation in the penis. - Its vasodilatory effects increase blood flow to the corpora cavernosa, leading to **penile erection**. *Modulates inflammatory responses* - **PGE1** is involved in **inflammatory processes**, often exerting both pro- and anti-inflammatory effects depending on the context and specific receptors activated. - It can help to **reduce inflammation** and pain, as well as influencing immune cell function. *Maintains the patency of the ductus arteriosus* - In newborns with **congenital heart defects**, **PGE1** is administered to maintain the **patency of the ductus arteriosus**, allowing for blood flow between the aorta and pulmonary artery. - This is crucial for conditions where pulmonary or systemic blood flow is dependent on a patent ductus, bridging the infant to surgery or other interventions.

Q: Which of the following is a renin inhibitor?

Remikiren. **Remikiren** - **Remikiren** is a direct **renin inhibitor** that acts by binding to the active site of renin, preventing its interaction with angiotensinogen. - This inhibition reduces the formation of **angiotensin I** and subsequently **angiotensin II**, leading to decreased blood pressure. *Losartan* - **Losartan** is an **Angiotensin II Receptor Blocker (ARB)**, meaning it blocks AT1 receptors, preventing angiotensin II from binding. - It does not inhibit renin activity directly but rather acts downstream in the **renin-angiotensin-aldosterone system (RAAS)**. *Benazepril* - **Benazepril** is an **Angiotensin-Converting Enzyme (ACE) inhibitor**, which blocks the enzyme responsible for converting **angiotensin I** to **angiotensin II**. - It does not directly inhibit renin production or activity. *Imidapril* - **Imidapril** is also an **Angiotensin-Converting Enzyme (ACE) inhibitor**, similar to benazepril. - Its mechanism of action involves inhibiting ACE, thereby reducing **angiotensin II** levels, rather than directly inhibiting renin.

Q: What is a common side effect of salmeterol?

Tremors. ***Tremors*** - **Salmeterol** is a **long-acting beta-2 adrenergic agonist (LABA)** that can stimulate beta-2 receptors in skeletal muscle, leading to **fine muscle tremors**. - This side effect is dose-dependent and more common with higher doses or in patients sensitive to sympathomimetic effects. *Seizures* - **Seizures** are a rare and atypical side effect of **salmeterol** and other beta-2 agonists; they are not considered a common adverse event. - While systemic absorption can occur, the central nervous system effects leading to seizures are not frequently observed. *Hypertension* - While beta-2 agonists can cause a slight increase in **heart rate** due to systemic absorption, **hypertension** is not a common side effect of inhaled salmeterol. - Other cardiovascular effects like palpitations can occur, but significant or sustained hypertension is rare. *Hyperkalemia* - **Hyperkalemia** (elevated potassium) is not a side effect of **salmeterol**; in fact, beta-2 agonists commonly cause the **opposite effect - hypokalemia** (decreased serum potassium). - Beta-2 receptor stimulation activates Na⁺-K⁺-ATPase pumps, driving potassium from serum into cells, causing transient hypokalemia. - This effect is clinically relevant and requires monitoring, especially when combined with other medications that lower potassium.

Q: Which drug is used for sympathectomy in experimental animals?

Guanethidine. ***Guanethidine*** - **Guanethidine** is a potent **adrenergic neuron blocking drug** that is taken up by noradrenergic neurons and prevents the release of norepinephrine, leading to a chemical sympathectomy. - In experimental animal models, it is used to induce a **pharmacological sympathectomy** to study the effects of sympathetic nervous system blockade on various physiological processes. *Atropine* - **Atropine** is a **muscarinic acetylcholine receptor antagonist** that blocks the effects of acetylcholine at parasympathetic postganglionic terminals. - It is primarily used to block **parasympathetic responses**, not sympathetic ones, and therefore would not induce a sympathectomy. *Diazoxide* - **Diazoxide** is a direct **arteriolar vasodilator** that works by opening potassium channels in vascular smooth muscle. - It is used to quickly reduce blood pressure in **hypertensive emergencies** and for treating hypoglycemia due to insulin oversecretion, and does not cause sympathectomy. *Thebaine* - **Thebaine** is an **opioid alkaloid** found in opium, structurally similar to morphine and codeine, but with primarily stimulatory rather than depressant effects. - It acts as a **convulsant** and is used as a precursor in the synthesis of other opioids, but has no role in causing sympathectomy.

Q: Which calcium channel blocker has the shortest duration of action?

Nimodipine. ***Nimodipine*** - Nimodipine is a **dihydropyridine calcium channel blocker** specifically formulated for cerebral vasodilation and used in conditions like **subarachnoid hemorrhage**. - It has a relatively **short half-life** and rapid onset, making its duration of action shorter compared to other commonly used calcium channel blockers. *Amlodipine* - Amlodipine is known for its **long duration of action** and once-daily dosing due to its slow absorption and high bioavailability. - Its prolonged action is beneficial for conditions like **hypertension and angina**, where sustained vasodilation is desired. *Diltiazem* - Diltiazem's duration of action is **intermediate** compared to other calcium channel blockers, often requiring BID to TID dosing for immediate-release formulations. - It's a **non-dihydropyridine calcium channel blocker** with effects on both vascular smooth muscle and cardiac conduction. *Verapamil* - Verapamil also has an **intermediate duration of action**, similar to diltiazem, with immediate-release forms requiring multiple daily doses. - As a **non-dihydropyridine calcium channel blocker**, it has significant effects on myocardial contractility and AV nodal conduction.

Q: What is the drug of choice for a classical angina attack?

GTN. ***GTN*** - **Glyceryl trinitrate (GTN)** is the drug of choice for immediate relief of a classical angina attack because it rapidly dilates coronary arteries and peripheral blood vessels, reducing **myocardial oxygen demand** and improving blood flow [2]. - Its **nitric oxide** mediated vasodilatory effects quickly alleviate chest pain by decreasing **preload** and afterload [2], [3]. *CCBs* - **Calcium channel blockers (CCBs)** are used for long-term prevention of angina by reducing myocardial oxygen demand, but they are not the first-line treatment for acute relief due to their slower onset of action [1]. - While they can dilate coronary arteries and reduce heart rate/contractility, their role is more in **prophylaxis** rather than acute symptom management [1]. *β-blocker* - **Beta-blockers** are primarily used for chronic management and prevention of angina by reducing heart rate, contractility, and blood pressure, thereby decreasing myocardial oxygen demand. - They are generally avoided for acute angina attacks as they do not provide rapid symptomatic relief and can potentially worsen symptoms in some acute ischemic conditions. *Prazocin* - **Prazosin** is an **alpha-1 adrenergic blocker** primarily used to treat hypertension and benign prostatic hyperplasia. - It causes vasodilation but is not indicated for the treatment of acute angina, as its mechanism of action and onset of effect are not suitable for rapid relief of myocardial ischemia.

Q: Which of the following medications is most likely to cause reflex tachycardia?

Nifedipine. ***Nifedipine*** - Nifedipine is a **dihydropyridine calcium channel blocker** that causes significant peripheral vasodilation, leading to a rapid drop in blood pressure. - This sudden drop in blood pressure triggers a **baroreflex response**, compensatory increase in heart rate. *Verapamil* - Verapamil is a **non-dihydropyridine calcium channel blocker** that primarily acts on the cardiac pacemaker cells and slows AV nodal conduction. - While it can cause vasodilation, its direct negative chronotropic effect on the heart often **blunts or prevents reflex tachycardia**. *Propranolol* - Propranolol is a **non-selective beta-blocker** that blocks beta-1 and beta-2 adrenergic receptors. - It directly **decreases heart rate and myocardial contractility**, thereby preventing reflex tachycardia. *Amlodipine* - Amlodipine is a **dihydropyridine calcium channel blocker**, similar to nifedipine, but it has a **slower onset of action and a longer half-life**. - Its more gradual onset of vasodilation often results in a significantly **less pronounced or absent reflex tachycardia** compared to nifedipine.

Q: In which of the following conditions is Verapamil not typically used?

Ventricular tachycardia. ***Ventricular tachycardia*** - Verapamil, a **non-dihydropyridine calcium channel blocker**, can worsen hemodynamics in patients with **ventricular tachycardia (VT)** by causing profound hypotension or precipitating cardiac arrest. - VT often requires prompt treatment with **antiarrhythmics like amiodarone** or **electrical cardioversion**, as it can be life-threatening. - Verapamil is **contraindicated in VT** due to its negative inotropic effects and risk of hemodynamic collapse. *Angina pectoris* - Verapamil is effectively used to treat angina pectoris by **decreasing myocardial oxygen demand** through negative chronotropic and inotropic effects, and by causing **coronary vasodilation**, improving blood flow. - Its effects help to reduce the frequency and severity of anginal episodes, particularly in **stable angina**. *Atrial fibrillation* - Verapamil is commonly used for **rate control in atrial fibrillation** by **slowing conduction through the AV node**, which decreases the ventricular response rate. - It helps to manage symptoms and prevent complications related to rapid heart rates in this arrhythmia. *Hypertension* - Verapamil is used in the treatment of **hypertension** through its vasodilatory effects and reduction in peripheral vascular resistance. - It is particularly useful in patients who cannot tolerate other antihypertensive agents or as part of combination therapy.

Q: Aminophylline inhibits which of the following enzymes?

Phosphodiesterase. ***Phosphodiesterase*** - **Aminophylline** is a methylxanthine derivative that primarily acts as a **phosphodiesterase (PDE) inhibitor** [1], [2]. - By inhibiting PDE, aminophylline increases intracellular levels of **cAMP** and **cGMP**, leading to **bronchodilation** and other effects [2], [3]. *MAO* - **MAO (monoamine oxidase)** inhibitors are antidepressants that prevent the breakdown of neurotransmitters like serotonin, norepinephrine, and dopamine. - Aminophylline does not significantly inhibit MAO. *Alcohol dehydrogenase* - **Alcohol dehydrogenase** is an enzyme responsible for metabolizing alcohol (ethanol) in the liver. - Aminophylline has no direct inhibitory effect on alcohol dehydrogenase. *Cytochrome P450* - **Cytochrome P450 (CYP450)** enzymes are a group of enzymes primarily involved in the metabolism of drugs and other xenobiotics in the liver [4]. - While aminophylline (and its active metabolite theophylline) can be metabolized by and *affect* certain **CYP450** isoenzymes (e.g., CYP1A2), it does not act as a general inhibitor of the entire CYP450 system; its primary therapeutic action is not through CYP450 inhibition.

Question 1

Which of the following is NOT a beta-2 agonist?

Accepted Answer

Ketotifen

Answer

Terbutaline

Answer

Salbutamol

Answer

Bambuterol

Question 2

Which of the following is NOT a function of Prostaglandin E1 (PGE1)?

Accepted Answer

Plays a role in initiating puberty

Answer

Modulates inflammatory responses

Answer

Used in the management of erectile dysfunction

Answer

Maintains the patency of the ductus arteriosus

Question 3

Which of the following is a renin inhibitor?

Accepted Answer

Remikiren

Answer

Losartan

Answer

Benazepril

Answer

Imidapril

Question 4

What is a common side effect of salmeterol?

Accepted Answer

Tremors

Answer

Seizures

Answer

Hypertension

Answer

Hyperkalemia

Question 5

Which drug is used for sympathectomy in experimental animals?

Accepted Answer

Guanethidine

Answer

Atropine

Answer

Diazoxide

Answer

Thebaine

Question 6

Which calcium channel blocker has the shortest duration of action?

Accepted Answer

Nimodipine

Answer

Diltiazem

Answer

Amlodipine

Answer

Verapamil

Question 7

What is the drug of choice for a classical angina attack?

Accepted Answer

GTN

Answer

CCBs

Answer

β-blocker

Answer

Prazosin

Question 8

Which of the following medications is most likely to cause reflex tachycardia?

Accepted Answer

Nifedipine

Answer

Verapamil

Answer

Propranolol

Answer

Amlodipine

Question 9

In which of the following conditions is Verapamil not typically used?

Accepted Answer

Ventricular tachycardia

Answer

Angina pectoris

Answer

Atrial fibrillation

Answer

Hypertension

Question 10

Aminophylline inhibits which of the following enzymes?

Accepted Answer

Phosphodiesterase

Answer

MAO

Answer

Alcohol dehydrogenase

Answer

Cytochrome P450

NEET-PG 2013 — Pharmacology