NEET-PG 2015 - Pharmacology Practice Questions

Q: Which of the following is a long-acting beta-2 agonist?

Formoterol. ***Formoterol*** - **Formoterol** is a **long-acting beta-2 agonist (LABA)** commonly used in the treatment of asthma and COPD. - It provides **bronchodilation** for up to 12 hours due to its high lipophilicity, allowing it to remain in the cell membrane and continuously activate beta-2 receptors. *Isoprenaline (non-selective adrenergic agonist)* - **Isoprenaline** is a **non-selective beta-adrenergic agonist**, meaning it activates both beta-1 and beta-2 receptors. - It is **short-acting** and primarily used as a vasodilator or to stimulate heart rate, not as a long-acting bronchodilator. *Ephedrine (non-selective adrenergic agonist)* - **Ephedrine** is a **mixed-acting sympathomimetic amine** that increases the release of norepinephrine and directly stimulates alpha and beta receptors. - It has a short duration of action and is primarily used as a decongestant or bronchodilator in emergency situations, not as a long-acting agent. *Salbutamol (short-acting beta-2 agonist)* - **Salbutamol** is a **short-acting beta-2 agonist (SABA)**, providing rapid onset but a short duration of action (typically 4-6 hours). - It is used for **relieving acute bronchospasm** and is not considered a long-acting medication for maintenance therapy.

Q: Which triptan is available in nasal spray form?

Sumatriptan. ***Sumatriptan*** - **Sumatriptan** is available in multiple formulations, including **oral, subcutaneous injection, and nasal spray**, making it versatile for migraine treatment [1], [2]. - The nasal spray formulation allows for **faster absorption** and onset of action, which can be beneficial for patients with nausea or vomiting during migraine attacks [1]. *Rizatriptan* - **Rizatriptan** is primarily available in **oral tablet** and **orally disintegrating tablet** (ODT) forms [2]. - It does not have a commonly available nasal spray formulation for migraine treatment [2]. *Naratriptan* - **Naratriptan** is available as an **oral tablet** and is known for its **longer half-life** and generally milder side effect profile compared to sumatriptan [2]. - It is not available in a nasal spray formulation [2]. *Frovatriptan* - **Frovatriptan** is available exclusively as an **oral tablet** and is notable for having the **longest half-life** among triptans, making it useful for preventing recurring migraines [2]. - There is no nasal spray formulation for frovatriptan [2].

Q: Acetaminophen [Paracetamol] induced liver toxicity is due to which metabolite?

NAPQI. ***NAPQI*** - **N-acetyl-p-benzoquinone imine (NAPQI)** is a highly reactive and toxic metabolite produced during acetaminophen metabolism, especially in overdose situations [1, 3]. - When glutathione stores are depleted due to excessive NAPQI formation, this metabolite covalently binds to hepatic macromolecules, causing **hepatocellular damage and necrosis** [1, 3].*N-acetylcysteine* - **N-acetylcysteine (NAC)** is the antidote for acetaminophen overdose, not the toxic metabolite itself [2, 3]. - NAC works by replenishing hepatic **glutathione stores**, which helps detoxify NAPQI and prevent liver injury [2, 3].*Co-Q* - **Coenzyme Q10 (CoQ10)** is an endogenous antioxidant and electron carrier in the mitochondrial respiratory chain. - It is not a metabolite of acetaminophen and plays no direct role in acetaminophen-induced liver toxicity.*Cytochrome 'C'* - **Cytochrome c** is a protein involved in the electron transport chain in mitochondria and plays a critical role in apoptosis. - While cellular damage from NAPQI can eventually lead to cytochrome c release and apoptosis, cytochrome c itself is not a metabolite of acetaminophen or the direct cause of toxicity.

Q: Which of the following drugs is commonly used as a rescue medication for acute asthma attacks?

Salbutamol. ***Salbutamol*** - **Salbutamol** (albuterol) is a **short-acting beta-2 agonist (SABA)** that rapidly relaxes bronchial smooth muscle. - Its quick onset of action makes it ideal for immediate relief of **bronchoconstriction** during an acute asthma attack. - It is the **most commonly used** and **first-line rescue medication** for acute asthma worldwide. *Terbutaline* - **Terbutaline** is also a **short-acting beta-2 agonist (SABA)** similar to salbutamol and can be used as a rescue medication. - While it has comparable bronchodilator effects, **salbutamol is more commonly used** as the preferred rescue inhaler in clinical practice. - Both are SABAs, but salbutamol has become the standard first-choice rescue medication globally. *Theophylline* - **Theophylline** is a **methylxanthine** that acts as a bronchodilator but has a **narrow therapeutic index** and slower onset of action. - It is used as a **maintenance therapy** for chronic asthma and not as a rescue drug for acute exacerbations. *Budesonide* - **Budesonide** is an **inhaled corticosteroid (ICS)** used as a **long-term controller medication** to reduce airway inflammation. - It has a slow onset of action and is *not* effective for immediate relief during an acute asthma attack.

Q: What is the mechanism of action of ticagrelor?

Reversible inhibition of ADP action. ***Reversible inhibition of ADP action*** - **Ticagrelor** is a **P2Y12 receptor antagonist** that works by preventing ADP from binding to its receptor on platelets [2]. - This binding is **reversible**, meaning ticagrelor can dissociate from the receptor, allowing for some recovery of platelet function over time [2]. *Irreversible inhibition of ADP action* - **Clopidogrel** and **prasugrel** are examples of **irreversible P2Y12 inhibitors**, forming a permanent bond with the receptor [2]. - Irreversible inhibition leads to a longer duration of platelet inhibition, as new platelets must be generated for function to return [2]. *Reversible inhibition of GPIIb/IIIa* - **GPIIb/IIIa inhibitors** like **eptifibatide** and **tirofiban** block the final common pathway of platelet aggregation by preventing fibrinogen binding [1]. - While their action is reversible, they target a *different* mechanism than ticagrelor. *Irreversible inhibition of GPIIb/IIIa* - **Abciximab** is a GPIIb/IIIa inhibitor that binds **irreversibly** (or with very slow dissociation) to the receptor [1]. - Unlike reversible GPIIb/IIIa inhibitors, abciximab is a monoclonal antibody with a prolonged antiplatelet effect [1]. - This is still an incorrect answer as ticagrelor targets the P2Y12 receptor, not GPIIb/IIIa.

Q: Which of the following medications is classified as a stool softener?

Docusates. **Docusates** - **Docusates** (e.g., docusate sodium, docusate calcium) are **stool softeners** that work by reducing the surface tension of stool, allowing water and lipids to penetrate. - This increases the water content in the stool, making it softer and easier to pass, which is particularly useful in preventing straining after surgery or in conditions like hemorrhoids. *Bran* - **Bran** is a **bulk-forming laxative**, a type of dietary fiber that adds mass to the stool. - It absorbs water in the intestines, which increases stool volume and stimulates bowel movements, but it does not directly soften the stool in the same way docusates do. *Senna* - **Senna** is a **stimulant laxative** that works by irritating the bowel wall to promote peristalsis and bowel evacuation. - While it can help move stool, it does not act primarily by softening it, and prolonged use can lead to dependency or electrolyte imbalances. *Phenolphthalein* - **Phenolphthalein** is a **stimulant laxative** that was historically used to promote bowel movements. - It is no longer widely used due to concerns about potential carcinogenicity and other adverse effects, and it does not function as a stool softener.

Q: What is the drug of choice for drug-induced peptic ulcer?

Proton pump inhibitors. ***Proton pump inhibitors*** - **PPIs** are the most effective agents for treating and preventing **NSAID-induced peptic ulcers** by profoundly suppressing gastric acid secretion. - They provide **rapid symptom relief** and promote ulcer healing by creating an environment conducive to mucosal repair. *Prostaglandin analogues* - **Misoprostol**, a prostaglandin E1 analogue, can prevent NSAID-induced ulcers, but its use is limited by **gastrointestinal side effects** such as diarrhea and abdominal cramping. - While they protect the gastric mucosa, their efficacy in healing established ulcers is generally **inferior to PPIs**. *H2-receptor antagonists* - **H2-blockers** are effective in reducing gastric acid, but they are **less potent** than PPIs and typically do not heal **gastric ulcers** as effectively, especially those induced by NSAIDs. - They are more commonly used for preventing **duodenal ulcers** and managing symptoms of GERD. *Antacids* - Antacids provide **immediate, temporary relief** of ulcer symptoms by neutralizing existing stomach acid. - They do not address the underlying pathology or promote **ulcer healing** and are therefore not considered the drug of choice for treatment.

Q: Ximelagatran is used as ?

Anticoagulant. ***Anticoagulant*** - Ximelagatran is a **direct thrombin inhibitor**, meaning it directly blocks the action of thrombin, a key enzyme in the coagulation cascade. - By inhibiting thrombin, it prevents the formation of **fibrin clots**, thus acting as an anticoagulant. *Platelet inhibitor* - **Platelet inhibitors** prevent platelets from clumping together to form a clot, often by targeting pathways like ADP receptors or COX-1 enzyme. - Examples include **aspirin** and **clopidogrel**, which have different mechanisms of action than Ximelagatran. *Clot buster* - **Clot busters** are also known as thrombolytic agents, which actively dissolve existing blood clots. - They work by activating **plasminogen** to produce plasmin, an enzyme that breaks down fibrin. *Fibrinolytic* - **Fibrinolytics** are a class of drugs that enhance **fibrinolysis**, the natural process of breaking down blood clots. - **Thrombolytics** are a subset of fibrinolytic drugs used therapeutically to dissolve clots.

Q: Which of the following is a characteristic of simvastatin?

Derived from fungal metabolite. ***Derived from fungal metabolite*** - **Simvastatin** and lovastatin are **naturally-derived statins** obtained from **fungal metabolites** (*Aspergillus terreus*), distinguishing them from synthetic statins like atorvastatin, rosuvastatin, and pravastatin [2]. - This is the **most distinguishing characteristic** for classification purposes, as it represents the drug's origin and places it in a specific subclass of HMG-CoA reductase inhibitors. - The discovery of fungal-derived statins led to the development of the entire statin drug class. *Prodrug requiring hepatic activation* - While **simvastatin** is a **lactone prodrug** requiring hepatic hydrolysis to its active beta-hydroxy acid form, this is a pharmacokinetic property shared with lovastatin [1]. - This is a characteristic but not the most distinguishing feature for classification. *Specific CYP3A4 substrate with high interaction potential* - **Simvastatin** is extensively metabolized by **CYP3A4**, leading to significant drug-drug interactions with CYP3A4 inhibitors (e.g., ketoconazole, erythromycin, grapefruit juice). - While clinically important, many drugs are CYP3A4 substrates, making this less distinctive as a defining characteristic. *Short half-life requiring evening dosing* - **Simvastatin** has a **short half-life** (2-3 hours) and is preferably administered in the evening because cholesterol synthesis is highest at night. - This is a dosing consideration based on pharmacokinetics rather than a fundamental distinguishing characteristic of the drug's identity.

Question 1

Which of the following is a long-acting beta-2 agonist?

Accepted Answer

Formoterol

Answer

Isoprenaline

Answer

Ephedrine

Answer

Salbutamol

Question 2

Which triptan is available in nasal spray form?

Accepted Answer

Sumatriptan

Answer

Rizatriptan

Answer

Naratriptan

Answer

Frovatriptan

Question 3

Acetaminophen [Paracetamol] induced liver toxicity is due to which metabolite?

Accepted Answer

NAPQI

Answer

Co-Q

Answer

Cytochrome 'C'

Answer

N-acetylcysteine

Question 4

Which of the following drugs is commonly used as a rescue medication for acute asthma attacks?

Accepted Answer

Salbutamol

Answer

Theophylline

Answer

Terbutaline

Answer

Budesonide

Question 5

Which of the following statements best describes the underlying mechanism of heparin-induced thrombocytopenia?

Accepted Answer

Antibodies are formed against heparin-platelet factor 4 complexes.

Answer

Low molecular weight heparin can also cause heparin-induced thrombocytopenia.

Answer

Vitamin K is not an antidote for heparin-induced thrombocytopenia.

Answer

Heparin-induced thrombocytopenia can occur after several days of heparin therapy.

Question 6

What is the mechanism of action of ticagrelor?

Accepted Answer

Reversible inhibition of ADP action

Answer

Irreversible inhibition of ADP action

Answer

Reversible inhibition of GPIIb/IIIa

Answer

Irreversible inhibition of GPIIb/IIIa

Question 7

Which of the following medications is classified as a stool softener?

Accepted Answer

Docusates

Answer

Bran

Answer

Senna

Answer

Phenolphthalein

Question 8

What is the drug of choice for drug-induced peptic ulcer?

Accepted Answer

Proton pump inhibitors

Answer

Prostaglandin analogues

Answer

H2-receptor antagonists

Answer

Antacids

Question 9

Ximelagatran is used as ?

Accepted Answer

Anticoagulant

Answer

Fibrinolytic

Answer

Platelet inhibitor

Answer

Clot buster

Question 10

Which of the following is a characteristic of simvastatin?

Accepted Answer

Derived from fungal metabolite

Answer

Specific CYP3A4 substrate with high interaction potential

Answer

Prodrug requiring hepatic activation

Answer

Short half-life requiring evening dosing

NEET-PG 2015 — Pharmacology