Respiratory System Drugs Practice Questions

Q: Omalizumab is:

Anti IgE antibody. **Explanation:** **Omalizumab** is a recombinant DNA-derived humanized monoclonal antibody specifically designed for the management of severe allergic asthma. **1. Why Option B is Correct:** Omalizumab acts as an **Anti-IgE antibody**. It selectively binds to the Fc region of free circulating **IgE** molecules. This binding prevents IgE from attaching to the high-affinity receptors (FcεRI) on the surface of mast cells and basophils. By limiting the degree of IgE receptor binding, it prevents the subsequent degranulation of these cells and the release of inflammatory mediators (like histamine and leukotrienes) upon allergen exposure. **2. Why Incorrect Options are Wrong:** * **Option A (IL-2 Receptor Blocker):** Drugs like **Basiliximab** and Daclizumab are IL-2 receptor blockers, primarily used as immunosuppressants in organ transplantation. * **Option C (Anti-IgM Antibody):** There is no major clinical drug in respiratory pharmacology that acts as an anti-IgM antibody. * **Option D (Leukotriene Receptor Blocker):** This describes **Montelukast** and Zafirlukast, which block the CysLT1 receptor to prevent bronchoconstriction. **3. High-Yield Clinical Pearls for NEET-PG:** * **Indication:** Used in patients (age >6 years) with moderate-to-severe persistent **allergic asthma** who are inadequately controlled with inhaled corticosteroids. * **Route:** Administered **subcutaneously** every 2–4 weeks. * **Key Benefit:** It significantly reduces the frequency of asthma exacerbations and the requirement for oral corticosteroids. * **Side Effect:** The most serious (though rare) side effect is **anaphylaxis**; patients should be monitored after injection. * **Related Drugs:** Do not confuse with **Mepolizumab/Reslizumab** (Anti-IL-5) or **Dupilumab** (Anti-IL-4/IL-13), which are also used in severe eosinophilic asthma.

Q: A machinery worker in a factory presents with profuse rhinorrhea and sneezing. Which of the following is the most appropriate medication for symptomatic relief?

Cetirizine. **Explanation:** The patient is presenting with symptoms of allergic rhinitis (rhinorrhea and sneezing). The key clinical consideration in this question is the patient’s occupation: a **machinery worker**. **Why Cetirizine is correct:** Cetirizine is a **second-generation H1 antihistamine**. Unlike first-generation agents, second-generation antihistamines are highly selective for peripheral H1 receptors and have poor lipid solubility, meaning they do not cross the blood-brain barrier significantly. Consequently, they are **non-sedating** and do not impair psychomotor performance. For a machinery worker, avoiding sedation is critical to prevent workplace accidents. **Why the other options are incorrect:** * **Diphenhydramine, Promethazine, and Hydroxyzine** are all **first-generation H1 antihistamines**. These drugs are highly lipophilic and readily cross the blood-brain barrier. They cause significant sedation, drowsiness, and impairment of cognitive/motor functions. * **Promethazine** is particularly known for its strong sedative and anti-emetic properties. * **Hydroxyzine** is often used for its anxiolytic and antipruritic effects but is highly sedating. **High-Yield NEET-PG Pearls:** * **Second-generation antihistamines:** Cetirizine, Loratadine, Fexofenadine, Desloratadine, and Azelastine. * **Fexofenadine** is considered the least sedating of all antihistamines (the "purest" non-sedating agent). * **Cetirizine** is a metabolite of Hydroxyzine; while generally non-sedating, it may cause mild drowsiness in a small percentage of patients compared to Fexofenadine. * **Contraindication:** First-generation antihistamines should be avoided in pilots, drivers, and machinery operators.

Q: Which of the following is a lipoxygenase inhibitor?

Zileuton. **Explanation:** The correct answer is **Zileuton**. This question tests your knowledge of the leukotriene pathway in the management of bronchial asthma. **1. Why Zileuton is correct:** Leukotrienes are potent bronchoconstrictors derived from arachidonic acid via the **5-Lipoxygenase (5-LOX)** enzyme pathway. **Zileuton** is a specific inhibitor of the 5-LOX enzyme. By blocking this enzyme, it prevents the synthesis of all leukotrienes (LTB4, LTC4, LTD4, and LTE4), thereby reducing airway inflammation and bronchospasm. **2. Why other options are incorrect:** * **Montelukast:** This is a **Leukotriene Receptor Antagonist (LTRA)**. It does not inhibit the enzyme; instead, it selectively blocks the **CysLT1 receptor**, preventing the action of cysteinyl leukotrienes (LTC4, LTD4, LTE4). * **Thromboxanes:** These are eicosanoids produced via the **Cyclooxygenase (COX)** pathway, not the lipoxygenase pathway. They primarily mediate platelet aggregation and vasoconstriction. * **Sodium cromoglycate:** This is a **Mast Cell Stabilizer**. It works by preventing the degranulation of mast cells and the subsequent release of inflammatory mediators like histamine; it has no direct effect on the lipoxygenase enzyme. **Clinical Pearls for NEET-PG:** * **Hepatotoxicity:** Zileuton is known to cause a rise in liver enzymes; therefore, periodic **Liver Function Tests (LFTs)** are mandatory. * **Aspirin-Exacerbated Respiratory Disease (AERD):** Leukotriene modifiers (both Zileuton and Montelukast) are particularly effective in patients with the "Samter’s Triad" (Asthma, Aspirin sensitivity, and Nasal polyps). * **Churg-Strauss Syndrome:** Be aware of the rare association between LTRA (Montelukast/Zafirlukast) use and the development of this systemic vasculitis.

Q: What is the advantage of salmeterol over salbutamol?

Longer duration of action. **Explanation:** The primary pharmacological difference between Salmeterol and Salbutamol lies in their **pharmacokinetics**, specifically their duration of action. **1. Why "Longer duration of action" is correct:** Salmeterol is a **Long-Acting Beta-2 Agonist (LABA)**. It possesses a long, lipophilic side chain that anchors the molecule into the cell membrane near the $\beta_2$-adrenoceptor. This allows the active head of the drug to repeatedly engage with the receptor site, resulting in a prolonged bronchodilatory effect lasting **12 hours or more**. In contrast, Salbutamol is a **Short-Acting Beta-2 Agonist (SABA)** with a duration of only 4–6 hours. **2. Why other options are incorrect:** * **Shorter duration of action:** This describes Salbutamol (SABA), which is used for "rescue" relief of acute symptoms. * **More potency:** While their binding affinities differ, "potency" is not the clinically defining advantage. The therapeutic choice is based on the *timing* of the effect. * **Lesser cardiac effects:** Both drugs are $\beta_2$-selective but can cause tachycardia and tremors at high doses due to some $\beta_1$ cross-reactivity or reflex mechanisms. Salmeterol does not inherently possess a significantly safer cardiac profile than Salbutamol. **Clinical Pearls for NEET-PG:** * **Onset of Action:** Salbutamol acts within 5 minutes (ideal for acute attacks). Salmeterol has a **slow onset** (15–20 mins) and should **never** be used for acute relief. * **Black Box Warning:** LABAs (Salmeterol/Formoterol) should generally not be used as monotherapy in asthma; they must be combined with an **Inhaled Corticosteroid (ICS)** to reduce the risk of asthma-related mortality. * **Formoterol Exception:** Unlike Salmeterol, Formoterol is a LABA that has a **fast onset** of action.

Q: What is the drug of choice for the treatment of acute asthmatic attacks?

Beta 2 agonists. **Explanation:**Why Beta-2 Agonists are the Correct Choice:Short-acting Beta-2 Agonists (SABA), such as **Salbutamol (Albuterol)** and Terbutaline, are the drugs of choice for acute asthmatic attacks [1, 3]. Their mechanism involves stimulating $\beta_2$ receptors on bronchial smooth muscle, leading to increased intracellular cAMP. This results in rapid and potent **bronchodilation**, providing immediate relief from symptoms like wheezing and dyspnea [2]. Because they have a rapid onset of action (within 5 minutes), they are termed "rescue medications."Analysis of Incorrect Options:* **Leukotriene Antagonists (e.g., Montelukast):** These are used for **prophylaxis** and chronic management of asthma, especially aspirin-induced or exercise-induced asthma. They are not effective in acute attacks because they do not provide immediate bronchodilation.* **Lipoxygenase Inhibitors (e.g., Zileuton):** Similar to leukotriene antagonists, these are controller medications used for long-term maintenance, not for emergency relief.* **Anticholinergics (e.g., Ipratropium bromide):** While they cause bronchodilation by blocking M3 receptors, they are slower-acting and less potent than $\beta_2$ agonists. They are typically used as **add-on therapy** in acute severe asthma or as the drug of choice in COPD.High-Yield Clinical Pearls for NEET-PG:* **Route of Choice:** Inhalation is preferred over oral/parenteral routes for acute attacks to ensure rapid action and minimal systemic side effects (like tremors and tachycardia).* **Drug of Choice for Exercise-Induced Asthma:** SABA (taken 15 minutes before exercise).* **Status Asthmaticus:** If SABA fails, the next steps include systemic corticosteroids and nebulized Ipratropium.* **Side Effects:** Muscle tremors (most common), palpitations, and hypokalemia (due to shift of $K^+$ into cells).

Q: What is the most unpleasant side effect of salbutamol?

Tremors. Salbutamol is a Short-Acting Beta-2 Agonist (SABA) primarily used as a bronchodilator in asthma and COPD. **Why Tremors are the correct answer:** The most common and characteristic side effect of Salbutamol is **skeletal muscle tremors**, specifically involving the hands. This occurs due to the direct stimulation of **Beta-2 receptors located on the voluntary skeletal muscles**. This stimulation causes an increase in the speed of muscle contraction and a decrease in the refractory period, leading to fine tremors. While not life-threatening, patients find this side effect highly "unpleasant" and distressing, often affecting their manual dexterity. **Analysis of Incorrect Options:** * **B. Hypertension:** Salbutamol primarily acts on Beta-2 receptors (vasodilation), which typically causes a slight decrease or no change in blood pressure. While high doses can cause reflex tachycardia via Beta-1 stimulation, hypertension is not a standard side effect [1, 2]. * **C. Rhinorrhoea:** This is not associated with Beta-agonists. In fact, alpha-agonists are used to treat rhinorrhoea (nasal congestion). * **D. Headache:** While headaches can occur due to vasodilation, they are less frequent and less characteristic than tremors. **NEET-PG High-Yield Pearls:** 1. **Tolerance:** Continuous use of Salbutamol leads to **downregulation (tachyphylaxis)** of Beta-2 receptors. 2. **Metabolic Effect:** Salbutamol can cause **hypokalemia** (by driving potassium into cells), which is why it is used therapeutically in hyperkalemia. 3. **Drug of Choice:** Salbutamol remains the drug of choice for **acute episodes** (rescue inhaler) of bronchospasm. 4. **Tachycardia:** Occurs due to both direct Beta-1 stimulation (at high doses) and reflex action due to Beta-2 mediated peripheral vasodilation [1, 2].

Q: What are the complications of inhalational steroid use?

Oral candidiasis. **Explanation:** Inhalational corticosteroids (ICS), such as Budesonide and Fluticasone, are the mainstay for long-term management of bronchial asthma. The primary advantage of the inhalational route is that it delivers the drug directly to the target site (airway), minimizing systemic absorption and associated side effects. **Why Oral Candidiasis is the Correct Answer:** When using a Metered-Dose Inhaler (MDI), a significant portion of the drug (approx. 80-90%) deposits in the oropharynx. Steroids cause local immunosuppression in the oral mucosa, which facilitates the overgrowth of opportunistic fungi, most commonly *Candida albicans*. This results in **Oral Candidiasis (Thrush)**. Another common local side effect is **Dysphonia** (hoarseness of voice) due to myopathy of the laryngeal muscles. **Analysis of Incorrect Options:** * **A & C (Cushing’s Syndrome & Decreased ACTH):** These are features of systemic corticosteroid toxicity. While high doses of potent ICS can theoretically cause some adrenal suppression, they rarely cause full-blown Cushingoid features or significant ACTH suppression at standard therapeutic doses. * **D (Systemic Complications):** The inhalational route is specifically designed to avoid systemic complications like osteoporosis, hyperglycemia, and growth retardation, which are common with oral or parenteral steroids. **High-Yield Clinical Pearls for NEET-PG:** * **Prevention:** Patients should be advised to **rinse their mouth with water and spit** after every use of an ICS to remove oropharyngeal deposits. * **Spacers:** Using a spacer device with an MDI reduces oropharyngeal deposition and increases lung delivery, further decreasing the risk of candidiasis. * **Ciclesonide:** This is a **prodrug** activated by esterases in the lungs; it has minimal activity in the oropharynx, significantly reducing the risk of local side effects.

Q: Salbutamol is used in which of the following conditions?

Bronchial asthma. ### Explanation **Correct Option: B. Bronchial Asthma** Salbutamol is a **short-acting beta-2 ($\beta_2$) agonist (SABA)**. Its primary mechanism involves stimulating $\beta_2$ receptors located on the bronchial smooth muscle. This activation increases intracellular cyclic AMP (cAMP), leading to potent **bronchodilation**. It is the drug of choice for the relief of acute bronchospasm in bronchial asthma because of its rapid onset of action (5–15 minutes). **Why other options are incorrect:** * **A. Cardiac Asthma:** This is not true asthma; it is wheezing caused by left-sided heart failure leading to pulmonary congestion. The primary treatment involves diuretics (Furosemide) and morphine, not bronchodilators. * **C. Pulmonary Oedema:** This is an accumulation of fluid in the lungs, usually due to heart failure. Treatment focuses on reducing preload (nitrates, diuretics) and improving cardiac output. Salbutamol has no role here and may even worsen tachycardia. * **D. Cor Pulmonale:** This refers to right-sided heart failure resulting from chronic lung disease (like COPD). While bronchodilators may treat the underlying COPD, Salbutamol is not a treatment for the resulting heart failure itself. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Increases cAMP $\rightarrow$ Bronchodilation. * **Side Effects:** Muscle tremors (most common), tachycardia (due to $\beta_1$ cross-reactivity), and **hypokalemia** (used therapeutically to treat hyperkalemia). * **Drug of Choice:** Salbutamol/Albuterol is the "rescue inhaler" for acute asthma attacks. * **Contraindication:** Use with caution in patients with hyperthyroidism or severe cardiac disease due to risk of arrhythmias.

Q: A 28-year-old female with a known history of asthma, currently prescribed inhalational salbutamol, budesonide, and salmeterol, presents with dyspnea. Her peak expiratory flow (PEF) shows mild improvement. Zafirlukast has been added to her treatment regimen. What is the mechanism of action of zafirlukast?

Inhibition of the actions of LTC4, LTD4. ### Explanation **1. Mechanism of Action (Correct Answer: B)** Zafirlukast and Montelukast are **selective CysLT₁ receptor antagonists**. In asthma, cysteinyl leukotrienes (LTC4, LTD4, and LTE4) are potent bronchoconstrictors that also increase mucus secretion and airway edema. By competitively blocking the CysLT₁ receptor, zafirlukast inhibits the **actions** of these leukotrienes, leading to bronchodilation and reduced airway inflammation. **2. Analysis of Incorrect Options** * **Option A:** LTB4 is primarily a chemoattractant for neutrophils. While it plays a role in inflammation, CysLT₁ antagonists do not target LTB4 receptors. * **Option C:** This describes the mechanism of **Zileuton**, which is a 5-Lipoxygenase (5-LOX) inhibitor. Zileuton prevents the *synthesis* (formation) of leukotrienes, whereas zafirlukast blocks their *receptors*. * **Option D:** This describes the mechanism of **Mast Cell Stabilizers** (e.g., Sodium Cromoglicate), which prevent the degranulation and release of various mediators, including leukotrienes. **3. NEET-PG High-Yield Clinical Pearls** * **Indications:** Used for prophylactic treatment of chronic asthma and aspirin-induced asthma (AIA). They are **not** used for acute attacks. * **Metabolism:** Zafirlukast is an inhibitor of CYP2C9 and CYP3A4; it can increase the serum levels of **Warfarin**, leading to increased prothrombin time. * **Side Effects:** Generally well-tolerated, but rarely associated with **Churg-Strauss syndrome** (eosinophilic granulomatosis with polyangiitis) when systemic steroids are tapered. * **Administration:** Montelukast is taken once daily (usually at night), while Zafirlukast is taken twice daily.

Question 1

Omalizumab is:

Accepted Answer

Anti IgE antibody

Answer

Interleukin 2 receptor blocker

Answer

Anti IgM antibody

Answer

Leukotriene receptor blocker

Question 2

A machinery worker in a factory presents with profuse rhinorrhea and sneezing. Which of the following is the most appropriate medication for symptomatic relief?

Accepted Answer

Cetirizine

Answer

Diphenhydramine

Answer

Promethazine

Answer

Hydroxyzine

Question 3

Which of the following is a lipoxygenase inhibitor?

Accepted Answer

Zileuton

Answer

Montelukast

Answer

Thromboxanes

Answer

Sodium cromoglycate

Question 4

What is the advantage of salmeterol over salbutamol?

Accepted Answer

Longer duration of action

Answer

Shorter duration of action

Answer

More potency

Answer

Lesser cardiac effects

Question 5

What is the drug of choice for the treatment of acute asthmatic attacks?

Accepted Answer

Beta 2 agonists

Answer

Leukotriene antagonists

Answer

Lipoxygenase inhibitors

Answer

Anticholinergics

Question 6

What is the most unpleasant side effect of salbutamol?

Accepted Answer

Tremors

Answer

Hypertension

Answer

Rhinorrhoea

Answer

Headache

Question 7

What are the complications of inhalational steroid use?

Accepted Answer

Oral candidiasis

Answer

Cushing's syndrome

Answer

Decreased ACTH

Answer

Systemic complications

Question 8

Salbutamol is used in which of the following conditions?

Accepted Answer

Bronchial asthma

Answer

Cardiac asthma

Answer

Pulmonary oedema

Answer

Cor pulmonale

Question 9

A 28-year-old female with a known history of asthma, currently prescribed inhalational salbutamol, budesonide, and salmeterol, presents with dyspnea. Her peak expiratory flow (PEF) shows mild improvement. Zafirlukast has been added to her treatment regimen. What is the mechanism of action of zafirlukast?

Accepted Answer

Inhibition of the actions of LTC4, LTD4

Answer

Inhibition of the actions of LTB4

Answer

Inhibition of the formation of LTC4, LTD4

Answer

Inhibition of the release of leukotrienes from mast cells

Question 10

Which of the following H1 blockers has high anticholinergic activity?

Accepted Answer

Chlorpheniramine

Answer

Cetirizine

Answer

Fexofenadine

Answer

Astemizole

Respiratory System Drugs — MCQs

Respiratory System Drugs — MCQs

On this page

Practice by Chapter

Want unlimited practice?