Respiratory System Drugs Practice Questions

Q: Salbutamol is preferred over adrenaline in an asthmatic patient because:

Adrenaline has more adverse effects.. **Explanation:** The core pharmacological difference between Salbutamol and Adrenaline lies in their **receptor selectivity**. **1. Why Option B is Correct:** Adrenaline is a non-selective adrenergic agonist acting on $\alpha_1, \alpha_2, \beta_1,$ and $\beta_2$ receptors. While its $\beta_2$ action causes bronchodilation, its $\alpha_1$ and $\beta_1$ actions lead to significant adverse effects, including **tachycardia, palpitations, hypertension, and arrhythmias**. In contrast, Salbutamol is a **selective $\beta_2$ agonist**. By targeting receptors primarily located in the bronchial smooth muscle, it provides effective bronchodilation with significantly fewer systemic cardiovascular side effects, making it the preferred choice for asthma. **2. Analysis of Incorrect Options:** * **Option A:** This is incorrect because Salbutamol actually has a **longer** duration of action (4–6 hours) compared to Adrenaline, which is rapidly metabolized by COMT and MAO, lasting only minutes to an hour. * **Option C:** While Salbutamol is "safer," this is a vague clinical observation rather than the underlying pharmacological reason. Option B provides the specific medical justification (the profile of adverse effects) required for a competitive exam like NEET-PG. **Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC):** Salbutamol (SABA) is the DOC for acute asthma attacks. * **Adrenaline’s Role:** It remains the **Drug of Choice for Anaphylactic Shock** (given IM 1:1000) because its $\alpha_1$ action treats hypotension and laryngeal edema, which Salbutamol cannot do. * **Side Effects of $\beta_2$ Agonists:** Even selective drugs like Salbutamol can cause **muscle tremors** (most common) and **hypokalemia** at high doses.

Q: Disodium cromoglycate is used by which of the following routes?

Inhalation. **Explanation:** **Disodium cromoglycate (DSCG)** is a **mast cell stabilizer** used primarily in the prophylactic management of bronchial asthma. 1. **Why Inhalation is Correct:** Disodium cromoglycate is highly polar and poorly absorbed from the gastrointestinal tract (less than 1%). To achieve therapeutic concentrations at the target site—the bronchial mucosa—it must be administered directly via **inhalation**. It works by stabilizing the membrane of sensitized mast cells, preventing the degranulation and release of inflammatory mediators like histamine and leukotrienes (LTC4, LTD4) triggered by allergens. It is available as a pressurized metered-dose inhaler (pMDI) or as a fine powder via a Spinhaler. 2. **Why Other Options are Incorrect:** * **Oral:** Due to its highly ionized nature, oral bioavailability is negligible (<1%), making it ineffective for systemic or respiratory action via this route. * **Intravenous/Intramuscular:** Injectable formulations are not used because the drug's primary utility is local mucosal stabilization. Furthermore, its short half-life would require frequent dosing if given systemically. **High-Yield Clinical Pearls for NEET-PG:** * **Prophylaxis Only:** DSCG is **not a bronchodilator**; it is useless in acute attacks of asthma (Status Asthmaticus). * **Mechanism:** It inhibits "Cl⁻ channels" in mast cells, preventing the calcium influx necessary for degranulation. * **Other Uses:** It is used topically for allergic rhinitis (nasal spray) and allergic conjunctivitis (eye drops). * **Side Effects:** The most common side effect is local irritation, cough, or bronchospasm caused by the inhalation of the dry powder itself.

Q: Which of the following is NOT an adverse effect of salbutamol?

Hypoglycemia. Salbutamol is a short-acting **eta_2$-selective agonist** primarily used as a bronchodilator [1, 2]. To understand its adverse effects, one must look at the systemic distribution of eta_2 receptors. **Why Hypoglycemia is the Correct Answer:** Salbutamol actually causes **Hyperglycemia**, not hypoglycemia. Stimulation of eta_2 receptors in the liver promotes **glycogenolysis** (breakdown of glycogen to glucose) and **gluconeogenesis**. It also stimulates the release of glucagon. Therefore, hypoglycemia is not an adverse effect of this drug. **Analysis of Incorrect Options:** * **Tachycardia:** Although selective for eta_2, high doses of salbutamol cause "cross-reactivity" with eta_1 receptors in the heart. Additionally, eta_2 stimulation causes peripheral vasodilation, leading to **reflex tachycardia**. * **Tolerance:** Prolonged or excessive use of eta_2 agonists leads to **downregulation (internalization)** of the receptors, resulting in tachyphylaxis or decreased clinical responsiveness. * **Hypokalemia:** eta_2 stimulation activates the **Na+/K+ ATPase pump**, driving potassium from the extracellular fluid into the skeletal muscles. This effect is actually utilized clinically to treat hyperkalemia. **NEET-PG High-Yield Pearls:** * **Muscle Tremors:** The most common side effect of salbutamol (due to eta_2 stimulation in skeletal muscles). * **Drug of Choice:** Salbutamol is the DOC for **acute asthma exacerbations** (rescue inhaler) [1]. * **Metabolic Effects:** Expect hyperglycemia, hypokalemia, and hypomagnesemia. * **Safety:** It is considered safe in pregnancy for treating asthma.

Q: All of the following drugs can be given in status asthmaticus except?

Salmeterol. **Explanation:** The core concept in managing **Status Asthmaticus** (Acute Severe Asthma) is the need for **rapid-acting** bronchodilation and anti-inflammatory action to reverse life-threatening airway obstruction. [1] **Why Salmeterol is the correct answer:** Salmeterol is a **Long-Acting Beta-2 Agonist (LABA)**. While it is highly effective for maintenance therapy and prophylaxis, it has a **slow onset of action** (approximately 15–20 minutes) [3]. In an emergency like status asthmaticus, drugs must work almost instantly. Using a slow-acting drug like Salmeterol in an acute crisis can delay necessary treatment and lead to fatal outcomes. Therefore, it is contraindicated for acute symptom relief. **Analysis of incorrect options:** * **Salbutamol & Terbutaline:** These are **Short-Acting Beta-2 Agonists (SABA)**. They are the first-line "rescue" medications because they have a rapid onset of action (within 1–5 minutes) when given via inhalation or nebulization [1]. In severe cases, they can also be administered parenterally. * **Hydrocortisone:** Systemic corticosteroids are a cornerstone in status asthmaticus management [2]. While they don't cause immediate bronchodilation, they reduce airway inflammation and, crucially, **upregulate beta-receptors**, making the patient more responsive to SABA therapy [4]. **High-Yield Clinical Pearls for NEET-PG:** * **Formoterol Exception:** Unlike Salmeterol, Formoterol is a LABA with a **fast onset of action**, allowing it to be used for both maintenance and rescue (SMART therapy). * **Drug of Choice:** Nebulized Salbutamol (SABA) + Ipratropium bromide (SAMA) is the initial treatment of choice for acute severe asthma. * **Magnesium Sulfate:** IV Magnesium sulfate is used as an add-on in refractory status asthmaticus for its smooth muscle relaxant properties.

Q: What is the optimal particle size for aerosol therapy?

1-5 µm. The effectiveness of aerosol therapy depends on the **Mass Median Aerodynamic Diameter (MMAD)** of the particles, which determines where they deposit in the respiratory tract. ### Why 1–5 µm is Correct For a drug to be clinically effective in conditions like asthma or COPD, it must reach the **lower airways (bronchi and bronchioles)**. Particles sized **1–5 µm** are ideal because they are small enough to bypass the upper airway but heavy enough to settle in the smaller airways via **sedimentation**. This range ensures maximum deposition in the target site for bronchodilators and inhaled corticosteroids. ### Analysis of Incorrect Options * **5–10 µm (Option C) & 10–15 µm (Option D):** These particles are too large. Due to **inertial impaction**, they hit the back of the throat (oropharynx) and are swallowed rather than inhaled. This increases systemic side effects (e.g., oral candidiasis with steroids) and decreases therapeutic efficacy. * **0.5–1 µm (Option A):** These particles are too light. They behave like a gas and remain suspended in the air. Instead of settling on the airway mucosa, they are typically **exhaled** out before deposition can occur. ### NEET-PG High-Yield Pearls * **Deposition Mechanisms:** * >10 µm: Oropharyngeal deposition (Impaction). * 1–5 µm: Small airways (Sedimentation). * 10 µm), reducing oropharyngeal deposition and improving delivery to the lungs.

Q: All of the following statements regarding sodium cromoglycate are true EXCEPT:

Used in the management of acute bronchial asthma. ### Explanation **Sodium Cromoglycate** is a **mast cell stabilizer** used primarily in the prophylactic management of bronchial asthma. **1. Why Option A is the Correct Answer (The False Statement):** Sodium cromoglycate is **ineffective in acute bronchial asthma**. It does not possess any intrinsic bronchodilatory or anti-inflammatory activity once the mediators have already been released. It acts by preventing the release of mediators (prophylaxis) rather than reversing their effects. In an acute attack, rapid-acting bronchodilators like Salbutamol (SABA) are the drugs of choice. **2. Analysis of Other Options:** * **Option B (Inhibits degranulation):** This is the primary mechanism of action. It stabilizes the mast cell membrane by inhibiting the trigger-induced influx of calcium, thereby preventing the release of histamine, leukotrienes, and other inflammatory mediators. * **Option C (Not a bronchodilator):** Unlike beta-2 agonists or theophylline, cromoglycate has no direct action on bronchial smooth muscle tone. It only prevents bronchoconstriction triggered by allergens or exercise. * **Option D (Inhalational route):** Sodium cromoglycate is highly polar and poorly absorbed from the GI tract. Therefore, it must be administered via inhalation (as a microfine powder via Rotahaler or as an aerosol) to act locally on the bronchial mucosa. **3. High-Yield Clinical Pearls for NEET-PG:** * **Indications:** Prophylaxis of bronchial asthma, allergic rhinitis (nasal spray), and allergic conjunctivitis (eye drops). * **Exercise-Induced Asthma:** It is particularly effective when taken 10–15 minutes before exercise. * **Adverse Effects:** Generally safe, but may cause throat irritation, cough, or rare bronchospasm (prevented by pre-administering a bronchodilator). * **Rule of Thumb:** Remember that mast cell stabilizers are "preventers," not "relievers."

Q: Which anti-IgE monoclonal antibody is used in the management of bronchial asthma?

Omalizumab. **Explanation:** **Omalizumab** is a recombinant DNA-derived humanized monoclonal antibody that specifically binds to **free circulating IgE** in the blood and interstitial fluid. By binding to the Fc portion of the IgE antibody, it prevents IgE from attaching to the high-affinity receptors (FcεRI) on the surface of mast cells and basophils. This prevents the subsequent release of inflammatory mediators (histamine, leukotrienes) that trigger an asthma attack. It is clinically indicated for patients with moderate-to-severe persistent allergic asthma who are inadequately controlled with inhaled corticosteroids. **Analysis of Incorrect Options:** * **Mepolizumab:** This is a monoclonal antibody against **Interleukin-5 (IL-5)**. It is used in the management of severe eosinophilic asthma by reducing eosinophil production and survival. * **Keliximab:** This is a monoclonal antibody directed against the **CD4 receptor** on T-lymphocytes. While it was studied for asthma, it is not a standard clinical treatment for the condition. * **Altrakincept:** This is a recombinant soluble **IL-4 receptor** (not a monoclonal antibody). It acts as a decoy receptor to neutralize IL-4, thereby inhibiting Th2-mediated inflammation. **High-Yield Clinical Pearls for NEET-PG:** * **Route:** Omalizumab is administered **subcutaneously** every 2–4 weeks. * **Dosing:** The dose is determined by the patient’s baseline serum IgE levels and body weight. * **Black Box Warning:** It carries a risk of **anaphylaxis**; therefore, patients must be monitored for a period after injection. * **Other Monoclonals:** Remember **Reslizumab** (Anti-IL-5) and **Dupilumab** (Anti-IL-4 receptor alpha subunit).

Q: What is the primary action of glucocorticoids in bronchial asthma?

Reduce airway inflammation. **Explanation:** **Why Option B is Correct:** Glucocorticoids are the most effective **anti-inflammatory** agents used in asthma. Their primary action is to suppress the underlying airway inflammation by inhibiting the recruitment and activation of inflammatory cells (eosinophils, T-lymphocytes, and macrophages). At a molecular level, they bind to cytoplasmic receptors, translocate to the nucleus, and decrease the transcription of pro-inflammatory cytokines (IL-4, IL-5, TNF-α) while increasing the expression of anti-inflammatory proteins. This leads to reduced mucosal edema and decreased airway hyper-responsiveness. **Analysis of Incorrect Options:** * **Option A:** Glucocorticoids are **not bronchodilators**. They do not have a direct effect on airway smooth muscle relaxation and are therefore ineffective for the immediate relief of an acute asthma attack (rescue therapy). * **Option C:** While they have some inhibitory effects on inflammatory cells, **Mast Cell Stabilizers** (like Sodium Cromoglicate) are specifically known for preventing mast cell degranulation. * **Option D:** While steroids reduce the production of mediators (like prostaglandins and leukotrienes via Phospholipase A2 inhibition), they do not "block" the action of humoral mediators at the receptor level; that is the role of drugs like **Leukotriene Receptor Antagonists (LTRAs)**. **NEET-PG High-Yield Pearls:** * **Synergistic Effect:** Glucocorticoids "prime" the lungs by upregulating **β2-receptors**, making the airways more responsive to β2-agonists. * **Drug of Choice:** Inhaled Corticosteroids (ICS) like Budesonide or Fluticasone are the **first-line maintenance therapy** for persistent asthma. * **Side Effects:** The most common local side effects of ICS are **Oropharyngeal Candidiasis** (thrush) and **hoarseness of voice** (dysphonia). Patients should be advised to rinse their mouth after use.

Q: All of the following glucocorticoids can be given by inhalation EXCEPT?

Dexamethasone. **Explanation:** The correct answer is **Dexamethasone**. **Why Dexamethasone is the correct answer:** Glucocorticoids used in the management of bronchial asthma and COPD are categorized into **Inhaled Corticosteroids (ICS)** and **Systemic Corticosteroids**. Dexamethasone is a highly potent, long-acting systemic glucocorticoid. It lacks the specific pharmacokinetic properties required for effective inhalation, such as high first-pass metabolism and high topical-to-systemic potency ratio. If inhaled, it would be absorbed systemically in significant amounts, leading to severe side effects (Cushingoid features, HPA axis suppression) without providing the localized benefit required for airway inflammation. **Why the other options are incorrect:** * **Beclomethasone dipropionate:** A classic ICS. It is a prodrug converted by esterases in the lungs to its active form, ensuring localized action. * **Budesonide:** A widely used ICS with high topical potency and significant first-pass metabolism in the liver, which minimizes systemic toxicity if swallowed. * **Fluticasone propionate:** Known for its high affinity for glucocorticoid receptors and near-zero oral bioavailability, making it one of the most effective and safe inhaled options. **High-Yield Clinical Pearls for NEET-PG:** * **Ciclesonide** is a "soft drug" (prodrug) activated only by bronchial esterases, further reducing the risk of oropharyngeal candidiasis. * **Flunisolide** and **Mometasone** are other examples of inhaled steroids. * **Side Effects of ICS:** The most common local side effects are **Oropharyngeal Candidiasis** (thrush) and **Hoarseness of voice** (dysphonia). These can be prevented by using a spacer or rinsing the mouth with water after inhalation. * **Systemic Steroids in Asthma:** Reserved for acute severe asthma (Status Asthmaticus) or severe persistent asthma (e.g., Hydrocortisone IV or Prednisolone orally).

Question 1

Salbutamol is preferred over adrenaline in an asthmatic patient because:

Accepted Answer

Adrenaline has more adverse effects.

Answer

It has a shorter duration of action.

Answer

It is safer for asthmatic patients.

Answer

None of the above.

Question 2

A patient suffers from troublesome allergic rhinitis due to pollen. Which drug, when prescribed, is least likely to cause sedation?

Accepted Answer

loratadine

Answer

betamethasone

Answer

cimetidine

Answer

hydroxyzine

Question 3

Disodium cromoglycate is used by which of the following routes?

Accepted Answer

Inhalation

Answer

Oral

Answer

Intravenous

Answer

Intramuscular

Question 4

Which of the following is NOT an adverse effect of salbutamol?

Accepted Answer

Hypoglycemia

Answer

Tachycardia

Answer

Tolerance

Answer

Hypokalemia

Question 5

All of the following drugs can be given in status asthmaticus except?

Accepted Answer

Salmeterol

Answer

Terbutaline

Answer

Hydrocortisone

Answer

Salbutamol

Question 6

What is the optimal particle size for aerosol therapy?

Accepted Answer

1-5 µm

Answer

0.5-1 µm

Answer

5-10 µm

Answer

10-15 µm

Question 7

All of the following statements regarding sodium cromoglycate are true EXCEPT:

Accepted Answer

Used in the management of acute bronchial asthma

Answer

Inhibits degranulation of mast cells

Answer

It is not a bronchodilator

Answer

Administered via the inhalational route

Question 8

Which anti-IgE monoclonal antibody is used in the management of bronchial asthma?

Accepted Answer

Omalizumab

Answer

Mepolizumab

Answer

Keliximab

Answer

Altrakincept

Question 9

What is the primary action of glucocorticoids in bronchial asthma?

Accepted Answer

Reduce airway inflammation

Answer

Act as potent bronchodilators

Answer

Inhibit degranulation of mast cells

Answer

Block the action of humoral mediators

Question 10

All of the following glucocorticoids can be given by inhalation EXCEPT?

Accepted Answer

Dexamethasone

Answer

Beclomethasone

Answer

Budesonide

Answer

Fluticasone

Respiratory System Drugs — MCQs

Respiratory System Drugs — MCQs

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