Respiratory System Drugs — MCQs

Respiratory System Drugs Indian Medical PG Practice Questions and MCQs

Question 271: What is the classification of Omalizumab?

A. Anti-IgM antibody
B. Anti-IgG antibody
C. Anti-IgE antibody (Correct Answer)
D. Anti-IgD antibody

Explanation: ***Anti-IgE antibody*** - **Omalizumab** is a **monoclonal antibody** specifically designed to bind to free **immunoglobulin E (IgE)** in the blood [1], [2]. - By binding IgE, it prevents IgE from attaching to its receptors on **mast cells** and **basophils**, thus inhibiting the release of inflammatory mediators involved in allergic reactions [3]. *Anti-IgM antibody* - **Anti-IgM antibodies** are not used as a therapeutic intervention for asthma or allergies as IgM is primarily involved in primary immune responses and forms a pentamer. - Therapeutic antibodies typically target specific molecules involved in disease pathology, and IgM is not a primary target for allergic conditions. *Anti-IgG antibody* - **Anti-IgG antibodies** are generally not used in the treatment of allergic conditions or asthma, as **IgG** is mainly involved in secondary immune responses and provides long-term immunity. - While IgG can be targeted in some autoimmune conditions, it is not the mechanism of action for omalizumab. *Anti-IgD antibody* - **Anti-IgD antibodies** have no known therapeutic application in allergic asthma or similar conditions. - **IgD** is found on the surface of B cells and plays a role in B cell activation, but it is not directly involved in the allergic cascade targeted by omalizumab.

Question 272: What is the primary use of leukotriene antagonists in asthma management?

A. To reduce the frequency of asthma attacks in mild to moderate cases.
B. As an adjunct therapy to inhaled corticosteroids.
C. For long-term control of asthma symptoms. (Correct Answer)
D. As a first-line treatment for acute asthma attacks.

Explanation: ***For long-term control of asthma symptoms.*** - Leukotriene antagonists, such as **montelukast** and **zafirlukast**, work by blocking the action of leukotrienes, which are inflammatory mediators. - This action helps to reduce airway inflammation and bronchoconstriction, leading to improved **lung function** and fewer asthma symptoms over time. - They are classified as **controller medications** for long-term asthma management, not rescue medications. *To reduce the frequency of asthma attacks in mild to moderate cases.* - While leukotriene antagonists can help reduce asthma attack frequency, their primary role is broader, focusing on **overall long-term symptom control**. - Their efficacy in preventing attacks in mild to moderate cases is part of their long-term control mechanism, rather than their sole or primary use. *As an adjunct therapy to inhaled corticosteroids.* - Leukotriene antagonists are often used as an **add-on therapy** when inhaled corticosteroids alone are insufficient, but this describes their placement in treatment rather than their primary purpose. - Their primary use is to achieve better symptom control and reduce inflammation, complementing, rather than simply supplementing, first-line treatments. *As a first-line treatment for acute asthma attacks.* - Leukotriene antagonists have a **slow onset of action** and are not suitable for the rapid relief required during an acute asthma attack. - **Short-acting beta-agonists (SABAs)** are the preferred medication for immediate relief of acute asthma symptoms due to their rapid bronchodilatory effects.

Question 273: A patient comes with a history of asthma and sinusitis. On looking into his medical records, you notice this has been attributed to Samter’s triad. Which drug should be avoided in this patient due to its potential to exacerbate respiratory symptoms?

A. Cotrimoxazole
B. Co-amoxiclav
C. Chloramphenicol
D. Aspirin (Correct Answer)

Explanation: ***Aspirin (Correct Answer)*** - Samter's triad, or **aspirin-exacerbated respiratory disease (AERD)**, is characterized by **asthma**, **nasal polyps with chronic rhinosinusitis**, and a severe reaction to **aspirin** and other **NSAIDs**. - **Aspirin** inhibits COX-1, leading to an overproduction of **leukotrienes**, which causes bronchoconstriction and exacerbates respiratory symptoms in susceptible individuals. - This is the drug that **must be avoided** in patients with Samter's triad. *Cotrimoxazole (Incorrect)* - **Cotrimoxazole** (trimethoprim-sulfamethoxazole) is an antibiotic not directly involved in the cyclooxygenase pathway. - While allergic reactions can occur, it is **not specifically contraindicated** in Samter's triad. *Co-amoxiclav (Incorrect)* - **Co-amoxiclav** (amoxicillin/clavulanic acid) is a penicillin-class antibiotic, and its mechanism of action does not involve prostaglandin synthesis. - It does not pose a specific risk for exacerbating respiratory symptoms in patients with **Samter's triad**. *Chloramphenicol (Incorrect)* - **Chloramphenicol** is an antibiotic that inhibits bacterial protein synthesis and is not associated with the pathogenesis of Samter's triad. - It does not impact the **cyclooxygenase or lipoxygenase pathways** that are central to AERD.

Question 274: What is an atypical side effect of montelukast?

A. Goodpasture syndrome
B. Membranous glomerulonephritis
C. Bronchial asthma
D. Churg-Strauss syndrome (Correct Answer)

Explanation: ***Churg-Strauss syndrome*** - The apparent development of **Churg-Strauss syndrome** (eosinophilic granulomatosis with polyangiitis) has been reported in patients treated with montelukast, although it is believed to be related more to the unmasking of the disease rather than a direct drug effect. - This typically occurs when **corticosteroids** are tapered or withdrawn as montelukast takes over, revealing the underlying vasculitis. *Goodpasture syndrome* - **Goodpasture syndrome** is an autoimmune disease causing rapidly progressive glomerulonephritis and pulmonary hemorrhage, characterized by anti-glomerular basement membrane (GBM) antibodies. - There is no established association between montelukast use and the development of Goodpasture syndrome. *Membranous glomerulonephritis* - **Membranous glomerulonephritis** is a common cause of nephrotic syndrome, characterized by immune complex deposition on the glomerular basement membrane. - This condition is not typically linked to the use of montelukast. *Bronchial asthma* - **Bronchial asthma** is the condition montelukast is used to treat, acting as a leukotriene receptor antagonist to reduce inflammation and bronchoconstriction. - It is a primary indication for the drug, not a side effect.

Question 275: Which of the following drugs is commonly used as a rescue medication for acute asthma attacks?

A. Salbutamol (Correct Answer)
B. Theophylline
C. Terbutaline
D. Budesonide

Explanation: ***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.

Question 276: Which of the following is a long-acting beta-2 agonist?

A. Isoprenaline
B. Ephedrine
C. Salbutamol
D. Formoterol (Correct Answer)

Explanation: ***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.

Question 277: Maximum effect of bronchodilatation in asthma is caused by -

A. Beta 2-Agonist (Correct Answer)
B. Corticosteroids
C. Theophylline
D. Anticholinergic

Explanation: ***Beta 2-Agonist*** - **Beta-2 agonists** directly relax bronchial smooth muscle by stimulating beta-2 adrenergic receptors, leading to significant and rapid bronchodilation. - This direct action on airway muscle relaxation makes them the most potent and fastest-acting bronchodilators for acute asthma symptoms. *Corticosteroids* - **Corticosteroids** reduce airway inflammation and hypersensitivity over time but do not provide immediate or maximal bronchodilation. - Their primary role is in long-term control of asthma, preventing exacerbations rather than acutely reversing bronchospasm. *Theophylline* - **Theophylline** is a methylxanthine that causes modest bronchodilation by inhibiting phosphodiesterase and blocking adenosine receptors. - It has a narrow therapeutic index, numerous side effects, and is less effective than beta-2 agonists for bronchodilation. *Anticholinergic* - **Anticholinergics** (e.g., ipratropium) block muscarinic receptors, preventing acetylcholine-induced bronchoconstriction. - They provide bronchodilation but are generally less potent and have a slower onset of action compared to beta-2 agonists in asthma.

Question 278: What is the drug of choice for most forms of interstitial lung disease?

A. Antibiotics
B. Bronchodilators
C. Aspirin
D. Corticosteroids (Correct Answer)

Explanation: ***Corticosteroids*** - **Corticosteroids** are the **drug of choice** for many forms of **interstitial lung disease (ILD)** due to their potent **anti-inflammatory** and **immunosuppressive properties**, which help reduce lung inflammation and prevent fibrosis. - They are particularly effective in inflammatory ILDs such as **sarcoidosis**, **hypersensitivity pneumonitis**, and some **connective tissue disease-associated ILDs**. *Antibiotics* - **Antibiotics** are primarily used to treat bacterial and other microbial infections and are **not effective** against the **inflammatory and fibrotic processes** characteristic of most ILDs. - They might be used if there's a **secondary bacterial infection** complicating ILD, but not as primary treatment for the ILD itself. *Bronchodilators* - **Bronchodilators** work by relaxing the muscles around the airways, making them wider and easier to breathe through, which is beneficial in conditions like **asthma** or **COPD**. - They are **not primarily used** in ILD as the main problem is **inflammation and scarring of the lung tissue**, not reversible airway constriction. *Aspirin* - **Aspirin** is an **NSAID** with **anti-inflammatory**, **anti-platelet**, and **analgesic properties**, commonly used for pain relief, fever reduction, and cardiovascular protection. - It has **no established role** in the primary treatment of **interstitial lung disease**, as its anti-inflammatory effects are typically insufficient for the severe inflammation seen in ILD.

Question 279: Aminophylline inhibits which of the following enzymes?

A. MAO
B. Alcohol dehydrogenase
C. Cytochrome P450
D. Phosphodiesterase (Correct Answer)

Explanation: ***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 280: Which of the following is NOT a beta-2 agonist?

A. Ketotifen (Correct Answer)
B. Terbutaline
C. Salbutamol
D. Bambuterol

Explanation: ***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.

Practice by Chapter

Bronchodilators

Practice Questions

Corticosteroids in Respiratory Disorders

Practice Questions

Anti-inflammatory Respiratory Agents

Practice Questions

Mast Cell Stabilizers

Practice Questions

Leukotriene Modifiers

Practice Questions

Antitussives and Expectorants

Practice Questions

Nasal Decongestants

Practice Questions

Pulmonary Surfactants

Practice Questions

Drugs for Pulmonary Hypertension

Practice Questions

Oxygen Therapy

Practice Questions

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