Respiratory and GIT Pharmacology MCQs

Pharmacology · 78 free questions with answers & explanations.

1. A patient with moderate persistent asthma on inhaled corticosteroid (budesonide) and a long-acting beta-agonist (LABA — formoterol) has well-controlled disease but develops oral candidiasis. The most practical intervention to prevent recurrence of oral candidiasis is:
2. A 45-year-old asthmatic on inhaled salmeterol plus budesonide for 6 months has well-controlled symptoms but is found to have reduced bone mineral density at follow-up. The most likely contributing drug-related mechanism is:
3. Ondansetron is effective in chemotherapy-induced nausea and vomiting. Its mechanism is:
4. Dupilumab is a biologic approved for severe asthma uncontrolled on high-dose ICS/LABA. Its specific mechanism targets:
5. A patient on omeprazole develops hypomagnesemia and vitamin B12 deficiency after 2 years. The mechanism for B12 deficiency with long-term PPIs involves:
6. Dupilumab is a biologic approved for severe atopic asthma and atopic dermatitis. Its mechanism addresses which cytokine signalling pathway?
7. Rifaximin, used for hepatic encephalopathy prophylaxis, differs from systemic rifamycins in a pharmacokinetically crucial manner. This difference explains why rifaximin does not produce systemic antibiotic adverse effects:
8. Dupilumab, an IL-4/IL-13 receptor alpha antagonist, is approved for severe eosinophilic asthma and atopic dermatitis. Which specific cytokine signaling pathway does it target and why does blocking this single receptor affect both IL-4 and IL-13?
9. Dupilumab, a newer biologic for severe asthma, blocks the shared receptor component of which two cytokines to reduce Type 2 airway inflammation?
10. Proton pump inhibitors (PPIs) irreversibly block gastric acid secretion. Their activation requires which specific condition?
11. Dupilumab, approved for moderate-to-severe atopic dermatitis and asthma, blocks the shared receptor subunit for IL-4 and IL-13. This shared subunit is:
12. Tezepelumab is a novel biological for severe asthma that targets a cytokine secreted by airway epithelial cells in response to environmental triggers (allergens, pollutants, viruses). This cytokine is:
13. Dupilumab is a biologic used in severe eosinophilic asthma and atopic dermatitis. Its mechanism targets which upstream cytokine signalling pathway?
14. A patient with H. pylori-associated peptic ulcer disease is prescribed a bismuth quadruple regimen (bismuth, PPI, metronidazole, tetracycline). What is the primary mechanism by which bismuth subsalicylate/tripotassium dicitratobismuthate exerts anti-H. pylori activity?
15. Dupilumab is approved for severe eosinophilic/type 2 asthma. Its mechanism involves blocking the receptor shared by IL-4 and IL-13. This shared receptor subunit is:
16. Lubiprostone, used for chronic idiopathic constipation and IBS-C, works by activating which channel/receptor in intestinal epithelial cells?
17. Dupilumab is approved for severe uncontrolled asthma. It blocks the shared receptor component of IL-4 and IL-13 signalling. Which receptor subunit does it specifically target and what is the downstream consequence?
18. Vonoprazan, a potassium-competitive acid blocker (P-CAB), is being used in H. pylori eradication regimens. How does its mechanism differ from proton pump inhibitors (PPIs), and what clinical advantage does this confer?
19. Dupilumab is a monoclonal antibody used in moderate-to-severe asthma with eosinophilic or type 2 inflammation. It targets which cytokine signalling pathway?
20. Pantoprazole is a proton pump inhibitor (PPI) that irreversibly inhibits the H+/K+-ATPase on the luminal surface of parietal cells. Why is pantoprazole more acid-stable and pharmacologically preferred in IV formulations over omeprazole?
21. Dupilumab, approved for severe eosinophilic asthma and atopic dermatitis, targets which interleukin receptor subunit, and what is its mechanism of action on Type 2 immunity?
22. Sucralfate exerts its antiulcer effect by forming a protective barrier on ulcer base. The sub-mechanism critical to its action at the molecular level is:
23. Dupilumab is effective in both atopic dermatitis and severe eosinophilic asthma because it targets a shared pathogenic cytokine pathway. The specific mechanism is:
24. Vonoprazan, a newer potassium-competitive acid blocker (P-CAB), has more rapid and consistent acid suppression than omeprazole because:
25. Roflumilast is a selective PDE4 inhibitor used in severe COPD with frequent exacerbations. Its anti-inflammatory mechanism relevant to COPD pathophysiology is:
26. A patient on long-term omeprazole 40 mg daily develops hypomagnesemia, hypocalcemia, and tetany. The mechanism of PPI-induced hypomagnesemia is:
27. Dupilumab, a biologic used for severe eosinophilic asthma, targets which cytokine pathway, and what molecular mechanism underlies its efficacy?
28. Dupilumab is a biologic agent approved for severe eosinophilic/atopic asthma. Which cytokine signaling pathway does it target?
29. Elexacaftor/tezacaftor/ivacaftor (Trikafta) is transformative therapy for cystic fibrosis. The F508del CFTR mutation causes which protein folding defect corrected by elexacaftor/tezacaftor?
30. Omeprazole is a proton pump inhibitor. The step at which it becomes an active sulfenamide is:
31. Montelukast reduces asthmatic bronchoconstriction by blocking:
32. Dupilumab, used in severe eosinophilic asthma, targets the shared IL-4Ralpha subunit. Which signalling cascade is blocked by this mechanism?
33. A patient with delayed gastric emptying post-vagotomy is started on metoclopramide. Which receptor combination explains its prokinetic effect in the GI tract?
34. Proton pump inhibitors (PPIs) such as omeprazole are prodrugs that require an acidic environment for activation. This means they must be:
35. N-acetylcysteine is used to prevent paracetamol hepatotoxicity. Its mechanism involves:
36. Ipratropium bromide is preferred over atropine for bronchodilation in COPD because:
37. A patient with severe asthma not controlled on ICS-LABA is started on a biologic. It is a monoclonal antibody that blocks IL-5 signaling, reducing eosinophil survival and proliferation. Which drug is this?
38. Proton pump inhibitors (PPIs) are most effective when taken at which time relative to meals?
39. Theophylline's bronchodilatory mechanism at therapeutic concentrations is PRIMARILY through:
40. Ondansetron, a 5-HT3 antagonist, is the first-line antiemetic for chemotherapy-induced nausea and vomiting (CINV). The peripheral trigger zone for CINV involves 5-HT3 receptors primarily located on:
41. Lubiprostone is used for chronic idiopathic constipation and irritable bowel syndrome with constipation. Its mechanism is:
42. Omeprazole is a proton pump inhibitor (PPI) that irreversibly inhibits the H+/K+-ATPase. Which statement about PPI pharmacokinetics is most accurate?
43. In severe acute asthma (status asthmaticus) not responding to inhaled beta-2 agonists, IV magnesium sulphate is given. The mechanism by which it produces bronchodilation is:
44. Roflumilast is used as an add-on anti-inflammatory in severe COPD with frequent exacerbations. Its mechanism involves inhibition of:
45. Montelukast is used as add-on therapy in aspirin-exacerbated respiratory disease (AERD). It acts by blocking:
46. Proton pump inhibitors (PPIs) are pro-drugs that require acid activation. The therapeutic implication of this is:
47. Omeprazole is a proton pump inhibitor that requires acidic conditions in the secretory canaliculus of parietal cells for activation. The mechanism of activation is:
48. Theophylline has a narrow therapeutic index and multiple adverse effects. At therapeutic plasma concentrations (10–20 mcg/mL), its primary mechanism of bronchodilation is:
49. Ondansetron prevents chemotherapy-induced nausea but has no effect on motion sickness. The receptor selectivity that explains this clinical difference is:
50. A 5-year-old child with moderate persistent asthma is prescribed a leukotriene receptor antagonist (LTRA). Montelukast blocks which receptor to prevent bronchoconstriction and airway inflammation?
51. Dupilumab is approved for severe uncontrolled atopic dermatitis and add-on therapy for severe asthma with eosinophilic phenotype. Its mechanism is:
52. Proton pump inhibitors (PPIs) require specific dosing recommendations for maximum efficacy. The correct guidance regarding PPI administration is:
53. Neostigmine reverses non-depolarizing neuromuscular blockade and is also used for postoperative ileus (Ogilvie syndrome). Its mechanism in treating Ogilvie syndrome is:
54. Ipratropium bromide is used as a bronchodilator in COPD. It differs from tiotropium in that ipratropium:
55. A patient with peptic ulcer disease is given omeprazole. Its mechanism of gastric acid suppression involves:
56. Roflumilast is a phosphodiesterase-4 (PDE4) inhibitor used as add-on therapy in severe COPD with frequent exacerbations. Its anti-inflammatory mechanism involves:
57. Proton pump inhibitors (PPIs) like omeprazole require acid environment for activation. Which pharmacokinetic property explains why PPIs must be taken before meals?
58. A 55-year-old asthmatic on step 4 therapy develops eosinophilic asthma (blood eosinophils >300 cells/µL). A biologic is added. Mepolizumab works by:
59. A patient with GERD refractory to standard-dose PPI is switched to vonoprazan. This drug differs from PPIs because it:
60. A patient with acute severe ulcerative colitis not responding to IV methylprednisolone is started on cyclosporine. The mechanism by which cyclosporine suppresses T-cell-mediated colonic inflammation is:
61. Montelukast is used in asthma prophylaxis. It blocks leukotriene receptors (CysLT1). Which mechanism best explains why montelukast is particularly useful as an add-on therapy in aspirin-exacerbated respiratory disease (AERD)?
62. Omeprazole is a proton pump inhibitor (PPI) that is itself inactive. The mechanism of its activation and irreversible inhibition of the proton pump is:
63. Montelukast (a cysteinyl leukotriene receptor 1 antagonist) is used as add-on therapy in asthma. Its advantage over inhaled corticosteroids includes:
64. A 55-year-old patient with GERD on long-term proton pump inhibitor therapy develops hypomagnesemia and recurrent Clostridioides difficile infections. PPI-induced hypomagnesemia occurs because PPIs:
65. Omeprazole is a prodrug that requires acid activation. The specific step in its mechanism of action is:
66. Montelukast, used in asthma prophylaxis, blocks which specific mediator pathway?
67. Montelukast is used as add-on therapy in asthma. It is a cysteinyl leukotriene type-1 (CysLT1) receptor antagonist. Which pathophysiological effects of leukotrienes does it block?
68. Ondansetron prevents chemotherapy-induced acute vomiting but is less effective for anticipatory vomiting. The pharmacological explanation is:
69. Omeprazole is a proton pump inhibitor (PPI). It requires acid activation to become the active sulfenamide. The consequence of this for drug administration is:
70. Roflumilast is used as an add-on therapy in severe COPD. Its mechanism is:
71. A patient on long-term omeprazole therapy has a serum magnesium of 0.55 mmol/L (normal 0.7-1.0). Which statement BEST explains this finding?
72. Ondansetron prevents chemotherapy-induced vomiting by blocking which receptor in the gastrointestinal tract and the chemoreceptor trigger zone?
73. Metoclopramide given as a prokinetic acts primarily by:
74. A patient with Crohn's disease affecting the terminal ileum is started on sulfasalazine. Which component is responsible for the therapeutic effect in IBD?
75. Which laxative works by retaining water in the intestinal lumen through osmotic action and is safe for use in hepatic encephalopathy?
76. Loperamide is preferred over diphenoxylate for self-medication of acute diarrhoea because:
77. A patient is prescribed ranitidine (H2 blocker) for peptic ulcer. H2 blockers reduce acid secretion by blocking histamine action on which cell?
78. Ondansetron prevents chemotherapy-induced nausea and vomiting (CINV) by: