Expectorants – mechanism and examples MCQs With Answer

Introduction

Expectorants are drugs that enhance clearance of bronchial secretions by changing their volume, viscosity or transport — essential knowledge for B.Pharm students studying respiratory pharmacology. This topic covers mechanisms (secretolytic, mucolytic, mucokinetic, mucoregulator), examples such as guaifenesin, bromhexine, ambroxol and N-acetylcysteine (NAC), and clinical uses in productive cough, bronchitis and COPD. You will learn molecular actions like disulfide bond reduction, stimulation of serous cells, and reflex-mediated secretions, plus pharmacokinetics, adverse effects and drug interactions. Mastering these concepts helps in rational drug selection and counseling. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which mechanism best describes how N-acetylcysteine (NAC) acts as a mucolytic?

• Inhibition of mucin synthesis
• Stimulation of ciliary beat frequency
• Cleavage of disulfide bonds in mucoproteins
• Increasing surfactant production

Correct Answer: (Cleavage of disulfide bonds in mucoproteins)

Q2. Which of the following is a commonly used expectorant that primarily increases bronchial secretion volume via reflex stimulation?

• Bromhexine
• Ambroxol
• Guaifenesin
• N-acetylcysteine

Correct Answer: (Guaifenesin)

Q3. Ambroxol’s therapeutic effects include which of the following actions?

• Direct alkylation of mucus glycoproteins
• Stimulation of surfactant production and lysosomal enzyme release
• Competitive antagonism of muscarinic receptors
• Inhibition of beta-2 adrenergic receptors

Correct Answer: (Stimulation of surfactant production and lysosomal enzyme release)

Q4. Bromhexine is best described as which of the following?

• A potent antiviral agent used in cough
• A prodrug of ambroxol with secretolytic activity
• A systemic steroid used to reduce mucus
• An antitussive opioid derivative

Correct Answer: (A prodrug of ambroxol with secretolytic activity)

Q5. Which clinical situation is an expectorant most appropriate for?

• Productive cough with thick sputum
• Nonproductive dry cough due to ACE inhibitors
• Asymptomatic allergic rhinitis
• Isolated hoarseness without secretions

Correct Answer: (Productive cough with thick sputum)

Q6. Which adverse effect is most commonly associated with oral guaifenesin?

• Severe hepatotoxicity
• Gastrointestinal upset and nausea
• Life-threatening arrhythmias
• Renal failure

Correct Answer: (Gastrointestinal upset and nausea)

Q7. Which property distinguishes mucokinetic agents from mucolytics?

• Mucokinetics decrease mucus production
• Mucokinetics increase ciliary transport and expectoration
• Mucokinetics cleave mucin disulfide bonds
• Mucokinetics reduce bronchial blood flow

Correct Answer: (Mucokinetics increase ciliary transport and expectoration)

Q8. Which inhaled therapy acts as an expectorant by creating an osmotic gradient to draw water into airway secretions?

• Hypertonic saline
• Albuterol nebulizer
• Nebulized corticosteroid
• Inhaled ipratropium

Correct Answer: (Hypertonic saline)

Q9. Which enzyme-related action contributes to ambroxol’s mucolytic effects?

• Inhibition of proteases that degrade mucus
• Stimulation of lysosomal hydrolytic enzymes
• Blockade of phospholipase A2
• Activation of cyclooxygenase-2

Correct Answer: (Stimulation of lysosomal hydrolytic enzymes)

Q10. Which statement about guaifenesin pharmacology is correct?

• It primarily acts by direct proteolysis of mucins.
• It increases respiratory tract fluid via vagal reflex, improving expectoration.
• It is an inhaled mucolytic only used in hospitals.
• It irreversibly inhibits mucin gene expression.

Correct Answer: (It increases respiratory tract fluid via vagal reflex, improving expectoration.)

Q11. Which laboratory effect is most likely after high-dose NAC therapy?

• Prolonged QT interval on ECG
• Increase in serum transaminases
• Reduction in serum glutathione levels
• Increase in plasma viscosity

Correct Answer: (Increase in serum transaminases)

Q12. Which drug interaction is relevant for long-term, high-dose N-acetylcysteine?

• Inhibition of warfarin metabolism leading to bleeding
• Possible interference with nitroglycerin causing hypotension
• Enhanced effect of beta-blockers
• Decreased absorption of oral antibiotics

Correct Answer: (Possible interference with nitroglycerin causing hypotension)

Q13. Which formulation is preferred when rapid mucolytic action in lower airways is required?

• Oral sustained-release guaifenesin
• Nebulized N-acetylcysteine
• Topical throat lozenge
• Transdermal patch

Correct Answer: (Nebulized N-acetylcysteine)

Q14. Which patient group should use expectorants cautiously due to risk of aspiration?

• Young adults with seasonal allergies
• Elderly patients with impaired cough reflex
• Patients with well-controlled asthma
• Healthy athletes

Correct Answer: (Elderly patients with impaired cough reflex)

Q15. Mechanistically, bromhexine improves mucus clearance primarily by:

• Blocking histamine H1 receptors
• Increasing serous cell secretion and reducing mucous viscosity
• Acting as a beta-agonist to dilate bronchi
• Neutralizing acidic sputum

Correct Answer: (Increasing serous cell secretion and reducing mucous viscosity)

Q16. Which of the following is a mucoregulator rather than a mucolytic?

• N-acetylcysteine
• Bromhexine
• Carbocisteine
• Hypertonic saline

Correct Answer: (Carbocisteine)

Q17. In chronic bronchitis, expectorant therapy aims to:

• Completely stop mucus production
• Facilitate sputum clearance and reduce airflow obstruction
• Replace antibiotics as first-line therapy
• Suppress cough reflex permanently

Correct Answer: (Facilitate sputum clearance and reduce airflow obstruction)

Q18. Which adverse reaction is associated with inhaled NAC and hypertonic saline nebulization?

• Bronchospasm
• Nephrotoxicity
• Severe hyperglycemia
• Cardiac ischemia

Correct Answer: (Bronchospasm)

Q19. Which expectorant is known to have weak local anesthetic properties that may reduce cough reflex?

• Ambroxol
• Guaifenesin
• N-acetylcysteine
• Carbocisteine

Correct Answer: (Ambroxol)

Q20. Which pharmacokinetic property is true for guaifenesin?

• Extensive hepatic first-pass metabolism with short half-life
• Primarily renally excreted unchanged with long half-life
• Highly protein bound and accumulates in fat
• Not absorbed orally; only effective by inhalation

Correct Answer: (Extensive hepatic first-pass metabolism with short half-life)

Q21. Which laboratory test should be monitored during prolonged high-dose carbocisteine therapy?

• Serum creatinine only
• Liver function tests
• Serum potassium exclusively
• Coagulation profile only

Correct Answer: (Liver function tests)

Q22. Which expectorant mechanism involves altering mucus viscoelasticity by breaking peptide or carbohydrate cross-links?

• Secretomotor action
• Mucokinetic stimulation
• Proteolytic or glycosidic cleavage (mucolytic)
• Anticholinergic blockade

Correct Answer: (Proteolytic or glycosidic cleavage (mucolytic))

Q23. In cystic fibrosis management, which expectorant strategy is commonly used?

• Oral guaifenesin alone
• Nebulized hypertonic saline and dornase alfa to reduce sputum viscosity
• Systemic steroids as primary expectorants
• Long-term high-dose aspirin

Correct Answer: (Nebulized hypertonic saline and dornase alfa to reduce sputum viscosity)

Q24. Which of the following is NOT an expected pharmacological effect of ambroxol?

• Enhancement of ciliary motility
• Stimulation of surfactant production
• Direct bactericidal activity against Pseudomonas
• Promotion of lysosomal enzyme release

Correct Answer: (Direct bactericidal activity against Pseudomonas)

Q25. Which contraindication is most relevant for mucolytic nebulization?

• Active hemoptysis
• Well-controlled hypertension
• Migraine headaches
• History of seasonal allergies

Correct Answer: (Active hemoptysis)

Q26. Which statement about carbocisteine (carbocysteine) is correct?

• It is an expectorant that increases sialomucin production to thin secretions.
• It irreversibly inhibits mucin genes.
• It is primarily used as an antitussive to suppress dry cough.
• It is a systemic steroid analogue.

Correct Answer: (It is an expectorant that increases sialomucin production to thin secretions.)

Q27. Which monitoring is important when using expectorants in patients with peptic ulcer disease?

• No monitoring is required
• Watch for worsening reflux or gastric irritation with oral expectorants
• Monitor pulmonary function only
• Monitor blood glucose strictly

Correct Answer: (Watch for worsening reflux or gastric irritation with oral expectorants)

Q28. Which expectorant is derived from cough syrup formulations and often combined with decongestants?

• N-acetylcysteine
• Guaifenesin
• Ambroxol
• Bromhexine

Correct Answer: (Guaifenesin)

Q29. The primary pharmacodynamic goal when prescribing an expectorant for COPD with chronic sputum is to:

• Completely dry up airway secretions
• Improve mucus clearance and reduce infection risk
• Replace bronchodilators entirely
• Induce long-term immunosuppression

Correct Answer: (Improve mucus clearance and reduce infection risk)

Q30. Which precaution is appropriate when combining mucolytics with inhaled bronchodilators?

• Bronchodilator should be given after mucolytic to prevent bronchospasm
• Administer bronchodilator prior to mucolytic to reduce risk of bronchospasm
• They are always contraindicated together
• No sequencing or monitoring is necessary

Correct Answer: (Administer bronchodilator prior to mucolytic to reduce risk of bronchospasm)

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com