Indirect acting agents – Pseudoephedrine MCQs With Answer

Introduction: Indirect acting agents such as pseudoephedrine are essential topics in B. Pharm pharmacology, focusing on sympathomimetics that primarily release noradrenaline to produce vasoconstriction and nasal decongestion. This introduction covers mechanism of action, pharmacokinetics, therapeutic uses, adverse effects, drug interactions, contraindications, and regulatory concerns relevant to pharmacy practice. Understanding pseudoephedrine’s receptor activity, clinical dosing, metabolism, and safety profile prepares students for safe dispensing and patient counseling. Keywords: Indirect acting agents, Pseudoephedrine, MCQs, B. Pharm, pharmacology, decongestant, sympathomimetic, mechanism of action, adverse effects, drug interactions. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which best describes the primary mechanism of action of pseudoephedrine?

• Direct agonist at alpha-1 receptors only
• Selective beta-2 receptor agonist
• Indirect release of noradrenaline from presynaptic terminals
• Inhibition of acetylcholinesterase

Correct Answer: Indirect release of noradrenaline from presynaptic terminals

Q2. Pseudoephedrine is classified pharmacologically as which type of agent?

• Direct sympathomimetic
• Indirect sympathomimetic
• Muscarinic antagonist
• Central alpha-2 agonist

Correct Answer: Indirect sympathomimetic

Q3. Compared to phenylephrine, pseudoephedrine’s nasal decongestant effect is primarily due to:

• Stronger direct alpha-1 agonism
• Higher oral bioavailability and indirect NE release
• Significant beta-2 bronchodilation
• Antihistaminic activity

Correct Answer: Higher oral bioavailability and indirect NE release

Q4. Which statement about pseudoephedrine’s stereochemistry is correct?

• It has no chiral centers and is achiral
• It exists as enantiomers with differing pharmacologic potency
• Only the R-enantiomer is inactive
• It is a racemic mixture of three stereoisomers

Correct Answer: It exists as enantiomers with differing pharmacologic potency

Q5. The most common therapeutic use of pseudoephedrine is:

• Antitussive for chronic cough
• Nasal decongestion in upper respiratory tract infections
• First-line antihypertensive agent
• Long-term asthma controller

Correct Answer: Nasal decongestion in upper respiratory tract infections

Q6. Which adverse effect is most commonly associated with pseudoephedrine?

• Excessive salivation
• Hypotension
• Insomnia and nervousness
• Severe bronchospasm

Correct Answer: Insomnia and nervousness

Q7. Which patient condition is a relative contraindication to pseudoephedrine use?

• Controlled hypothyroidism
• Benign prostatic hyperplasia with urinary retention
• Mild seasonal allergic rhinitis
• Controlled type 2 diabetes

Correct Answer: Benign prostatic hyperplasia with urinary retention

Q8. Pseudoephedrine can increase blood pressure primarily via:

• Inhibition of nitric oxide synthesis
• Peripheral vasoconstriction due to alpha-adrenergic stimulation
• Direct stimulation of baroreceptors
• Reduction of plasma volume

Correct Answer: Peripheral vasoconstriction due to alpha-adrenergic stimulation

Q9. Which drug interaction with pseudoephedrine is potentially dangerous?

• Concurrent use with beta-blockers causing additive bronchodilation
• Concurrent use with MAO inhibitors causing hypertensive crisis
• Concurrent use with antibiotics increasing anticoagulation
• Concurrent use with antacids reducing absorption

Correct Answer: Concurrent use with MAO inhibitors causing hypertensive crisis

Q10. Pseudoephedrine is metabolized primarily by which process?

• Hepatic cytochrome P450-mediated oxidation with extensive metabolism
• Extensive first-pass glucuronidation
• Minimal metabolism with renal excretion of unchanged drug
• Rapid demethylation to amphetamine

Correct Answer: Minimal metabolism with renal excretion of unchanged drug

Q11. Which formulation difference affects pseudoephedrine’s pharmacokinetics?

• Immediate-release vs sustained-release affecting duration of action
• Liquid vs tablet causing different receptor selectivity
• Enema vs oral affecting hepatic clearance
• Topical nasal spray leading to systemic stimulant effects

Correct Answer: Immediate-release vs sustained-release affecting duration of action

Q12. In pediatric dosing considerations, pseudoephedrine use is:

• Recommended for infants under 2 years for nasal congestion
• Not recommended for young children due to safety concerns
• First-line therapy for pediatric sinusitis beyond 1 month
• Optimal for routine use in neonates

Correct Answer: Not recommended for young children due to safety concerns

Q13. Which physiological effect is least likely with therapeutic doses of pseudoephedrine?

• Increased heart rate
• Bronchodilation via beta-2 stimulation
• Urinary retention due to alpha stimulation
• Central sedation

Correct Answer: Central sedation

Q14. Which laboratory value or monitoring might be relevant when a hypertensive patient takes pseudoephedrine?

• Regular liver function tests
• Frequent blood glucose monitoring
• Regular blood pressure monitoring
• Serum potassium levels

Correct Answer: Regular blood pressure monitoring

Q15. The main reason for legal restrictions on pseudoephedrine sales in many countries is:

• High potential for causing liver failure
• Its use as a precursor in illicit methamphetamine synthesis
• Excessive prescription costs
• Widespread fatal allergic reactions

Correct Answer: Its use as a precursor in illicit methamphetamine synthesis

Q16. Which descriptor best fits pseudoephedrine’s onset and duration when given orally in immediate-release form?

• Onset within 15–30 minutes, duration about 4–6 hours
• Onset after 12 hours, duration 72 hours
• Instantaneous onset with effects lasting 1 hour
• Onset after 24 hours with cumulative effect

Correct Answer: Onset within 15–30 minutes, duration about 4–6 hours

Q17. Which receptor profile explains pseudoephedrine’s mild bronchodilator effect?

• Strong direct beta-2 agonism only
• Indirect increase in circulating catecholamines stimulating beta receptors
• Muscarinic receptor blockade
• Serotonin receptor antagonism

Correct Answer: Indirect increase in circulating catecholamines stimulating beta receptors

Q18. Pseudoephedrine’s ability to cross the blood–brain barrier is:

• Extremely high, producing marked central effects at low doses
• Moderate, accounting for some CNS stimulation such as insomnia
• Nonexistent; it has no central effects
• Dependent on co-administration with antihistamines

Correct Answer: Moderate, accounting for some CNS stimulation such as insomnia

Q19. A patient on monoamine oxidase inhibitors (MAOIs) presents seeking pseudoephedrine for nasal congestion. The safest advice is:

• Use standard doses of pseudoephedrine as needed
• Avoid pseudoephedrine due to risk of hypertensive crisis
• Combine with aspirin to prevent interactions
• Use it only with added antihistamine

Correct Answer: Avoid pseudoephedrine due to risk of hypertensive crisis

Q20. Which is a common combination in over-the-counter cold remedies including pseudoephedrine?

• Pseudoephedrine with MAO inhibitors
• Pseudoephedrine with antihistamines and analgesics
• Pseudoephedrine with ACE inhibitors
• Pseudoephedrine with high-dose corticosteroids

Correct Answer: Pseudoephedrine with antihistamines and analgesics

Q21. The alpha-adrenergic mediated effect of pseudoephedrine primarily causes:

• Bronchoconstriction
• Vasodilation of nasal mucosa
• Vasoconstriction of nasal mucosal blood vessels
• Increased gastrointestinal motility

Correct Answer: Vasoconstriction of nasal mucosal blood vessels

Q22. Which pharmacokinetic parameter is most influenced by urinary pH for pseudoephedrine?

• Volume of distribution
• Renal excretion and clearance
• Hepatic extraction ratio
• Protein binding

Correct Answer: Renal excretion and clearance

Q23. In case of pseudoephedrine overdose, which is an expected clinical feature?

• Profound sedation and respiratory depression
• Severe hypoglycemia
• Agitation, tachycardia, hypertension, and possible seizures
• Marked bradycardia and hypotension

Correct Answer: Agitation, tachycardia, hypertension, and possible seizures

Q24. Which monitoring is important when dispensing pseudoephedrine to elderly patients?

• Monitoring for urinary retention and increased blood pressure
• Frequent pregnancy tests
• Liver biopsy before treatment
• Regular pulmonary function tests

Correct Answer: Monitoring for urinary retention and increased blood pressure

Q25. Which statement about tolerance to pseudoephedrine’s effects is correct?

• No tolerance develops; effects remain constant with chronic use
• Tolerance to nasal decongestant effects may develop with prolonged use
• Tolerance only occurs for cardiovascular effects
• Tolerance results in immediate need for dose reduction

Correct Answer: Tolerance to nasal decongestant effects may develop with prolonged use

Q26. Which lab or diagnostic test is directly affected by pseudoephedrine use?

• Elevated liver enzymes due to hepatotoxicity
• False-positive urine drug screen for amphetamines
• Severe leukopenia on CBC
• Decreased serum creatinine

Correct Answer: False-positive urine drug screen for amphetamines

Q27. Pseudoephedrine exhibits which of the following pharmacodynamic properties?

• Pure dopamine agonism
• Indirect sympathomimetic action with some direct receptor effects
• Selective serotonin reuptake inhibition
• Competitive antagonism at alpha receptors

Correct Answer: Indirect sympathomimetic action with some direct receptor effects

Q28. Which adverse effect makes pseudoephedrine use cautious in patients with coronary artery disease?

• Potential to cause bradycardia and hypoperfusion
• Risk of tachycardia and increased myocardial oxygen demand
• Direct cardiac cytotoxicity causing infarction
• Induction of hyperkalemia

Correct Answer: Risk of tachycardia and increased myocardial oxygen demand

Q29. When counseling a patient, which point about pseudoephedrine should a pharmacist emphasize?

• It is safe to use with MAO inhibitors
• Do not exceed recommended dose and avoid in uncontrolled hypertension
• It cures viral infections causing the cold
• It enhances sedative effects of benzodiazepines

Correct Answer: Do not exceed recommended dose and avoid in uncontrolled hypertension

Q30. Which structural class does pseudoephedrine belong to?

• Quinolone antibiotics
• Phenethylamine sympathomimetics
• Benzodiazepines
• Sulfonylurea antidiabetics

Correct Answer: Phenethylamine sympathomimetics

Q31. Which property explains pseudoephedrine’s oral effectiveness compared to topical decongestants?

• Poor oral absorption but strong topical effect
• Reasonable oral bioavailability and systemic action
• High first-pass metabolism rendering it inactive orally
• Exclusive topical receptor selectivity

Correct Answer: Reasonable oral bioavailability and systemic action

Q32. Which change in dosing is appropriate for patients with renal impairment?

• No adjustment needed regardless of severity
• Reduce dose or extend dosing interval due to renal excretion
• Switch to intravenous administration only
• Increase dose to achieve therapeutic levels

Correct Answer: Reduce dose or extend dosing interval due to renal excretion

Q33. Which clinical scenario suggests pseudoephedrine should be avoided?

• Pregnant woman in first trimester with mild congestion
• Patient with uncontrolled hypertension and tachyarrhythmias
• Adult with seasonal allergic rhinitis and normal BP
• Intermittent use at recommended dose in healthy adult

Correct Answer: Patient with uncontrolled hypertension and tachyarrhythmias

Q34. Which of the following best differentiates ephedrine from pseudoephedrine?

• Ephedrine is purely topical; pseudoephedrine is only oral
• Ephedrine has more direct and central stimulant effects than pseudoephedrine
• Pseudoephedrine causes profound sedation compared to ephedrine
• They are pharmacologically identical with no differences

Correct Answer: Ephedrine has more direct and central stimulant effects than pseudoephedrine

Q35. Which statement about pseudoephedrine and breastfeeding is most appropriate?

• It is completely safe and recommended during lactation
• Use with caution; may reduce milk production and cause infant irritability
• It increases milk production and is helpful for lactating mothers
• It is contraindicated due to teratogenicity in infants

Correct Answer: Use with caution; may reduce milk production and cause infant irritability

Q36. Which pharmacological test would show pseudoephedrine effect on vasculature?

• Reduction in peripheral vascular resistance due to vasodilation
• Increase in nasal mucosal blood vessel diameter
• Decrease in nasal mucosal blood flow due to vasoconstriction
• Marked endothelial nitric oxide release

Correct Answer: Decrease in nasal mucosal blood flow due to vasoconstriction

Q37. Which dosing frequency is typical for sustained-release pseudoephedrine formulations?

• Every 2–3 hours
• Once daily only
• Every 12 hours
• Hourly administration

Correct Answer: Every 12 hours

Q38. Which electrolyte imbalance may alter pseudoephedrine renal clearance?

• Hypercalcemia increasing hepatic metabolism
• Alkalinization of urine reducing excretion and increasing half-life
• Hypomagnesemia increasing protein binding
• Hyperglycemia enhancing renal secretion

Correct Answer: Alkalinization of urine reducing excretion and increasing half-life

Q39. Which adverse CNS effect is associated with high doses of pseudoephedrine?

• Severe depression and somnolence
• Anxiety, agitation, and possible seizures
• Marked analgesia
• Hallucinations only in therapeutic doses

Correct Answer: Anxiety, agitation, and possible seizures

Q40. Which patient advice reduces risk of pseudoephedrine-related insomnia?

• Take the medication at bedtime for better sleep
• Take last dose earlier in the afternoon or early evening
• Double the evening dose to minimize morning symptoms
• Combine with caffeine to offset drowsiness

Correct Answer: Take last dose earlier in the afternoon or early evening

Q41. Which mechanism explains false-positive amphetamine screens after pseudoephedrine use?

• Pseudoephedrine directly binds opiate immunoassays
• Structural similarity causing cross-reactivity in immunoassays
• Pseudoephedrine enhances production of endogenous amphetamines
• It alters urine pH to mask other drugs

Correct Answer: Structural similarity causing cross-reactivity in immunoassays

Q42. What regulatory control is commonly applied to pseudoephedrine in many countries?

• Prescription-only status and sales tracking due to abuse potential
• Free over-the-counter sales without limits
• Banning use in all adults over 40
• Mandatory combination with opioids

Correct Answer: Prescription-only status and sales tracking due to abuse potential

Q43. Which patient population should use pseudoephedrine with extreme caution?

• Young healthy adults with no comorbidities
• Patients with severe coronary artery disease or uncontrolled hypertension
• Patients taking multivitamins
• Patients with seasonal allergies only

Correct Answer: Patients with severe coronary artery disease or uncontrolled hypertension

Q44. Which therapeutic advantage does pseudoephedrine have over topical nasal decongestant sprays?

• Eliminates systemic side effects completely
• Provides longer systemic relief and avoids rebound congestion from topical overuse
• Acts faster than any topical agent
• Cannot produce tolerance

Correct Answer: Provides longer systemic relief and avoids rebound congestion from topical overuse

Q45. Pseudoephedrine’s interaction with tricyclic antidepressants (TCAs) may lead to:

• Reduced sympathomimetic effects
• Enhanced pressor response and risk of hypertension
• Inhibition of TCA absorption in the gut
• Increased clearance of pseudoephedrine

Correct Answer: Enhanced pressor response and risk of hypertension

Q46. Which clinical sign would suggest pseudoephedrine misuse or overdose in a patient?

• Excessive yawning and lethargy
• Marked agitation, rapid heartbeat, and dilated pupils
• Bradycardia and miosis
• Profuse lacrimation and rhinorrhea only

Correct Answer: Marked agitation, rapid heartbeat, and dilated pupils

Q47. Which metabolic factor may reduce pseudoephedrine elimination?

• Acidic urine increasing renal ionization
• Alkaline urine reducing ionization and slowing excretion
• High hepatic enzyme induction
• Increased plasma protein binding

Correct Answer: Alkaline urine reducing ionization and slowing excretion

Q48. Which adjunct therapy is contraindicated to combine with pseudoephedrine without medical advice?

• Nonprescription antihistamines for seasonal rhinitis
• Topical saline nasal sprays
• Monoamine oxidase inhibitors prescribed for depression
• Acetaminophen for mild pain

Correct Answer: Monoamine oxidase inhibitors prescribed for depression

Q49. Which patient education point reduces risk when using pseudoephedrine?

• Do not drive or operate machinery during the day due to severe sedation
• Avoid excessive caffeine and stimulants to minimize CNS stimulation
• Always combine with an opioid for cough suppression
• Take a double dose if symptoms persist

Correct Answer: Avoid excessive caffeine and stimulants to minimize CNS stimulation

Q50. For a B. Pharm student, the most important clinical takeaway about pseudoephedrine is:

• It is harmless and requires no counseling at the pharmacy
• Understand its indirect sympathomimetic mechanism, adverse effects, interactions, and legal controls
• It is the preferred long-term therapy for hypertension
• It should be routinely prescribed with MAO inhibitors for depression

Correct Answer: Understand its indirect sympathomimetic mechanism, adverse effects, interactions, and legal controls

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