Introduction: Chlorpheniramine maleate is a commonly used first‑generation H1 antihistamine important in B.Pharm curriculum for its pharmacology, mechanism of action, pharmacokinetics, adverse effects and drug interactions. This topic covers alkylamine chemistry, maleate salt formulation, central nervous system penetration, anticholinergic effects, clinical uses such as allergic rhinitis, urticaria and symptomatic cold relief, and safety considerations in special populations. Understanding dosing, formulations, monitoring parameters and interaction risks is essential for safe therapeutic use and patient counseling. These MCQs focus on core concepts, clinical application, and exam‑relevant details to strengthen your pharmacology and therapeutics knowledge. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which pharmacological class does chlorpheniramine maleate belong to?
- First-generation H1 antihistamine
- Second-generation H1 antihistamine
- B2 agonist bronchodilator
- Cyclooxygenase inhibitor
Correct Answer: First-generation H1 antihistamine
Q2. What is the primary mechanism of action of chlorpheniramine?
- Competitive antagonism at H1 histamine receptors
- Inhibition of cyclooxygenase enzymes
- Beta-adrenergic receptor agonism
- Muscarinic receptor agonism
Correct Answer: Competitive antagonism at H1 histamine receptors
Q3. To which chemical subclass of antihistamines does chlorpheniramine belong?
- Alkylamine
- Ethanolamine
- Piperazine
- Tricyclic antihistamine
Correct Answer: Alkylamine
Q4. Why is chlorpheniramine formulated as the maleate salt?
- To increase water solubility and stability
- To make it more lipophilic for CNS targeting
- To reduce bitter taste only
- To convert it into a prodrug
Correct Answer: To increase water solubility and stability
Q5. Which of the following are primary clinical indications for chlorpheniramine?
- Allergic rhinitis, urticaria and pruritus
- Chronic obstructive pulmonary disease maintenance
- Acute myocardial infarction
- Bacterial sinusitis
Correct Answer: Allergic rhinitis, urticaria and pruritus
Q6. Chlorpheniramine is NOT recommended as monotherapy for which condition?
- Bronchial asthma maintenance
- Allergic rhinitis symptom relief
- Urticaria control
- Pruritus relief
Correct Answer: Bronchial asthma maintenance
Q7. Which central nervous system effect is commonly associated with chlorpheniramine?
- Sedation and drowsiness
- Profound stimulation and insomnia
- Analgesia
- Improved cognitive performance
Correct Answer: Sedation and drowsiness
Q8. Which anticholinergic adverse effects can chlorpheniramine produce?
- Dry mouth, blurred vision, urinary retention
- Excessive salivation and lacrimation
- Profuse sweating and rhinorrhea
- Bradycardia and increased gastric motility
Correct Answer: Dry mouth, blurred vision, urinary retention
Q9. Chlorpheniramine typically begins to relieve allergic symptoms within what time frame after oral dosing?
- Within 30–60 minutes
- After 24 hours
- Only after repeated daily dosing for a week
- Within 5 minutes
Correct Answer: Within 30–60 minutes
Q10. What is the usual clinical duration of action for chlorpheniramine, requiring repeat dosing every few hours?
- Approximately 4–6 hours
- Approximately 24–48 hours
- Less than 30 minutes
- More than 72 hours
Correct Answer: Approximately 4–6 hours
Q11. How is chlorpheniramine primarily eliminated from the body?
- Hepatic metabolism followed by renal excretion
- Exclusively unchanged via feces
- Exhalation as unmetabolized drug
- Direct biliary excretion without metabolism
Correct Answer: Hepatic metabolism followed by renal excretion
Q12. What is the FDA pregnancy category most often assigned to chlorpheniramine?
- Category C
- Category A
- Category X
- Category B
Correct Answer: Category C
Q13. Which paradoxical reaction may occur in children after chlorpheniramine administration?
- Hyperexcitability or agitation
- Prolonged sedation only
- Enhanced appetite and weight gain
- Marked hypertension
Correct Answer: Hyperexcitability or agitation
Q14. Co-administration of chlorpheniramine with alcohol most likely causes:
- Additive central nervous system depression
- Reduced antihistaminic effect
- Complete antagonism of alcohol effects
- Improved alertness
Correct Answer: Additive central nervous system depression
Q15. In which of the following conditions is chlorpheniramine use relatively contraindicated due to anticholinergic effects?
- Narrow‑angle glaucoma
- Hypothyroidism without symptoms
- Closed nasal septum only
- Mild seasonal allergies in adults
Correct Answer: Narrow‑angle glaucoma
Q16. Which adverse effect is most commonly reported and clinically significant with chlorpheniramine?
- Drowsiness impairing daily activities
- Severe hepatotoxicity in most patients
- Ototoxicity with tinnitus as the rule
- Profound neutropenia
Correct Answer: Drowsiness impairing daily activities
Q17. Why is chlorpheniramine classified as a first‑generation antihistamine?
- It crosses the blood–brain barrier causing CNS effects
- It selectively avoids CNS penetration
- It is administered only by inhalation
- It has no anticholinergic properties
Correct Answer: It crosses the blood–brain barrier causing CNS effects
Q18. Which formulations of chlorpheniramine are commonly available?
- Oral tablets, syrups and parenteral injections
- Inhaler aerosols only
- Transdermal patches only
- Intranasal sprays only
Correct Answer: Oral tablets, syrups and parenteral injections
Q19. Which statement about the stereochemistry of chlorpheniramine is correct?
- Dexchlorpheniramine (dextro isomer) is the more active enantiomer
- The levo isomer is exclusively responsible for toxicity
- It exists as a racemic mixture where neither is active
- It has no stereoisomers
Correct Answer: Dexchlorpheniramine (dextro isomer) is the more active enantiomer
Q20. Blocking H1 receptors with chlorpheniramine reduces which histamine-mediated effects?
- Vasodilation and increased vascular permeability
- Gastric acid secretion via H2 receptors
- Platelet aggregation
- Insulin release from pancreas
Correct Answer: Vasodilation and increased vascular permeability
Q21. Chlorpheniramine is commonly combined in OTC cold products with which class of drug?
- Alpha‑adrenergic decongestants (e.g., pseudoephedrine)
- ACE inhibitors
- Insulin preparations
- Oral antibiotics
Correct Answer: Alpha‑adrenergic decongestants (e.g., pseudoephedrine)
Q22. Which findings are typical in chlorpheniramine overdose?
- Anticholinergic signs, severe sedation or paradoxical CNS excitation, and possible seizures
- Profound hypoglycemia as the primary feature
- Delayed bleeding due to platelet dysfunction
- Immediate renal failure in most cases
Correct Answer: Anticholinergic signs, severe sedation or paradoxical CNS excitation, and possible seizures
Q23. Which parameters should clinicians monitor during chlorpheniramine therapy?
- Degree of sedation, anticholinergic symptoms and urinary retention
- Daily liver biopsy results
- Frequent coagulation profile testing
- Serum electrolyte levels hourly
Correct Answer: Degree of sedation, anticholinergic symptoms and urinary retention
Q24. Routine laboratory monitoring for chlorpheniramine therapy is generally:
- Not required in otherwise healthy patients
- Mandatory weekly liver enzyme testing for all patients
- Required daily serum drug concentration measurements
- Necessary for routine platelet counts every dose
Correct Answer: Not required in otherwise healthy patients
Q25. Concurrent use of monoamine oxidase (MAO) inhibitors with chlorpheniramine may cause:
- Prolonged and intensified anticholinergic and CNS depressant effects
- Complete neutralization of both drugs
- Guaranteed therapeutic synergy without risk
- Immediate reversal of antihistamine action
Correct Answer: Prolonged and intensified anticholinergic and CNS depressant effects
Q26. Chlorpheniramine has minimal activity at which histamine receptor subtype?
- H2 receptors (minimal effect)
- H1 receptors (no effect)
- H3 receptors (primary target)
- H4 receptors (primary target)
Correct Answer: H2 receptors (minimal effect)
Q27. Which upper respiratory symptom is reduced mainly through anticholinergic drying rather than H1 blockade?
- Rhinorrhea (nasal discharge)
- Nasal congestion from vasodilation
- Bronchospasm relief
- Fever reduction
Correct Answer: Rhinorrhea (nasal discharge)
Q28. Recommended storage conditions for chlorpheniramine preparations are generally:
- Store at room temperature, protected from light and moisture
- Keep frozen at all times
- Store under direct sunlight
- Require storage under nitrogen in a glove box
Correct Answer: Store at room temperature, protected from light and moisture
Q29. Which population requires special caution or avoidance of chlorpheniramine use?
- Newborns and premature infants
- Healthy young adults with no comorbidity
- Adults with seasonal pollen allergy only
- Patients with well‑controlled hypothyroidism without symptoms
Correct Answer: Newborns and premature infants
Q30. How is chlorpheniramine best described for exam answers in pharmacology?
- An oral first‑generation H1 antihistamine (alkylamine) with anticholinergic and sedative properties
- A selective H2 blocker used primarily for peptic ulcer disease
- An inhaled corticosteroid for chronic asthma
- A peripherally selective second‑generation antihistamine with no sedation
Correct Answer: An oral first‑generation H1 antihistamine (alkylamine) with anticholinergic and sedative properties
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.
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