Loratadine MCQs With Answer

Loratadine MCQs With Answer

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Loratadine MCQs With Answer is a focused study set designed for B. Pharm students to master the pharmacology, clinical uses, dosing, pharmacokinetics and safety profile of loratadine, a second‑generation antihistamine. This resource emphasizes mechanism of action, active metabolite desloratadine, metabolism by CYP3A4/CYP2D6, onset and duration of effect, adverse effects, drug interactions, dose adjustments in hepatic impairment, and relevant therapeutic indications like allergic rhinitis and urticaria. The questions blend recall, application and clinical reasoning to prepare students for exams and practical therapeutics. Clear explanations and targeted practice help consolidate knowledge for safe medication use and counselling. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which class of drug does loratadine belong to?

  • First-generation H1 antihistamine
  • Second-generation H1 antihistamine
  • H2 receptor antagonist
  • Leukotriene receptor antagonist

Correct Answer: Second-generation H1 antihistamine

Q2. What is the primary mechanism of action of loratadine?

  • Muscarinic receptor blockade
  • Selective peripheral H1 receptor antagonism
  • Inhibition of prostaglandin synthesis
  • Beta-2 adrenergic agonism

Correct Answer: Selective peripheral H1 receptor antagonism

Q3. Loratadine is mainly converted in the liver to which active metabolite?

  • Fexofenadine
  • Desloratadine
  • Cetirizine
  • Loratadinone

Correct Answer: Desloratadine

Q4. Which cytochrome P450 isoenzymes are primarily involved in loratadine metabolism?

  • CYP1A2 and CYP2C19
  • CYP3A4 and CYP2D6
  • CYP2E1 and CYP2C9
  • CYP4A11 and CYP2B6

Correct Answer: CYP3A4 and CYP2D6

Q5. Typical recommended adult oral dose of loratadine for allergic rhinitis is:

  • 5 mg twice daily
  • 10 mg once daily
  • 20 mg once daily
  • 50 mg once daily

Correct Answer: 10 mg once daily

Q6. Compared with first‑generation antihistamines, loratadine is less likely to cause:

  • Anticholinergic side effects
  • Gastrointestinal bleeding
  • Central nervous system sedation
  • Renal failure

Correct Answer: Central nervous system sedation

Q7. The major route of excretion for loratadine and its metabolites is:

  • Exhaled air
  • Feces and urine
  • Sweat
  • Saliva

Correct Answer: Feces and urine

Q8. Which of the following drugs can increase loratadine plasma concentrations by inhibiting its metabolism?

  • Rifampicin
  • Ketoconazole
  • Carbamazepine
  • St. John’s wort

Correct Answer: Ketoconazole

Q9. Which pharmacokinetic property best describes desloratadine compared to loratadine?

  • Shorter half-life
  • Inactive metabolite
  • Longer elimination half-life and active H1 blockade
  • Poorer oral absorption

Correct Answer: Longer elimination half-life and active H1 blockade

Q10. Onset of action for oral loratadine is typically within:

  • 5 minutes
  • 1–3 hours
  • 24–48 hours
  • 5–7 days

Correct Answer: 1–3 hours

Q11. Which of the following is a common adverse effect associated with loratadine?

  • Severe hypotension
  • Moderate sedation in most patients
  • Headache
  • Severe antimuscarinic effects

Correct Answer: Headache

Q12. In patients with significant hepatic impairment, loratadine therapy requires:

  • No adjustment; safe at any dose
  • Use of higher doses to overcome reduced metabolism
  • Caution and possible dose reduction or alternative therapy
  • Immediate discontinuation and avoidance forever

Correct Answer: Caution and possible dose reduction or alternative therapy

Q13. Which statement about loratadine’s penetration of the blood–brain barrier is most accurate?

  • It extensively penetrates and causes marked sedation
  • It has limited penetration, resulting in minimal central effects
  • It is actively transported into the CNS via P-glycoprotein
  • It accumulates preferentially in cerebrospinal fluid

Correct Answer: It has limited penetration, resulting in minimal central effects

Q14. For which indication is loratadine commonly used?

  • Hypertension
  • Allergic rhinitis and chronic urticaria
  • Type 2 diabetes mellitus
  • Bacterial sinusitis

Correct Answer: Allergic rhinitis and chronic urticaria

Q15. Which of the following describes a clinically relevant interaction with loratadine?

  • Co‑administration with erythromycin may increase loratadine levels
  • Co‑administration with vitamin C markedly reduces loratadine efficacy
  • Loratadine significantly induces CYP3A4, reducing warfarin levels
  • Loratadine potentiates insulin activity

Correct Answer: Co‑administration with erythromycin may increase loratadine levels

Q16. Which patient population should use loratadine with extra caution or dose adjustment?

  • Young healthy adults with no comorbidity
  • Patients with severe hepatic impairment
  • Patients with well-controlled hypothyroidism
  • Individuals with mild seasonal allergies only

Correct Answer: Patients with severe hepatic impairment

Q17. The elimination half-life of desloratadine (active metabolite) is approximately:

  • 1–2 hours
  • 8–14 hours
  • 24–30 hours
  • 72–96 hours

Correct Answer: 24–30 hours

Q18. Which formulation or route is loratadine commonly available as?

  • Intravenous injection only
  • Oral tablets and syrup (oral formulations)
  • Topical cream for dermatitis only
  • Intranasal spray only

Correct Answer: Oral tablets and syrup (oral formulations)

Q19. Loratadine is considered which of the following in terms of sedation risk compared to diphenhydramine?

  • More sedating than diphenhydramine
  • Equally sedating as diphenhydramine
  • Less sedating than diphenhydramine
  • Causes paradoxical agitation in all patients

Correct Answer: Less sedating than diphenhydramine

Q20. Which statement is true regarding loratadine and pregnancy?

  • It is absolutely contraindicated in pregnancy
  • Historically considered relatively safe (category B) but use only if clearly needed
  • It is a known teratogen at therapeutic doses
  • It markedly increases risk of neural tube defects

Correct Answer: Historically considered relatively safe (category B) but use only if clearly needed

Q21. Which laboratory parameter is most likely to be affected significantly by loratadine therapy?

  • Serum potassium markedly increased
  • Prolongation of QT interval only at high concentrations or with interacting drugs
  • Marked elevation of liver enzymes in all patients
  • Severe leukopenia

Correct Answer: Prolongation of QT interval only at high concentrations or with interacting drugs

Q22. In overdose situations, which of the following symptoms may be observed with loratadine?

  • Profound cholinergic excess (salivation, miosis)
  • Tachycardia and CNS excitation or somnolence
  • Immediate respiratory arrest within minutes
  • Severe hyperglycemia

Correct Answer: Tachycardia and CNS excitation or somnolence

Q23. Which property contributes to loratadine’s minimal sedation compared to first‑generation antihistamines?

  • High lipophilicity allowing rapid CNS entry
  • Poor penetration across the blood–brain barrier and selective peripheral action
  • Potent central antimuscarinic activity
  • Strong inhibition of monoamine oxidase

Correct Answer: Poor penetration across the blood–brain barrier and selective peripheral action

Q24. For pediatric dosing, loratadine is commonly approved for children aged:

  • 6 months and older at adult dose
  • 2 years and older with age-appropriate dosing
  • 12 years and older only
  • Not approved for pediatric use

Correct Answer: 2 years and older with age-appropriate dosing

Q25. Which clinical scenario would favor choosing loratadine over a first‑generation antihistamine?

  • Patient needs rapid, deep sedation for sleep
  • Patient requires antihistamine with minimal daytime sedation for driving
  • Patient with acute bacterial infection
  • Patient with uncontrolled glaucoma needing strong antimuscarinic effects

Correct Answer: Patient requires antihistamine with minimal daytime sedation for driving

Q26. How does food intake generally affect loratadine absorption?

  • Food completely prevents absorption
  • Food modestly alters Cmax but clinical effect remains adequate
  • Food causes immediate drug inactivation
  • Food converts loratadine to an inactive metabolite

Correct Answer: Food modestly alters Cmax but clinical effect remains adequate

Q27. What is the significance of high plasma protein binding for loratadine?

  • No clinical implications at all
  • May affect distribution and displacement interactions with highly protein-bound drugs
  • Prevents hepatic metabolism entirely
  • Makes the drug excreted mainly via lungs

Correct Answer: May affect distribution and displacement interactions with highly protein-bound drugs

Q28. Which monitoring or counseling point is appropriate when dispensing loratadine?

  • Advise patients to avoid operating machinery if they feel sedated
  • Warn that loratadine cures allergic rhinitis permanently after one dose
  • No need to report any side effects ever
  • Recommend combining with alcohol to improve efficacy

Correct Answer: Advise patients to avoid operating machinery if they feel sedated

Q29. Compared to other second‑generation antihistamines, loratadine’s clinical duration of action is generally:

  • Shorter, requiring dosing every 4–6 hours
  • Similar, allowing once‑daily dosing
  • So long it requires weekly dosing
  • Unpredictable and extremely short-lived

Correct Answer: Similar, allowing once‑daily dosing

Q30. Which of the following is a correct counseling point for pregnant patients asking about loratadine?

  • It is universally recommended for all pregnant women with allergies
  • Discuss potential benefits and risks; use only if necessary after consultation
  • It is contraindicated due to proven teratogenicity
  • It must be taken at double the usual dose during pregnancy

Correct Answer: Discuss potential benefits and risks; use only if necessary after consultation

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