Promethazine hydrochloride MCQs With Answer

Promethazine hydrochloride MCQs With Answer

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Promethazine hydrochloride MCQs With Answer

Promethazine hydrochloride is a first‑generation H1 antihistamine with prominent sedative, anticholinergic and antiemetic properties widely studied in pharmacology, therapeutics and pharmaceutical analysis. This topic covers mechanism of action, pharmacokinetics, dosage forms, stability, adverse effects, contraindications (including pediatric risks), drug interactions, and analytical assays relevant to B. Pharm students. Understanding promethazine’s clinical uses, safety profile, formulation considerations, and laboratory testing (e.g., HPLC assays, impurity control) is essential for safe dispensing and rational therapeutics. Clear knowledge of dose limits, parenteral precautions and monitoring improves patient outcomes. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which statement best describes the primary pharmacological action of promethazine hydrochloride?

  • Selective H2 receptor agonist at gastric parietal cells
  • First‑generation H1 receptor antagonist with anticholinergic and sedative effects
  • Selective dopamine D2 receptor antagonist used as a primary antipsychotic
  • Peripheral mu‑opioid receptor agonist for analgesia

Correct Answer: First‑generation H1 receptor antagonist with anticholinergic and sedative effects

Q2. Promethazine’s antiemetic effect is primarily mediated through blockade of which sites?

  • Peripheral 5‑HT3 receptors in the gut only
  • H1 and muscarinic receptors in the vestibular system and chemoreceptor trigger zone
  • Central opioid receptors in the medulla
  • Selective blockade of nicotinic receptors in the brainstem

Correct Answer: H1 and muscarinic receptors in the vestibular system and chemoreceptor trigger zone

Q3. Which formulation is commonly available for promethazine hydrochloride for rapid parenteral use?

  • Intravenous bolus concentrated solution recommended for children under 2
  • Intramuscular injection formulation designed for deep IM administration
  • Transdermal patch for sustained antihistamine delivery
  • Inhalation nebulizer solution for bronchospasm

Correct Answer: Intramuscular injection formulation designed for deep IM administration

Q4. A major safety contraindication for promethazine in pediatrics is:

  • Use in neonates only if premedicated with benzodiazepines
  • Use in children younger than 2 years due to risk of severe respiratory depression
  • Use only in children with asthma because it relieves bronchospasm
  • There are no pediatric contraindications

Correct Answer: Use in children younger than 2 years due to risk of severe respiratory depression

Q5. Which hepatic property correctly applies to promethazine hydrochloride?

  • Excreted unchanged predominantly in bile without hepatic metabolism
  • Undergoes extensive hepatic metabolism and first‑pass effect after oral dosing
  • Is not metabolized and has complete oral bioavailability
  • Is exclusively metabolized by renal tubular enzymes

Correct Answer: Undergoes extensive hepatic metabolism and first‑pass effect after oral dosing

Q6. The most commonly reported CNS adverse effect of promethazine is:

  • Heightened alertness and insomnia
  • Severe choreiform movements in most patients
  • Marked sedation and drowsiness
  • Enhanced psychomotor performance

Correct Answer: Marked sedation and drowsiness

Q7. Which of the following drug interactions with promethazine is clinically significant?

  • Co‑administration with CNS depressants (e.g., opioids, benzodiazepines) increasing sedation and respiratory depression
  • Promethazine neutralizes the effect of all antibiotics
  • Concurrent use with vitamin C reduces promethazine clearance
  • Promethazine prevents absorption of orally administered insulin

Correct Answer: Co‑administration with CNS depressants (e.g., opioids, benzodiazepines) increasing sedation and respiratory depression

Q8. Which adverse effect profile reflects promethazine’s anticholinergic activity?

  • Diarrhea, diaphoresis, and miosis
  • Dry mouth, blurred vision, urinary retention, and constipation
  • Excessive salivation and bronchorrhea
  • Hypersalivation and lacrimation

Correct Answer: Dry mouth, blurred vision, urinary retention, and constipation

Q9. Regarding promethazine dosing, a commonly recommended adult oral regimen is:

  • 12.5–25 mg every 4–6 hours as needed (with typical daily limits)
  • Single dose of 500 mg daily to control allergy
  • 1–2 mg once weekly for long‑term maintenance
  • Continuous intravenous infusion at 100 mg/hr

Correct Answer: 12.5–25 mg every 4–6 hours as needed (with typical daily limits)

Q10. Which laboratory or analytical technique is commonly used for quantitative assay of promethazine in pharmaceuticals?

  • Thin layer chromatography only, with no HPLC methods available
  • High‑performance liquid chromatography (HPLC) with UV detection
  • Nuclear magnetic resonance as the routine QC release test for tablets
  • Flameless atomic absorption spectroscopy

Correct Answer: High‑performance liquid chromatography (HPLC) with UV detection

Q11. Which statement about promethazine and pregnancy is correct for counseling?

  • It is absolutely contraindicated in all trimesters with no exceptions
  • Risk–benefit evaluation is required; it has been used but requires caution, especially in late pregnancy
  • It is a proven folate supplement safe in pregnancy
  • It causes certain teratogenic effects in every exposed fetus

Correct Answer: Risk–benefit evaluation is required; it has been used but requires caution, especially in late pregnancy

Q12. The onset and duration characteristics of oral promethazine are best described as:

  • Rapid onset within 5 minutes and duration of 2–3 hours
  • Delayed onset (30–60 minutes) with effects lasting several hours due to distribution and hepatic metabolism
  • Onset only after 24 hours with cumulative weekly effects
  • Immediate absorption and permanent receptor blockade

Correct Answer: Delayed onset (30–60 minutes) with effects lasting several hours due to distribution and hepatic metabolism

Q13. In the event of acute promethazine overdose, the first‑line approach is:

  • Administer flumazenil immediately
  • Provide supportive care including airway management, activated charcoal if appropriate, and symptomatic treatment
  • Give naloxone as the only antidote
  • Rapid extracorporeal dialysis as the sole therapy

Correct Answer: Provide supportive care including airway management, activated charcoal if appropriate, and symptomatic treatment

Q14. Which storage recommendation is appropriate for promethazine hydrochloride oral formulations?

  • Store frozen at −20 °C to preserve potency
  • Store protected from light and at controlled room temperature (generally below 25 °C)
  • Store in direct sunlight to enhance stability
  • Store in strong acidic solution only

Correct Answer: Store protected from light and at controlled room temperature (generally below 25 °C)

Q15. Which warning is particularly important for promethazine use in elderly patients?

  • Increased risk of sedation, cognitive impairment, anticholinergic effects and falls
  • Guaranteed improvement in memory and cognition
  • No dose adjustment or monitoring is ever required
  • Promethazine acts as a stimulant in the elderly

Correct Answer: Increased risk of sedation, cognitive impairment, anticholinergic effects and falls

Q16. Which mechanism explains promethazine‑induced orthostatic hypotension?

  • Stimulation of alpha‑1 adrenergic receptors increasing vascular tone
  • Blockade of alpha‑adrenergic receptors leading to vasodilation
  • Enhancement of sympathetic outflow causing hypertension
  • Direct inotropic cardiac stimulation

Correct Answer: Blockade of alpha‑adrenergic receptors leading to vasodilation

Q17. Which impurity or stability test is a routine part of quality control for promethazine tablets?

  • Determination of tablet radioactivity as the primary assay
  • Assay of active ingredient by HPLC and related‑substance (impurity) evaluation
  • Testing for photosynthetic activity under light
  • Measurement of electrical conductivity of powdered tablets

Correct Answer: Assay of active ingredient by HPLC and related‑substance (impurity) evaluation

Q18. Promethazine’s chemical class is best described as:

  • A benzodiazepine derivative
  • A phenothiazine derivative with antihistaminic properties
  • A selective serotonin reuptake inhibitor
  • An opioid alkaloid

Correct Answer: A phenothiazine derivative with antihistaminic properties

Q19. Which monitoring parameter should be emphasized when a patient takes promethazine with other QT‑prolonging drugs?

  • Regular measurement of serum potassium and ECG monitoring for QT prolongation risk
  • No monitoring needed since promethazine shortens QT interval
  • Weekly MRI scans
  • Daily platelet counts only

Correct Answer: Regular measurement of serum potassium and ECG monitoring for QT prolongation risk

Q20. During formulation development for an oral promethazine syrup, which excipient consideration is most important?

  • Avoid preservatives because promethazine is sterile on manufacture
  • Ensure appropriate pH, preservative system and taste‑masking to maintain stability and palatability
  • Use volatile solvents to improve flavor
  • Formulate only as an enteric coated pellet to bypass stomach

Correct Answer: Ensure appropriate pH, preservative system and taste‑masking to maintain stability and palatability

Q21. Which statement about promethazine and MAO inhibitors is correct?

  • MAO inhibitors have no interaction with promethazine
  • Co‑administration may potentiate anticholinergic and sedative effects and requires caution
  • MAO inhibitors neutralize promethazine making it ineffective
  • Promethazine reverses MAO inhibitor effects completely

Correct Answer: Co‑administration may potentiate anticholinergic and sedative effects and requires caution

Q22. Which adverse neurologic reaction can occur with promethazine, particularly with higher doses?

  • Extrapyramidal symptoms and dystonic reactions
  • Guaranteed improvement of Parkinsonian tremor
  • Permanent enhancement of reflexes
  • Selective neurogenesis in the hippocampus

Correct Answer: Extrapyramidal symptoms and dystonic reactions

Q23. What is an appropriate counseling point for patients starting promethazine tablets?

  • Expect increased alertness; it will improve driving ability
  • Avoid alcohol and operating machinery due to sedation and additive CNS depression
  • Take extra doses if you feel drowsy to overcome sedation
  • It is safe to combine with stimulants without consultation

Correct Answer: Avoid alcohol and operating machinery due to sedation and additive CNS depression

Q24. In a stability study, which condition would most likely accelerate promethazine degradation?

  • Storage at recommended room temperature in dark packaging
  • Exposure to high temperature, humidity and light
  • Storage under nitrogen and dry conditions
  • Refrigeration at 4 °C in amber bottles

Correct Answer: Exposure to high temperature, humidity and light

Q25. Which manufacturing quality attribute is essential for promethazine tablets to ensure dose uniformity?

  • Random weight variation without control
  • Tight control of content uniformity and tablet weight during compression
  • Elimination of all binders to enhance disintegration only
  • Use of non‑validated coating colors only for aesthetics

Correct Answer: Tight control of content uniformity and tablet weight during compression

Q26. Which statement about promethazine and breastfeeding is most appropriate?

  • It is safe without any monitoring as it does not pass into breast milk
  • Caution advised; promethazine is excreted in breast milk and may cause sedation in the infant
  • Promotion of lactation is a known effect of promethazine
  • It enhances milk production and is recommended to increase supply

Correct Answer: Caution advised; promethazine is excreted in breast milk and may cause sedation in the infant

Q27. For analytic method validation of promethazine HPLC assay, which parameter is NOT typically evaluated?

  • Specificity/selectivity
  • Linearity, accuracy and precision
  • Limit of detection and quantitation
  • Color of the instrument housing

Correct Answer: Color of the instrument housing

Q28. Which precaution is important when administering promethazine by the intravenous route?

  • Rapid IV bolus is preferred to avoid sedation
  • IV administration carries risk of severe tissue injury and should be given cautiously, diluted and slowly or avoided in children
  • It is always administered undiluted at high concentration to reduce volume
  • IV promethazine prevents thrombosis reliably

Correct Answer: IV administration carries risk of severe tissue injury and should be given cautiously, diluted and slowly or avoided in children

Q29. Which statement best describes promethazine’s effect on seizure threshold?

  • Promethazine raises the seizure threshold and prevents seizures
  • It may lower the seizure threshold and should be used with caution in patients with epilepsy
  • It has no CNS effects and is safe in all seizure disorders
  • It cures epilepsy when combined with antihistamines

Correct Answer: It may lower the seizure threshold and should be used with caution in patients with epilepsy

Q30. When performing a dose conversion from oral to IM promethazine in a clinical scenario, which principle is most appropriate?

  • Assume IM bioavailability may differ and use clinical judgment; IM often provides more rapid onset and may require dose adjustment
  • Use identical dosing with no consideration of route or bioavailability
  • Always double the oral dose when switching to IM
  • Convert to IM only by halving the tablet and injecting it subcutaneously

Correct Answer: Assume IM bioavailability may differ and use clinical judgment; IM often provides more rapid onset and may require dose adjustment

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