Phenidamine tartrate MCQs With Answer

Phenidamine tartrate MCQs With Answer

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Phenidamine tartrate MCQs With Answer

Phenidamine tartrate is a first‑generation H1 antihistamine important in B.Pharm pharmacology, medicinal chemistry and therapeutics. This compound exhibits H1 receptor antagonism (inverse agonism), central nervous system penetration, anticholinergic effects and variable pharmacokinetics due to hepatic metabolism and renal excretion. Understanding its mechanism of action, therapeutic uses (allergic rhinitis, urticaria), adverse effects (sedation, dry mouth), drug interactions, formulation as a tartrate salt and principles of assay and stability is essential for pharmacy students. These MCQs emphasize clinical relevance, dosage considerations, contraindications and overdose management to build competence in drug therapy and safe dispensing. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the primary pharmacological action of phenidamine tartrate?

  • Beta‑adrenergic receptor agonist
  • H1 receptor inverse agonist
  • H2 receptor blocker
  • Cyclooxygenase inhibitor

Correct Answer: H1 receptor inverse agonist

Q2. Which clinical indication is most appropriate for phenidamine tartrate?

  • Acute bacterial infection
  • Allergic rhinitis and urticaria
  • Hypertension control
  • Anticoagulation therapy

Correct Answer: Allergic rhinitis and urticaria

Q3. Which adverse effects are most commonly associated with phenidamine tartrate?

  • Hypoglycemia and weight gain
  • Renal failure and hematuria
  • Sedation and anticholinergic effects
  • Severe hyperkalemia

Correct Answer: Sedation and anticholinergic effects

Q4. A major contraindication for first‑generation antihistamines like phenidamine is:

  • Type 2 diabetes mellitus
  • Narrow‑angle glaucoma
  • Hyperthyroidism without symptoms
  • Iron deficiency anemia

Correct Answer: Narrow‑angle glaucoma

Q5. Which drug interaction is most clinically relevant with phenidamine tartrate?

  • Reduced levothyroxine efficacy
  • Additive CNS depression with alcohol and benzodiazepines
  • Enhanced effect of metformin
  • Inactivation by proton pump inhibitors

Correct Answer: Additive CNS depression with alcohol and benzodiazepines

Q6. The primary route of elimination for phenidamine after hepatic metabolism is:

  • Fecal excretion unchanged
  • Renal excretion of metabolites
  • Exhalation as volatile metabolites
  • Percutaneous loss through sweat

Correct Answer: Renal excretion of metabolites

Q7. The tartrate in phenidamine tartrate primarily serves to:

  • Convert the drug into a prodrug
  • Reduce receptor affinity
  • Improve water solubility and stability as a salt
  • Provide additional antihistaminic activity

Correct Answer: Improve water solubility and stability as a salt

Q8. The typical onset of action for orally administered phenidamine is best described as:

  • Delayed onset (24–48 hours)
  • Rapid onset (within 30 minutes)
  • Onset only after chronic administration
  • No systemic absorption, local action only

Correct Answer: Rapid onset (within 30 minutes)

Q9. Phenidamine shows preferential binding to which receptor subtype?

  • H2 receptors in the stomach
  • H1 receptors in peripheral and central tissues
  • Beta‑2 adrenergic receptors
  • Mitochondrial receptors

Correct Answer: H1 receptors in peripheral and central tissues

Q10. Which statement about the role of phenidamine in asthma is correct?

  • It is a first‑line bronchodilator for acute asthma
  • It effectively reverses bronchospasm in status asthmaticus
  • It may relieve allergic symptoms but is not effective as primary bronchospasm therapy
  • It acts as a leukotriene receptor antagonist

Correct Answer: It may relieve allergic symptoms but is not effective as primary bronchospasm therapy

Q11. Which anticholinergic symptom is commonly seen with phenidamine use?

  • Diarrhea and increased salivation
  • Excessive lacrimation
  • Dry mouth and urinary retention
  • Bradycardia and hypersalivation

Correct Answer: Dry mouth and urinary retention

Q12. In case of severe anticholinergic overdose from phenidamine, which antidotal therapy may be considered?

  • Flumazenil
  • Naloxone
  • Physostigmine (under monitoring)
  • Atropine

Correct Answer: Physostigmine (under monitoring)

Q13. For proper storage of phenidamine tartrate tablets, pharmacy guidelines recommend:

  • Freezing at −20°C
  • Store in airtight container protected from light and moisture
  • Continuous refrigeration in amber vials
  • Storage in strong alkaline solution

Correct Answer: Store in airtight container protected from light and moisture

Q14. Concerning pregnancy, phenidamine tartrate should be:

  • Routinely prescribed as first‑line therapy in all trimesters
  • Contraindicated in all pregnant women
  • Used with caution and only if potential benefit justifies risk
  • Used at double dose to ensure efficacy

Correct Answer: Used with caution and only if potential benefit justifies risk

Q15. Pediatric use of phenidamine requires special caution primarily because:

  • Children are resistant to antihistamines
  • Variable dosing, increased sensitivity to CNS effects and risk of paradoxical reactions
  • It causes rapid bone growth in children
  • Pediatrics metabolize it to toxic heavy metals

Correct Answer: Variable dosing, increased sensitivity to CNS effects and risk of paradoxical reactions

Q16. Pharmacologically, phenidamine tartrate is classified as a:

  • First‑generation H1 antihistamine
  • Second‑generation selective H1 blocker
  • Leukotriene inhibitor
  • Monoclonal antibody

Correct Answer: First‑generation H1 antihistamine

Q17. Which pharmacodynamic effect contributes to relief of pruritus with phenidamine?

  • Inhibition of cyclooxygenase‑2
  • Blockade of peripheral and central H1 receptors reducing itch signaling
  • Activation of opioid receptors in the skin
  • Enhancement of histamine release

Correct Answer: Blockade of peripheral and central H1 receptors reducing itch signaling

Q18. Which best describes phenidamine’s pharmacokinetic fate after absorption?

  • Extensive renal reabsorption without metabolism
  • Hepatic metabolism followed by renal excretion of metabolites
  • Direct excretion in bile unchanged
  • Immediate degradation in gastric juice

Correct Answer: Hepatic metabolism followed by renal excretion of metabolites

Q19. Which dosage forms are commonly available for phenidamine tartrate?

  • Topical only
  • Oral tablets and injectable preparations
  • Inhaler aerosol only
  • Transdermal patch exclusively

Correct Answer: Oral tablets and injectable preparations

Q20. A notable central nervous system effect of first‑generation antihistamines including phenidamine is:

  • Stimulant effect with increased alertness
  • Marked sedation and psychomotor impairment
  • Permanent cognitive enhancement
  • Selective memory improvement

Correct Answer: Marked sedation and psychomotor impairment

Q21. Co‑administration of phenidamine with other anticholinergic drugs is likely to:

  • Reduce anticholinergic burden
  • Exacerbate anticholinergic side effects such as dry mouth and constipation
  • Neutralize its antihistaminic activity
  • Cause immediate antihyperglycemic effects

Correct Answer: Exacerbate anticholinergic side effects such as dry mouth and constipation

Q22. Which analytical method is commonly used in quality control to quantify phenidamine in formulations?

  • High‑performance liquid chromatography (HPLC)
  • Gram staining
  • Animal bioassay only
  • pH titration without instrumentation

Correct Answer: High‑performance liquid chromatography (HPLC)

Q23. The tartrate salt form of phenidamine primarily affects which pharmaceutical property?

  • It makes the drug a gaseous molecule
  • It enhances water solubility and crystalline form for formulation
  • It converts the drug into a peptide
  • It removes the active pharmacophore

Correct Answer: It enhances water solubility and crystalline form for formulation

Q24. Cardiovascular manifestations of significant phenidamine overdose can include:

  • Severe bradycardia and hypotension only
  • Tachycardia and possible arrhythmias
  • Immediate myocardial infarction in all cases
  • No cardiovascular effects reported

Correct Answer: Tachycardia and possible arrhythmias

Q25. When monitoring a patient on phenidamine therapy, pharmacists should assess primarily for:

  • White blood cell count every 6 hours
  • Signs of sedation, anticholinergic effects and therapeutic response
  • Serum potassium daily
  • Evidence of antibiotic resistance

Correct Answer: Signs of sedation, anticholinergic effects and therapeutic response

Q26. The binding of phenidamine to the H1 receptor is best described as:

  • Irreversible covalent binding
  • Reversible binding with antagonist/inverse agonist activity
  • Permanent receptor internalization
  • Activation of H1 signaling (agonist)

Correct Answer: Reversible binding with antagonist/inverse agonist activity

Q27. A pharmacokinetic property that explains phenidamine’s sedative effect is its ability to:

  • Be trapped in the gastrointestinal lumen
  • Cross the blood‑brain barrier and act centrally
  • Bind exclusively to plasma albumin without CNS penetration
  • Be rapidly metabolized without central effects

Correct Answer: Cross the blood‑brain barrier and act centrally

Q28. Regarding breastfeeding, the safest statement about phenidamine tartrate is:

  • It is entirely excreted in breast milk and always safe
  • It is contraindicated in all lactating mothers
  • Use with caution and evaluate risk versus benefit due to excretion in milk
  • It enhances milk production and is recommended

Correct Answer: Use with caution and evaluate risk versus benefit due to excretion in milk

Q29. Combining phenidamine with other CNS depressants may lead to which clinical consequence?

  • Reduced antihistamine efficacy without sedation
  • Enhanced CNS depression and increased risk of respiratory depression
  • Complete pharmacological antagonism
  • Induction of antibiotic activity

Correct Answer: Enhanced CNS depression and increased risk of respiratory depression

Q30. Which simple spectroscopic method can be used in a laboratory to estimate phenidamine concentration in a formulation?

  • Ultraviolet (UV) spectrophotometry after appropriate extraction and validation
  • Nuclear magnetic resonance without standards
  • Direct olfactory measurement
  • Visual color matching against a chart

Correct Answer: Ultraviolet (UV) spectrophotometry after appropriate extraction and validation

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