Synthetic cholinergic blocking agents – Dicyclomine hydrochloride MCQs With Answer

Synthetic cholinergic blocking agents – Dicyclomine hydrochloride MCQs With Answer

by

Synthetic cholinergic blocking agents – Dicyclomine hydrochloride MCQs With Answer

Dicyclomine hydrochloride is a synthetic antimuscarinic agent widely used as an antispasmodic in gastrointestinal disorders. B. Pharm students must understand its mechanism as a cholinergic blocking drug, receptor profile, pharmacokinetics, therapeutic uses in irritable bowel syndrome and intestinal spasms, adverse effects such as dry mouth, blurred vision and urinary retention, contraindications, drug interactions and overdose management. This concise, keyword-rich introduction focuses on concepts essential for pharmacology, pharmaceutical formulation and clinical application. Mastery of these topics supports safe dispensing and patient counseling. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which class best describes dicyclomine hydrochloride?

  • Synthetic cholinergic blocking agent with antimuscarinic activity
  • Nicotinic agonist
  • AChE inhibitor
  • Beta-adrenergic blocker

Correct Answer: Synthetic cholinergic blocking agent with antimuscarinic activity

Q2. The primary therapeutic use of dicyclomine hydrochloride is:

  • Treatment of hypertension
  • Relief of gastrointestinal smooth muscle spasms and irritable bowel syndrome
  • Management of asthma
  • Diuretic for edema

Correct Answer: Relief of gastrointestinal smooth muscle spasms and irritable bowel syndrome

Q3. Dicyclomine exhibits its antispasmodic effect mainly by blocking which receptors?

  • Muscarinic (M) receptors
  • Nicotinic receptors
  • Benzodiazepine receptors
  • Histamine H2 receptors

Correct Answer: Muscarinic (M) receptors

Q4. Which property distinguishes dicyclomine as a tertiary amine rather than a quaternary ammonium compound?

  • Ability to cross the blood–brain barrier
  • Poor oral absorption
  • Permanent positive charge
  • High polarity preventing CNS entry

Correct Answer: Ability to cross the blood–brain barrier

Q5. Besides muscarinic blockade, dicyclomine also has which additional pharmacological action?

  • Direct smooth muscle relaxant effect on gut muscle
  • Beta-adrenergic agonist action
  • Calcium channel blockade in cardiac tissue only
  • Inhibition of monoamine oxidase

Correct Answer: Direct smooth muscle relaxant effect on gut muscle

Q6. A common central nervous system adverse effect of dicyclomine is:

  • Confusion and dizziness due to central anticholinergic action
  • Severe sedation via GABA potentiation
  • Serotonin syndrome
  • Extrapyramidal symptoms

Correct Answer: Confusion and dizziness due to central anticholinergic action

Q7. Which of the following is a frequent peripheral anticholinergic adverse effect of dicyclomine?

  • Dry mouth (xerostomia)
  • Hypoglycemia
  • Excessive sweating
  • Bradycardia

Correct Answer: Dry mouth (xerostomia)

Q8. Dicyclomine is contraindicated in which of the following conditions?

  • Acute narrow-angle glaucoma
  • Hypothyroidism
  • Iron deficiency anemia
  • Controlled hypertension

Correct Answer: Acute narrow-angle glaucoma

Q9. Which of the following represents an important drug interaction with dicyclomine?

  • Potentiation of anticholinergic effects when combined with antihistamines or tricyclic antidepressants
  • Antagonism of its activity by proton pump inhibitors
  • Neutralization by oral iron supplements
  • Reduced absorption with antacids

Correct Answer: Potentiation of anticholinergic effects when combined with antihistamines or tricyclic antidepressants

Q10. Overdose of dicyclomine is most likely to be treated with which antidote?

  • Physostigmine, a reversible cholinesterase inhibitor
  • Naloxone, an opioid antagonist
  • Flumazenil, a benzodiazepine antagonist
  • Activated charcoal only—no antidote necessary

Correct Answer: Physostigmine, a reversible cholinesterase inhibitor

Q11. Which formulation of dicyclomine is commonly available for clinical use?

  • Oral tablets and oral syrup; injectable forms available in some regions
  • Inhalation aerosol
  • Topical cream only
  • Transdermal patch

Correct Answer: Oral tablets and oral syrup; injectable forms available in some regions

Q12. In pharmacokinetics, dicyclomine is primarily metabolized by which organ?

  • Liver (hepatic metabolism)
  • Kidney (renal metabolism)
  • Lungs
  • Pancreas

Correct Answer: Liver (hepatic metabolism)

Q13. Which patient counseling point is important when dispensing dicyclomine?

  • Avoid driving or operating heavy machinery if experiencing dizziness or blurred vision
  • Consume with alcohol to enhance absorption
  • Double the dose if a dose is missed
  • Use concurrently with antacids to reduce GI upset

Correct Answer: Avoid driving or operating heavy machinery if experiencing dizziness or blurred vision

Q14. Dicyclomine’s antimuscarinic effects on the eye can cause:

  • Blurred vision and pupillary dilation (mydriasis)
  • Improved night vision
  • Decreased intraocular pressure
  • Constricted pupils (miosis)

Correct Answer: Blurred vision and pupillary dilation (mydriasis)

Q15. Which statement best describes dicyclomine’s receptor selectivity?

  • Non-selective muscarinic antagonist with notable action on M3 receptors in smooth muscle
  • Highly selective M2 receptor antagonist only
  • Selective nicotinic receptor blocker
  • Selective adrenergic alpha-1 antagonist

Correct Answer: Non-selective muscarinic antagonist with notable action on M3 receptors in smooth muscle

Q16. Use of dicyclomine in elderly patients requires caution primarily because:

  • Increased sensitivity to central and peripheral anticholinergic adverse effects
  • They metabolize the drug faster
  • It causes severe hypoglycemia in the elderly
  • It induces bone marrow suppression predominantly in older patients

Correct Answer: Increased sensitivity to central and peripheral anticholinergic adverse effects

Q17. Which monitoring parameter is most relevant when a patient is on chronic dicyclomine therapy?

  • Assessment for anticholinergic side effects and urinary retention
  • Serum potassium levels weekly
  • Liver biopsy every 6 months
  • Daily blood glucose measurements

Correct Answer: Assessment for anticholinergic side effects and urinary retention

Q18. Dicyclomine is classified under which WHO essential medicines category (therapeutic class)?

  • Antispasmodics and antimuscarinics for gastrointestinal spasm
  • Antibiotics
  • Anticoagulants
  • Antivirals

Correct Answer: Antispasmodics and antimuscarinics for gastrointestinal spasm

Q19. In a patient with benign prostatic hyperplasia (BPH), dicyclomine should be used with caution because it may cause:

  • Urinary retention due to decreased bladder contractility
  • Increased urinary flow
  • Prostate shrinkage
  • Improved micturition reflex

Correct Answer: Urinary retention due to decreased bladder contractility

Q20. Which physiological effect would you NOT expect with dicyclomine administration?

  • Increased salivation
  • Reduced gastric motility
  • Decreased sweat secretion
  • Tachycardia

Correct Answer: Increased salivation

Q21. The mechanism by which physostigmine reverses dicyclomine toxicity is:

  • Inhibition of acetylcholinesterase increasing ACh at muscarinic receptors
  • Direct competitive antagonism at muscarinic receptors
  • Activation of GABA receptors to counteract agitation
  • Binding and neutralization of the drug in plasma

Correct Answer: Inhibition of acetylcholinesterase increasing ACh at muscarinic receptors

Q22. Which symptom is a hallmark of central anticholinergic syndrome from dicyclomine overdose?

  • Delirium with hallucinations
  • Profuse lacrimation
  • Excessive salivation
  • Bradykinesia

Correct Answer: Delirium with hallucinations

Q23. For B. Pharm students, which laboratory test is most likely to be affected indirectly by anticholinergic therapy?

  • No specific routine lab test is directly altered; clinical monitoring is key
  • Marked, consistent rise in serum creatinine within hours
  • Immediate and sustained leucopenia
  • Persistent hypokalemia

Correct Answer: No specific routine lab test is directly altered; clinical monitoring is key

Q24. Which population is generally advised to avoid dicyclomine?

  • Infants and very young children due to risk of severe anticholinergic effects
  • Healthy young adults
  • Patients with isolated seasonal allergies only
  • Patients on topical antibiotics

Correct Answer: Infants and very young children due to risk of severe anticholinergic effects

Q25. Which statement about dicyclomine’s onset and duration is most accurate?

  • Acts relatively rapidly after oral dosing with moderate duration suitable for multiple daily dosing
  • Has an extremely long half-life requiring once-monthly dosing
  • Is ineffective orally and only given intravenously
  • Provides immediate, permanent relief after one dose

Correct Answer: Acts relatively rapidly after oral dosing with moderate duration suitable for multiple daily dosing

Q26. Dicyclomine’s effect on gastric secretions is to:

  • Reduce secretions by blocking muscarinic stimulation
  • Increase pepsin production via nicotinic receptors
  • Directly neutralize gastric acid
  • Stimulate gastrin release and increase acid

Correct Answer: Reduce secretions by blocking muscarinic stimulation

Q27. Which is a pharmacodynamic characteristic of synthetic cholinergic blocking agents like dicyclomine?

  • Competitive antagonism at muscarinic receptors producing reversible effects
  • Irreversible enzyme inhibition
  • Direct activation of muscarinic receptors
  • Selective blockade of nicotinic receptors only

Correct Answer: Competitive antagonism at muscarinic receptors producing reversible effects

Q28. In a patient with tachycardia at baseline, dicyclomine should be:

  • Used with caution because it may further increase heart rate
  • Preferred because it reduces heart rate
  • Unrelated to heart rate changes
  • Always combined with beta-blockers

Correct Answer: Used with caution because it may further increase heart rate

Q29. Which pharmacy practice consideration is important when storing dicyclomine tablets?

  • Store at room temperature, protected from light and moisture
  • Store frozen to preserve potency
  • Store in direct sunlight to accelerate dissolution
  • Keep refrigerated at all times

Correct Answer: Store at room temperature, protected from light and moisture

Q30. Which of the following best describes the onset of central nervous system side effects with dicyclomine?

  • May occur due to its tertiary amine structure allowing CNS penetration
  • Never occurs because it cannot cross the BBB
  • Only occurs when given topically
  • Occurs only after weeks of therapy

Correct Answer: May occur due to its tertiary amine structure allowing CNS penetration

Q31. Which symptom suggests anticholinergic-induced urinary retention after starting dicyclomine?

  • Difficulty initiating urination and decreased urine output
  • Frequent urination with burning pain
  • Hematuria immediately on first dose
  • Sudden incontinence without urge

Correct Answer: Difficulty initiating urination and decreased urine output

Q32. Which receptor subtype is primarily responsible for mediating smooth muscle contraction in the gut that dicyclomine antagonizes?

  • M3 muscarinic receptors
  • M1 muscarinic receptors exclusively in CNS
  • Nicotinic muscular receptors
  • Beta-2 adrenergic receptors

Correct Answer: M3 muscarinic receptors

Q33. When counselling pregnant patients, dicyclomine should be:

  • Used only if clearly needed and after risk–benefit assessment because of limited pregnancy data
  • Always recommended as first-line therapy
  • Contraindicated in all trimesters without exception
  • Safe to take in any dose without consultation

Correct Answer: Used only if clearly needed and after risk–benefit assessment because of limited pregnancy data

Q34. Which manufacturing consideration is relevant for producing dicyclomine tablets?

  • Ensuring uniform content and appropriate disintegration for reliable onset
  • No need for dissolution testing
  • Tablets must be coated with sugar only for stability
  • Active pharmaceutical ingredient is always administered as a suspension

Correct Answer: Ensuring uniform content and appropriate disintegration for reliable onset

Q35. A patient complains of constipation after starting dicyclomine. The pharmacological explanation is:

  • Inhibition of muscarinic receptors reduces gastric and intestinal motility
  • It increases peristalsis causing constipation paradoxically
  • It directly binds dietary fiber preventing digestion
  • It enhances secretion of digestive enzymes leading to constipation

Correct Answer: Inhibition of muscarinic receptors reduces gastric and intestinal motility

Q36. Which statement about tolerance to antimuscarinic effects of dicyclomine is correct?

  • Tolerance may develop to some effects with prolonged use, requiring monitoring
  • Tolerance never occurs with antimuscarinics
  • Immediate tachyphylaxis occurs after the first dose
  • Tolerance leads to permanent receptor destruction

Correct Answer: Tolerance may develop to some effects with prolonged use, requiring monitoring

Q37. Dicyclomine’s chemical salt form is important because:

  • The hydrochloride salt improves water solubility for oral absorption
  • The free base is the preferred injectable form worldwide
  • Salt form has no impact on formulation properties
  • The acetate salt is the only clinically used form

Correct Answer: The hydrochloride salt improves water solubility for oral absorption

Q38. During patient assessment, which of the following histories would prompt avoiding dicyclomine?

  • History of uncontrolled narrow-angle glaucoma
  • History of seasonal allergic rhinitis only
  • Past episodic tension headaches without visual changes
  • Remote history of eczema

Correct Answer: History of uncontrolled narrow-angle glaucoma

Q39. Which statement about medication errors with anticholinergics like dicyclomine is most appropriate for pharmacy practice?

  • Clear labeling and patient education are essential to avoid accidental overdose and interactions
  • Teaching patients to increase dose if symptoms persist is acceptable
  • Patients should be told to stop all other medications when starting dicyclomine
  • Medication errors are uncommon and minimal counseling is needed

Correct Answer: Clear labeling and patient education are essential to avoid accidental overdose and interactions

Q40. Which dosing consideration is typical for dicyclomine in most adult regimens?

  • Multiple daily dosing because of moderate duration of action
  • Single monthly injection
  • One-time lifetime dose
  • Hourly dosing round the clock

Correct Answer: Multiple daily dosing because of moderate duration of action

Q41. In compatibility with IV fluids, dicyclomine injectable preparations should be:

  • Used according to manufacturer instructions; compatibility must be checked before mixing
  • Freely mixed with any IV fluid without concerns
  • Only mixed with alkaline solutions by default
  • Always diluted in ethanol for IV use

Correct Answer: Used according to manufacturer instructions; compatibility must be checked before mixing

Q42. Which teaching point is important for patients experiencing dry mouth from dicyclomine?

  • Use sugar-free lozenges, maintain oral hygiene and stay hydrated
  • Increase intake of sugary drinks to stimulate salivation
  • Stop all oral hygiene to allow natural recovery
  • Take additional doses to relieve dry mouth

Correct Answer: Use sugar-free lozenges, maintain oral hygiene and stay hydrated

Q43. From a medicinal chemistry perspective, dicyclomine’s tertiary amine moiety contributes to:

  • Lipid solubility facilitating CNS penetration
  • Permanently charged nature preventing membrane passage
  • Strong metal chelation properties
  • Direct oxidative metabolism by plasma esterases only

Correct Answer: Lipid solubility facilitating CNS penetration

Q44. Which clinical scenario is most appropriate for prescribing dicyclomine?

  • Patient with irritable bowel syndrome experiencing crampy abdominal pain without contraindications
  • Patient with acute narrow-angle glaucoma presenting to ophthalmology
  • Patient in cardiogenic shock needing inotropes
  • Infant with suspected colic without physician consultation

Correct Answer: Patient with irritable bowel syndrome experiencing crampy abdominal pain without contraindications

Q45. A distinguishing feature between synthetic antimuscarinics and natural ones is:

  • Synthetic agents can be chemically modified to adjust pharmacokinetics and side-effect profile
  • Natural agents always cross the BBB more readily
  • Synthetic agents never cause adverse effects
  • Natural agents are always tertiary amines

Correct Answer: Synthetic agents can be chemically modified to adjust pharmacokinetics and side-effect profile

Q46. Which sign would indicate anticholinergic toxicity in a patient on dicyclomine?

  • Hyperthermia with dry, flushed skin and decreased bowel sounds
  • Hypothermia with excessive sweating
  • Profuse tearing and hypersalivation
  • Sustained bradycardia and muscle fasciculations

Correct Answer: Hyperthermia with dry, flushed skin and decreased bowel sounds

Q47. Which pharmacological group would most likely increase the risk of additive anticholinergic effects when taken with dicyclomine?

  • First-generation antihistamines
  • Topical antifungals only
  • Oral iron supplements exclusively
  • Insulin therapy

Correct Answer: First-generation antihistamines

Q48. Which educational point is important regarding alcohol consumption while on dicyclomine?

  • Avoid alcohol as it may exacerbate dizziness and sedation
  • Alcohol prevents anticholinergic side effects and is recommended
  • There is no interaction; alcohol can be consumed freely
  • Alcohol enhances gastrointestinal motility to counteract constipation

Correct Answer: Avoid alcohol as it may exacerbate dizziness and sedation

Q49. Which adverse effect would signal a need to discontinue dicyclomine therapy immediately?

  • Signs of acute glaucoma such as eye pain and sudden visual disturbance
  • Mild dry mouth manageable with lozenges
  • Occasional mild dizziness on standing
  • Transient mild constipation

Correct Answer: Signs of acute glaucoma such as eye pain and sudden visual disturbance

Q50. For B. Pharm students, which concept best summarizes safe dispensing of dicyclomine?

  • Assess contraindications and interactions, counsel on side effects, dosing and when to seek care
  • Provide maximum permissible dose without counseling to ensure efficacy
  • Advise patients to stop all other medications to prevent interactions
  • Recommend use in all abdominal pain cases regardless of cause

Correct Answer: Assess contraindications and interactions, counsel on side effects, dosing and when to seek care

Leave a Comment