Synthetic cholinergic blocking agents – Benztropine mesylate MCQs With Answer

Synthetic cholinergic blocking agents – Benztropine mesylate MCQs With Answer

Benztropine mesylate is a centrally acting synthetic cholinergic blocking agent widely taught in pharmacology for B.Pharm students. This anticholinergic tertiary amine crosses the blood–brain barrier to antagonize muscarinic receptors, restoring the cholinergic–dopaminergic balance in Parkinsonism and treating antipsychotic-induced extrapyramidal symptoms. Key learning points include mechanism of action, receptor selectivity, clinical uses (acute dystonia, tremor control), adverse effects (dry mouth, blurred vision, urinary retention, cognitive impairment), contraindications (narrow-angle glaucoma, prostatic hypertrophy), drug interactions, and monitoring. Understanding pharmacokinetics, dosing strategies, and overdose management is essential for safe dispensing and patient counseling. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which best describes the primary mechanism of action of benztropine?

• Selective dopamine D2 receptor agonist
• Central muscarinic receptor antagonist restoring cholinergic–dopaminergic balance
• Peripheral nicotinic receptor blocker at neuromuscular junction
• Cholinesterase inhibitor increasing acetylcholine levels

Correct Answer: Central muscarinic receptor antagonist restoring cholinergic–dopaminergic balance

Q2. Benztropine is classified chemically as which type of amine?

• Quaternary amine
• Tertiary amine
• Primary amine
• Secondary amine

Correct Answer: Tertiary amine

Q3. The main clinical indication of benztropine in neurology is:

• Treatment of major depressive disorder
• Management of essential hypertension
• Adjunct therapy for Parkinson’s disease tremor and drug-induced extrapyramidal symptoms
• Long-term memory enhancement in Alzheimer’s disease

Correct Answer: Adjunct therapy for Parkinson’s disease tremor and drug-induced extrapyramidal symptoms

Q4. Which of the following adverse effects is most characteristic of benztropine therapy?

• Excessive salivation and increased sweating
• Bronchorrhea and diarrhea
• Dry mouth, blurred vision and constipation
• Bradycardia and miosis

Correct Answer: Dry mouth, blurred vision and constipation

Q5. Benztropine is contraindicated or used with extreme caution in patients with:

• Hypothyroidism
• Narrow-angle glaucoma
• Iron deficiency anemia
• Osteoarthritis

Correct Answer: Narrow-angle glaucoma

Q6. In the management of acute dystonic reactions due to antipsychotics, benztropine is commonly given by which route for rapid effect?

• Topical application
• Intramuscular or intravenous injection
• Transdermal patch
• Intranasal spray

Correct Answer: Intramuscular or intravenous injection

Q7. Why does benztropine produce central nervous system effects?

• It is a quaternary ammonium compound that stays in the periphery
• It is rapidly converted to acetylcholine in the brain
• It is a tertiary amine that crosses the blood–brain barrier
• It only acts on peripheral muscarinic receptors

Correct Answer: It is a tertiary amine that crosses the blood–brain barrier

Q8. Overdose of benztropine typically produces which toxidrome?

• Opioid toxidrome (miosis, respiratory depression)
• Anticholinergic toxidrome (hyperthermia, dry skin, delirium)
• Cholinergic toxidrome (salivation, sweating, bradycardia)
• Sympathomimetic toxidrome (diaphoresis, hypertension)

Correct Answer: Anticholinergic toxidrome (hyperthermia, dry skin, delirium)

Q9. Which antidote is most appropriate for severe central anticholinergic toxicity from benztropine?

• Naloxone
• Neostigmine
• Physostigmine
• Flumazenil

Correct Answer: Physostigmine

Q10. Compared to quaternary anticholinergics, tertiary anticholinergics like benztropine:

• Do not cross the blood–brain barrier and lack central effects
• Cross the blood–brain barrier and produce central effects
• Are exclusively peripheral acting bronchodilators
• Are rapidly inactivated by acetylcholinesterase

Correct Answer: Cross the blood–brain barrier and produce central effects

Q11. Long-term use of benztropine in elderly patients is limited mainly due to:

• Increased risk of extrapyramidal symptoms
• High incidence of anticholinergic cognitive impairment and confusion
• Severe hypoglycemia
• Marked weight gain only

Correct Answer: High incidence of anticholinergic cognitive impairment and confusion

Q12. Benztropine’s therapeutic effect in Parkinsonism is most significant for which symptom?

• Bradykinesia
• Postural instability
• Tremor
• Freezing of gait

Correct Answer: Tremor

Q13. Which of the following is a common monitoring parameter when a patient starts benztropine?

• Serum acetylcholine concentration
• Intraocular pressure and urinary retention assessment
• Daily blood glucose checks
• Serum creatine kinase

Correct Answer: Intraocular pressure and urinary retention assessment

Q14. Benztropine mesylate is the salt form primarily used to:

• Reduce the drug’s potency
• Improve water solubility and stability for dosing
• Cause irreversible receptor binding
• Enhance cholinesterase activity

Correct Answer: Improve water solubility and stability for dosing

Q15. Which drug interaction with benztropine is most likely to increase central anticholinergic effects?

• Concurrent use of cholinesterase inhibitors like donepezil
• Concurrent use of other anticholinergic drugs such as tricyclic antidepressants or antihistamines
• Concurrent use of beta blockers alone
• Concurrent use of metformin

Correct Answer: Concurrent use of other anticholinergic drugs such as tricyclic antidepressants or antihistamines

Q16. In patients with benign prostatic hyperplasia (BPH), benztropine treatment may cause:

• Improved urine flow and decreased retention
• Urinary retention and worsening lower urinary tract symptoms
• Diuresis and decreased prostate size
• Reduced nocturia only

Correct Answer: Urinary retention and worsening lower urinary tract symptoms

Q17. Which clinical situation is benztropine particularly useful for in psychiatric practice?

• Treatment of major depressive disorder
• Management of tardive dyskinesia first-line
• Acute dystonic reactions caused by antipsychotics
• Prophylaxis of metabolic syndrome

Correct Answer: Acute dystonic reactions caused by antipsychotics

Q18. Which statement about benztropine and tardive dyskinesia is correct?

• Benztropine consistently improves tardive dyskinesia
• Benztropine may worsen or have little benefit in tardive dyskinesia
• Benztropine is the first-line therapy for tardive dyskinesia
• Benztropine reverses tardive dyskinesia by increasing acetylcholine

Correct Answer: Benztropine may worsen or have little benefit in tardive dyskinesia

Q19. Which population should receive benztropine with extreme caution due to anticholinergic sensitivity?

• Young adults aged 20–30
• Pediatric patients only
• Elderly patients with cognitive impairment
• Patients with hyperthyroidism exclusively

Correct Answer: Elderly patients with cognitive impairment

Q20. Which physiological effect results from muscarinic blockade by benztropine?

• Increased gastrointestinal motility
• Pupillary constriction (miosis)
• Decreased sweating and risk of heat intolerance
• Increased lacrimation

Correct Answer: Decreased sweating and risk of heat intolerance

Q21. Which of the following is true regarding benztropine’s effect on heart rate?

• It commonly causes bradycardia
• It may cause tachycardia due to antimuscarinic action
• It has no effect on cardiac conduction
• It lowers blood pressure dramatically without heart rate change

Correct Answer: It may cause tachycardia due to antimuscarinic action

Q22. Benztropine is metabolized primarily by which organ system?

• Renal excretion without hepatic metabolism
• Hepatic metabolism followed by renal excretion of metabolites
• Excreted unchanged in feces only
• Metabolized exclusively by salivary enzymes

Correct Answer: Hepatic metabolism followed by renal excretion of metabolites

Q23. Which clinical advice should be given to patients starting benztropine?

• Expect increased sweating and avoid cold climates
• Avoid tasks requiring mental alertness until you know how the drug affects you
• There are no interactions with over-the-counter antihistamines
• It will improve memory and cognition

Correct Answer: Avoid tasks requiring mental alertness until you know how the drug affects you

Q24. Which ocular effect is likely with benztropine and is a concern in glaucoma?

• Miosis with decreased intraocular pressure
• Mydriasis with increased intraocular pressure
• Improved accommodation and reduced IOP
• No ocular effects

Correct Answer: Mydriasis with increased intraocular pressure

Q25. Regarding use in Parkinson’s disease, benztropine is most appropriate for:

• Advanced Parkinson’s with predominating gait and postural instability
• Tremor-predominant, younger patients with minimal cognitive impairment
• All elderly patients irrespective of symptoms
• Replacing levodopa as first-line therapy in all patients

Correct Answer: Tremor-predominant, younger patients with minimal cognitive impairment

Q26. Which sign suggests anticholinergic adverse effect in a patient on benztropine?

• Excessive lacrimation and salivation
• Profuse sweating and pallor
• Dry mouth and difficulty urinating
• Pinpoint pupils and rhinorrhea

Correct Answer: Dry mouth and difficulty urinating

Q27. In a patient receiving benztropine, which concurrent medication would be least appropriate?

• Proparacaine eye drops for corneal anesthesia
• Oxybutynin for overactive bladder
• Levodopa for Parkinson’s disease
• Physostigmine for reversal of severe anticholinergic toxicity if needed

Correct Answer: Oxybutynin for overactive bladder

Q28. Why is benztropine sometimes used with antipsychotics?

• To potentiate antipsychotic dopamine blockade
• To prevent or treat antipsychotic-induced extrapyramidal symptoms
• To treat the psychotic symptoms directly
• To increase sedation for all patients

Correct Answer: To prevent or treat antipsychotic-induced extrapyramidal symptoms

Q29. Which statement about benztropine and pregnancy is most appropriate for counseling?

• It is universally safe and recommended for all pregnant women
• Use only if clearly needed and after risk–benefit assessment
• It is contraindicated in all trimesters due to teratogenicity proven in humans
• It enhances fetal cholinergic development and is preferred

Correct Answer: Use only if clearly needed and after risk–benefit assessment

Q30. The clinical effect of benztropine on drooling (sialorrhea) in Parkinson’s disease is due to:

• Stimulation of saliva production
• Suppression of salivary secretions via muscarinic blockade
• Increased swallowing reflex only
• Activation of nicotinic receptors in salivary glands

Correct Answer: Suppression of salivary secretions via muscarinic blockade

Q31. Which adverse cognitive effect is a particular concern with anticholinergics like benztropine in dementia patients?

• Improved attention and memory
• Worsening confusion and memory impairment
• Reversal of dementia pathology
• Enhanced language skills

Correct Answer: Worsening confusion and memory impairment

Q32. The most appropriate first-line management of an acute anticholinergic delirium in hospital caused by benztropine is:

• Administer naloxone
• Provide supportive care and consider physostigmine if severe and no contraindication
• Start high-dose benzodiazepines only
• Induce emesis immediately

Correct Answer: Provide supportive care and consider physostigmine if severe and no contraindication

Q33. Which laboratory test is routinely required to monitor benztropine therapy?

• Routine serum benztropine concentrations
• There is no routine laboratory monitoring; monitor clinically for side effects
• Daily liver function tests for all patients
• Frequent serum potassium levels

Correct Answer: There is no routine laboratory monitoring; monitor clinically for side effects

Q34. Benztropine’s effect on gastrointestinal motility typically results in:

• Increased bowel movements and diarrhea
• Reduced motility and constipation
• No change in GI function
• Rapid gastric emptying only

Correct Answer: Reduced motility and constipation

Q35. A pharmacist educating a patient should advise which over-the-counter product may worsen benztropine side effects?

• Aspirin
• Diphenhydramine (antihistamine with anticholinergic properties)
• Oral rehydration salts
• Topical hydrocortisone cream

Correct Answer: Diphenhydramine (antihistamine with anticholinergic properties)

Q36. Which of the following best explains why benztropine can precipitate heat intolerance in patients?

• It increases metabolic rate dramatically
• It inhibits sweating by blocking muscarinic receptors in sweat glands
• It causes peripheral vasoconstriction only
• It enhances thyroid hormone release

Correct Answer: It inhibits sweating by blocking muscarinic receptors in sweat glands

Q37. In terms of therapy duration for Parkinson’s tremor, benztropine is typically used:

• Indefinitely for all patients regardless of side effects
• Short-term or as needed, with regular reassessment due to anticholinergic burden
• Only once as a single-dose cure
• Exclusively during pregnancy

Correct Answer: Short-term or as needed, with regular reassessment due to anticholinergic burden

Q38. Which of the following symptoms is least likely to be relieved by benztropine in Parkinson’s disease?

• Tremor
• Rigidity
• Bradykinesia
• Excessive salivation

Correct Answer: Bradykinesia

Q39. Which statement about drug interactions with benztropine is correct?

• Concurrent use with cholinesterase inhibitors will enhance benztropine’s effect
• Combining with other anticholinergics increases risk of anticholinergic toxicity
• There are no known drug interactions
• It neutralizes the effect of all antidepressants

Correct Answer: Combining with other anticholinergics increases risk of anticholinergic toxicity

Q40. Which sign would suggest a need to stop benztropine therapy in an outpatient elderly patient?

• Improved tremor with no side effects
• New onset confusion, hallucinations and urinary retention
• Mild dry mouth manageable with fluids
• Slight constipation relieved by diet

Correct Answer: New onset confusion, hallucinations and urinary retention

Q41. Benztropine should be used cautiously with which class of psychiatric medications due to additive anticholinergic effects?

• SSRIs with no anticholinergic activity
• Tricyclic antidepressants
• Benzodiazepines only
• Typical antipsychotics without EPS risk

Correct Answer: Tricyclic antidepressants

Q42. Which of the following is an appropriate counseling point regarding heat exposure while on benztropine?

• Benztropine increases sweating, so no special precautions are needed
• Avoid overheating and strenuous exercise in hot weather due to reduced sweating
• Sunlight exposure should be maximized to increase drug clearance
• Benztropine protects against heatstroke

Correct Answer: Avoid overheating and strenuous exercise in hot weather due to reduced sweating

Q43. Which statement is true about using benztropine to treat extrapyramidal symptoms prophylactically in all patients starting antipsychotics?

• Prophylactic use is universally recommended for all antipsychotic starts
• Routine prophylaxis is not recommended; use is individualized due to side effects
• Benztropine prevents metabolic side effects of antipsychotics
• Benztropine enhances antipsychotic efficacy and is mandatory

Correct Answer: Routine prophylaxis is not recommended; use is individualized due to side effects

Q44. For a patient with suspected benztropine overdose presenting with severe agitation and tachycardia, which immediate measure is appropriate?

• Administer physostigmine after evaluating contraindications and with cardiac monitoring
• Give high-dose aspirin
• Administer naloxone intravenously
• Start hemodialysis immediately

Correct Answer: Administer physostigmine after evaluating contraindications and with cardiac monitoring

Q45. Which of the following best describes benztropine’s effect on nicotinic receptors?

• Benztropine is a potent nicotinic receptor agonist
• Benztropine primarily blocks muscarinic receptors and has minimal direct nicotinic activity
• Benztropine irreversibly inhibits all nicotinic receptors
• Benztropine increases nicotinic receptor density acutely

Correct Answer: Benztropine primarily blocks muscarinic receptors and has minimal direct nicotinic activity

Q46. Which clinical feature differentiates anticholinergic toxicity from sympathomimetic toxicity?

• Anticholinergic toxicity produces sweating; sympathomimetics cause dry skin
• Anticholinergic toxicity causes dry skin and decreased bowel sounds; sympathomimetics usually cause diaphoresis and hyperreflexia
• Both cause pinpoint pupils equally
• Sympathomimetic toxicity presents with bradycardia and miosis

Correct Answer: Anticholinergic toxicity causes dry skin and decreased bowel sounds; sympathomimetics usually cause diaphoresis and hyperreflexia

Q47. In a patient with renal impairment, benztropine dosing requires which consideration?

• No adjustments ever because renal function is irrelevant
• Use clinical judgment and consider dose reduction because metabolites are renally excreted
• Double the dose to overcome clearance issues
• Switch to a cholinesterase inhibitor instead

Correct Answer: Use clinical judgment and consider dose reduction because metabolites are renally excreted

Q48. Which feature of benztropine makes it effective in treating acute antipsychotic-induced dystonia?

• Its ability to stimulate acetylcholine release
• Rapid central muscarinic antagonism that restores neurotransmitter balance
• Long-acting cholinesterase inhibition
• Its opioid receptor blockade

Correct Answer: Rapid central muscarinic antagonism that restores neurotransmitter balance

Q49. Which clinical symptom would most likely improve after a single parenteral dose of benztropine in an acute dystonic reaction?

• Progressive cognitive decline over months
• Acute neck twisting and oculogyric crisis
• Chronic bradykinesia
• Permanent tardive dyskinesia movements

Correct Answer: Acute neck twisting and oculogyric crisis

Q50. Which statement is correct regarding discontinuation of benztropine?

• It must be stopped abruptly in all patients to avoid withdrawal
• Gradual tapering is considered in some patients to avoid abrupt recurrence of symptoms and to reassess need
• Discontinuation causes cholinergic crisis in all cases
• It should be replaced immediately with another anticholinergic

Correct Answer: Gradual tapering is considered in some patients to avoid abrupt recurrence of symptoms and to reassess need

G S Sachin

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.

Mail- Sachin@pharmacyfreak.com