Synthetic cholinergic blocking agents – Tridihexethyl chloride MCQs With Answer

Synthetic cholinergic blocking agents – Tridihexethyl chloride MCQs With Answer

Tridihexethyl chloride is a synthetic cholinergic blocking agent widely discussed in B.Pharm pharmacology for its antimuscarinic actions, antisecretory and antispasmodic effects. This anticholinergic drug works by competitively blocking muscarinic receptors, reducing gastric acid secretion and secretions from exocrine glands, while producing typical adverse effects such as dry mouth, blurred vision, constipation and urinary retention. Key B.Pharm topics include mechanism of action, receptor selectivity, quaternary ammonium structure and limited CNS penetration, clinical uses, contraindications, interactions and management of overdose. This focused set of MCQs will reinforce pharmacology concepts and exam preparation. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What is the primary pharmacological classification of tridihexethyl chloride?

• Synthetic cholinergic blocking agent
• Cholinesterase inhibitor
• Nicotinic agonist
• Beta-adrenergic blocker

Correct Answer: Synthetic cholinergic blocking agent

Q2. The main mechanism of action of tridihexethyl chloride is:

• Irreversible inhibition of acetylcholinesterase
• Competitive antagonism at muscarinic receptors
• Agonism at nicotinic receptors
• Beta receptor blockade

Correct Answer: Competitive antagonism at muscarinic receptors

Q3. Which receptor family is primarily blocked by tridihexethyl chloride?

• Muscarinic receptors
• Nicotinic receptors
• Adrenergic receptors
• Histamine receptors

Correct Answer: Muscarinic receptors

Q4. Chemically, tridihexethyl chloride exists mainly as which type of compound?

• Quaternary ammonium salt
• Tertiary amine
• Carboxylic acid
• Benzodiazepine derivative

Correct Answer: Quaternary ammonium salt

Q5. Because tridihexethyl chloride is a quaternary ammonium compound, it most likely has which pharmacokinetic property?

• Poor penetration of the blood–brain barrier
• Extensive CNS accumulation
• Rapid hepatic uptake into neurons
• High oral bioavailability in neonates only

Correct Answer: Poor penetration of the blood–brain barrier

Q6. One of the primary clinical uses of tridihexethyl chloride historically has been:

• Treatment of peptic ulcer disease/antisecretory therapy
• Management of acute asthma attack
• Long-term anticoagulation
• Antibiotic for H. pylori

Correct Answer: Treatment of peptic ulcer disease/antisecretory therapy

Q7. Which of the following side effects is most characteristic of tridihexethyl chloride?

• Xerostomia (dry mouth)
• Hypersalivation
• Hypoglycemia
• Excessive lacrimation

Correct Answer: Xerostomia (dry mouth)

Q8. Tridihexethyl chloride is likely to cause which ocular effect?

• Mydriasis (dilated pupil) and cycloplegia
• Miosis (constricted pupil)
• Increased lacrimation
• Reversal of glaucoma

Correct Answer: Mydriasis (dilated pupil) and cycloplegia

Q9. A major contraindication for using tridihexethyl chloride is:

• Angle-closure glaucoma
• Hypothyroidism
• Iron deficiency anemia
• Migraine without aura

Correct Answer: Angle-closure glaucoma

Q10. Which urinary effect is commonly produced by tridihexethyl chloride?

• Urinary retention due to decreased bladder detrusor contractility
• Increased diuresis
• Antibiotic-like eradication of UTI organisms
• Nephrogenic diabetes insipidus

Correct Answer: Urinary retention due to decreased bladder detrusor contractility

Q11. Tridihexethyl chloride would antagonize the action of which of the following drugs?

• Bethanechol, a muscarinic agonist
• Propranolol, a beta blocker
• Nicotine, a nicotinic agonist
• Furosemide, a loop diuretic

Correct Answer: Bethanechol, a muscarinic agonist

Q12. In treating antimuscarinic overdose from tridihexethyl chloride, the recommended antidote is:

• Physostigmine, a reversible cholinesterase inhibitor
• Atropine, another antimuscarinic
• Propranolol, a beta blocker
• Flumazenil, a benzodiazepine antagonist

Correct Answer: Physostigmine, a reversible cholinesterase inhibitor

Q13. Which effect on heart rate is expected with therapeutic antimuscarinic doses of tridihexethyl chloride?

• Tachycardia due to vagal blockade
• Profound bradycardia via sympathetic activation
• No change in heart rate
• Ventricular fibrillation

Correct Answer: Tachycardia due to vagal blockade

Q14. Compared with tertiary amine antimuscarinics, a quaternary ammonium antimuscarinic like tridihexethyl chloride typically shows:

• Less central nervous system side effects
• Greater central sedation
• Higher likelihood of crossing the BBB
• Stronger nicotinic receptor agonism

Correct Answer: Less central nervous system side effects

Q15. Which exocrine gland secretion is reduced by tridihexethyl chloride?

• Salivary and gastric secretions
• Insulin secretion
• Thyroid hormone secretion
• Adrenal catecholamine release

Correct Answer: Salivary and gastric secretions

Q16. A patient on tridihexethyl chloride complains of constipation. The pharmacological basis is:

• Reduced gastrointestinal motility from muscarinic blockade
• Excessive serotonin release
• Direct mucosal irritation causing stool hardening
• Enhanced peristalsis leading to fatigue

Correct Answer: Reduced gastrointestinal motility from muscarinic blockade

Q17. Which patient group requires extra caution when prescribing tridihexethyl chloride because of urinary retention risk?

• Men with benign prostatic hyperplasia (BPH)
• Children with no urinary issues
• Young athletes
• Patients with anemia

Correct Answer: Men with benign prostatic hyperplasia (BPH)

Q18. Which of the following best describes the reversibility of tridihexethyl chloride binding to muscarinic receptors?

• Reversible competitive antagonism
• Irreversible covalent blockade
• Allosteric agonism
• Enzyme-mediated destruction of receptors

Correct Answer: Reversible competitive antagonism

Q19. Which pharmacological property explains tridihexethyl chloride’s antisecretory action on the stomach?

• Blockade of muscarinic receptors on parietal and glandular cells reducing acid and mucus secretion
• Direct neutralization of gastric acid
• Inhibition of proton pumps at the cellular level
• Stimulation of gastrin release to inhibit acid

Correct Answer: Blockade of muscarinic receptors on parietal and glandular cells reducing acid and mucus secretion

Q20. Tridihexethyl chloride’s poor central effects make it preferable to tertiary amines for which situation?

• Reducing peripheral secretions without significant sedation or confusion
• Treating central Parkinsonian tremor
• Crossing the BBB to treat delirium
• Enhancing CNS cholinergic transmission

Correct Answer: Reducing peripheral secretions without significant sedation or confusion

Q21. Which of the following adverse reactions is a sign of severe anticholinergic toxicity from tridihexethyl chloride?

• Hyperthermia with dry, flushed skin and delirium
• Profuse sweating and salivation
• Severe hypoglycemia
• Acute hemolytic anemia

Correct Answer: Hyperthermia with dry, flushed skin and delirium

Q22. Tridihexethyl chloride should be used with caution when co-administered with which of the following drug classes due to additive anticholinergic effects?

• Antihistamines with anticholinergic properties
• ACE inhibitors
• Thyroid hormones
• Statins

Correct Answer: Antihistamines with anticholinergic properties

Q23. Which physiologic function is LEAST likely to be affected by tridihexethyl chloride?

• Skeletal muscle contraction at the neuromuscular junction (nicotinic)
• Salivation
• Gastric acid secretion
• Bronchial secretions

Correct Answer: Skeletal muscle contraction at the neuromuscular junction (nicotinic)

Q24. For a drug like tridihexethyl chloride, renal impairment could primarily affect:

• Elimination and duration of action if excreted unchanged in urine
• Immediate increase in hepatic activation
• Enhancement of BBB penetration
• Conversion to an active nicotinic agonist

Correct Answer: Elimination and duration of action if excreted unchanged in urine

Q25. Which clinical sign would most likely indicate antimuscarinic effect on the eye following tridihexethyl chloride administration?

• Difficulty focusing on near objects (blurred vision)
• Improved night vision
• Excessive tearing
• Constricted pupil with sharp near focus

Correct Answer: Difficulty focusing on near objects (blurred vision)

Q26. A pharmacology exam question: tridihexethyl chloride differs from atropine in that it:

• Is a synthetic quaternary compound with less CNS penetration than atropine
• Is a natural tertiary alkaloid with strong CNS effects
• Acts as an acetylcholinesterase activator
• Is a selective nicotinic receptor agonist

Correct Answer: Is a synthetic quaternary compound with less CNS penetration than atropine

Q27. Which symptom should prompt immediate discontinuation of tridihexethyl chloride therapy and urgent evaluation?

• Sudden vision changes and severe eye pain suggestive of acute glaucoma
• Mild dry mouth that improves with hydration
• Transient mild constipation
• Temporary sleepiness after a single dose

Correct Answer: Sudden vision changes and severe eye pain suggestive of acute glaucoma

Q28. Which receptor subtype primarily mediates glandular secretion that is blocked by antimuscarinic drugs like tridihexethyl chloride?

• M3 muscarinic receptors on exocrine glands
• Beta-2 adrenergic receptors
• NMDA glutamate receptors
• Alpha-1 adrenergic receptors

Correct Answer: M3 muscarinic receptors on exocrine glands

Q29. Which of the following is a common gastrointestinal adverse effect of tridihexethyl chloride?

• Decreased intestinal motility causing constipation
• Increased bowel sounds and diarrhea
• Profuse intestinal bleeding
• Immediate relief of bowel obstruction

Correct Answer: Decreased intestinal motility causing constipation

Q30. When explaining mechanism to a patient, the pharmacist should say tridihexethyl chloride reduces stomach acid by:

• Blocking vagal muscarinic stimulation of acid-secreting cells
• Directly neutralizing acid in the stomach lumen
• Stimulating bicarbonate secretion only
• Blocking histamine H2 receptors

Correct Answer: Blocking vagal muscarinic stimulation of acid-secreting cells

Q31. In elderly patients, antimuscarinic drugs require caution primarily because:

• They can worsen cognitive impairment and cause confusion, even if central penetration is less
• They always cure dementia
• They produce strong anticoagulant effects
• They increase renal clearance dramatically

Correct Answer: They can worsen cognitive impairment and cause confusion, even if central penetration is less

Q32. Which drug interaction is clinically relevant with tridihexethyl chloride?

• Concurrent use with other anticholinergic agents increases anticholinergic side effects
• It potentiates insulin activity directly
• It causes immediate potentiation of ACE inhibitors
• It neutralizes the effect of proton pump inhibitors

Correct Answer: Concurrent use with other anticholinergic agents increases anticholinergic side effects

Q33. The effect of tridihexethyl chloride on bronchial smooth muscle is best described as:

• Bronchodilation by blocking muscarinic bronchoconstrictor tone
• Bronchoconstriction due to histamine release
• No effect on airways whatsoever
• Enhancement of mucus production

Correct Answer: Bronchodilation by blocking muscarinic bronchoconstrictor tone

Q34. Which clinical measurement is useful to monitor anticholinergic toxicity in a patient on tridihexethyl chloride?

• Mental status and temperature for signs of delirium and hyperthermia
• Serum potassium as the primary toxicity marker
• Prothrombin time exclusively
• Fasting blood glucose for acute monitoring

Correct Answer: Mental status and temperature for signs of delirium and hyperthermia

Q35. In which gastrointestinal disorder might tridihexethyl chloride be contraindicated due to worsened motility?

• Paralytic ileus or severe intestinal atony
• Acid reflux without motility issues
• Simple constipation unrelated to drug therapy
• Peptic ulcer with normal motility

Correct Answer: Paralytic ileus or severe intestinal atony

Q36. Which property of tridihexethyl chloride contributes to reduced central side effects compared to tertiary antimuscarinics?

• Permanent positive charge on the molecule limiting BBB crossing
• High lipid solubility increasing CNS uptake
• Strong affinity for central dopamine receptors
• Active transport into the CNS via P-glycoprotein

Correct Answer: Permanent positive charge on the molecule limiting BBB crossing

Q37. Which physical sign is consistent with peripheral antimuscarinic activity of tridihexethyl chloride?

• Dry, flushed skin due to decreased sweating
• Excessive sweating and clammy skin
• Hypothermia from increased sweating
• Brisk peripheral cyanosis

Correct Answer: Dry, flushed skin due to decreased sweating

Q38. Which statement about receptor selectivity for tridihexethyl chloride is most accurate for exam purposes?

• It primarily blocks muscarinic receptor subtypes mediating peripheral parasympathetic responses
• It selectively stimulates M2 receptors
• It only blocks nicotinic receptors at high doses
• It is a selective beta-1 adrenoceptor blocker

Correct Answer: It primarily blocks muscarinic receptor subtypes mediating peripheral parasympathetic responses

Q39. In patients with myasthenia gravis, tridihexethyl chloride is generally:

• Contraindicated or used cautiously because it may worsen muscle weakness
• Recommended as primary therapy to improve muscle strength
• Used as an antibiotic adjunct
• Indicated to increase acetylcholine release at the NMJ

Correct Answer: Contraindicated or used cautiously because it may worsen muscle weakness

Q40. Which clinical test can indicate antimuscarinic blockade after administration of tridihexethyl chloride?

• Reduced salivary secretion in response to pilocarpine challenge
• Increased cholinesterase activity in plasma
• Positive edrophonium test for myasthenia
• Marked bradycardia on ECG tracing

Correct Answer: Reduced salivary secretion in response to pilocarpine challenge

Q41. Which of the following best describes the effect of tridihexethyl chloride on gastrointestinal smooth muscle tone?

• Reduced tone and diminished spasms via muscarinic blockade
• Increased peristaltic contractions
• Selective stimulation of ileocecal valve constriction only
• Direct mucosal ulceration

Correct Answer: Reduced tone and diminished spasms via muscarinic blockade

Q42. A patient with benign prostatic hyperplasia (BPH) is prescribed tridihexethyl chloride. What is the likely effect?

• Worsening of urinary retention due to decreased bladder contractility
• Immediate relief of urinary obstruction
• Strong bactericidal action on prostate pathogens
• Improved sperm motility

Correct Answer: Worsening of urinary retention due to decreased bladder contractility

Q43. Which laboratory or physiologic parameter is most directly affected by tridihexethyl chloride?

• Reduction in gastric acid output
• Increase in serum creatine kinase
• Immediate change in coagulation profile
• Marked increase in thyroid-stimulating hormone

Correct Answer: Reduction in gastric acid output

Q44. Which adverse effect would be most likely to complicate heat exposure in a patient taking tridihexethyl chloride?

• Impaired sweating leading to hyperthermia
• Excessive sweating causing dehydration
• Accelerated heat loss from vasodilation
• Increased shivering and hypothermia

Correct Answer: Impaired sweating leading to hyperthermia

Q45. When counseling a patient starting tridihexethyl chloride for gastric hypersecretion, which warning is important?

• Avoid prolonged exposure to hot environments; report vision changes or difficulty urinating
• Increase caffeine intake to counteract dry mouth
• Double the dose if symptoms persist after one day
• Stop all other medications permanently

Correct Answer: Avoid prolonged exposure to hot environments; report vision changes or difficulty urinating

Q46. Given its mechanism, tridihexethyl chloride would most likely reduce secretion stimulated by which endogenous mediator?

• Acetylcholine acting on muscarinic receptors
• Insulin acting on beta cells
• Thyroxine acting on nuclear receptors
• Glucagon stimulating hepatic glucose release

Correct Answer: Acetylcholine acting on muscarinic receptors

Q47. If a patient taking tridihexethyl chloride develops severe anticholinergic delirium, which clinician-administered treatment is appropriate?

• Intravenous physostigmine under supervision
• Oral activated charcoal only
• Intramuscular atropine to increase antimuscarinic effect
• Immediate administration of naloxone

Correct Answer: Intravenous physostigmine under supervision

Q48. Which statement about drug interactions is true for tridihexethyl chloride?

• It can have additive anticholinergic effects with tricyclic antidepressants
• It potentiates the effects of acetylcholinesterase inhibitors
• It neutralizes benzodiazepines leading to sedation loss
• It always enhances insulin sensitivity

Correct Answer: It can have additive anticholinergic effects with tricyclic antidepressants

Q49. Which sign differentiates antimuscarinic toxicity from sympathomimetic toxicity?

• Dry skin and decreased sweating are more typical of antimuscarinic toxicity
• Profuse sweating is typical of antimuscarinic toxicity
• Bradycardia is exclusive to sympathomimetics
• Pupil constriction is characteristic of antimuscarinic poisoning

Correct Answer: Dry skin and decreased sweating are more typical of antimuscarinic toxicity

Q50. For an oral antimuscarinic antisecretory drug like tridihexethyl chloride, key pharmacy counselling points include:

• Take as directed, expect dry mouth/constipation, report urinary retention or vision changes
• Stop the drug abruptly at first sign of mild dry mouth
• Only take with grapefruit juice to increase absorption
• Double the dose with meals to prevent ulcers

Correct Answer: Take as directed, expect dry mouth/constipation, report urinary retention or vision changes

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