Parasympatholytics MCQs With Answer offers B. Pharm students a focused review of antimuscarinic pharmacology, clinical uses, and safety. This concise collection emphasizes mechanism of action, muscarinic receptor subtypes (M1–M5), differences between tertiary and quaternary amines, therapeutic agents (atropine, scopolamine, glycopyrrolate, ipratropium, tiotropium, oxybutynin), pharmacokinetics, adverse effects, contraindications, and antidotes. Questions explore receptor selectivity, CNS versus peripheral effects, inhaled versus systemic drugs, and important drug interactions—essential for exam preparation and safe clinical practice. Each MCQ reinforces core concepts and problem-solving skills relevant to pharmacology, therapeutics, and toxicology. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What is the primary pharmacological classification of parasympatholytic drugs?
- Acetylcholinesterase inhibitors
- Antimuscarinics
- Nicotinic agonists
- Beta-adrenergic blockers
Correct Answer: Antimuscarinics
Q2. Parasympatholytics exert their main action by blocking which receptors?
- Nicotinic receptors
- Alpha-adrenergic receptors
- Muscarinic receptors
- Beta-adrenergic receptors
Correct Answer: Muscarinic receptors
Q3. Which muscarinic receptor subtype predominantly mediates cardiac effects (slowing heart rate)?
- M1
- M2
- M3
- M4
Correct Answer: M2
Q4. Which chemical class of antimuscarinics more readily crosses the blood–brain barrier?
- Quaternary amines
- Tertiary amines
- Peptide conjugates
- Metal complexes
Correct Answer: Tertiary amines
Q5. Which parasympatholytic is most frequently used for motion sickness and has prominent central effects?
- Atropine
- Scopolamine
- Glycopyrrolate
- Ipratropium
Correct Answer: Scopolamine
Q6. Which antimuscarinic is a long-acting inhaled bronchodilator commonly used in COPD?
- Ipratropium
- Tiotropium
- Atropine
- Glycopyrrolate
Correct Answer: Tiotropium
Q7. Which drug is a classic antimuscarinic used to treat overactive bladder?
- Glycopyrrolate
- Oxybutynin
- Scopolamine
- Neostigmine
Correct Answer: Oxybutynin
Q8. In organophosphate poisoning, which drug provides muscarinic receptor antagonism to relieve life‑threatening bronchorrhea and bronchospasm?
- Neostigmine
- Atropine
- Physostigmine
- Pralidoxime
Correct Answer: Atropine
Q9. Blockade of which muscarinic subtype in the bladder causes urinary retention by relaxing detrusor muscle?
- M1
- M2
- M3
- M4
Correct Answer: M3
Q10. Which antimuscarinic is a quaternary ammonium used perioperatively to reduce salivation with minimal CNS effects?
- Atropine
- Glycopyrrolate
- Scopolamine
- Ipratropium
Correct Answer: Glycopyrrolate
Q11. Topical ocular atropine produces which effects on the pupil and accommodation?
- Miosis only
- Mydriasis only
- Mydriasis and cycloplegia
- Cycloplegia only
Correct Answer: Mydriasis and cycloplegia
Q12. Which of the following is least likely to occur as an antimuscarinic adverse effect?
- Dry mouth
- Blurred vision
- Bronchoconstriction
- Tachycardia
Correct Answer: Bronchoconstriction
Q13. Which cholinesterase inhibitor reverses central anticholinergic toxicity because it crosses the blood–brain barrier?
- Neostigmine
- Physostigmine
- Edrophonium
- Pralidoxime
Correct Answer: Physostigmine
Q14. Compared with atropine, glycopyrrolate differs primarily because it:
- Has greater CNS penetration
- Is a quaternary ammonium with minimal CNS penetration
- Is more lipophilic and longer acting centrally
- Is an irreversible muscarinic antagonist
Correct Answer: Is a quaternary ammonium with minimal CNS penetration
Q15. Which muscarinic receptor subtype largely mediates glandular secretion (saliva, gastric acid, sweat)?
- M1
- M2
- M3
- M5
Correct Answer: M3
Q16. Ipratropium is primarily used therapeutically as a:
- Systemic antispasmodic for urinary incontinence
- Inhaled bronchodilator for COPD/asthma
- Topical mydriatic for eye exams
- CNS sedative for motion sickness
Correct Answer: Inhaled bronchodilator for COPD/asthma
Q17. Which antimuscarinic is most likely to cause central sedation and amnesia when absorbed systemically?
- Scopolamine
- Glycopyrrolate
- Ipratropium
- Tiotropium
Correct Answer: Scopolamine
Q18. The first‑line specific pharmacologic treatment for severe antimuscarinic (anticholinergic) overdose with delirium is:
- Activated charcoal
- Physostigmine
- Naloxone
- Flumazenil
Correct Answer: Physostigmine
Q19. Which property explains tiotropium’s long duration of action compared with ipratropium?
- Higher oral bioavailability
- Irreversible covalent binding to receptors
- Slow dissociation from muscarinic receptors
- Rapid renal clearance
Correct Answer: Slow dissociation from muscarinic receptors
Q20. Antimuscarinic drugs historically reduced gastric acid secretion by blocking which mechanism?
- Blocking histamine H2 receptors on parietal cells
- Blocking vagal M3 receptor-mediated stimulation of parietal cells
- Stimulating somatostatin release
- Inhibiting prostaglandin synthesis
Correct Answer: Blocking vagal M3 receptor-mediated stimulation of parietal cells
Q21. Antimuscarinic blockade of sweat glands leads to which clinical consequence?
- Excessive sweating and hypothermia
- Decreased sweating and risk of hyperthermia
- No change in thermoregulation
- Increased salivation to compensate
Correct Answer: Decreased sweating and risk of hyperthermia
Q22. Antimuscarinic drugs are contraindicated or used with extreme caution in patients with:
- Open‑angle glaucoma
- Narrow‑angle glaucoma
- Type 1 diabetes mellitus
- Hypothyroidism
Correct Answer: Narrow‑angle glaucoma
Q23. Which agent is used to reactivate acetylcholinesterase at nicotinic synapses in organophosphate poisoning?
- Atropine
- Pralidoxime (2‑PAM)
- Physostigmine
- Glycopyrrolate
Correct Answer: Pralidoxime (2‑PAM)
Q24. A common gastrointestinal adverse effect of antimuscarinics is:
- Diarrhea
- Constipation
- Increased GI secretions
- Hyperperistalsis
Correct Answer: Constipation
Q25. Which muscarinic subtype in the CNS has been most associated with cognitive function and is implicated when antimuscarinics cause confusion?
- M1
- M2
- M3
- M4
Correct Answer: M1
Q26. Which antimuscarinic is commonly used to reduce drooling (sialorrhea) in neurological patients?
- Atropine eye drops
- Glycopyrrolate
- Scopolamine patch
- Botulinum toxin (oral)
Correct Answer: Glycopyrrolate
Q27. In anesthesia practice, which antimuscarinic is preferred to reduce airway secretions while minimizing central side effects?
- Atropine
- Glycopyrrolate
- Scopolamine
- Ipratropium
Correct Answer: Glycopyrrolate
Q28. Pharmacologically, most therapeutic antimuscarinic agents act as which type of antagonists at muscarinic receptors?
- Irreversible antagonists
- Competitive reversible antagonists
- Allosteric potentiators
- Partial agonists
Correct Answer: Competitive reversible antagonists
Q29. A characteristic of quaternary ammonium antimuscarinic drugs is that they are:
- Highly lipophilic and penetrate the CNS readily
- Poorly absorbed orally with minimal CNS penetration
- Extensively metabolized to active CNS metabolites
- Strongly protein bound and accumulate in adipose tissue
Correct Answer: Poorly absorbed orally with minimal CNS penetration
Q30. Co‑administration of antimuscarinics with which class of drugs increases anticholinergic toxicity risk?
- ACE inhibitors
- Beta‑blockers
- Tricyclic antidepressants
- Cholinesterase inhibitors
Correct Answer: Tricyclic antidepressants
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