Direct acting parasympathomimetics – Pilocarpine MCQs With Answer

Direct acting parasympathomimetics – Pilocarpine MCQs With Answer

Pilocarpine is a prototypical direct-acting parasympathomimetic and a muscarinic agonist frequently covered in B.Pharm pharmacology. This focused set of MCQs reviews pilocarpine’s mechanism of action, receptor selectivity, pharmacokinetics, formulations, ocular and systemic therapeutic uses (notably glaucoma and xerostomia), adverse effects, contraindications, and drug interactions. Each question emphasizes clinical relevance, signaling pathways, and distinctions from other cholinergic agents to build exam-ready understanding. Ideal for revision and self-assessment, these pilocarpine MCQs reinforce key concepts in cholinergic pharmacology and therapeutics for pharmacy students. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which receptor subtype does pilocarpine primarily activate?

• Nicotine receptors on autonomic ganglia
• Muscarinic receptors, especially M3
• Alpha-adrenergic receptors
• Benzodiazepine receptors

Correct Answer: Muscarinic receptors, especially M3

Q2. Pilocarpine is classified pharmacologically as a:

• Indirect cholinergic agonist (AChE inhibitor)
• Beta-adrenergic agonist
• Direct-acting parasympathomimetic
• Antimuscarinic agent

Correct Answer: Direct-acting parasympathomimetic

Q3. Which therapeutic use of pilocarpine is most common in ophthalmology?

• Treatment of mydriasis
• Lowering intraocular pressure in glaucoma
• Long-term treatment of macular degeneration
• Inhibiting lacrimal secretion

Correct Answer: Lowering intraocular pressure in glaucoma

Q4. Pilocarpine’s mechanism to reduce intraocular pressure primarily involves:

• Decreasing aqueous humor production by ciliary epithelium
• Increasing trabecular meshwork outflow by contracting the ciliary muscle
• Blocking beta receptors in the eye
• Inhibiting carbonic anhydrase

Correct Answer: Increasing trabecular meshwork outflow by contracting the ciliary muscle

Q5. Which property of pilocarpine allows it to penetrate the cornea when used as eye drops?

• It is a large protein molecule
• It is a tertiary amine with sufficient lipid solubility
• It is an ionic salt that remains on the corneal surface
• It is highly protein-bound in tears

Correct Answer: It is a tertiary amine with sufficient lipid solubility

Q6. Systemic adverse effects of pilocarpine are primarily due to:

• Excess stimulation of muscarinic receptors
• Antagonism of nicotinic receptors
• Blockade of GABA receptors
• Inhibition of prostaglandin synthesis

Correct Answer: Excess stimulation of muscarinic receptors

Q7. Which of the following is a common systemic side effect of pilocarpine?

• Tachycardia
• Dry mouth
• Diarrhea and sweating
• Urinary retention

Correct Answer: Diarrhea and sweating

Q8. Pilocarpine is used orally to treat which condition related to salivary glands?

• Hyper-salivation
• Xerostomia (dry mouth), such as in Sjögren’s syndrome
• Oral candidiasis
• Salivary gland neoplasm

Correct Answer: Xerostomia (dry mouth), such as in Sjögren’s syndrome

Q9. Which statement about pilocarpine’s effect on heart rate is correct?

• It causes marked tachycardia via beta stimulation
• It has no effect on heart rate
• It may cause bradycardia through vagal muscarinic activation
• It directly blocks cardiac sodium channels

Correct Answer: It may cause bradycardia through vagal muscarinic activation

Q10. Pilocarpine’s action is NOT significantly affected by which of the following?

• Atropine (a muscarinic antagonist)
• Edrophonium (an AChE inhibitor)
• Renal clearance rates
• Ciliary muscle responsiveness

Correct Answer: Atropine (a muscarinic antagonist)

Q11. Pilocarpine differs from bethanechol mainly because:

• Pilocarpine is primarily nicotinic while bethanechol is muscarinic
• Pilocarpine crosses the blood-brain barrier more easily as a tertiary amine
• Bethanechol is a tertiary amine and crosses BBB readily
• Both are identical in receptor selectivity and penetration

Correct Answer: Pilocarpine crosses the blood-brain barrier more easily as a tertiary amine

Q12. Which contraindication is most relevant for pilocarpine therapy?

• Hypertension uncontrolled
• Asthma or COPD due to bronchospasm risk
• Hypothyroidism
• Hyperlipidemia

Correct Answer: Asthma or COPD due to bronchospasm risk

Q13. Pilocarpine-induced miosis is useful diagnostically to:

• Dilate the pupil for retinal examination
• Differentiate between tonic (Adie) pupil and pharmacologic blockade
• Induce cycloplegia for refraction testing
• Reduce tear production

Correct Answer: Differentiate between tonic (Adie) pupil and pharmacologic blockade

Q14. Which formulation of pilocarpine is commonly used for glaucoma?

• Intravenous solution
• Ophthalmic drops
• Topical cream
• Inhaler

Correct Answer: Ophthalmic drops

Q15. The onset of action for topical pilocarpine eye drops is generally:

• Within minutes
• After several days
• After 24 hours
• Not observable clinically

Correct Answer: Within minutes

Q16. Pilocarpine’s effect on accommodation (near vision) is due to:

• Paralysis of the ciliary muscle
• Contraction of the ciliary muscle increasing lens curvature
• Blocking of alpha-adrenergic receptors in the lens
• Dehydration of the lens

Correct Answer: Contraction of the ciliary muscle increasing lens curvature

Q17. Pilocarpine-induced sweating occurs because muscarinic receptors in sweat glands are mediated via:

• Parasympathetic cholinergic M2 receptors
• Sympathetic cholinergic muscarinic receptors
• Adrenergic beta receptors
• Nicotine receptor activation only

Correct Answer: Sympathetic cholinergic muscarinic receptors

Q18. Which statement is true regarding pilocarpine metabolism?

• It is primarily metabolized by intestinal flora
• It undergoes hepatic metabolism and renal excretion
• It is not metabolized and is excreted unchanged in feces
• It is inactivated only by acetylcholinesterase

Correct Answer: It undergoes hepatic metabolism and renal excretion

Q19. In acute angle-closure glaucoma, pilocarpine is used to:

• Immediately dilate the pupil to relieve pressure
• Constrict the pupil to open trabecular meshwork outflow once cornea is clear
• Increase aqueous humor production
• Act as first-line single therapy in all cases

Correct Answer: Constrict the pupil to open trabecular meshwork outflow once cornea is clear

Q20. Which drug interaction increases the effect of pilocarpine?

• Atropine administration
• Concomitant use of beta-blockers alone
• Other muscarinic agonists or cholinesterase inhibitors
• Anticholinergic antihistamines

Correct Answer: Other muscarinic agonists or cholinesterase inhibitors

Q21. Pilocarpine’s ability to stimulate sweat and saliva is due to activation of:

• M2 receptors only
• M3 receptors on exocrine glands
• Nicotinic receptors on skeletal muscle
• Beta-2 adrenergic receptors

Correct Answer: M3 receptors on exocrine glands

Q22. Which adverse ocular effect may occur with chronic topical pilocarpine use?

• Cataract formation
• Progressive myopia due to ciliary spasm
• Permanent mydriasis
• Retinal detachment prevention

Correct Answer: Progressive myopia due to ciliary spasm

Q23. Pilocarpine is effective in treating which type of glaucoma most directly?

• Open-angle glaucoma exclusively
• Angle-closure glaucoma after acute management
• Congenital glaucoma only
• Neovascular glaucoma with no surgical options

Correct Answer: Angle-closure glaucoma after acute management

Q24. Pilocarpine’s chemical nature as a tertiary amine implies:

• It cannot cross lipid membranes
• It has poor oral absorption and cannot cross BBB
• It is more lipid soluble and can cross the blood-brain barrier
• It is permanently ionized and inactive systemically

Correct Answer: It is more lipid soluble and can cross the blood-brain barrier

Q25. Compared to acetylcholine, pilocarpine has:

• Shorter duration of action and is rapidly hydrolyzed by AChE
• Greater resistance to acetylcholinesterase and longer duration of action
• No activity at muscarinic receptors
• Primarily nicotinic agonist effects

Correct Answer: Greater resistance to acetylcholinesterase and longer duration of action

Q26. Which patient history would be a caution for prescribing systemic pilocarpine?

• History of bradycardia or recent myocardial infarction
• History of gastroesophageal reflux disease only
• History of controlled seasonal allergies
• Minor postoperative nausea

Correct Answer: History of bradycardia or recent myocardial infarction

Q27. Pilocarpine’s effect on intraocular pressure is most closely linked to:

• Contraction of the dilator pupillae muscle
• Relaxation of trabecular meshwork
• Contraction of the ciliary muscle improving trabecular outflow
• Decreased venous drainage from the choroid

Correct Answer: Contraction of the ciliary muscle improving trabecular outflow

Q28. Which exam-focused point best distinguishes pilocarpine from indirect cholinomimetics?

• Pilocarpine requires AChE inhibition to act
• Pilocarpine directly binds and activates muscarinic receptors
• Pilocarpine is inactive in presence of atropine
• Pilocarpine acts primarily on nicotinic receptors

Correct Answer: Pilocarpine directly binds and activates muscarinic receptors

Q29. In pharmacology, pilocarpine is often used as a prototype to teach:

• Beta-blocker adverse effects
• Muscarinic agonist pharmacodynamics and ocular therapeutics
• Calcium channel blocker mechanisms
• Serotonin reuptake inhibitor pharmacology

Correct Answer: Muscarinic agonist pharmacodynamics and ocular therapeutics

Q30. Which laboratory sign might indicate excessive systemic pilocarpine activity?

• Hyperglycemia
• Excessive salivation and lacrimation
• Increased serum creatinine kinase
• Elevated thyroid hormones

Correct Answer: Excessive salivation and lacrimation

Q31. Why is pilocarpine sometimes used diagnostically in neurology?

• To confirm catecholamine deficiency
• To test parasympathetic innervation of the pupil (e.g., Adie pupil)
• To stimulate sympathetic sweat response exclusively
• To assess muscular dystrophy

Correct Answer: To test parasympathetic innervation of the pupil (e.g., Adie pupil)

Q32. Which of the following best explains pilocarpine’s use in Sjögren’s syndrome?

• It inhibits immune-mediated gland destruction
• It stimulates residual salivary and lacrimal gland secretions via muscarinic receptors
• It neutralizes autoantibodies
• It reduces gland inflammation by acting as an NSAID

Correct Answer: It stimulates residual salivary and lacrimal gland secretions via muscarinic receptors

Q33. Which pharmacological agent would antagonize pilocarpine’s ocular effects?

• Phenylephrine (alpha agonist)
• Atropine (muscarinic antagonist)
• Timolol (beta blocker)
• Acetazolamide (carbonic anhydrase inhibitor)

Correct Answer: Atropine (muscarinic antagonist)

Q34. Which sign indicates cholinergic crisis from overdose of pilocarpine?

• Dry skin, mydriasis, urinary retention
• Bradycardia, bronchospasm, excessive secretions
• Hyperreflexia and hypertension only
• Severe hyperglycemia and polyuria

Correct Answer: Bradycardia, bronchospasm, excessive secretions

Q35. Pilocarpine eye drops may be less effective in advanced glaucoma due to:

• Loss of ciliary muscle responsiveness and structural angle closure
• Excessive production of aqueous humor only
• Systemic tolerance that reduces ocular action
• Immediate metabolism by tear enzymes

Correct Answer: Loss of ciliary muscle responsiveness and structural angle closure

Q36. Which receptor subtype in the eye mediates pilocarpine-induced contraction of the sphincter pupillae?

• M1 muscarinic receptors
• M2 muscarinic receptors
• M3 muscarinic receptors
• Nicotinic receptors

Correct Answer: M3 muscarinic receptors

Q37. Pilocarpine’s role in lowering intraocular pressure is least dependent on:

• Contraction of ciliary muscle
• Opening of trabecular meshwork
• Decreased production of aqueous humor
• Increased uveoscleral outflow

Correct Answer: Increased uveoscleral outflow

Q38. Which patient population should receive pilocarpine with caution due to risk of blurred vision and difficulty in low light?

• Night drivers and elderly patients due to induced miosis and reduced night vision
• Young athletes only
• Patients with hyperopia only
• Patients with well-controlled diabetes

Correct Answer: Night drivers and elderly patients due to induced miosis and reduced night vision

Q39. Which drug class would most likely reduce the ocular effectiveness of pilocarpine when co-administered?

• Topical beta blockers
• Amino glycoside antibiotics
• Topical antimuscarinics like tropicamide
• Carbonic anhydrase inhibitors

Correct Answer: Topical antimuscarinics like tropicamide

Q40. Pilocarpine testing can help distinguish a pharmacologically dilated pupil from a third nerve palsy because:

• Pilocarpine constricts a pupil with intact muscarinic receptors but not one with denervation supersensitivity
• A pharmacologically dilated pupil will constrict to pilocarpine while a nerve palsy will not
• Denervated pupils show supersensitivity and may constrict to dilute pilocarpine
• Pilocarpine has no diagnostic utility in pupillary evaluation

Correct Answer: Denervated pupils show supersensitivity and may constrict to dilute pilocarpine

Q41. Which pharmacokinetic feature is relevant when switching from topical to systemic pilocarpine?

• Topical route leads to higher systemic bioavailability than oral
• Systemic dosing increases risk of generalized muscarinic side effects
• Systemic pilocarpine is not absorbed orally at all
• Topical pilocarpine causes systemic immunosuppression

Correct Answer: Systemic dosing increases risk of generalized muscarinic side effects

Q42. For exam purposes, pilocarpine is often contrasted with carbachol because:

• Both are muscarinic antagonists
• Carbachol has both muscarinic and nicotinic activity and is more resistant to AChE
• Carbachol is a pure beta agonist
• Pilocarpine is an irreversible enzyme inhibitor while carbachol is not

Correct Answer: Carbachol has both muscarinic and nicotinic activity and is more resistant to AChE

Q43. Which sign suggests that pilocarpine eye drops were accidentally ingested systemically in a child?

• Dry mouth and constipation
• Excessive salivation, vomiting, and sweating
• Mydriasis and tachycardia
• Hyperactivity with insomnia

Correct Answer: Excessive salivation, vomiting, and sweating

Q44. In emergency management of pilocarpine overdose, which antidote is appropriate?

• Neostigmine
• Atropine
• Propranolol
• Physostigmine

Correct Answer: Atropine

Q45. Which feature makes pilocarpine useful in stimulating secretions even after nerve injury?

• It requires presynaptic release of acetylcholine
• It acts directly on postsynaptic muscarinic receptors, bypassing presynaptic failure
• It enhances adrenergic stimulation of glands
• It inhibits muscarinic receptors to upregulate secretion

Correct Answer: It acts directly on postsynaptic muscarinic receptors, bypassing presynaptic failure

Q46. Which ocular measurement would you expect after pilocarpine instillation?

• Increase in pupil diameter
• Decrease in pupil diameter (miosis)
• Immediate corneal epithelial thickening
• Marked increase in axial length

Correct Answer: Decrease in pupil diameter (miosis)

Q47. Which of the following best describes tachyphylaxis with topical pilocarpine?

• No tolerance develops with repeated dosing
• Tolerance may occur with chronic use decreasing efficacy
• Tachyphylaxis leads to permanent loss of muscarinic receptors
• Tachyphylaxis is only relevant to oral corticosteroids

Correct Answer: Tolerance may occur with chronic use decreasing efficacy

Q48. Which structural property of pilocarpine is responsible for its muscarinic selectivity?

• Presence of a quaternary ammonium group
• Tertiary amine and ring structure that favor muscarinic receptor binding
• Peptide backbone similar to acetylcholine
• Highly lipophilic steroid core

Correct Answer: Tertiary amine and ring structure that favor muscarinic receptor binding

Q49. Which clinical scenario would make pilocarpine contraindicated?

• Patient with refractory dry mouth from radiation therapy
• Patient with uncontrolled asthma experiencing bronchospasm
• Patient with chronic glaucoma under specialist care
• Patient with mild, intermittent dry eye

Correct Answer: Patient with uncontrolled asthma experiencing bronchospasm

Q50. Which teaching point is important when advising patients about pilocarpine eye drops?

• Expect immediate increased night vision
• Avoid driving at night initially due to miosis and blurred vision
• Systemic absorption is impossible, so systemic side effects never occur
• They should discontinue other glaucoma meds without consulting physician

Correct Answer: Avoid driving at night initially due to miosis and blurred vision

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