Solanaceous alkaloids – Atropine sulphate MCQs With Answer

Solanaceous alkaloids – Atropine sulphate MCQs With Answer
Solanaceous alkaloids like atropine sulphate are essential topics in pharmacognosy and pharmacology for B. Pharm students. This introduction covers chemistry, sources (Atropa belladonna, Datura), mechanism as competitive muscarinic antagonists, pharmacokinetics (tertiary amine, crosses BBB), therapeutic uses (mydriasis, bradycardia, organophosphate poisoning), adverse effects, contraindications, and lab assay methods. Understanding atropine sulfate’s properties, formulation, and clinical application is critical for safe dispensing and therapeutics. The following MCQs reinforce core concepts, drug interactions, toxicology, and practical identification relevant to pharmacy practice. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which plant is a primary natural source of atropine?

• Digitalis purpurea
• Atropa belladonna
• Papaver somniferum
• Cinchona officinalis

Correct Answer: Atropa belladonna

Q2. Atropine sulfate is classified pharmacologically as a:

• Nicotinic agonist
• Muscarinic antagonist
• Beta-adrenergic blocker
• Cholinesterase inhibitor

Correct Answer: Muscarinic antagonist

Q3. Chemically, atropine is best described as:

• A glycoside
• A tropane alkaloid
• A benzodiazepine derivative
• An opioid peptide

Correct Answer: A tropane alkaloid

Q4. Atropine is a racemic mixture of which active alkaloid?

• Scopolamine
• Hyoscyamine
• Coniine
• Nicotine

Correct Answer: Hyoscyamine

Q5. Which receptor subtype primarily mediates the slowing of heart rate that atropine blocks?

• M1
• M2
• M3
• M4

Correct Answer: M2

Q6. Compared with tertiary amine antimuscarinics, quaternary ammonium antimuscarinics:

• Cross the blood–brain barrier more readily
• Have greater central nervous system effects
• Do not cross the blood–brain barrier easily
• Are always more potent at muscarinic receptors

Correct Answer: Do not cross the blood–brain barrier easily

Q7. The usual initial IV dose of atropine for symptomatic bradycardia in adults per ACLS is:

• 0.05 mg
• 0.5 mg
• 5 mg
• 10 mg

Correct Answer: 0.5 mg

Q8. For organophosphate poisoning, atropine’s primary role is to:

• Reactivate acetylcholinesterase
• Block muscarinic effects of excess acetylcholine
• Reverse nicotinic neuromuscular blockade
• Chelate the organophosphate

Correct Answer: Block muscarinic effects of excess acetylcholine

Q9. Which adverse effect is characteristic of atropine overdose?

• Excessive salivation
• Bradycardia
• Hyperthermia with dry skin
• Increased sweating

Correct Answer: Hyperthermia with dry skin

Q10. The mnemonic “dry as a bone, red as a beet, blind as a bat, mad as a hatter” describes:

• Cholinergic excess
• Anticholinergic (atropine) toxicity
• Opioid overdose
• Benzodiazepine withdrawal

Correct Answer: Anticholinergic (atropine) toxicity

Q11. Atropine sulfate is commonly formulated as the:

• Hydrochloride salt for topical use
• Sulfate salt for parenteral injection
• Free base for oral tablets
• Nitrate salt for inhalation

Correct Answer: Sulfate salt for parenteral injection

Q12. Which ocular effects are produced by topical atropine?

• Miosis and accommodation spasm
• Mydriasis and cycloplegia
• Conjunctival hemorrhage
• Cataract formation

Correct Answer: Mydriasis and cycloplegia

Q13. Which of the following is a contraindication to atropine therapy?

• Acute angle-closure glaucoma
• Sinus tachycardia
• Hypothyroidism
• Asthma

Correct Answer: Acute angle-closure glaucoma

Q14. Atropine crosses the placenta and may cause which of the following in the fetus/newborn?

• Excessive cholinergic stimulation
• Fetal bradycardia
• Potential neonatal anticholinergic effects
• Teratogenic limb defects

Correct Answer: Potential neonatal anticholinergic effects

Q15. Which laboratory method is commonly used for quantitative assay of atropine in pharmaceuticals?

• Gas chromatography with flame ionization detection only
• High-performance liquid chromatography (HPLC)
• Colorimetry without separation
• Infrared spectroscopy alone

Correct Answer: High-performance liquid chromatography (HPLC)

Q16. The pKa of atropine’s tertiary amine (approx.) indicates that at physiological pH it is:

• Mostly un-ionized
• Mostly ionized
• Completely insoluble in water
• Unreactive with receptors

Correct Answer: Mostly ionized

Q17. Which clinical use of atropine involves preoperative administration?

• To increase gastric acid secretion
• To reduce bronchial secretions and salivation
• To induce sedation
• To enhance neuromuscular blockade

Correct Answer: To reduce bronchial secretions and salivation

Q18. Atropine’s action at muscarinic receptors is best described as:

• Irreversible antagonist
• Non-competitive antagonist
• Competitive reversible antagonist
• Partial agonist

Correct Answer: Competitive reversible antagonist

Q19. Which of the following drugs can potentiate anticholinergic effects when co-administered with atropine?

• Neostigmine
• Physostigmine
• Amitriptyline
• Bethanechol

Correct Answer: Amitriptyline

Q20. The active isomer responsible for most of the pharmacologic effects in hyoscyamine is:

• R-hyoscyamine (d-hyoscyamine)
• S-hyoscyamine (l-hyoscyamine)
• R-scopolamine
• R-nicotine

Correct Answer: S-hyoscyamine (l-hyoscyamine)

Q21. Which of the following is the recommended antidote for severe central anticholinergic toxicity from atropine overdose?

• Atropine itself
• Pralidoxime (2-PAM)
• Physostigmine
• Naloxone

Correct Answer: Physostigmine

Q22. Compared to atropine, glycopyrrolate differs mainly by being:

• A tertiary amine that crosses the BBB easily
• A quaternary ammonium compound with limited CNS penetration
• A cholinesterase inhibitor
• An alpha-adrenergic agonist

Correct Answer: A quaternary ammonium compound with limited CNS penetration

Q23. Which effect is primarily mediated by blockade of M3 receptors by atropine?

• Decreased heart rate
• Urinary retention due to detrusor relaxation
• Increased salivation
• Enhanced sweat production

Correct Answer: Urinary retention due to detrusor relaxation

Q24. The most serious clinical ocular complication of topical atropine in a predisposed patient is:

• Conjunctivitis
• Acute angle-closure glaucoma
• Papilledema
• Retinal detachment

Correct Answer: Acute angle-closure glaucoma

Q25. In pharmacokinetics, atropine’s approximate plasma half-life in adults is:

• 30 minutes
• 2–4 hours
• 24–48 hours
• 7–10 days

Correct Answer: 2–4 hours

Q26. Atropine’s effect on airway smooth muscle is generally to:

• Cause bronchoconstriction via M2 stimulation
• Cause bronchodilation by blocking M3-mediated constriction
• Increase mucus secretion
• Enhance histamine release

Correct Answer: Cause bronchodilation by blocking M3-mediated constriction

Q27. Which spectrometric technique provides structural information and is used in alkaloid identification, including atropine?

• Ultraviolet-visible (UV-Vis) spectrophotometry only
• Mass spectrometry (MS)
• pH titration
• Paper chromatography without detection

Correct Answer: Mass spectrometry (MS)

Q28. Which symptom differentiates central anticholinergic syndrome from peripheral atropine effects?

• Dry mouth
• Delirium and hallucinations
• Mydriasis
• Tachycardia

Correct Answer: Delirium and hallucinations

Q29. Atropine is effective in treating bradyarrhythmias because it:

• Stimulates vagal tone
• Blocks vagal effects on the heart
• Directly activates beta-1 receptors
• Prolongs AV conduction via calcium channels

Correct Answer: Blocks vagal effects on the heart

Q30. Which statement about atropine sulfate stability and storage is correct?

• It is highly photosensitive and must be stored in amber containers
• It is volatile and stored under inert gas only
• It decomposes only at −20°C
• It is stable at any temperature indefinitely

Correct Answer: It is highly photosensitive and must be stored in amber containers

Q31. In the context of biosynthesis, atropine is formed by esterification of tropine with:

• Benzoic acid
• Tropic acid
• Acetic acid
• Formic acid

Correct Answer: Tropic acid

Q32. Which clinical condition might be worsened by atropine because of urinary retention risk?

• Benign prostatic hyperplasia (BPH)
• Insulin-dependent diabetes mellitus
• Hypotension
• Hyperthyroidism

Correct Answer: Benign prostatic hyperplasia (BPH)

Q33. Which laboratory test result may be seen in severe anticholinergic toxicity?

• Hypothermia
• Miosis
• Elevated core body temperature
• Excessive sweating

Correct Answer: Elevated core body temperature

Q34. Which of the following is true regarding atropine’s action on gastrointestinal motility?

• It increases gastric motility and secretions
• It decreases motility and reduces secretions
• It selectively increases bowel peristalsis
• It acts as a prokinetic agent via dopamine receptors

Correct Answer: It decreases motility and reduces secretions

Q35. The ocular cycloplegic effect of atropine is due to blockade of which process?

• Smooth muscle contraction of the ciliary body
• Lens capsule elasticity change
• Inhibition of retinal phototransduction
• Stimulation of lacrimal secretion

Correct Answer: Smooth muscle contraction of the ciliary body

Q36. Which formulation of atropine is least likely to produce systemic anticholinergic effects?

• IV injection of atropine sulfate
• Oral immediate-release tablets
• Topical ophthalmic drops in small dose
• IM injection of atropine

Correct Answer: Topical ophthalmic drops in small dose

Q37. Which pharmacological agent antagonizes both central and peripheral effects of atropine overdose?

• Neostigmine (does not cross BBB)
• Physostigmine (crosses BBB)
• Propranolol
• Diphenhydramine

Correct Answer: Physostigmine (crosses BBB)

Q38. During chromatographic identification, atropine is classified as which type of compound affecting Rf values?

• Highly polar ionic compound when protonated
• Nonpolar neutral hydrocarbon
• Large peptide
• Inorganic salt

Correct Answer: Highly polar ionic compound when protonated

Q39. For eye examinations requiring prolonged cycloplegia, atropine’s duration of action is typically:

• Minutes
• Hours to days
• Less than 30 seconds
• Indefinite

Correct Answer: Hours to days

Q40. Atropine’s effect on sweat glands is to:

• Increase sweating via sympathetic cholinergic blockade
• Decrease sweating because thermoregulatory sweating is cholinergically mediated
• Have no effect because sweat glands are adrenergic
• Stimulate apocrine secretion exclusively

Correct Answer: Decrease sweating because thermoregulatory sweating is cholinergically mediated

Q41. Which diagnostic test can detect atropine or related alkaloids in biological fluids in forensic toxicology?

• Thin-layer chromatography without confirmation
• Gas chromatography–mass spectrometry (GC-MS)
• Urine dipstick
• Complete blood count (CBC)

Correct Answer: Gas chromatography–mass spectrometry (GC-MS)

Q42. An interaction of atropine with which drug class increases risk of severe anticholinergic effects and delirium?

• Beta blockers
• Typical and atypical antipsychotics with anticholinergic properties
• SSRIs without anticholinergic effects
• ACE inhibitors

Correct Answer: Typical and atypical antipsychotics with anticholinergic properties

Q43. Which statement regarding atropine’s effect on blood pressure is most accurate?

• It always causes hypertension by vasoconstriction
• It may cause modest tachycardia and variable blood pressure changes
• It causes prolonged hypotension due to vasodilation
• It has no effect on heart rate or blood pressure

Correct Answer: It may cause modest tachycardia and variable blood pressure changes

Q44. Atropine’s mechanism of reversing organophosphate-induced bronchorrhea is primarily through blockade of:

• Nicotinic receptors at the neuromuscular junction
• Muscarinic receptors on bronchial glands
• Beta-2 adrenergic receptors
• Histamine H1 receptors

Correct Answer: Muscarinic receptors on bronchial glands

Q45. Which structural feature is essential for atropine’s antimuscarinic activity?

• Peptide bond
• A tertiary nitrogen atom in the tropane ring
• Sulfhydryl group
• Phenolic hydroxyl group only

Correct Answer: A tertiary nitrogen atom in the tropane ring

Q46. When formulating atropine sulfate injection, why is sulfate often used as the counterion?

• To decrease water solubility
• To increase water solubility and stability for parenteral use
• To make it volatile for inhalation
• To render it inactive until metabolized

Correct Answer: To increase water solubility and stability for parenteral use

Q47. Which of the following is a peripheral sign of antimuscarinic action from atropine?

• Bradycardia
• Excessive salivation
• Dry mouth (xerostomia)
• Pinpoint pupils

Correct Answer: Dry mouth (xerostomia)

Q48. In pharmacology practicals, a common qualitative test for tropane alkaloids uses which reagent to produce characteristic color?

• Biuret reagent
• Dragendorff’s reagent
• Lead acetate
• Potassium permanganate only

Correct Answer: Dragendorff’s reagent

Q49. Which of the following best explains why atropine does not reverse nicotinic receptor-mediated muscle weakness in organophosphate poisoning?

• Atropine selectively blocks muscarinic receptors, not nicotinic receptors at the neuromuscular junction
• Atropine enhances nicotinic receptor activation
• Atropine irreversibly inactivates acetylcholinesterase
• Atropine acts as a nicotinic agonist causing further weakness

Correct Answer: Atropine selectively blocks muscarinic receptors, not nicotinic receptors at the neuromuscular junction

Q50. Which practice is important when dispensing atropine-containing eye drops to a patient?

• Advise patient that repeated systemic doses are beneficial for glaucoma
• Warn about potential photophobia and advise sunglasses due to mydriasis
• Recommend driving immediately after instillation
• State that no systemic absorption is possible so side effects are impossible

Correct Answer: Warn about potential photophobia and advise sunglasses due to mydriasis

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