Pharmacology MCQs- 252

Q- Which of the following differentiates neostigmine from pilocarpine?

A- Acceleration of heart rate

B- Prolonged skeletal muscle contraction

C- Stimulation of bowel motility

D- Stimulation of salivary glands

B- Prolonged skeletal muscle contraction- Neostigmine is an acetylcholinesterase inhibitor, so it increases acetylcholine at both muscarinic and nicotinic receptors, including the neuromuscular junction, leading to enhanced skeletal muscle contraction. Pilocarpine is a pure muscarinic agonist and has no effect on nicotinic receptors, so it does not cause prolonged skeletal muscle contraction.



Q- An 80 mg dose of a drug was administered to a patient. 40 mg was eliminated during the first hour. This drug follows first-order elimination kinetics.

Which of the following is the amount of the drug that remains 3 hours after administration?

A- 30 mg

B- 20 mg

C- 10 mg

D- None

C- 10 mg- The drug follows first-order kinetics, and since the amount decreased from 80 mg to 40 mg in 1 hour, its half-life is 1 hour.

Amount remaining after 3 half-lives:
80 → 40 (1 hour) → 20 (2 hours) → 10 (3 hours)

So after 3 hours, 10 mg remains.



Q- Which one of the following actions of epinephrine is blocked by prazosin?

A- Bronchial dilation

B- High stroke volume

C- Pupil dilation

D- Tachycardia

C- Pupil dilation- Prazosin is an α₁-adrenergic blocker. Epinephrine causes pupil dilation (mydriasis) through α₁ stimulation, so prazosin blocks this effect. Bronchial dilation is β₂-mediated, tachycardia is β₁-mediated, and increased stroke volume is also mainly β₁-mediated — none of these are blocked by prazosin.

 

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3 thoughts on “Pharmacology MCQs- 252”

  1. I’m sorry. I didn’t include an explanation for some of them. I’m working on that. I have a lot of answers with explanations, though. Thank you for your comment.

  2. Dr please give the answer with explanation
    Thanks

  3. Very good

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