B.Pharm. Bachelor of Pharmacy Pharmacology 1 — Questions and Answers
Question 1: Which receptor type mediates the bronchodilatory effect of epinephrine in the lungs?
- Alpha-1 adrenergic
- Beta-2 adrenergic (Correct answer)
- Muscarinic M2
- Dopamine D2
Correct answer: Beta-2 adrenergic
Epinephrine activates beta-2 adrenergic receptors in bronchial smooth muscle, causing relaxation and bronchodilation.
Question 2: What is the primary mechanism of action of aspirin (acetylsalicylic acid)?
- Reversible inhibition of COX-1 and COX-2
- Irreversible inhibition of COX-1 and COX-2 (Correct answer)
- Selective COX-2 inhibition
- Inhibition of lipoxygenase
Correct answer: Irreversible inhibition of COX-1 and COX-2
Aspirin irreversibly acetylates and inhibits both COX-1 and COX-2 enzymes, reducing prostaglandin synthesis.
Question 3: Which pharmacokinetic parameter describes the fraction of an administered drug that reaches systemic circulation unchanged?
- Volume of distribution
- Clearance
- Bioavailability (Correct answer)
- Half-life
Correct answer: Bioavailability
Bioavailability (F) is the fraction of an administered dose that reaches systemic circulation in its active form.
Question 4: The therapeutic index of a drug is calculated as:
- ED50 / LD50
- LD50 / ED50 (Correct answer)
- EC50 / LD50
- LD50 / EC50
Correct answer: LD50 / ED50
The therapeutic index equals LD50 divided by ED50; a higher value indicates a wider margin of safety.
Question 5: Which class of antihypertensive drugs acts by blocking angiotensin-converting enzyme (ACE)?
- ARBs
- Beta-blockers
- ACE inhibitors (Correct answer)
- Calcium channel blockers
Correct answer: ACE inhibitors
ACE inhibitors (e.g., lisinopril, enalapril) block ACE, preventing conversion of angiotensin I to angiotensin II, lowering blood pressure.
Question 6: First-pass metabolism primarily occurs in which organ after oral drug administration?
- Kidney
- Lung
- Liver (Correct answer)
- Small intestine only
Correct answer: Liver
The liver is the primary site of first-pass metabolism, where orally absorbed drugs undergo extensive biotransformation before reaching systemic circulation.
B.Pharm. Bachelor of Pharmacy Pharmacology 1
Which receptor type mediates the bronchodilatory effect of epinephrine in the lungs?