DO Osteopathic Pharmacology 2

Question 1

A patient on carbamazepine for epilepsy presents with hyponatremia. What is the most likely mechanism?

Accepted Answer

Stimulation of ADH secretion and enhanced ADH activity causing SIADH

Answer

Renal wasting of sodium via mineralocorticoid antagonism

Answer

Inhibition of aldosterone synthesis

Answer

Osmotic diuresis leading to free water retention

Question 2

What is the primary mechanism of action of metformin in treating type 2 diabetes mellitus?

Accepted Answer

Activates AMPK to reduce hepatic gluconeogenesis

Answer

Stimulates insulin secretion from pancreatic beta cells

Answer

Inhibits intestinal alpha-glucosidase

Answer

Blocks renal SGLT-2 transporter to enhance glucose excretion

Question 3

A patient on phenelzine (MAOI) eats aged cheddar cheese and develops a severe hypertensive crisis. What is the mechanism?

Accepted Answer

Tyramine displaces stored catecholamines from presynaptic vesicles

Answer

Tyramine directly stimulates alpha-1 adrenergic receptors

Answer

Tyramine inhibits catecholamine reuptake transporters

Answer

Tyramine increases renal renin secretion

Question 4

A patient presents with acetaminophen overdose 4 hours after ingestion. What is the correct antidote and its mechanism?

Accepted Answer

N-acetylcysteine — replenishes glutathione stores

Answer

Flumazenil — benzodiazepine receptor antagonist

Answer

Fomepizole — inhibits alcohol dehydrogenase

Answer

Pralidoxime — regenerates acetylcholinesterase

Question 5

A patient with chronic gout is started on allopurinol. What is the mechanism by which allopurinol reduces serum uric acid?

Accepted Answer

Inhibits xanthine oxidase reducing uric acid production

Answer

Inhibits prostaglandin synthesis reducing inflammation

Answer

Increases renal uric acid excretion via OAT transporters

Answer

Blocks URAT1 transporter preventing uric acid reabsorption

Question 6

Which antibiotic class inhibits the 30S ribosomal subunit, is contraindicated in children under 8, and frequently causes photosensitivity?

Accepted Answer

Tetracyclines

Answer

Macrolides

Answer

Fluoroquinolones

Answer

Aminoglycosides

Question 7

What is the mechanism underlying aspirin's antiplatelet effect that distinguishes it from other NSAIDs?

Accepted Answer

Irreversible acetylation of COX-1 permanently blocking thromboxane A2 synthesis

Answer

Reversible inhibition of cyclooxygenase-1 in platelets

Answer

Competitive blockade of ADP receptors on platelet membranes

Answer

Inhibition of thromboxane A2 receptors on platelets