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

Carbamazepine stimulates ADH release and potentiates its action on V2 receptors in renal collecting ducts, causing SIADH and hyponatremia.

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

Metformin activates AMP-activated protein kinase (AMPK), which suppresses hepatic glucose production without directly stimulating insulin secretion.

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

Without GI MAO to metabolize it, tyramine is absorbed systemically and enters presynaptic terminals where it displaces stored norepinephrine, causing massive NE release.

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

N-acetylcysteine provides cysteine as a glutathione precursor, allowing hepatocytes to detoxify NAPQI before it causes irreversible oxidative damage.

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

Allopurinol is a xanthine oxidase inhibitor that reduces conversion of hypoxanthine to xanthine and xanthine to uric acid, lowering uric acid production.

DO - Doctor of Osteopathic Medicine Practice Test

DO - Doctor of Osteopathic Medicine Practice Test

DO Osteopathic Pharmacology 2