BCSE Pharmacology and Toxicology 3

Question 1

A patient with major depression is started on phenelzine. Which dietary restriction is most critical to prevent a hypertensive crisis?

Accepted Answer

Tyramine-containing foods

Answer

MAO inhibitors like phenelzine prevent the breakdown of tyramine in the gut, causing massive norepinephrine release and a potentially fatal hypertensive crisis when tyramine-rich foods are consumed.

Question 2

Heparin-induced thrombocytopenia (HIT) is caused by:

Accepted Answer

IgG antibodies against heparin-PF4 complex activating platelets

Answer

In HIT, IgG antibodies form against the heparin-platelet factor 4 (PF4) complex, activating platelets via FcγRIIA receptors and causing paradoxical thrombosis despite thrombocytopenia.

Question 3

Which drug class works by inhibiting the Na+/K+/2Cl- cotransporter (NKCC2) in the thick ascending limb of the loop of Henle?

Accepted Answer

Loop diuretics

Answer

Loop diuretics such as furosemide inhibit NKCC2 in the thick ascending limb, preventing reabsorption of sodium, potassium, and chloride, producing the most potent diuresis of any diuretic class.

Question 4

A 45-year-old patient develops rhabdomyolysis while taking a statin. Which co-administered drug most likely contributed to this toxicity?

Accepted Answer

Gemfibrozil

Answer

Gemfibrozil inhibits OATP1B1 and CYP2C8, impairing statin hepatic uptake and increasing plasma statin concentrations, dramatically raising the risk of myopathy and rhabdomyolysis.

Question 5

The cardiotoxicity of digoxin overdose is primarily managed with:

Accepted Answer

Digoxin-specific antibody fragments (Digibind)

Answer

Digoxin-specific Fab antibody fragments bind free digoxin in the plasma, rapidly reversing toxicity; because digoxin has a large volume of distribution, dialysis is ineffective.

BCSE - Basic and Clinical Sciences Examination Practice Test

BCSE - Basic and Clinical Sciences Examination Practice Test

BCSE Pharmacology and Toxicology 3