Pharmacology Basics Flashcards

Which laboratory test is used to monitor warfarin therapy?

Answer: PT/INR

Warfarin lowers vitamin K-dependent factors, including factor VII, which shows most clearly in the PT/INR.

Unfractionated heparin therapy is usually monitored with which test?

Answer: aPTT or anti-Xa activity

Heparin boosts antithrombin, which prolongs the aPTT and lowers anti-Xa activity.

Warfarin acts by inhibiting which enzyme?

Answer: Vitamin K epoxide reductase

Blocking vitamin K epoxide reductase stops gamma-carboxylation of factors II, VII, IX, and X.

Vancomycin belongs to which antibiotic class?

Answer: Glycopeptide

Vancomycin is a glycopeptide that blocks cell wall synthesis by binding D-Ala-D-Ala.

Carbamazepine levels can fall over the first weeks of therapy even though the dose stays the same. Why?

Answer: Auto-induction of its own hepatic metabolism

Carbamazepine induces the CYP3A4 enzymes that metabolize it, so its clearance speeds up.

Which specimen is preferred for measuring tacrolimus or cyclosporine levels?

Answer: EDTA whole blood

These immunosuppressants concentrate in red cells, so whole blood is required.

Which electrolyte abnormality is commonly caused by thiazide diuretics?

Answer: Hypokalemia

Thiazides increase sodium delivery to the distal nephron, which increases potassium loss.