STEP 1 Uworld Drugs Part 4

Question 1

Aspirin

Answer 1

Irreversibly inhibits platelet aggregation by acetylating serine residues of the platelet COX enzyme

Question 2

Azoles

Answer 2

Inhibit the synthesis of ergosterol by the fungal cytochrome P450 enzymes (they also suppress human P450 –> drug-drug interactions)

Question 3

Febuxostat

Answer 3

Reduces serum uric acid levels by inhibiting xanthine oxidase, the enzyme that converts xanthine to uric acid

Question 4

Rifaximin

Answer 4

poorly absorbed antibiotic that eradicates ammonia producing intestinal bacteria (treats hepatic encephalopathy)