Major Drug interactions

Question 1

oral chelation with di and trivalent cations

Answer 1

tetracyclines and FQs

Question 2

warfarin

Answer 2

metronidazole, bactrim (highly protein bound), and FQs (leads to increased prothrombin time and potential bleeding)

Question 3

alcohol

Answer 3

metronidazole and MTT chain cephalosporins

Question 4

CYP3A4

Answer 4

macrolides (erythromycin and clarithromycin), Synercid (affects lipid lowering agents, immunosuppressive agents, and carbamazepine)

Question 5

CYP2C9

Answer 5

erythromycin and clarithromycin

Question 6

MAO inhibition

Answer 6

oxazolidinones (cause risk of serotonin syndrome in patients using other serotonin drugs, ie SSRIs)

Question 7

drugs that interact with statins

Answer 7

daptomycin, synercid

Question 8

drugs that should not be used in pregnancy or lactation

Answer 8

tetracyclines and analogs (Category D)
Bactrim (Category C)
metronidazole (category B)
telavancin and other lipopeptides (category C)

Question 9

drugs that should not be used in children

Answer 9

> 8 yo: tetracyclines and analogs due to chelation
babies < 2 mos: bactrim due to kernicterus in newborn
peds: FQs due to risk of articular damage and chelation

Question 10

which macrolide doesn’t inhibit 3A4?

Answer 10

azithromycin, but still monitor PTT and INR!