Learning Drug Interactions

Question 1

CYP Inducers

Answer 1

PS PORCS
Phenytoin
Smoking
Phenobarbital
Oxcarbazepine (and eslicarbazepine)
Rifampin (rifabutin, rifapentine)
Carbamazepine (auto-inducer)
St. John's wort

Question 2

Effects of CYP Inducers

Answer 2

inDucers = Decreased levels/effects of substrates

Effect on prodrugs = increased levels of active drug form

Question 3

CYP Inhibitors

Answer 3

G PACMAN
Grapefruit
Protease Inhibitors - check all but don’t forget ritonavir
Azole antifungals (fluconazole, itraconazole, ketoconazole, posaconazole, voriconazole, isavuconazole)
C- cyclosporine, cimetidine, cobicistat
Macrolide abx (clarithromycin and erythromycin only)
Amiodarone (and dronedarone)
Non-DHP CCBs (diltiazem and verapamil)

Question 4

Effects of CYP inhibitors

Answer 4

INhibitors = INcreased effects/levels/ADR/toxicities of substrates
Effect on prodrugs: Inhibitors decrease levels of active drug form

Question 5

Common P-gp Substrates

Answer 5

anticoagulants: apixaban, edoxaban, rivaroxaban, dabigatran
CV drugs: carvedilol, digoxin, ranolazine
Immunosuppressants: cyclosporine, tacrolimus, sirolimus
HCV drugs: dasabuvir, ombitasvir, paritaprevir, sofosbuvir
Others: atazanavir, colchicine, dolutegravir, posaconazole, raltegravir, saxagliptin

Question 6

Common P-gp Inducers

Answer 6

Carbamazepine, dexamethasone, phenobarbital, phenytoin, rifampin, St, John’s wort, tipranavir

Question 7

Common P-gp Inhibitors

Answer 7

Anti-Infectives: clarithromycin, itraconazole, posaconazole
CV drugs: amiodarone, carvedilol, conivaptan, dronedarone, diltiazem, quinidine, verapamil
HIV drugs: cobicistat, ritonavir
HCV drugs: daclatasvir, ledipasvir, paritaprevir
Others: cyclosporine, flibanserin, ticagrelor