W13_04 drug interactions Flashcards
whichP450 enzyme metabolizes sulfonylurea?
2C9
SMX/TMP (septra) inhibits which P450?
2C9
which P450 metabolizes codeine?
2D6. puts codeine into morphine
paroxetine inhibits which P450?
2D6
2D6 is absent in how much of the population?
7-10% are poor metabolizers
how does grapefruit juice affect statins?
GFJ inhibits 3A4 in the gut, and really upregulates the amount of statin that gets absorbed, which would usually be metabolized by 3A4
which classes of drugs are affected by grapefruit juice
some statins;
all CCBs;
some benzos;
randoms, including sildenafil
which macrolide is not an inhibitor of 3A4?
azithromycin
what are some inducers of 3A4?
anticonvulsants;
dexamethasone;
tamoxifen;
st john’s wort
how do digoxin and clarithromycin interact?
clarithromycin turns of P-glycoprotein exporter, and digoxin is more absorbed into the blood
verapamil and dabigitran are often given together. How do they interact?
verapamil an hour before dabigitran causes 80% increase in dabigitran concentration. Due to P-glycoprotein inhibition
how does refamipin alter P-GP levels?
upregulates expression, causing more efflux of drug
how does acetaminophen interact with warfarin?
NAPQI (toxic metabolite of acetaminophen) inhibits an enzyme that activates the clotting factors 2, 7, 9, 10
which drugs have interactions with warfarin?
amiodarone;
antibiotics;
antidepressants (depletes serotonin in platelets to reduce their stickiness;
analgesics;
antiplatelets
what are some usual causes of hyperkalemia?
renal disease;
ace inhibitors;
ARBs;
K supplements;
spironolactone, amiloride, triamterene
