pharmacodynamics (interactions, inhibitors, inducers)

PoP1 exam 3

what are CYP450s

enzymes found in many cells (mostly liver and intestines) that metabolize around 75% of drugs

around 50% of the drugs metabolized by a CYP450 are specifically metabolized by

CYP3A4

what are p-glycoproteins

efflux transporters that pump drugs out of the bloodstream into the gut

inducers result in

higher level of enzyme but lower levels of substrate (drug)

inhibitors result in 

inactive enzyme (so less drugs metabolized), so higher level of substrate (drug)

inducers and prodrugs

is substrate is prodrug, inducer results in a higher level of enzyme and higher levels of active drug (bc prodrug has to be metabolized by enzyme to be active)

inhibitors and prodrugs

if substrate is prodrug, less enzyme means prodrug can’t be converted into active drug

FDA characterized strong inhibitors

drugs that cause >5 fold of plasma AUC values or more than 80% decrease in substrate clearance

big inducers

PS PORCS

phenytoin, smoking, phenobarbital, oxcarbazepine, rifampin, carbamazepine, st johns wort

big inhibitors

G PACMAN

grapefruit juice, protease inhibitors, azole antifungals, cimetidine, macrolides, amiodarone, nonDHP calcium channel blockers

drugs that can increase bleeding risks

anticoagulant, antiplatelet, NSAIDs, some natural products

drugs that can cause hyperkalemia

ACE inhibitors, ARBs, K+ sparing diuretics

drugs that can cause CNS depression

drugs that cause sedation and confusion such as alcohol, opioids, anti-convulsants, anti-depressants

what drugs can cause QT prolongation and tosades de pointes

class Ia and III anti-arrhythmics, fluoroquinolones, anti-cancers, azole antifungals, and anti-depressants