Pharm Flashcards
InDUCErs of cytochrome P450
Dexamethasone
Phenobarbital
Phenytoin
Rifampin
InHIBITors of cytochrome p450
chloramphenicol
cimetidine
erytromycin
fluconazole
indomethacin
methadone
omeprazole (and other PPIs)
ranitidine
PPI that does not interfere with p450
pantoprazole
Most important enzyme in Phase 1 metabolism
cytochrome p450
- transfers electrons from NADPH to cyp450
- lack substrate specificity
- important for 75% of all drugs
Phase 1 metabolism
oxiation
reduction
hydrolysis
demethylation
(CYP450)
Phase 2 metabolism
conjugation of drug with endogenous components
(glycine, glucuronic acid, sulfate, glutathione, or hippurate)
Most common phase II reaction
glucuronidation
*important for metabolism of morphine and acetaminophen
*neonates have undeveloped liver enzymes and slower glucuronidation
Why are gent troughs measured
to monitor for toxicity
Number of half-lives to reach steady state
~5
Number of half-lives to eliminate (if at steady state)
~5
Caffeine half life
50 hours
What prevents iNO from having systemic effects
iNO is inactivated by the hemoglobin when it binds to the heme moieties after entering the blood stream
Methemoglobin from iNO (how)
NO + Fe in hemoglobin
oxidation from ferrous (Fe2+) to ferric (Fe3+) state;
gives rise to MetHb
causes leftward shift in curve; c/f tissue hypoxia
*normal levels of MetHg 1%
Ranking of drug administration modes from GREATEST to LEAST effect on maternal blood levels
IV
Paracervical
IM
Epidural
Spinal
contraindication to naloxone during initial resuscitation
maternal CHRONIC optiate exposure
*may precipitate sudden withdrawal, seizures
