Pharmacology Flashcards
biochemical factors that improve absorption
lmw
lipid soluble
non ionized
pinocytosis
energy dependent
compounds engulfed and packaged by cells
Vd =
total amount of drug in body (mg) / [(plasma concentration of drug (mg/L) x weight (kg)]
preterm vs full term in regards to Vd
preterm higher Vd
what do acidic and basic drugs bind to
acidic - albumin
basic - alpha-glycoproteins and lipoproteins
phase 1 reactions
- oxidation
- reduction
- hydrolysis
- demethylation
enzyme not specific for substrate
phase 2 reactions
conjugation of drug with endogenous component (glycine, glucuronic acid, sufate, glutathione or hippurate)
glucoronidation most important
which common drugs undergo glucuronidation
morphine
tylenol
zero order excretion
constant amount per time regardless of concentration
half life dependent on dosage
drugs that are zero-order
aspirin
chloramphenicol
ethanol
diazepam
first order exretion
constant percentation of drug per time
half life is independent of dosage
equation for determining dose to achieve steady state
- dose 1 = x dose
- steadystate goal
drugs that are first order
- theophylline
- phenobarbital
loading dose calculation
Vd (L/kg) X Cp (mg/L) / (S x F)
Cp = plasma concentration (Cp desired = Cp current)
S = fraction of drug that is active
F = fraction of drug that is bioavailable
Assume S and F = 1 if not specified
rate of clearance between preterm and term
preterm is slower due to higher Vd
clearance of drug equation
elimination rate constant x volume of distribution
how many half lives are needed to reach steady state
5
steady state equation
= infusion rate/clearance of drug = infusion rate/(elimination rate constant x Vd)
half life equation
= 0.693/Kel = 0.693/(Clearance/Vd) = (0.693x Vd)/Clearance
at steady state what is true about peaks and troughs
they are both equal
peak level dependent on:
infusion rate
longer rate = lower peak
aminoglycosides are measured 30 minutes after end of infusion
if time dependent killing what should you measure?
trough
trough level dependent on:
interval of drug
factors that allow drugs to be excreted into breastmilk
lmw
high lipid solubility
low protein binding
non ioninzed
drugs contraindicated for mothers who are breastfeeding
lithium
methotrexate
phencylclidine
radioactive agents
drugs that interfere with neonatal oxidation of vitamin K
anticonvulsants - phenytoin and phenobarbital
antiTB - isoniazid and rifampin
warfarin
cephalosporins
drugs that displace unconjugated bilirubin from albumin
ceftriaxone
sulfonamides
indomethacin
drugs that increase p450 metabolism and increase conjugation
phenobarbital and rifampin
