Elimination and Distribution Flashcards
Fexofenadine
Allegra
excluded from the brain unlike other antihistamines
thus is nonsedating
Ciprofloxacin
Cipro
penetrates the prostate gland so it good for bacterial prostatitis
most antibodies do not penetrate
how is penicillin eliminated?
transported into the proximal tubules and therefore rapidly excreted by the kidneys
what prolongs Raloxifene in the body?
Raloxifene or Evista
for osteoporosis
transported by liver into the intestines where it is reabsorbed - enterohepatic recirculation
What factors determine drug distribution?
organ blood barriers to drug diffusion adipose tissue tissue protein binding Plasma protein binding drug transport Ion trapping
Organs with high blood flow will
have larger amounts of drug delivered
experience initial high concentrations of drug but will diminish as it redistributes
Benzodiazepine
examples: diazepam, Valium
sedatives/hypnotics that produces initial, but short lived profound CNS effects
Drug distribution involving the BBB
capillaries in the brain have tight junctions
wrapped by pericapillary glial cells that further contribute to BBB
endothelial cells in the brain capillaries have P-glycoprotein that pumps drugs out of endothelial cells
restricts movement of Hydrophilic drugs into the brain
what can break the BBB?
inflammation and ischemia
what is a down side to lipophilic drug?
can redistribute to adipose tissue so may need a larger initial bolus
may also lengthen time to eliminate drug from the body
In blood, acid drugs may bind to
albumin
In blood, basic drugs bind to
alpha-acid glycoprotein
Binding of drugs may limit the delivery of drugs to drug
elimination mechanisms and this increases the time required for the drug to be removed from the body
Displacement of unconjugated bilirubin from albumin by drugs may PPT
bilirubin encephalopathy in newborns
Probenecid
for gout
blocks the transport of diuretics into the proximal tubules and thereby markedly blunts the effects of diuretics on salt and water excretion