The kidney and drugs Flashcards
xenobiotics=
a chemical compound foreign to a given biological system
pH of kidney
5-7
clearance=
rate at which substance is removed from the blood
if something is uncharged how does this affect reabsorption from the kidney tubule
charged reabsorbed more quickly (so cleared slowly)
what does a tablet have to go through before entering the blood system
first pass mechanism through liver
what diet is more alkaline
fruit and vegetable
what diet is more acidic
more protein based
2 things concentration of drug in urine is determined by
- entrance of the drug into tubular fluid
- reabsorption from tubular fluid
what happens to ionized drugs in the tubule
they stay there
what happens to lipid soluble drugs in the tubule
almost completely reabsorbed
clearance of acidic drug=
slower
clearance of alkaline drug=
faster
half life (T1/2) =
the time needed to halve plasma conc of drug
half life is dependant on (2)
volume of distribution
clearance
what can aminoglycosides and loop diuretics cause in renal failure
otoxicity
what happens to drugs in renal failure
clearance is reduced so they build up in the body
4 drugs affecting the PCT directly
- aminoglycosides
- cisplatin
- immunoglobulins
- mannitol
4 drugs affecting the DCT directly
- NSAIDs
- ACE inhibitors
- Ciclosporin
- cyclophosphamide
e.g of osmotic diuretic
mannitol
where do osmotic diuretics work
proximal convoluted tubule
when to use osmotic diuretics (3)
prior to neurosurgery
early cerebral oedema
reduce intraocular pressure
where do carbonic anhydrase inhibitors work
proximal tubule
MOA of carbonic anhydrase inhibitors
target H+/Na+ exchange so Na+ stays in filtrate and more H2O
e.g of carbonic anhydrase
Actazolamide
what do loop diuretics act on
Na+/K+/2Cl- co-transporter on Cl- binding site
e.g loop diuretic
furosemide
when are loop diuretics used
- pulmonary oedema from LV failure
- chronic heart failure
what drugs work on the DCT
thiazides
what do thiazides target
Na/Cl/K co-transporter
what do you lose lots from thiazides (and need to give supplements for)
Potassium
what is the dose like for thiazides
low
aldosterone antagonist (MR- antagonist)
spironolactone
what does spironolactone spare
potassium
2 drugs causing tubular toxicity
aminoglycosides
tetracyclines
NSAIDs effect on afferent arteriole=
vasoconstriction
what 2 drugs need intense hydration when taking
methotrexate
cisplatin
what drugs cause glomerulopathy
NSAIDs
