Pharmacology-Renal Flashcards
Name the drugs that work at the PCT:
mannitol, acetazolamide
Name the drugs that work at the Thick Ascending LOH
loop diuretics: furosemide, ethacrynic acid
Name the drugs that work at the DCT
hydrochlorothiazide
Name the drugs that work at the collecting duct
K+ sparing diuretics
name the K+ sparing diuretics:
spironolactone, eplerenone, amiloride, triamterine
Mannitol – mechanism
- osmotic diuretic (increases tubular fluid osmolarity), increased urine flow
- decreased intracranial and intraoccular pressure
Mannitol – site of action
PCT
Mannitol – use
Drug overdose, hydrocephaly, glaucoma
Mannitol – toxicity
pulmonary edema, dehydration
Mannitol – contraindications
anuria, CHF
Acetazolamide – mechanism
- carbonic anhydrase inhibitor
- self-limited NaHCO3 diuresis and reduction in total-body HCO3- stores
Acetazolamide – site of action
PCT
Acetazolamide – use
- Glaucoma
- Urinary alkinization, metabolic alkalosis, alt. sickness
- pseudotumor cerebri
Acetazolamide – toxicity
- hyperchloremic metabolic acidosis
- paresthesias
- NH3 toxicity
- sulfa allergy
Loop diuretics – names
furosemide, ethacrynic acid
Furosemide – type of loop diuretic
sulfonamide loop diuretic
Furosemide – mechanism
- inhibits cotransport system (Na+, K+, 2Cl-) of thick ascending limb
- abolishes hypertonicity of medulla, preventing [] of urine
- Ca2+ excretion
What does furosemide stimulate the release of? effects?
PGE, vasodilatory effect on afferent arteriole
What is furosemide inhibited by?
NSAIDS
Furosemide – use
edematous states (CHF, cirrhosis, nephrotic syndrome, pulmonary edema), HTN, hypercalcemia
Furosemide – toxicity
OH DANG! O - ototoxicity H - hypokalemia D - dehydration A - allergy (sulfa) N - nephritis (intersitial) G - gout
Ethacrynic acid – type of Loop diuretic
phenoxyacetic acid derivative ** NOT A SULFA
Ethacryic acid – action
same as furosemide
ethacrynic acid – use
diuresis in patients allergic to sulfa drugs
Ethacrynic acid – toxicity
similar to furosemide
CAN CAUSE HYPERURICEMIA – NEVER USE TO TREAT GOUT!
Hydrochlorothiazide – site of action
DCT
Hydrochlorothiazide – mechanism
- Thiazide diuretic
- (-) NaCl reabsorption in early DCT
- reduces diluting capacity of the nephron
- decrease Ca2+ excretion
Hydrochlorothiazide – use
HTN, CHF, idiopathic hypercalciuria, nephrogenic diabetes insipidus
Hydrochlorothiazide – toxicity
- Hypokalemic metabolic alkalosis, Hyponatremia
- (Hyper)GLUC: hyperGlycemia, hyperLipidemia, hyperUricemia, hyperCalcemia
- Sulfa allergy
K+ sparing diuretics – names
SEAT – Spironolactone, Ethacrynic acid, Amiloride, Triamterene
K+ sparing diuretics – site of action
cortical collecting tubule
Spironolactone, Eplerenone – mechanism
competetive aldosterone receptor antagonists
Triamterene, amiloride – mechanism
Block Na+ channels
K+ sparing diuretics – use
hyperaldosteronism, K+ depletion, CHF
K+ sparing diuretics – toxicity
hyperkalemia -> arrhythmias
Spironolactone – toxicity
endocrine effects (gynecomastia, antiandrogenic effects)
Diuretic induced electrolyte change: Urine NaCl
- increase in all diuretics
- NaCl in serum may decrease as a result
Diuretic induced electrolyte change: Urine K+
- increase in all diuretics except K+sparing
- serum K+ decrease as result
Diuretic induced electrolyte change: Decreased Blood pH
carbonic anhydrase inhibitors – decrease HCO3- reabsorption
K+ sparing – aldosterone blockade prevent K+ and H+ secretion
- hyperkalemia -> K+ entering all cels via H+/K+ exchanger so H+ exits and leads to more H+ in blood
Diuretic induced electrolyte change: Increased Blood pH
loops and thiazides via contraction alkalosis and paradoxical aciduria
Explain contraction alkalosis
volume contraction, leading to increased angiotensin II, therefore increased Na+/H+ exchange in PCT leading to increased HCO3- reabsorption
Explain paradoxical aciduria
- K+ loss leads to K+ exiting all cells (H+/K+ exchanger) in exchange for H+ entering cells
- In low K+ state, H+ rather than K+ is exchanged for Na+ in cortical collecting tubule leading to alkalosis
Diuretic induced electrolyte change: increased Urine Ca2+
with loop diuretics: decrease paracellular Ca2+ reabsorption leading to hypocalcemia
Diuretic induced electrolyte change: decreased urine Ca2+
thiazides: enhanced paracellular Ca2+ reabsorption in proximal tubule and LOH
ACE inhibitors: names
captopril, enalapril, lisinopril (-pril)
Ace inhibitors: mechanism
(-)ACE -> decrease ATII, leading to decreased GFR by (-) constriction of efferent arterioles
- renin increase because loss of feedback inhibition
ACE-I use
HTN, CHF, proteinuria, diabetic renal dz
ACE-I prevent what two things
unfavorable heart remodeling and diabetic nephropathy
ACE-I toxicity
“Captoprils CATCHH”
Cough (prevent inactivation of bradykinin a potent vasodilator), Angioedema, Teratogen (fetal renal malformations), Creatinine increase (decrease GFR), Hyperkalemia, Hypotension
ACE-I contraindications
avoid in bilateral renal artery stenosis because ACE-I will further decrease GFR, leading to renal failure
ARB’s: name
“-sartan” eg: losartan
ARB’s – toxicity difference with ACE-I
do not increase bradykinin so no cough or angioedema