Flashcards in FA Renal Deck (35):
Osmotic diuretic in the PCT, increased tubular fluid osmolarity, producing increased urine flow, decreased intracranial/ intraocular pressure.
Carbonic anhydrase inhibitor in PCT. Causes self limited NaHC03 diuresis and reduction in total-body HC03- stores.
Sulfonamide loop diuretic.
Inhibits cotransport system (Na+, K+, 2 Cl-) of thick ascending limb of loop of Henle.
Abolishes hypertonicity of medulla, preventing concentration of urine. Stimulates PGE release (vasodilatory effect on afferent arteriole); inhibited by NSAIDs. Increased Ca2+ excretion.
Loop diuretic (furosemide)
Phenoxyacetic acid derivative (not a sulfonamide). Inhibits cotransport system (Na+, K+, 2 Cl-) of thick ascending limb of loop of Henle.
Inhibits ￼NaCl reabsorption in early DCT, reducing diluting capacity of the nephron. Decreased Ca2+ excretion.
Competitive aldosterone receptor antagonists in the cortical collecting tubule.
Block Na+ channels in the CCT.
Mannitol clinical use
elevated intracranial/intraocular pressure.
Acetazolamide clinical use
pseudotumor cerebri (idiopathic intracranial HTN)
Furosemide clinical use
Edematous states (CHF, cirrhosis, nephrotic syndrome, pulmonary edema),
Hydrochlorothiazide clinical use
nephrogenic diabetes insipidus.
K+-sparing diuretic clinical use
Ethacrynic acid clinical use
Diuresis in patients allergic to sulfa drugs.
Contraindicated in anuria, CHF.
Hyperchloremic metabolic acidosis,
Similar to furosemide; can cause hyperuricemia; never use to treat gout.
Ethacrynic acid toxicity
Hypokalemic metabolic alkalosis,
Hyperkalemia (can lead to arrhythmias), gynecomastia, anti androgen effects,
Which diuretics cause increased urine NaCl
All of them! (serum NaCl may decrease as a result)
Which diuretics cause increased urine K+?
All except K+ sparing (spironolactone, eplerenone, amiloride, triamterene)
which drugs cause acidemia?
Carbonic anhydrase inhibitors, K+ sparing
How do K+ sparing diuretics cause acidemia?
Aldosterone blockade prevents K+ secretion and H+ secretion. Additionally, hyperkalemia leads to K+ entering all cells (via H+fK+ exchanger) in exchange for H+ exiting cells.
Which diuretics cause alkalemia?
Loop and thiazides
How does volume contraction lead to alkalosis?
Increased AT II --> increased Na+/H+ exchange in PCT -> increased HC03- reabsorption ("contraction alkalosis")
What is the mechanism of "paradoxical acuduria?"
In low K+ state, H+ (rather than K+) is exchanged for Na+ in cortical collecting tubule, leading
to alkalosis and "paradoxical aciduria"
How do loop and thiazide diuretics lead to alkalemia?
1. volume contraction.
2. K+ loss leads to K+ exiting all cells (via H+/K+ exchanger) in exchange for H+ entering cells
3. In low K+ state, H+ exchanged for Na+ in cortical collecting tubule
Which diuretics cause high urine calcium?
How do loop diuretics cause high urine calcium?
Decreased paracellular Ca2+ reabsorption - hypocalcemia
Which diuretics cause low urine calcium?
How do thiazides cause low urine calcium?
Enhanced paracellular Ca2+ reabsorption in proximal tubule and loop of Henle.
Inhibit angiotensin-converting enzyme (ACE) --> decreased angiotensin II --> decreased GFR by preventing constriction of efferent arterioles. Levels
of renin increase as a result of loss of feedback inhibition. Inhibition of ACE also prevents inactivation of bradykinin, a potent vasodilator.
Clinical use of ACE inhibitors
diabetic renal disease.
Prevent unfavorable heart remodeling as a result of chronic hypertension.
Cough, Angioedema, Teratogen (fetal renal malformations), Creatinine increase (decreased GFR), Hyperkalemia, and Hypotension.
ACE inhibitor toxicity (Captopril's CATCHH)