Renal Drugs

Question 1

mannitol mechanism, clinical use and toxicity

Answer 1

• mech: osmotic diuretic, inc urine flow and decreases intracranial/intraocular pressure
• used in drug overdose or inc ICP/ocular pressure
• tox: pulmonary edema, dehydration, hypernatremia. contraindicated in anuria, CHF.

Question 2

acetazolamide mechanism, clinical use and toxicity

Answer 2

• mech: carbonic anhydrase inhibitor, causes self-limited NaHCO3 diuresis and decreased bicarb stores
• clinical use: glaucoma, urinary alkalinization, metabolic alkalosis, altitude sickness, pseudotumor cerebri
• tox: hyperchloremic met acidosis, paresthesias, NH3 tox, sulfa allergy, hypokalemia

Question 3

furosemide mechanism

Answer 3

• sulfonamide loop diuretic
• inhibits Na/K/Cl transport of thick ascending loop
• abolishes hypertonicity of the medulla, preventing concentration of urine.
• stimulates PGE release (vasodilate afferent), inhibited by NSAIDs.
• inc Ca excretion

Question 4

furosemide clinical use and toxicity

Answer 4

• used in edematous states (CHF, cicrrhosis, nephrotic syndrome, pulmonary edema), HTN and hypercalcemia
• tox: OH DANG!
• ototoxicity, hypokalemia, dehydration, allergy (sulfa), nephritis (interstitial), gout
• also metabolic alkalosis, hypocalcemia and hypomag

Question 5

ethacrynic acid

Answer 5

• phenoxyacetic acid derivative (not a sulfonamide) with the same action as furosemide
• clinical use: diuresis in sulfa-allergic pts
• tox: similar to furosemide, can cause hyperuricemia so dont give to people with gout

Question 6

HCTZ

Answer 6

• mech: thiazide diuretic, inhibits NaCl reabsorption in early distal tubule, dec diluting capacity of nephron and dec Ca excretion
• clinical use: HTN, CHF, idiopathic hypercalciuria, nephrogenic DI, osteoporosis
• tox: HyperGLUC (glycemia, lipidemia, uricemia, calcemia), hypokalemia, hypotension. sulfa allergy

Question 7

K+ sparing diuretics (names)

Answer 7

• spironolactne and eplerenone, triamterene, amiloride

Question 8

spironolactone and eplerenone mechanism

Answer 8

• inhibits apical ENaC channel and basolateral Na/K ATPase pump in cortical collecting tubules
• competitive aldosterone receptor antagonists

Question 9

triamterene and amiloride mechanism

Answer 9

• inhibit apical ENaC channel in cortical collecting duct

Question 10

K sparing diuretics clinical use and tox

Answer 10

• use: hyperaldo, K depletion, CHF
• tox: hyperkalemia
• spironolactone has endocrine effects because it is structurally similar to steroids (gynecomastia, antiandrogen effects)
• • can be used for idiopathic hirsuitism

Question 11

diuretics that cause acidemia

Answer 11

• carbonic anhydrase inhibitors and spironolactone/eplenorone

Question 12

diuretics that cause alkalemia

Answer 12

loop diuretics and thiazides
- 2/2 contraction and K loss (K shifts out of cells in exchange of H, and prox tubule starts more Na/H exchange instead of Na/K - “paradoxical aciduria”)

Question 13

diuretic effects on urine Ca

Answer 13

• increases with loop diuretics

- decreases with thiazides

Question 14

ACE inhibitors

Answer 14

• dec Ang II and prevents inactivation of bradykinin (vasodilator)
• used in HTN, CHF, proteinuria, diabetic nephropathy. prevent unfavorable heart remodeling as a result of chronic HTN
• tox: CATCHH - cough, angioedema, teratogen, inc creatinine, hyperkalemia and hypotension
• avoid in bilateral RAS, can further decrease GFR and lead to renal failure