Renal

Question 1

Mannitol

Answer 1

Osmotic Diuretic

Acts on Proximal convoluted tubule

MOA:
Increase tubular fluid osmolarity —> increase urine flow
Decrease intracranial/intraocular pressure

Use:
Drug overdose
Elevated intracranial/intraocular pressure

Adv. effects:
Pulmonary edema, dehydration

Contraindicated in anuria, HF

Question 2

Acetazolamide

Answer 2

Acts on Proximal convu=oluted tubule

Carbonic anhydrase inhibitor

MOA:
Self limited NaHCOs diuresis
Decrease total body HCO3- stores

Use: 
Glaucoma*
Mountain sickness*
Alkalinization
Metabolic alkalosis
Pseudotumore cerebri

Adv. effects:
PT acidosis
Paresthesias
NH3 toxicity
Sulfa allery

“Acid-azolamide causes ACIDosis”

Question 3

Loop diuretics

Furosemide, Bumetanide, Torsemide

Answer 3

Act on thick ascending loop of henle

MOA:
Inhibit cotransport system (Na+/K+/2Cl-) of thick ascending limb
Remove hypertonicity of medulla, preventing conc. of urine
Stimulate PGE release (vasodilation of afferent arteriole)
Increase in Ca2+ excretion - “loops lose calcium”

Use:
Edematous state (HF, cirrhosis, nephrotic syndrome, pulmonary edema)
Hypertension
Hypercalcemia

Adv. effects:
Ototoxicity*
Hypokalemia
Dehydration
Sulfa allery
Metabolic Alkalosis
Interstial nephritis
Gout

Question 4

Ethacrynic acid

Answer 4

MOA:
Nonsulfonamide inhibitor of cotransport system (Na+/K+/2Cl-) of thick ascending limb

Use: Diuresis in patients allergic to sulfa drugs

Adv. effects: similar to furosemide but more ototoxic

Question 5

Thiazide diuretics

Hydrochlorothiazide, Chlorthalidone, Metolazone

Answer 5

MOA:
Inhibit NaCl reabsorption in early DCT –> decrease diluting capacity of nephron
Decrease in Ca2+ excretion

Use: 
Hypertension
HF
Idiopathic hypercalciuria
Nephrogenic diabetes insipidus
Osteoporosis

Adv. effects:
Hypokalemic metabolic alkalosis
Hyponatremia
Hyperglycemia
Hyperlipidemia
Hyperurecemia
Hypercalcemia
Sulfa allergy

Question 6

K+ sparing diuretics

Spironolactone & Eplerenone
Triamterene & Amiloride

Answer 6

MOA:
Spironolactone / Eplerenone - Aldosterone receptor antagonists in cortical collecting tubule
Triamterene / Amiloride - Block Na+ channels in cortical collecting tubule

Use:
Hyperaldosteronism
K+ depletion
HF
Hepatic ascites (spironolactone)
Nephrogenic DI (amiloride)

Adv. effects:
Hyperkalemia (can lead to arrhythmias)
Gynecomastia, antiandrogen effects (spironolactone)

Question 7

ACE Inhibitors

Captopril, Enalapril, Lisinopril, Ramipril

Answer 7

MOA:
Inhibit ACE –> dec. AT II –> dec. GFR by preventing constriction of efferent arterioles.
Increase in renin due to loss of negative feedback
Inhibition of ACE prevents inactivation of bradykinin (potent vasodilator)

Use:
Hypertension
HF (dec. mortality)
Proteinuria
Diabetic neuropathy (dec intraglomerular pressure)
Prevent unfavorable heart remodeling due to chronic htn

Adv. effects:
Cough*
Angioedema (conta in C1 esterase inhibitor deficiency)
Teratogen (fetal renal malformations)
Increase in Creatinine (dec. GFR)
Hyperkalemia
Hypotension

Used w/ caution in bilateral renal artery stenosis
— ACE inhibitors will further dec. GFR –> renal failure

Question 8

ARBs

Losartan, Candesartan, Valsartan

Answer 8

MOA:
Selectively block binding of angiotensin II to AT1 receptor.

Effects similar to ACEI but ARBs do not increase bradykinin*

Use:
Hypertension
HF
Proteinuria
Diabetic nephropathy w/ intolerance to ACE inhibitors

Adv. effects:
Hyperkalemia
Dec. GFR
Hypotension
Teratogen

Question 9

Aliskiren

Answer 9

MOA:
Direct renin inhibitor, blocks conversion of angiotensinogen to angiotensin I

Use:
Hypertension

Adv. effects:
Hyperkalemia
Dec. GFR
Hypotension

Contraindicated in patients already taking ACE inhibitors or ARBs