Renal

Question 1

Acetazolamide

Answer 1

Carbonic anhydrase inhibitor that increases NaHCO₃ excretion in the proximal tubule

Treats glaucoma, metabolic alkalosis, altitude sickness, and pseudotumor cerebri. Results in alkalinized urine.

Toxicity: hyperchloremic metabolic acidosis, paresthesias, NH₃ toxicity, sulfa allergy

Question 2

Furosemide, ethacrynic acid, bumetanide

Answer 2

Loop diuretics that inhibit Na-K-2Cl cotransport in the thick ascending limb of the loop of Henle.

• Increases excretion of NaCl, K, Ca
• Decreases ability to concentate urine (decreases corticopapillary gradient
• Decreases ability to dilute urine (inhibition of diluting segment)

Treats edematous states, HTN, hypercalcemia

Toxicity: ototoxicity, hypokalemia, sulfa allergy (not ethacrynic acid), interstitial nephritis, gout

Question 3

Chlorothiazide, HCTZ

Answer 3

Thiazide diuretics that inhibit the Na-Cl co-transport in the early distal tubule

• Increases excretion of NaCl, K
• Decreases Ca excretion
• No effect on ability to concentrate urine
• Decreases ability to dilute urine (inhibition of cortical diluting segment

Treats HTN, CHF, idiopathic hypercalciuria, nephrogenic diabetes insipidus, osteoporosis

Toxicity: hypokalemia metabolic alkalosis, hyperGlycemia, hyperLipidemia, hyperUricemia, hyperCalcemia (“hyperGLUC”) Sulfa allergy.

Question 4

Spironolactone and eplerenone

Triamterene and Amiloride

Answer 4

K-sparing diuretics.

Spironolactone and eplerenone are competitive aldosterone receptor antagonists in the cortical collecting tubule (CCT)

Triamterene and Amiloride block Na channels in the CCT.

Treats hyperaldosteronism, K depletion, CHF.

Toxicity: hyperkalemia (arrhythmias), antiandrogen effects (spironolactone)