1. Diuretics
Blake Briggs, Class of 2017

2. Introduction
Understanding nephron function is essential in learning diuretics
PCT (acetazolamide) DCT (thiazides) CD
-K sparing
diuretics
TAL ((loops)

3. Mannitol
MOA- Osmotic load (increase tubular osmolarity  increase osmosis  increase urine flow)
Uses: drug overdoses, lowering ICP/IOP
Toxicity: Pulmonary edema, dehydration
Contraindications: heart failure, anuria
Water extracted from tissue, increase medullary blood flow and thus decrease the tonicity, impairs water absorption in the TDL

4. Acetazolamide
MOA- Carbonic anhydrase inhibitor: prevents reabsorption of Na- HCO3 in the PCT.
Uses: lowers IOP (glaucoma), alkalinizes urine (drug OD), altitude sickness, pseudotumor cerebri

5. Loop diuretics
Drugs: Furosemide , Bumetanide, Torsemide (longest half life)
MOA: block reabsorption of Na/K/2Cl in Thick Ascending limb; increases RBF.
Uses: when a large diuresis is needed: CHF, Pulm Edema, cirrhosis, nephrotic Syndrome
Toxicity: OH DANG! Ototoxicity, hypokalemia, dehydration, allergy (sulfas)/alkalosis, nephritis , gout
Ethacrynic Acid- more ototoxic, but not a sulfa drug!
Unique facts:
Loops need to be secreted into the tubule to work. So they work less in renal failure.
Abolish hypertonicity of medulla and prevents concentration of urine
Stimulates PGE release
Can cause Acute Interstitial Nephritis

6. Thiazides Drugs: HCTZ, Chlorthalidone, Metolazone
MOA: block NaCl absorption in DCT decreases diluting capability of nephron
Uses: HTN (1st line), idiopathic hypercalciuria, Nephrogenic DI, Osteoporosis
Toxicity: HyperGLUC- Glucose, Lipids, Uric acid, Calcium

7. K+ Sparing Diuretics Drugs: Spironolactone, Eplerenone:
MOA: competitive aldosterone receptor antagonists in cortical CD
Remember the trio of aldosterone effects: K secretion, Na reabsorption, H secretion.
Toxicity: “feminization due to anti-androgen effects (aldosterone has androgenic properties and receptor crossover)”, hyperkalemia
Uses: Ascites, hyperaldosteronism, hypokalemia, heart failure, hirsutism
Eplerenone has less/no anti-androgen effects

8. K+ Sparing diuretics Drugs: Triamterene, Amiloride:
MOA: block NaCl channels in cortical CD.
Toxicity: hyperkalemia. NO anti-androgen effects (does not block aldosterone)
Uses: HTN, nephrogenic DI (amiloride)

9. Thanks for listening
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