Diuretics and Aquaretics - MUST KNOW Flashcards
Acetazolamide
• Classification
• MOA
• Clinical Use
Classification:
• Carbonic Anhydrase Inhibitor
MOA:
• Potent Inhibitor of Carbonic Anhydrase
• Acts 90% in proximal Tubule and 10% in distal Tubule
• Results in Bicarbonate Loss into the Urine
• URINE BECOMES ALKALINE, MORE Cl- Reabsorption (Hyperchloremic Systemic Acidosis)
Clinical Uses in: • Glaucoma to Reduce Intraocular Pressure • Cystinuria to alkalinize tubular urine • Management of Mountain Sickness • Prophylaxis of Mountain Sickness
Osmotic Diuretics
• MOA
• Net Effect
Mechanism of action:
• Osmotically inhibit Na+/H2O reabsorption in proximal
convoluted tubule.
• Expand extracellular volume & INCREASE renal medullary blood
flow.
• REDUCE medullary tonicity to impair ability of thin segments of loop of Henle to extract water and absorb NaCl.
Net effect:
•INCREASE urine flow with small increments of Na, K+ & Cl-.
•Initially INCREASES plasma volume & B.P.
Clinical uses:
• Reduce intracranial pressure.
Loop Diuretics
• MOA
• Net Effect
MOA: • Inhibit NK2C symporter in TALH • INCREASED renal blood flow • INCREASED renal prostaglandins • Stimulates Renin release and maintain GFR
Net Effect:
• Copious Diuresis with significant Na loss
• INCREASED K+, Ca2+, and Mg2+ excretion
• INCREASED H+ resulting in mild metabolic alkalosis
Loop Diuretics
• Therapeutic Utility
• Effects
Therapeutic Utility:
• Edema of Cardiac, Hepatic and Renal Origin (oral)
• Acute Pulmonary Edema
• Given IV for rapid mobilization of Edema Fluid
Effects:
•DECREASED pulmonary wedge pressure
• DECREASED Left Ventricular Filling Pressure from venodilation
• INCREASED compliance of pulmonary vasculature that facilitates fluid mobilization
•HYPERCALCEMIA - increase Ca2+ mobilization
• Maintenance of renal PGs and renin to prevent renal failure
• Washout of Toxins
• Antihypertensive Particularly when GFR is very low
Furosemide
• Drug Category
• KEY FEATURES
• Side effects
Drug Category:
LOOP diuretic
KEY FEATURES:
• High Margin of Safety
• Dilates veins, increases venous capacitance => DECREASE in Left Ventricle Filling Pressure
SIDE EFFECTS:
• Fluid and electrolyte imbalance
• OTOTOXICITY
• INCREASED: BUN, Hyperglycemia, Hyperuricemia
Bumetanide
• Drug Category
• When is it practicle to use this drug?
Drug Category:
• LOOP diuretic
Practicality:
May be substituted for Furosemide in patients who are on WARFARIN
Costs significantly MORE $$$
Torsemide
• Drug Category
• KEY feature
Drug Category:
• LOOP diuretic
Key Feature:
• VASODILATOR
Thiazide Diuretics • MOA • Net Effect • Therapeutic Utility • Side Effects
MOA:
• Inhibition of Na-Cl symporter in early distal tubule
Net Effect:
• Mild Loss of Na+ and H2O
Therapeutic Utility: • Treats Mild to Moderate Edema • Essential HTN • Diabetes insipidus • Hypercalciuria
Side Effects:
• Hypokalemia and HypoMAGNESEMIA
• Hyperuricemia, Hypercalcemia, Hyperglycemia
• Lipid disorders
What is a more Potent Thiazide Diuretic?
METOLAZONE
What are the two Aldosterone Antagonists?
• MOA
• Net Effect
• Side Effects
Spironolactone and Eplenorone
MOA:
• Competitive Inhibitors to aldosterone in late Distal Tubule and Collecting Ducts
Net Effect:
• INCREASED Na+ excretion, REDUCES K+ secretion
Side Effect:
• Spirnolactone Gynecomastia = MAN BOOBS (in males)
• HIRSUTISM and uterine bleeding (in females)
What is the active metabolite of Spironolactone?
Spironolactone is EXTENSIVELY metabolized
• its active metabolite is Canrenone
What are the true K+ sparing diuretics?
• effect?
• used in combination with?
Triamterene and Amiloride
Effect:
• Inhibits Na+ reabsorption and K+ secretion in the late distal Tubule and Collecting Ducts
Combined Frequently with Thiazides
What is the effect of ADH and ADH-like drugs?
- Increases water Permeability in Collecting Tubule (V2)
* Is a vasopressor (V1)
What drugs are used for the two different versions of diabetes insipidus?
ADH-sensitive Diabetes insipidus:
• DESMOPRESSIN
Nephrogenic Diabetes Insipidus:
• THIAZIDES
What drugs are given for Inappropriate Secretion of Antidiuretic Hormone (SIAHD)
- Demeclocycline
* Vaptans
