Diuretics Flashcards
Most diuretics work by
Increasing Na excretion
Osmotic diuretics
The only non-natriuretic drug–they just truly increase urine volume
Clinical uses for diuretics
hypertension, CHF, edema, electrolyte abnormalities
Where do carbonic anyhydrase inhibitors work
Proximal tubule of kidney
Where do loop diuretics work
Thick ascending loop of Henle
Where do thiazides work
Distal tubule
Where do K+ sparing diuretics work
Collecting ducts
Example of osmotic diuretic
Mannitol
present throughout tubule
Therapeutic uses for mannitol
Decrease ICP in cerebral edema
Decrease IOP in glaucoma
Preserve urine volume in acute oliguric renal failure
Increase clearance of toxins
Adverse effects of mannitol
Acute hypovolemia
Mannitol is contraindicated in
CHF and pulmonary edema due to initial increase in ECF volume
Carbonic anhydrase inhibitors
“-zolamide”
Block reabsorption of HCO3- in proximal tubule, which decreases Na reabsorption
Can cause metabolic acidosis and severe hypokalemia
Most commonly used in glaucoma and mountain sickness
Most widely used loop diuretics
Furosemide
Loop diuretics
Inhibits Na/K/Cl cotransporter and increases Na in the lumen causing diuresis
Causes increased excretion of K+, Mg, and Ca
Induces expression of COX-2 and prostaglandins causing vasodilation
Therapeutic uses of loop diuretics
acute pulmonary edema and CHF, other edematous states, hypercalcemia and hyperkalemia, hypertension
Adverse effects of loop diuretics
Hypokalemia, metabolic acidosis, hypomagnesia and hypocalcemia, ototoxicity, sulfa allergy
Most common thiazides
Hydrochlorothiazide
Thiazides
Inhibit Na/Cl cotransporter in distal tubule causing increases Na and Cl excretion
Increased Ca reabsorption–decreased risk of Calcium renal stones
Therapeutic uses for thiazides
Hypertension, CHF, calcium renal stones, nephrogenic DI
Adverse effects of thiazides
Hypokalemia, metabolic alkalosis, hypercalcemia, decreased insulin
Potassium sparing diuretics
Not good by themselves
Used in adjunct to other diuretics
Block aldosterone mainly: decreased Na reabsorption and decreased K+ secretion
Ungated Na channel blockers
Amiloride and Triamterene
Inhibits Na channels in collecting ducts causing less Na to go in and less K to go out–K sparing
Aldosterone receptor antagonists
Spironolactone
Competitive antagonist of aldosterone receptors
Can cause hyperkalemia
Spironolactone negatively interacts with
digoxin, ACEI, ARBs, and NSAIDs
Acetazolamide
Works in the proximal tubule; inhibits carbonic anhydrase which causes decreased reabsorptions of bicarb, pulls Na in the tubule and causes diuresis
Causes metabolic acidosis
Acetazolamide uses
Decrease CSF in intracranial hypertension, decrease aqueous humor in glaucoma, and mountain sickness
Examples of loop diuretics
Furosemide and ethacrynic acid
1st line diuretic for hypertension
thiazide
First line diuretic for HF
Loop diuretics
Thiazide effect on insulin
Can decrease insulin and cause hyperglycemia
Side effects of spirinolactone
Decreased testosterone, increased gynecomastia, increased impotence and decreased libido
Potassium sparing diuretics and HF
Can be helpful to decrease cardiac remodeling