Diuretics (exam 2)

What are the classes of diuretics?

loop diuretics, thiazides, K+ sparing diuretics, carbonic anhydrase inhibitors (CAI), vasopressin, vasopressin antagonists, osmotic diuretics

How is diuretic resistance induced?

pathology

How does one prevent diuretic resistance?

give loop diuretic by continuous IV

Is chronic renal failure seen with diuretic resistance or braking?

resistance

Is nephrotic syndrome seen with diuretic resistance or braking?

resistance

Is hepatic cirrhosis seen with diuretic resistance or braking?

resistance

Is heart failure seen with diuretic resistance of braking?

resistance

Is drug-induced (NSAIDs) diuretic resistance or braking?

resistance

Is a high intake of sodium diuretic resistance or braking?

resistance

How is diuretic braking induced?

physiology

What diuretic braking is response to?

rapid diuresis

When can diuretic braking occur?

short or long-term due to hemodynamic/neurohormonal changes

MoA of loop diuretics

inhibits Na/K/2CL symport at thick ascending loop of henle

What can loop diuretics result in?

loss of Na/K/Cl/Ca/Mg, increased uric acid reabsorption/renal blood flow, decreased vascular resistance/pulmonary resistance

What is the most efficacious class of diuretics?

loop

ADRs of loop diuretics

hypokalemia, hypocalcemia, ototoxicity, allergy reaction due to sulfonamide

What is the most potent loop diuretic?

bumetanide (bumex)

MOA of thiazides

inhibits Na/Cl symport at distal convoluted tubule

What can thiazides result in?

• decreased reabsorption of Na, Cl

• increased loss of K, Mg

• decreased excretion of Ca

• decreased ability of kidney to produce dilute urine

• decreased blood volume

• decreased arteriolar resistance

ADRs of thiazides

hypokalemia, hypercalcemia, allergy reactions to sulfonamide

Hypertension: thiazide, loop, or both?

both

Heart failure: thiazide, loop, or both?

both; thiazide (mild), loop (moderate to severe)

Chronic renal failure: thiazide, loop, or both

both; acute (loop)

Osteoporosis (decreased Ca excretion): thiazide or loop or both?

thiazide

Hypercalcemia (increased Ca excretion): thiazide, loop, or both?

loop

Nephrogenic diabetes insipidus: thiazide, loop, or both?

thiazide

Nephrotic syndrome: thiazide, loop, or both?

loop

Hyperkalemia: thiazide, loop, or both?

both

Acute pulmonary edema: thiazide, loop, or both?

loop

What is the effect of NSAIDs on loop diuretics?

decreased diuretic action

What is the effect of digoxin on loop diuretics?

increased effects (toxic due to hypokalemia)

What is the effect of quinidine on loop diuretics?

QT prolongation (aggravated by hypokalemia)

What is the effect of corticosteroids on loop diuretics?

additive hypokalemia effect

What is the effect of aminoglycoside on loop diuretics?

ototoxicity

What is the MOA of Na channel inhibitors?

blocks Na channel in cortical collecting tubule

ADRs of Na channel inhibitors

hyperkalemia, metabolic acidosis

Na channel inhibitor drugs

triamterene, amiloride

Triamterene brand

dyrenium, dyazide, maxzide

Amiloride brand

midamor, moduretic

What is the MOA of MRA?

blocks mineralcorticoreceptors → prevents formation of aldosterone proteins → indirectly decreases Na channel permeability

What are the results of K+ sparing diuretics?

decrease in Na reabsorption, increase in K retention

MRA drugs

spironolactone, eplerenone

Spironolactone brand

aldactone

Eplerenone brand

inspra

MOA of CAI

inhibits action of carbonic anhydrase

ADRs of CAI

metabolic acidosis, hypokalemia, kidney stones

How do kidney stones happen?

Ca salt is insoluble → alkalosis in urine

What diuretic treats glaucoma?

CAI

What diuretic treats urinary alkalization?

CAI

What diuretic treats metabolic alkalosis?

CAI

What diuretic class treats acute mountain sickness?

CAI

Deficiency of ADH leads to what?

diabetes insipidus

Excessive of ADH leads to what?

syndrome of inappropriate ADH (SIADH)

What treats DI?

desmopressin

What treats syndrome of inappropriate ADH?

demeclocycline, lithium

What are the effects seen when thiazides treat DI?

may increase sensitivity to ADH, increase salt in urine (more concentrated), decreases serum sodium/bp

MoA of vasopressin antagonist

AVP receptor antagonist at V2 to promote excretion of free water w/o loss of serum electrolytes

What are the results of vasopressin antagonists?

increase in urine output, decrease in urine osmolality, restoration of normal Na levels

What diuretic class treats hyponatremia (hypovolemic, euvolemic)?

vasopressin antagonist

What diuretic class treats acute heart failure?

vasopressin antagonist

What effect can be seen in edema on ECFV?

edema can cause increased distribution of ECFV to interstitial space

Furosemide brand/class

lasix - loop

HZT brand/class

microzide - thiazide

Metolazone brand/class

zaroxolyn - thiazide

Chlortalidone brand/class

hygroton - thiazide

Torsemide brand/class

demadex - loop

What do diuretic agents do?

increase urine volume

What is the goal of diuretics?

to increase excretion of salt and water