Diuretics Flashcards by Corinne Perra

What are diuretic drugs typically used to treat?

Edema (localized or generalized0

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What are the main classes of diuretic drugs?

Osmotic diuretic 
Loop direct 
Thiazides diuretics 
Potassium -sparking 
Carbonic-anhydrase inhibitor

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What is the MOA of osmotic diuretics?

Filtered at glomerulus and poorly reabsorbed in nephron -> water stays in nephrons with the drug -> urine volume increased

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what is the osmotic diuretic?

Mannitol

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How is mannitol administered?

IV (can crystallized at room temp)

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Does mannitol enter the CNS or eye?

Nope

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What drug is used to manage acute cerebral edema and acute glaucoma?

Mannitol

Osmotically draws water out of these compartment back to the circulating blood

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When is use of mannitol contraindicated?

If BBB or BOB is disrupted and mannitol enters this compartment –> worsen edema

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What is the MOA of loop diuretics?

Inhibit Na/K/2Cl cotransporter at the luminal membrane of the tick ascending Loop of Henle

Sodium is not reabsorbed -> water stays in the nephron –> increased urine

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Loops diuretics inhibit reabsorption of _________ and increases _______ loss, in addition to its effect on sodium and water.

Ca and Mg; K and H

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What is the drug of choice to treat pulmonary edema/acute pulmonary edema ?

Furosemide

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What drugs is used for treatment of exercise induced pulmonary hemorrhage in horse?

Furosemide

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What diuretic drug would be useful in treatment of hypercalcemia ?

Furosemide

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What are adverse effects to furosemide use?

Fluid and electrolyte imbalances (cats more sensitive than dog)
Chronically -> metabolic ALKALOSIS, hypocalcemia, hypomagnesium, hyponatermia, hyperuricemia
Ototoxicity (esp in cats)

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When is use of furosemide contraindicated?

Dehydrated patients

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What is the MOA of thiazide diuretics

Inhibiting Na/Cl symporter in the early part of the distal convoluted tubule -> less Na and Cl reabsorption -> less water reabsorbed -> diuretics

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Which has more diuretic effect, thiazide or loop diuretic?

Loop diuretic (25% of water reabsorption in the loop vs 5% in distal convoluted tubule j

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Are thiazide diuretics potassium wasting or potassium sparing?

Potassium wasting -> can lead to hypokalemia

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What are side effects of this aside diuretics?

Inhibit conversion of proinsulin to insulin -> hyperglycemia

Fluid and electrolyte imbalances (less severe than furosemide )

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T/F: furosemide and hydrochlorothiazide decrease calcium absorption, therefore hypercalcemia can be a side effect

Furosemide decreases calcium -> hypocalcemia

Hydrochlorothiazide increase calcium -> hypercalcemia

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What drug can be used to treat edema, treat nephrogenic diabetes insipidus, and manage calcium oxalate urolithiasis?

Hydrochlorothiazide

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What are precautions to using hydrochlorothiazide ?

Fluid and electrolyte imbalances
Dehydration
Hyponatermia, hypokalemia, hypomagnesemia, hyperuricemia, metabolic ALKALOSIS

Hypercalcemia
Hyperglycemia

Spironolactone is what type of drug?

Potassium-sparing diuretic

What is the MOA of spironolactone?

Reduce aldosterone-mediated Na/K exchange in late distal convoluted tubule -> Na/Cl loss and K reabsorption

What drug is sometimes used to manage ascites or treat mineralocortocoid producing tumors?

Spironolactone

What are precautions to using spironolactone ?

Can lead to HYPERkalemia especially if used in combination with ACE inhibitors Metabolic ACIDOSIS Block androgens Block mineralocorticoids

In what patients is spironolactone contraindicated?

Addison's disease (hypoadrenocorticism) -> blocks mineralocorticoids

What type of drug in amiloride?

Potassium-sparing diuretics

What is the MOA of amilordie ?

Block Na reabsorption in distal convoluted tubule and in the collecting duct -> Na blocked -> reduced the net driving force for K secretion

What are cautions to using amiloride?

HYPERkalemia | Metabolic acidosis

What drug is a carbonic anhydrase inhibitor?

Acetazolamide

What is the MOA of acetazolamide?

Reversible inhibition of carbonic anhydrase (CA) in proximal convoluted tubule and collecting duct -> inhibit exchange of Na for H

What is the main use of carbonic anhydrase inhibitors

Decrease aqueous humor production in eye -> decrease IOP for treatment of glaucoma

What are the topical carbonic anhydrase inhibitors used for glaucoma treatment?

Dorzolamide Brinzolamide Sulfonamides derivatives

When should acetazolamide not be used ?

Significant renal/hepatic disease Hypoadrenocorticism, hyponatremia, hypokalemia, or hyperchloremic acidosis, other electrolyte imbalances

Acetazolamide can increase ammonia levels. What drug can bind these ions for excretion?

Lactulose

Explain RAAS

Low BP or hyponatremia-> renin (juxtaglomular cells) -> covert angiotensinogen to angiotensin I -> vasoconstriction and aldosterone release -> aldosterone increase water reabsorption

How is renin secretion inhibited?

Local or systemic hypertension Antigotenin II (pos feedback) ADH, increased Na B-adrenergic blockers

What is the function of angiotensin II ?

Vasoconstriction Stimulate aldosterone secretion Positive feedback to inhibit renin

What are the ACE- inhibitors?

Enalaril | Benazepril

How are enalapril and benazepril administered?

Oral

How are Enalapril and Benazepril excreted?

Enalapril - 95% at kidney Benazepril - 45% kidney and 55% liver

What are the indications to using ACE-inhibitors?

Secondary physiological effects of chronic heart failure Systemic hypertension Protein losing neuropathy

What are cautions to using ACE inhibitors

In animals with renal insufficiency> lower doses Not in critically ill renal failure patients Monitor Hyperkalemia

What is the action of ADH in the body?

Normally secreted in response to decreased vascular volume -> work on V2 receptors in collecting ducts -> increase water reabsorption through aquaporins -> increase vascular volume

What are the two types of diabetes insipidus?

Central ->. Decreased secretion of ADH (pituitary) Nephrogenic -> ADH is secreted but kidney is not responding

What is the hallmark of diabetes insipidus?

``` PU/PD Hyposethenuric urine (more dilute than plasma) ```

What do we use to treat central DI?

Desmopressin - synthetic ADH analog

What can be used in a dose-dependent manner to increase plasma factor VIII to manage von Willebrands disease?

Desmopressin

How is desmopressin administered?

Topically on conjunctiva

Can desmopressin be administered orally?

Yes. But is broken down in GI tract -> low oral bioavailability -> dose needs to be much higher if given orally

Do you do a water deprivation test to determine central vs neprhogenic DI?

NO | Dr. BOOTS SAYS NO!

How can you determine central vs nephrogenic DI?

Give desmopressin - > concentrated urine = central - >still no concentration = nephrogenic

How do you treat nephron DI?

Thiazides diuretics (hydrochlorothiazide) -> help reduce clinical symptoms (polyuria) upregulate aquaporin in collecting duct