Pharmacology of Diuretics Flashcards Preview

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Flashcards in Pharmacology of Diuretics Deck (16):

Diuretics do what?

Increase urine volume by altering ion transport in the nephron.


When and why do we use diuretics?

They are a first line defense in the treatment of HTN and edematous states such as CHF, nephrosis, and cirrhosis


What are our osmotic agents?

Mannitol and urea


Mechanism of Mannitol? Uses?

Mannitol is filtered into the tubular lumen but not reabsorbed, increasing osmotic pressure in the lumen and retaining water in the urine.

We do it in order to reduce intraocular or intracranial pressure. It increases excretion of water more than Sodium, urinary excretion and metabolic toxins


Side effects of osmotic agents like Mannitol and Urea

Dehydration if you don't drink enough water

Increased ECF volume, leading to pulmonary edema


What is acetazolamide and how does it work

Carbonic Anhydrase Inhibitor

Blocks carbonic anhydrase primarily in the Proximal tubule, preventing reabsorption of sodium bicarbonate and leading to diuresis


What are the uses and side effects of acetazolamide?

We use acetazolamide for:

1. Glaucoma to decrease production of aqueous humor

2. Acute Mountain sickness to stimulate ventilation via metabolic acidosis

3. Elimination of acidic toxins (Alkalinizes urine, leading to increased excretion of weak acids)

4. Corrects Alkalosis

Side effects

1. Renal stones: increases urine concentration of Ca2+ and phosphates

2. Potassium wasting (increased HCO3- in tubules attracts K+)

3. Hypercholemic metabolic acidosis


What are furosemide, bumetanide, ethacrynic acid and how do they work

They are loop agents .

They work by inhibitng Na+ K+ 2Cl- transporter in thick ascending limb. Decreases positive luminal potential, leading to increased excretion of calcium and magnesium


What do we use loop diuretics for and what are the side effects

Hypokalemic (low k+) alkalosis (low H+)
Severe Dehydration
Allergic Reactions


What are HCTZ and Metolazone and how do they work?

Thiazide Diuretics

Work by inhibiting Na+-Cl- cotransporter in DCT


Uses and side effects of thiazide diuretics

First line agent for treatment of HTN, CHF, nephrosis, hypercalciuria, and nephrogenic DI.

Thiazides reduce ECF volume which activates RAAS which increases proximal reabsorption of NaCl and H2O which decreases delivery of fluid to distal nephron which decreases urine output

Side effects: Dehydration, hypokalemia, hypercalcemia, hyperglycemia, hyperlipidemia, hyperuricemia, hyponatremia, allergic reactions


Spironolactone, Eplerenone, are what? How do they work?

Potassium sparing agents

Spironolactone and eplerenone directly antagonize the mineralcorticoid receptor (target of aldosterone), thereby reducing Na+ reuptake in the late DCT and collecting duct. Both drugs prevent the aldosterone-mediated increase in apical membrane permeability to K+ (ROMK channels) and therefore are considered "potassium-sparing"


What do we use the potassium sparing agents spironolactone and eplerenone for?

Spironolactone and eplerenone we use primarily in hyperaldosteronism (Conn syndrome) and edematous states caused by secondary hyperaldosteronism like cirrhosis, nephrotic syndrome and cardiac failure. Antiandrogen activity can be useful for treatment of polycystic ovary syndrome and hirsutism


Amiloride and Triamterene are what? How do they work?

Amiloride and triamterene directly inhibit ENaCs in the late DCT and collecting duct which aso reduces Na+ reabsorption. This renders the charge in the lumen more positive, which is unfavorable for K+ secretion.

Hence, these ENaC antagonists are also considered "potassium-sparing"


What do we use amiloride and triamterene for?

Counteract the K+ loss caused by other diuretics, adjunct therapy to other diuretics to treat edema or HTN


Side effects of Potassium-sparing agents

Hyperkalemia (yea no shit)
Hyperchloremic metabolic acidosis, gynecomastia with spironolactone, impotence in males and abnormal menses in females