Diuretics Flashcards
15.18-15.20
What are the 3 carbonic anhydrase inhibitors?
- Acetazolamide
- Methazolamide
- Dichlorphenamide
What are the 4 osmotic agents?
- Mannitol
- Isosorbide
- Glycerin
- Urea
What are the 4 loop diuretics?
- Furosemide
- Bumetanide
- Ethacrynic acid
- Torsemide
What are the 11 thiazide diuretics?
- Hydrochlorothiazide
- Chlorothiazide
- Methyclothiazide
- Bendroflumethiazide
- Hydroflumethiazide
- Polythiazide
- Trichlormethiazide
- Indapamide
- Chlorthalidone
- Quinethazone
- Metolazone
What are 4 potassium-sparing diuretics?
- Triamterene
- Amiloride
- Spironolactone
- Eplerenone
What is the diuretic agent that is a natriuretic peptide?
Nesiritide
Acetazolamide; Methazolamide; Dichlorphenamide - MOA (2)
- Carbonic anhydrase inhibitor –> luminal inhibition prevents H2CO3-> H20+CO2 so less entry into cell and intracellular inhibition prevents HCO3- formation –> decreases basolateral Na+ reabsorption via Na/HCO3- (1:3) symport
- Acts at PCT-> Low diuretic b/c of tubuloglomerular feedback (TGF) activation in macula densa –> decrease in RBF/GFR –> self-limited diuresis
Acetazolamide; Methazolamide; Dichlorphenamide - Potency
Acetazolamide < methazolamide < dichlorphenamide (30X more potent that acetazolamide)
Acetazolamide; Methazolamide; Dichlorphenamide - Uses (3)
Glaucoma, urinary alkalinization; metabolic alkalosis (b/c of increased bicarbonate excretion)
Acetazolamide; Methazolamide; Dichlorphenamide - SE/Toxicity (4)
Metabolic acidosis; Ca-Ph (renal) stone formation; hypokalemia; allergic sulfur rxn
Mannitol, Isosorbide, Glycerin, Urea - MOA (3)
Osmotic diuretic
- Limit Na+ and water reabsorption
- Increase urinary excretion of nearly all electrolytes including Na+, K+, Ca+2, Mg+2, Cl-, phosphate
- Increases oncotic P and pulls water from ICF to expand extracellular fluid volume –> causes decreased renin release and increased RBF which causes medullary washout and thus diuresis (decreased concentrating ability)
Mannitol, Isosorbide, Glycerin, Urea - Formulation
Isosorbide/Glycerin –> oral
Mannitol/Urea –> IV –> more for increased intracranial P
Mannitol, Isosorbide, Glycerin, Urea - Uses (3)
- Acute renal failure
- Reduction of intracranial/intraocular P
- Dialysis disequilibrium (loss of solutes causes shift from ECF –> ICF)
Mannitol, Isosorbide, Glycerin, Urea - SE/Toxicity (3)
- Pulmonary edema
- Expansion of extracellular volume problem w/CHF
- Electrolyte loss
What is the special SE associated w/Glycerin?
Hyperglycemia
Urea/Mannitol - C/I (2)
Mannitol/Urea w/ intracranial bleeding
Urea w/ liver dysfunction
Furosemide, Bumetanide, Ethacrynic acid, Torsemide - MOA (4)
Loop diuretic in thick ascending limb (TAL)
- Inhibits Na-K-2Cl symport –> increased luminal [salt] = decreased water reabsorption
- Inhibits macula densa sensing mechanism –> interprets this as low luminal [NaCl] –> thus block TGF and do not decrease GFR
- Loss of interstitial gradient from medullary washout –> decreased urine concentrating abilities –> diuresis
- Increased urinary excretion of Na, Cl, K, and Ca/Mg (less positive lumen so decrease electrical gradient)
Furosemide, Bumetanide, Ethacrynic acid, Torsemide - Potency (2)
- Ethacrynic acid < furosemide < torsemide < bumetanide
2. Dose-response curve shift to R w/ chronic renal failure (impaired drug secretion into PCT)
Furosemide, Bumetanide, Ethacrynic acid, Torsemide - Uses
Pulmonary edema and other edematous states (e.g. CHF), HTN, acute renal failure
Furosemide, Bumetanide, Ethacrynic acid, Torsemide - SE
Ototoxicity (esp. Ethacrynic acid); electrolyte loss; metabolic alkalosis; allergic sulfur reaction (not w/ Ethacrynic acid); hyperglycemia, hyperuricemia
Furosemide, Bumetanide, Ethacrynic acid, Torsemide - D/I
Compounded ototoxicity w/ aminoglycosides, cisplatin/carboplatin, paclitaxel
Hydrochlorothiazide, Chlorothiazide, Methyclothiazide , Bendroflumethiazide, Hydroflumethiazide, Polythiazide, Trichlormethiazide, Indapamide, Chlorthalidone, Quinethazone, Metolazone - MOA (3)
Thiazide diuretics
- Inhibit Na/Cl symport in distal convoluted tubule (DCT) => decreased water reabsorption = diuresis; 2. Increased excretion of Na, Cl, and K and decreased excretion of Ca2+ (stimulated reabsorption)
- No tubuloglomerular feedback (after macula densa) or RBF
Hydrochlorothiazide, Chlorothiazide, Methyclothiazide , Bendroflumethiazide, Hydroflumethiazide, Polythiazide, Trichlormethiazide, Indapamide, Chlorthalidone, Quinethazone, Metolazone - Potency
Chlorothiazide-> lowest potency
Polythiazide/Trichlormethiazide-> highest potency
Chlorthalidone-> longest 1/2-life (47hrs)
Hydrochlorothiazide, Chlorothiazide, Methyclothiazide , Bendroflumethiazide, Hydroflumethiazide, Polythiazide, Trichlormethiazide, Indapamide, Chlorthalidone, Quinethazone, Metolazone - Uses (3)
HTN, mild edema, calcium nephrolithiasis
Hydrochlorothiazide, Chlorothiazide, Methyclothiazide , Bendroflumethiazide, Hydroflumethiazide, Polythiazide, Trichlormethiazide, Indapamide, Chlorthalidone, Quinethazone, Metolazone - SE/Toxicity
Hyponatremia, hypokalemia, hypercalcemia, metabolic alkalosis, allergic sulfur rxn, hyperglycemia (diabetes mellitus)
Hydrochlorothiazide, Chlorothiazide, Methyclothiazide , Bendroflumethiazide, Hydroflumethiazide, Polythiazide, Trichlormethiazide, Indapamide, Chlorthalidone, Quinethazone, Metolazone - D/I
Quinidine –> hypokalemia increases risk of torsades de pointes (ventricular tachycardia)
Triamterene, Amiloride - MOA
- K+ sparing diuretic-> inhibition of ENaC Na channels in late distal tubule/collecting ducts => decreased Na reabsorption (i.e. increased urinary excretion of Na+) = decreased water reabsorption and decreased K and H excretion
- Do not affect TGF or RBF
Triamterene, Amiloride - Potency (2)
Amiloride -> longer 1/2-life, more potent, renal excretion
Triamterene-> metabolized for excretion
Triamterene, Amiloride - Uses (2)
Used in combo w/ other diuretics to treat HTN, mild edema
Triamterene, Amiloride - SE (2)
Hyperkalemia; metabolic acidosis
Triamterene, Amiloride - D/I
Pentamide/trimethoprim (used to treat Pneumocystis infxn in AIDS pts) –> also ENaC inhibitors
Spironolactone, Eplerenone - Class and MOA (3)
- Steroid K+ sparing diuretic
- Mineralocorticoid receptor (MR) (aka aldosterone receptor antagonist) –> inhibits aldosterone induced expression of Na channels (ENaC) and Na/K ATPase=> reduced Na/water retention (increased urinary excretion of Na+) and decreased K, H+ urinary excretion
- Also inhibits androgen synthesis (use in prostate cancer)
Spironolactone, Eplerenone - Tx
Hyperaldosteronism (and endocrine diseases), HTN
Spironolactone, Eplerenone - Toxicity
Cross rxn w/ androgen receptor (gynecomastia, impotence) –> less w/ eplerenone
Hyperkalemia; metabolic acidosis
Spironolactone, Eplerenone - D/I
ACE inhibitor/angiotensin receptor blocker –> hyperkalemia
Nesiritide - Class and MOA
- Brain natriuretic peptide (BNP)
- Binds to specific receptors and via c-GMP signaling inhibits Na+ reabsorption in the inner medullary collecting duct and thus increase Na+ excretion
- Also inhibits renin-angiotensin II-aldosterone pathway
Nesiritide - Formation
Peptide –> given IV
Nesiritide - Uses
Currently limited Tx use
Acutely decompensated CHF
What type of diuretics are thiazide diuretics?
Na+-Cl- symport inhibitors
What type of diuretics are loop diuretics?
Na+-K+-2Cl symport inhibitors
What type of diuretics are K+ sparing diuretics?
Na+ channel inhibitors