diuretics 51/52 Flashcards
Acetazolamide (Diamox)
Carbonic Anhydrase Inhibitor
sulfonamide derivatives
inhib NaHCO3 reabsorption via CA @ the proximal tubule (organic acid secretory system) site of secretion and action
limited effectiveness: enhanced Na reabsorption (in the form of NaCl) by all the remaining tubule segments
not very effective diuretics; places further down in the tubule where Na+ (NaCl) can be reabsorbed
“amides”
Mannitol (Osmitrol)
Osmotic Diuretic
in EC space but doesn’t cross BBB
filtered by the glomeruli (no tubular secretion), with minimal tubular reabsorption
increase in the osmotic pressure of the glomerular filtrate, which leads to decreased reabsorption of water (and its solutes) in nephron segments that are freely permeable to water
Na+ follows the water- unique!
proximal tubule and descending limb of loop of Henle
Furosemide (Lasix)
Loop Diuretic/High ceiling Diuretic (Inhibitors of apical Na+‐K+‐2Cl‐ symport)
sulfonamide derivatives
Ethacrynic Acid (Edecrin)
Loop Diuretic/High ceiling Diuretic (Inhibitors of apical Na+‐K+‐2Cl‐ symport)
phenoxyacetic acid derivative
no sulfa like rxn!
but worse ototoxicity
Hydrochlorothiazide (Microzide)
Thiazide and thiazide‐like diuretic (Inhibitor of apical Na+‐Cl‐symport
Chlorothiazide (Diuril)
Thiazide and thiazide‐like diuretic (Inhibitor of apical Na+‐Cl‐symport
Chlorthalidone (Thalitone)
Thiazide and thiazide‐like diuretic (Inhibitor of apical Na+‐Cl‐symport
Indapamide
Thiazide and thiazide‐like diuretic (Inhibitor of apical Na+‐Cl‐symport
Triamterene (Dyrenium)
K+ sparing Diuretic (Inhibitor of renal Na+ Channels)
poorly soluble and may precipitate kidney stones
Amiloride
K+ sparing Diuretic (Inhibitor of renal Na+ Channels)
Spironolactone (Aldactone)
K+ sparing Diuretic (Aldosterone antagonist)
“-one”
Eplerenone (Inspra)
K+ sparing Diuretic (Aldosterone antagonists)
Drospirenone + ethinyl estradiol (Yasmin)
K+ sparing Diuretic (Aldosterone antagonists)
Desmopressin acetate (1‐Deamino‐8‐D‐Arginine Vasopressin) (DDAVP, Stimate)
Anti‐diuretic drug
similar in structure to arginine vasopressin (the antidiuretic hormone; ADH)
increases water reabsorption by the collecting duct system in the kidney, increase in the insertion of water channels in the apical membrane
greater antidiuretic activity than vasopressin itself but has less cardiovascular vasopressor activity
skip pgs
7,8,9, table pg 10
Most diuretics have in common the ability to ???
inhibit sodium reabsorption and thus promote sodium excretion–>promote water excretion
keep in mind the nephron segment where the diuretic acts and the capabilities of distal and proximal nephron segments
drugs acting proximal of the collecting duct increase the delivery of Na+ to the collecting duct and increase K+ excretion which causes hypokalemia
edema
in the interstitial space
generalized (ANASARCA = severe generalized edema)
OR
localized to a specific part of the body (e.g. hydrothorax, hydropericardium, ascites).
Edema is caused by
increased movement of fluid from the capillary intravascular space into the interstitial space
main factors influencing fluid movement in and out of the capillary
Capillary intravascular hydrostatic pressure (pushes out)
and plasma colloid osmotic pressure (pulls back in)- via plasma proteins
Factors that increase transudation (oozing like movement of fluid through a membrane or between cells) into the interstitium and cause edema:
Increase in capillary intravascular hydrostatic pressure
Decrease in capillary intravascular colloid osmotic pressure
Impaired lymphatic drainage of interstitial
Renal retention of salt and water
Increased capillary permeability
Increase in capillary intravascular hydrostatic pressure
*arteriolar dilation
venular constriction
increased venous pressure as in CHF
*venous obstruction
Decrease in capillary intravascular colloid osmotic pressure
- decreased production of plasma proteins
- increased loss of plasma proteins
accumulation of osmotically active substances in the interstitial
space
Impaired lymphatic drainage of interstitial (can’t tx with meds)
Obstruction, e.g. neoplastic blockage and Filariasis (elephantiasis)
Radical Mastectomy (destruction of lymphatics)
Renal retention of salt and water due to
(1) Kidney disease
(2) Liver disease
(3) Heart disease
Increased capillary permeability due to
inflammatory substances (histamines, kinins) i.e. anaphylactic shock
CHF ??
ventricular pumping is inadequate
CO is low
renal perfusion is decreased–>RAAS activated
both ventricles, so systemic (R) and pulmonary (L) edema
Edema associated with liver disease (Cirrhosis)
Decreased synthesis of plasma proteins (albumin) and thus lowered colloid osmotic pressure.
b. Decreased liver metabolism of sodium and water retaining hormones (e.g. aldosterone and vasopressin)
c. Scarring of liver tissue in cirrhosis increases hydrostatic pressure in the portal capillaries, the result is transudation of fluid into the peritoneum and the development of ascites.
d. decreased renal blood flow due to sequestration of fluid in the liver leads to compensatory renal retention of sodium and water.
Edema associated with renal disease
Nephrotic syndrome (aluminuria/hypoproteinemia–>dec. osmotic pressue–>edema)
Acute renal failure, prevent progression to irreversible failure
non-edematous uses of diuretics
HTN
Nephrolithiasis (kidney stones)
Hypercalcemia (Furosemide increases renal excretion of calcium)
Nephrogenic Diabetes Insipidus
Glaucoma therapy and Ocular surgery
Acute Mountain sickness
Urinary excretion of toxins, overdose treatment, prevention of renal toxicity
NOT for edema of pregnancy