Diuretics Flashcards
What happens to water if we block Na resorption into the blood?
More water leaves in the urine
What does higher blood volume cause?
Higher blood pressure
How much volume is filtered in Bowman’s capsule?
20%
How much fluid filtered in Bowman’s capsule gets resorbed?
> 19%
How much plasma entering the kidney get sent back into circulation and how much gets excreted?
> 99% back into circulation
What is the site of action for diuretics?
Nephron
What does Carbonic anhydrase do?
Facilitates Na reabsorption and H20 retention
Osmotic diuretics
A type of diuretic that inhibits reabsorption of water and sodium
Pharmacologically inert substances that are given intravenously
Increase osmolarity of blood and renal filtrate
Where do osmotic diuretics act?
Proximal convoluted tubule and
Proximal straight tubule
Loop diuretics
Act on the ascending loop of Henle
Primarily used in meds that treat hypertension and edema often due to congestive heart failure and renal insufficiency
More effective in patients with impaired kidney function
What is the site of action of loop diuretics
Thick ascending loop of Henle
What is the mechanism of how Loop Diuretics work?
Should be excreted in the lumen
Inhibits Na, K, 2Cl transporter –> this significantly increases the excretion of Na, K, and Cl
Osmotic gradient for water resorption is also decreased –> Increasing water excretion
Ca and Mg are excreted as well
What site do Thiazide diuretics act on?
Distal convoluted tubule
What is the mechanism of how Thiazide diurtics work?
Secreted by Proximal tubules but work in the distal convoluted tubules
Inhibit Na-Cl symporter from the lumen to tubular cells –> this increases Na and Cl excretion (and water)
K+ sparing diuretics site of aciton
Collecting tubule
Potassium sparing diuretics
Do not promote the secretion of potassium in the urine
Used as adjunctive therapy (together with other drugs) in the treatment of hypertension and management of congestive heart failure
Used with other drugs that would otherwise tend to lower K levels