Diuretics Flashcards
What is a diuretic
Any drug that accelerates the rate of urine formation
How does a diuretic work (general)
Removes Na+ by blocking Na+ ion channels so it cannot be reabsorbed, which in turn causes water to follow, which increases urine output
How much Na+ is reabsorbed at the loop of Henle
20-25%
How much Na+ is reabsorbed at the distal tubule
5-10%
How much Na+ is reabsorbed at the collecting duct
3%
What is the main clinical use of diuretics
To manage disorders involving abnormal fluid retention or treating hypertension
Where on the nephron is the most Na+ absorbed (as well as other ions)
At the proximal tubule
Where are organic acids and bases secreted at along the nephron
Proximal tubule
What is hyperuricemia
Too much uric acid in the blood
What acid do diuretics compete with in the bloodstream
Uric acid
What can happen with diuretics and uric acid
Diuretics compete with uric acid and are transferred out of the bloodstream. Because of this, the patient may end up with an abnormally high level of uric acid in the bloodstream, that would otherwise be normally excreted
What part of the nephron is the target portion for diuretics, specifically loop diuretics
Loop of Henle
What drugs cause hyperuricemia more often
Furosemide and hydrochlorothiazide
What happens to the osmolarity of the urine as it passes through the descending loop of Henle
The osmolarity increases because of the countercurrent mechanism that induces water reabsorption at this part of the nephron
What effect does the increase in osmolarity at the loop of henle have on Na+
It increases the salt concentration 3 fold
Where is one site along the nephron that osmotic diuretics works
Descending loop of Henle
Which portion of the nephron is impermeable to water
Ascending loop of Henle
What part of the nephron does loop diuretics work on
The work on the ascending loop of Henle because it blocks Na+ reabsorption at that sight. It is also the place along the nephron that is impermeable to water
What kind of diuretics work best at the site of the distal tubule
Thiazide diuretics
What happens at the the distal tubule
Mostly just Cl- is reabsorbed, also impermeable to water
Where on the nephron do antidiuretics work (ADH)
The collecting duct
What types of drugs work best on the proximal tubule
Carbonic anhydrase inhibitors
What types of drugs work on the descending limb and part of the proximal tubule
Osmotic diuretcs
What types of drugs work best on the ascending loop
Loop diuretics
What drugs work best on the distal tubule
Thiazide diuretics