Diuretics Flashcards
Where to Carbonic Anhydrase Inhibitors act?
Proximal convoluted tubule.
Where to osmotic diuretics act?
PCT, Thin descending loop, and the collecting duct.
Where do Loop diuretics act?
Thick ascending duct.
Where to Thiazides and Thiazide-like analogs act?
Distal convoluted tubule.
Where do Potassium sparing drugs and vasopressin receptor antagonists act?
Collecting duct.
Where in the nephron is Na reabsorbed?
Every portion of the nephron except the thin limbs of the Loop of Henle.
Is movement of Na from the lumen to the tubular cell an active or passive process?
Always passive.
Is movement of Na from the cell to the the blood active or passive?
Always active, requiring Na/K ATPase.
Do most diuretics block the active step or the passive step of Na reabsorption?
The passive step.
Where is the MAJORITY of Na reabsorbed.
PCT
Which diuretics block the active step of Na reabsorption?
None.
What are the two routes by which diuretics reach they site of action in the nephron?
1) Blood to site. 2) Tubular Fluid (lumen) to site.
Which route do Aldosterone antagonists act on?
Blood to site.
What is the function to the organic acid secretory system?
To transfer large substances from the blood into the renal tubules.
How can diuretics negatively effect gout patients.
They can compete for transfer with uric acid, leading to less uric acid excretion.
What are the 4 loop diuretics that act on the Thick Ascending Loop?
Furosemide, Torsemide, Bumetanide, Ethacrynic acid.
What is the transporter site of action for Furosemide, Torsemide, Bumetanide, and Ethacrynic acid?
NaK/2Cl transporter on luminal membrane of Thick ascending limb.
How to Furosemide, Torsemide, Bumetanide, and Ethacrynic acid reach their site of action?
Via the OASS in the Proximal Convoluted Tubule.
There is excess K+ accumulation inside cells. What effect does this have on Ca and Mg?
It will cause Ca and Mg to be driven out of the lumen and into the blood. Excessive K is a major reason for Ca and Mg reabsorption at the Thick Ascending Limb.
What is the effect of Furosemide, Torsemide, Bumetanide, and Ethacrynic acid on water, Na, Cl, Ca, Mg, and K reabsorption?
It DECREASES reabsorption for all of them.
What is the effect of renal prostaglandins (PGE2) on loop diuretics?
They contribute to the diuretic effects of loop diuretic drugs.
What is the effect of NSAIDs on loop diuretics?
They decrease the effects of loop diuretic drugs.
What are possible adverse effects of loop diuretics?
Severe decrease in BP, risk of hypokalemia, increased gout risk, hypovolemia.
Can loop diuretics be used to treat acute pulmonary edema caused by heart failure?
Yes, because they have a very rapid onset.
What are the two Thiazide diuretics?
Chlorothiazide and Hydrochlorothiazide.
What are the three Thiazide-like diuretics?
Chlorthalidone, Metolazone, Indapamine.
Where do the Thiazide and Thiazide-like drugs act?
DCT.
What is the transporter site of action for Thiazides?
NaCl transporter on the luminal membrane of DCT.
What is the effect of Thiazide diuretics on Ca reabsorption?
They increase Ca reabsorption, causing a net rise in blood Ca levels.
What is the effect of NSAIDs on Thiazide diuretics?
NSAIDs decrease overall efficacy of Thiazide diuretics.
What is the speed of action of Thiazide diuretics?
They have a slow onset. 1-3 weeks before effects fully seen.
What are the two classes of potassium sparing drugs?
Na channel blockers and Aldosterone antagonists.
What are the two potassium sparing drugs that are Na channel blockers?
Amiloride and Triamterene.
What are the three potassium sparing drugs that are aldosterone antagonists?
Spironolactone, Canrenone, Eplerenone.
Where in the nephron do potassium sparing drugs act?
Collecting ducts.
What are the three major effects of aldosterone in the collecting duct?
Decreases K reabsorption. Increases Na and water reabsorption.
What are the effects of Amiloride and Triamterene?
Decrease Na reabsorption (slight), increase K reabsorption (major), decrease water reabsorption.
What are the effects of Spironolactone, Canrenone, and Eplerenone?
Decrease Na reabsorption (slight), increase K reabsorption (major), decrease water reabsorption.
What are the effects of aldosterone antagonists?
Decrease in Na channel expression and Na channel activity. Decrease in K channel expression.
What is the most common side effect of potassium sparing drugs?
Hyperkalemia
Explain the reaction of aldosterone antagonists with steroid receptors.
These drugs are synthetic steroids and can interact with steroid receptors in cells other than the kidney. Can cause impotence, gynecomastia, menstrual irregularities.
True or false: Aldosterone antagonists can treat excess hair growth in women.
True.
What is the advantage of using Eplerenone vs Spironolactone?
It has little or no affinity for non-aldosterone receptors. Thus, no unpleasant hormone side effects occur.
What are the two classes of Vasopressin Receptor Antagonists?
Tetracyclines and Vaptans
What are the Tetracycline class Vasopressin Receptor Antagonists?
Demeclocycline.
What are the Vaptan class Vasopressin Receptor Antagonists?
Tolvaptan, Conivaptan, Lixivaptan.
What is the major effect of Vasopressin receptors being activated by ADH?
Increase in water reabsorption via insertion of water channels into the luminal membrane of the collecting ducts.
What is the major effect of Vasopressin Receptor Antagonists?
Decrease in water reabsorption.
What are Vasopressin receptor antagonists used to treat?
Hypoatremia.
What is the most common osmotic diuretic?
Mannitol.
What are the two sites of action of osmotic diuretics?
PCT and Thin Descending Limb.
How to osmotic diuretics reach their site of action?
They are freely filtered at the glomerulus.
What are the three carbonic anhydrase inhibitors?
Acetozolamide, Dorzolamide, Brinzolamide.
What are the renal sites of action of carbonic anhydrase inhibitors?
PCT and collecting duct.
What are carbonic anhydrase inhibitors most used for?
To decrease the elevated intraocular pressure caused by glaucoma.
