Diuretics Flashcards
What is an example of an osmotic diuretic?
Mannitol, possibly glucose
What is acetazolamide?
A carbonic anhydrase inhibitor
What are some examples of thiazide diuretics?
Hydrochlorothiazide, metolazone
What are some examples of loop diuretics?
Furosemide, bumetanide, ethacrynic acid (non-sulfonamide)
What are some examples of potassium sparing diuretics?
Spironolactone, eplerenone
What is conivaptan?
An anti-diuretic hormone antagonist
What is dapaglifozin?
A sodium glucose transport inhibitor
3rd line drug
What is a diuretic?
An agent that increases urine flow to block sodium reabsorption/increase sodium excretion
What is the typical GFR?
100-120 ml/min
What occurs in the proximal tubule?
Glucose and HCO3 (bicarbonate) are reabsorbed
What occurs in the ascending loop of henle?
Na, K and 2 Cl are pumped out and Ca and Mg follow
Water is not reabsorbed
What occurs in the distal tubule?
NaCl is reabsorbed
Ca is excreted
What occurs in the collecting ducts?
Water is reabsorbed in the presence of ADH (vasopressin) to concentrate urine
Na is reabsorbed while K is excreted when aldosterone is present
What are osmotic diuretics?
Osmotically active (hold onto water) compounds in the plasma. Stops water reabsorption, giving a high urine volume with little sodium
Filtered, not reabsorbed, pharmacologically inert and resistant to alteration
Mannitol, glucose
What can osmotic diuretics be used for?
Mannitol (IV), glycerol (oral) used for vascular surgery, renal transplant and opthalmological procedures
How can glucose become an osmotic diuretic?
In diabetes mellitus, there is so much glucose in the blood that it is not all reabsorbed in the proximal tubule. The glucose goes to parts of the kidney that have never seen it and holds onto water.
What are carbonic anhydrase inhibitors?
Very weak diuretics that inhibit carbonic anhydrase. Thus decreases HCO3 reabsorption and increases HCO3 excretion (with some Na) in proximal tubule
Acetazolamide
What are the uses of carbonic anhydrase inhibitors?
Severe alkalosis
Alkalinization of filtrate ionizes acidic drugs (increases renal excretion of aspirin)
Glaucoma
What is acute mountain sickness?
When someone goes to high altitudes and they hyperventilate due to the decreased oxygen. This causes decreased CO2 (increased bicarbonate)
What do thiazide diuretics do?
Increase NaCl excretion and decrease Ca excretion in the distal tubule (opposite of loop diuretics)
Some proximal tubular effect, only important when combined with loop
Hydrochlorothiazide
Up to 5% off filtered load
How does dose of thiazide diuretics affect its effect?
Lower dose is just as effective as higher dose, just takes longer to work. Will have fewer side effects.