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Pharm - Ch. 40
Diuretics
Question | Answer |
---|---|
At what site of action would a diuretic produce the greatest diuresis? | Proximal tubule |
Most diruetics block sodium and chloride _______ | Reabsorption |
True or false: diuretics directly remove fluid from the nephrons | False. Creates osmotic pressure within nephron to prevent passive reabsorption of water, which is then excreted |
List the adverse effects of diuretics | Hypovolemia, acid-base imbalance, electrolyte imbalances, hypotension and ototoxicity |
List the four classes of diuretics | High ceiling/loop, thiazide, potassium sparing, osmotic |
Match each drug with its diuretic class: spironolactone, hydrochlorothiazide, mannitol, furosemide | Spironolactone -> potassium sparing Hydrochlorothiazide -> thiazide diuretic Mannitol -> osmotic diuretic Furosemide -> high ceiling (loop) diuretic |
For furosemide, list the following: site of action, onset, and uses | Site of action = ascending part of loop of Henle; profound diuresis Rapid onset Uses in priority: CHF, HTN, edema unresponsive to other drugs |
List the adverse effects of furosemide/high-ceiling diuretics | Hypotension, ototoxicity, electrolyte imbalance, hyper(glycemia, uricemia, lipidemia), dehydration, multiple DDIs, danger in pregnancy |
True or false: high-ceiling diuretics are effective even when GFR is low | True |
For patients taking digoxin, ______ caused by diuretics is a special problem | Hypokalemia |
True or false: thiazide diuretics are effective even when GFR is low | False. Thiazide diuretics depend on kidney function. |
List the site, mechanism of action, and use for hydrochlorothiazide | Site: distal convoluted tubule MoA: Blocks reabsoprtion of Na+/Cl- by priority: HTN, edematous states, diabetes |
True or false: hydrochlorothiaizdes are ototoxic | False |
Can thiazide diuretics cross the placental barrier to produce direct fetal harm? | Yes |
List the site and mechanism of action for spironolactone | Site: distal nephron MoA: blocks aldosterone actions, leading to retention of K and excretion of Na. Produces only modest increase in urine production and decrease in K execretion. |
List the therapeutic uses of spironolactone | Takes up to 48 hours to work. Used for HTN, edema, severe heart failure, and primary hyperaldosteronism. Commonly given c. TZD or loop diuretic. |
List the adverse effects and DDIs of spironolactone | Adverse: hyperkalemia, endocrine effects, TZDs and loop diuretics to counteract K loss. Don't use c. drugs that increase potassium (e.g., ACE inhibitors) |
What is mannitol? | An osmotic diuretic which is a 6-carbon sugar freely filtered at glomerulus. Minimal reabsorption and metabolism. |
What is the site and mechanism of action of mannitol? | Site: lumen of nephron MoA: osmotic force prevents passive H2O reabsorption and increases urine output |
What are the therapeutic uses of mannitol? | IV rapid (30-60 min); prophylaxis of renal failure, reduction of intracranial/intraocular pressure by removing H2O from CNS. |
What are the adverse effects of osmotic diuretics? | Can leave vascular system at capillary beds (except CNS), lead to edema. Be cautious c. heart disease patients. |