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31 Cards in this Set
- Front
- Back
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At what locations and at what percentrages is sodium and water reabsorbed along the Nephron?
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1. proximal conv tub - 60-70% of Na actively reabsorbed exchanged for H
- followed passively by water, CL, K 2. ascending loop of Henle - 25% of CL actively reabsorbed - followed by Na, water 3. distal convoluted tubule - 5-10% of Na/K exchange - followed by water, Cl |
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Where does aldosterone and ADH act on the nephrone?
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aldosterone - distal convoluted tubule, where Na/K exchange occures
ADH - collecting duct |
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What is the funciton of carbonic anhydrase?
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provides H ions for exchange for sodium in proximal convoluted tubule, allowing for reabsorption of water and electrolytes
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What is the mechanism of carbonic anydrase inhibitors? (CAI)
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prevents production of H ions for exchange in proximal convulted tubule, preventing reabsorption
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adverse effects of CAI?
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most commonly - meabolic acidosis, hypokalemia
also, drowsiness, anorexia, paresthesia, photosensitvity |
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Drug ineractions with CAI?
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causes hypokalemia --> inc risk for digoxin
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What electrolyte do loop diurteics act on? Where?
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Cl, indirectly Na
thick part of ascending loop of Henle |
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Pt. creatinine clearance is <25mL/min. What dirutic can be used?
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loop diuretics can be used with impaired renal function (<25mL/min creatinine clearance)
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What is the effect of renal prostaglandins?
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relaxing hormone
vasodilation in kidneys, lungs, systemically |
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What diuretic would be used when rapid diuresis is needed?
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loop diuretics
rapid onset lasts at least 2 hours also operates with poor renal function |
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What mechanisms of action do loop diuretics have?
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- block Cl, Na, Water -> profound diureses
- activate renal prostaglandins -> vasodilation - reduce preload and CVP - excrete Ca |
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What are indications for loop diuretics?
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edema --> HF
HTN ---> renal or hepatic disease renal excretion of Ca --> hypercalcemia |
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Can loop diuretics be used during pregnancy?
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only if absolutely necessary
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Adverse effects of loop diuretics
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obvi - hypotension, hyponat, hypokalem, dehydration, hypochloremia,
also ototoxicity (when combined with other ototoxic drugs) digoxin toxicity risk |
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hypokalemia sets the stage for what drug toxicity?
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digoxin
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This drug blunts the diuretic effects of loop diuretics
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aspirin and NSAIDs
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What is the most frequently prescribed Loop diuretic?
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furosemide (lasix)
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T or F. Thiazides can only work when kidney functioning (creatinine clearance) is above 30-50 ml/min.
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both T and F.
T - all thiaides should not be used with impaired renal funcn EXCEPT F - metolazone - only thiazide that can work as low as 10ml/min |
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WHat is the mechanism of action for thiazides?
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operate on the early distal conv tubule
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What are the effects and indications of thiazides
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effect: areteriole relaxation
--> dec afterload and preload, --> HTN and HF also edema, diabetes insipidus |
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What drug should be prescribed for a hypertensive patient takin ototoxic drugs?
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thiazide. loops cause ototoxicicty.
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What drugs are usually used in concert with K - sparing diuretics?
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loop or Thiazides given with K-sparing to compensate hypokalemia
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What is the mechanism of action of Spinolactone?
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(Ksparing) spinolactone - aldosterone antagonist - blocks aldosterone
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What is mechansim of triamterine?
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(Ksparing) triamterine - non aldosterone antag - blocks Na/K exchange
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What is mechansim of amiloride?
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(Ksparing) amiloride- non aldosterone antag - blocks Na/K exchange
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Adverse effect of Ksparing?
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hyperkalemia. duh
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NEver combine K sparing with..?
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K supplement
salt substit (contains K) ACE inhibitor other Ksparing all cause hyperK |
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What does restricing sodium do to K levels?
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inc K levels
less sodium, less Na/K exchange, inc K levels |
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What is the problem with decreased renal functioning and diuretics?
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diuretics need to reach the kidneys in order to act on nephron
in dec renal, low kidney perfusion, dec drug reaching action site |
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What is mechanism of action of osmotic diuretic?
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osmotic diuretic, ie mannitol, cannot be reabsorbed back into circulation.
this creates osmotic force, pulling water into nephron, with minimal electrolyte losses |
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indication for osmotic diuretic?
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prophylaxis of renal failure
reduce intracranial and intraocular pressure |
