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60 Cards in this Set
- Front
- Back
What percentage of CO do the kidneys receive at rest?
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~20%
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Acetazolamide: what is it?
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A carbonic anhydrase inhibitor
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Acetazolamide: what does it do?
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Carbonic anhydrase inhibitor
- NaHCO3 reabsorption in PCT down. - Greatly increases excretion of HCO3 (so that 1/3 of all HCO3 filtered is excreted) - Decreases H and NH4 excretion in the collecting tubules - Causes urinary pH to rise to about 8 - Causes metabolic acidosis - Na and K excretion go up. |
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Acetazolamide: the ceiling effect
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Carbonic anhydrase inhibitor
? |
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Acetazolamide: other effects
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Carbonic anhydrase inhibitor
- Dec aqueous humor formation in the eye - Dec IOP - Dec seizures - Dec in mountain sickness |
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Acetazolamide: AE
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Carbonic anhydrase inhibitor
- Somnolence - Paresthesias - Metabolic acidosis - Inc amine reabsorption --> worsen hepatic encephalopathy - Inc urinary pH --> renal stones - Hypersensitivity reactions -- this is a sulfonamide derived medication |
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Acetazolamide: uses
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Carbonic anhydrase inhibitor
Poor diuretic due to refractoriness Glaucoma Mountain sickness (prophylaxis > treatment) Epilepsy |
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Osmotic diuretics: general
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Freely filtered
Not reabsorbed Not metabolized Pharmacologically inert |
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Osmotic diuretics: site of action
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PCT and the loop of Henle
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Osmotic diuretics: M of A?
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Increase extracellular fluid volume by drawing out intracellular water.
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Osmotic diuretics: effects of using?
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RBF: up
Excretion of all ions: up NaCl concentrating ability in medulla: down Urine concentrating ability: down |
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Osmotic diuretics: AE
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Increase in extracellular fluid volume can exacerbate pulmonary edema.
Can mess with plasma ion concentrations. Contraindicated in anuria |
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Osmotic diuretics: uses
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Prophylaxis of ARF, ATN prior to ischemia, nephrotoxin (??)
Decreases cerebral edema Decreases intraocular pressure (IOP) Mannitol is a free-radical scavenger |
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Loop diuretics: what do they do?
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Inhibit Na/K/2Cl symporter in the ascending limb.
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Loop diuretics: effects
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- Greatly increase NaCl excretion
- Increase K and H excretion due to increased delivery of Na to the distal tubule. - Decrease medullary tonicity - Decrease urine concentrating ability - Ethacrynic acid is the only non-sulfonamide loop diuretic. |
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Furosemide: class
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Sulfonamide
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Furosemide: also inhibits?
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Carbonic anhydrase
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Furosemide: other effect besides diuresis?
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Venous dilation
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Loop diuretics: protein binding, filtration rate.
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High protein binding, not well filtered.
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Loop diuretics: secreted where?
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In the PCT
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Loop diuretics: oral bioavailability
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Furosemide: ~60%
Ethacrynic acid: 100% |
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Loop diuretics: metabolism
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2/3 excreted unchanged
1/3 metabolized |
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Loop diuretics: AE
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Increased delivery of Na to distal tubule --> increased K, H excretion -->
Hypokalemia Hypochloremia Hypomagnesemia Metabolic alkalosis Increased Ca excretion in osteoporotic women Ototoxicity due to altered endolymph --> hearing loss, vertigo (usually reversible) |
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Loop diuretics: rare AE
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- Hyperuricemia (occasionally causes gout)
- Hyperglycemia (occasionally worsens glycemic control) - Hypersensitivity cross reaction with other sulfonamides (except ethacrynic acid) |
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Loop diuretics: uses
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- Acute pulmonary edema
- CHF - Edema of the nephrotic syndrome - Edema of cirrhosis - To increase excretion of some drugs |
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Thiazide diuretics: what do they do?
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Inhibit the Na Cl symporter in the distal tubule.
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Thiazide diuretics: derived from what
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Sulfonamides
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Thiazide diuretics: prototype
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Hydrochlorothiazide
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Thiazide diuretics: affect on carbonic anhydrase?
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Weakly inhibits
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Thiazide diuretics: secreted where?
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PCT
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Thiazide diuretics: half-lives
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HCTZ: ~2.5 hrs
Chlorthalidone (used in the ALLHAT study): ~47 hrs! |
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Thiazide diuretics: AE
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Increased Na delivery to the DT --> K, H excretion up -->
Hypokalemia Hypochloremia Metabolic alkalosis Hyperuricemia (occasionally gout) Hyperglycemia (occasionally worsens glycemic control) Hypersensitivity cross reaction with other sulfonamides - Erectile dysfunction! |
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Thiazide diuretics: uses
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HTN
CHF Edema of the nephrotic syndrome Edema of cirrhosis |
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Thiazide diuretics: can be used with what for maximum diuretic effect?
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Metolazone + loop diuretic
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Spironolactone: what is it?
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Aldosterone antagonist
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Spironolactone: what does it do?
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Increases Na excretion
Increases K, H retention Also binds to sex hormone receptors! |
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Spironolactone: AE
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- Hyperkalemia
- Estrogen effects: gynecomastia, impotence - Androgen effects: hirsutism, deepening of voice - Increases malignancies? |
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Spironolactone: uses
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- To increase aldosterone concentrations (??)
- Decrease mortality in CHF - Used in combination with loop or thiazide diuretics to minimize hypokalemia - Used for hyperaldosteronism |
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Name two aldosterone antagonists
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Spironolactone
Eplerenone |
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Name two K sparing diuretics
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Triamterene
Amiloride |
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K sparing diuretics: what do they do?
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Block ENaC channel in distal tubule and collecting duct
Block Na reabsorption, so block K, H, Ca, Mg excretion Increase Na excretion (a little) Increase K reabsorption (a little more) |
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K sparing diuretics: AE
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Hyperkalemia
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K sparing diuretics: common useage?
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In combination with other diuretics
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ADH: released from where in response to what?
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Released from the posterior pituitary in response to increased osmolality.
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ADH: what does it do?
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Increases water permeability in the collecting duct.
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ADH: effect on vessels
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ADH is a potent vasoconstrictor
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Diabetes insipidus: what is it?
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An underproduction or lack of ADH
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Diabetes insipidus: most significant clinical presentation
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Huge volume of dilute urine (~20 L/day)
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Diabetes insipidus: treated with what?
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Treated with long-acting ADH analogue (desmopressin)
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Desmopressin: what is it?
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Long-acting ADH analogue
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Desmopressin: route
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Nasally, orally, or via long-acting injection.
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What is a drug combination that can cause nephrogenic DI?
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Lithium + demeclocyline
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SIADH: what is it?
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When there is too much ADH released
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SIADH: what is the concentration of the urine?
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Concentrated urine
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SIADH: often follows what type of injury?
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Head injury
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SIADH: resolution
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Usually resovles spontaneously
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SIADH: treatment
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Usually resolves spontaneously
May be treated with loop diuretics |
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Conivaptan: what is it?
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A V1 and V2 antagonist approved for the treatment of euvolemic and hypervolemic hyponatremia
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Probenecid: what does it do?
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- Inhibits the organic acid transporter
- Inhibits tubular secretion of many acids (e.g. penicillin) - Inihibits tubular reabsorption of uric acid |
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Probenecid: uses
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Useful in gout because it increases the amount of uric acid excreted.
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