Diuretics Flashcards
What are the classes of diuretics?
thiazides loop K sparing CA inhibitors Osmotics
Osmotic diuretics increase urine flow with _____ salt excretion.
low
Osmotic diuretics can cause an immediate inital ________ of the ECF.
expansion
Mechanism of action for osmotic diuretics.
Osmotics distribute throughout the ECF and water moves out of the cells down the osmotic gradient. Expansion of ECF increases renal blood flow.
Osmotic diuretics increases the excretion of which electrolytes?
All: Na, K, Ca, Mg, Cl, HCO3, PO4
What are the osmotic diuretic agents?
Mannitol
Glycerin
Isosorbide
Which osmotic diuretics are IV?
Mannitol
Which osmotic diuretics are PO?
glycerine and isosorbide
In what case would mannitol be contraindicated?
frank renal failure
pulmonary edema
When is mannitol most commonly used?
shock brain edema (trauma) rhabdomyolysis
When are glycerin and isosorbide commonly used?
before ophthalmic surgery
What are the carbonic anhydrase inhibitor agents?
Acetazolamide (Diamox)
dichlorphenamide (Daranide)
methazolamide (Neptazane)
What is the carbonic anhydrase inhibitor ending?
-amide
What is one of the main limitations of carbonic anhydrase inhibitors?
excessive bicarbonate secretion and subsequent metabolic acidosis
What are carbonic anhydrase inhibitors generally used for?
open-angle glaucoma
altitude sickness
alkalosis in CHF patients
Mechanism of action of carbonic anhydrase inhibitors
reversible inhibition of carbonic anhydrase which prevents the formation of CO2 and the recovery of HCO3 from the tubule
Carbonic anhydrase inhibitors are contraindicated in what groups?
pregnancy
hepatic cirrhosis
severe COPD
What overdose situations would you use carbonic anhydrase inhibitors?
aspirin and barbituate
What are the benzothiazide diuretic agents?
chlorothiazde hydrochlorothiazide hydroflumethiazide methylchlothiazide polythiazide chlorthalidone indapamide metolazone
What is the mechanism/site of action of benzothiazides?
Block the Na/Cl transporter in the early distal tubule
What are the therapeutic uses of benzothiazides?
HTN
diabetes insipidus
kidney stones
What is the first line diuretic (and antihypertensive)?
HCTZ
Benzothiazides provide _____ diuresis.
mild/safe
Benzothiazides lower BP by __-__ mm Hg
15-20
How do benzothiazides improve diabetes insipidus?
In normo-natremic individuals, thiazides causes mild hyponatremia. This causes increased Na and water reabsorption in the proximal tubule meaning that less water reaches the distal tubule and thus urine output is decreased.
How do benzothiazides treat kidney stones?
Thiazides decrease Ca exretion by unknown mechanism.
What are the major adverse effects of benzothiazides?
hyPOkalemia
hyPOmagnesia
hyPERglycemia
hyPERlipidemia
Chlorthalidone is about ___x as potent as HCTZ and has about ___x the half life.
1.5x as potent
18x longer half-life
What are the loop diuretic agents?
furosemide (Lasix)
bumetanide (Bumex)
ethacrynic acid (Edecrin)
torsemide (Demadex)
For what conditions are loop diuretics commonly used?
edema
hypercalcemia
HTN unresponsive to thiazides
renal failure
Mechanism/site of action of loop diuretics
Blockade of the Na/K/2Cl uptake in the TALH
Loop diuretics promote __ _______, potentially to a serious level.
K excretion
Along with K, what other electrolytes do loop diuretics promote excretion?
Ca and Mg
In the use of loop diuretics, renin secretion is/isn’t suppressed.
Renin secretion is not suppressed
In the use of loop diuretics, GFR is/is not reduced.
GFR is not reduced
What are the adverse effects with loop diuretics?
electrolyte imbalances ototoxicity GI disturbances, bleeding, diarrhea pancreatitis lupus erythematosis
Which loop diuretic agent is most common cause of ototoxicity?
ethacrynic acid
What condition can be revealed by loop diuretics and thiazides?
gout
Loop diuretics cause ____ diuresis.
high/potent
Loop diuretics can interact with warfarin, causing _______ anticoagulation.
increased
What are the K sparing diuretic agents?
Spironolactone
Eplerenone
Triamterene
Amiloride
In what conditions are K sparing diuretics used?
HTN CHF ascites (cirrhosis) primary and secondary aldosteronism hypokalemia
How/where do the K sparing diuretics Triamterene and Amiloride work?
Triamterene and Amiloride block the Na channel in the late distal tubule and collecting duct.
How/ where do the K sparing diuretics Spirololactone and Eplerenone work?
Spironolactone and Eplerenone are competitive antagonists of aldosterone at the mineralocorticoid receptor. They block the binding of aldosterone and thus decrease the synthesis and activity of the luminal Na channel.
K sparing diuretics are _____ effective than ARBs in African Americans.
more
Triamterene and Amiloride are/are not dependent on aldosterone levels.
are not
Spironolactone and Eplerenone are/ are not dependent on aldosterone levels.
are
K sparing diuretics are most effective when combined with _______ ________.
other diuretics
Eplerenone has _______ specificity for MR than spironolactone.
greater
What are the adverse effects of K sparing diuretics?
Hyperkalemia
gynecomastia and impotence
menstruel irregularities and hirsutism
gastric bleeding
Eplerenone is metabolized by _____ and shouldn’t be used with inhibitors.
CYP3a4
