Diuretics Flashcards
What do diuretics do?
Increase rate of Na excretion and urine outflow
Phosphodiesterase inhibitors are derivatives of …
Caffeine
How do cardiovascular diuretics work?
positive inotropes –> increase heart contractility –> increase CO and GFR –> diuretic effect
What would you use cardiovascular diuretics to treat?
edema associated with CHF
What are some examples of cardiovascular diuretics?
Digitalis (Digoxin)
Phosphodiesterase inhibitors: Aminophyllin, Inamrinone, Milrinone
What are 2 examples of physiological diuretics?
water - pee more
NaCl - drink more and therefore pee more
Where in the nephron do osmotic diuretics primarily act? Secondarily?
primarily: aLOH
secondarily: PCT
What is the main osmotic diuretic and how is it administered?
Mannitol
IV
What would you use Mannitol to treat?
Localized edema - cerebral edema, acute glaucoma
Acute renal failure
Poison/toxicity
Which drug is used to treat localized edema?
Mannitol
How do osmotic diuretics act?
They pull water towards them into the vasculature, increasing volume in the vasculature and therefore increasing GFR
T/F. Mannitol is the diuretic least likely to cause electrolyte imbalance.
True
How would you administer a loop diuretic?
oral or IV
T/F. Loop diuretics decrease renal blood flow and GFR.
False. Increase RBF and GFR
Loop diuretics have a (short/long) duration and a (slow/fast) onset.
short duration
fast onset
Which is the most common loop diuretic?
Furosemide/Lasix
What is the method of action of loop diuretics?
inhibit the NaK2Cl symporter –> there is electrolyte imbalance and positive charge in the urine –> luminal membrane cells sense this and want to put positive charges in the urine (i.e. - K and H)
What is the effect on the body of putting K and H into the urine?
Hypokalemia
Systemic alkalosis
How does Furosemide trigger the RAAS?
by causing a Na deficiency in the blood
What is a very important problem in horses that Lasix is used to treat?
Exercise-induced pulmonary hemorrhage Nose bleeds (Epistaxis)
What is Furosemide used to treat?
Edema of nephrotic syndrome, pulmonary edema/congestion, hypercalcemia (because loops excrete Ca), generalized edema, acute renal failure
What is the best drug to use for emergency renal failure?
Loop diuretics (because they increase the RBF)
Adverse effects of loop diuretics include… (6)
- hypokalemia
- cardiac arrhythmias
- systemic alkalosis
- ototoxicity
- hypovolemia
- hypersensitivity
Which drug is best to use for enhancing elimination of toxic agents/poisoning?
Mannitol
What is the only way to administer thiazide diuretics?!
per os
T/F. Absorption with thiazide diuretics is slow and incomplete.
True
Do thiazide diuretics increase or decrease BP?
decrease
T/F. Thiazide diuretics are used to treat renal failure.
FALSE. they decrease RBF - don’t use them to treat renal failure
Thiazide diuretics are the drug of choice to treat…
nephrogenic diabetes insipidus
What are 2 examples of thiazide diuretics?
hydrochlorothiazide
chlorothiazide
Which diuretic can be used to prevent or treat calcium crystals/uroliths?
Thiazide diuretics
T/F. Thiazide diuretics are weak bases.
False. weak acids
Which diuretics can cause hyperlipidemia?
Thiazide diuretics
What are some adverse effects of thiazide diuretics?
alkalosis, hypokalemia, electrolyte imbalance
T/F. Potassium-sparing diuretics should be given IV.
False. per os only!
K-sparing diuretics have a (fast/slow) onset and a (long/short) duration.
slow onset
long duration
Where in the nephron does Spironolactone work?
basolateral membrane in the late DCT and CD
What would you use Spironolactone to treat?
- hypokalemia (use with another diuretic, the other will be the main diuretic and this will counteract the hypokalemia)
- hyperaldosteronism (especially during heart failure)
How does Spironolactone work regarding aldosterone?
competitively blocks aldosterone binding to receptors in the late DCT and CD, therefore decrease aldosterone levels
What are some adverse effects of Spironolactone?
hyperkalemia, systemic acidosis, reproduction effects with aldosterone
How should you administer Triamterene and Amiloride?
per os
How do Triamterene and Amiloride differ from Spironolactone?
They don’t have an effect on aldosterone
They block epithelial sodium channels in the luminal membrane of the DCT and CD
Which Carbonic anhydrase inhibitors can be given oral or IV? only oral? ophthalmic?
Oral/IV: Acetazolamide
Oral: Methazolamide
Ophthalmic: Dorzolamide, Brinzolamide
Why aren’t CA inhibitors used as diuretics?
because of their ability to cause systemic acidosis
How do CA inhibitors lower IOP?
inhibit production of aqueous humor
What would you use CA inhibitors to treat?
open angle glaucoma
Why would you opt to use ophthalmic CA inhibitors to treat open angle glaucoma?
to decrease the possibility of systemic acidosis
