Drugs Used in Heart Failure Flashcards
What is the mechanism of action of furosemide?
blocks the Na+/K+ 2Cl- cotransporter
What are the major clinical applications for furosemide?
- edema associated w/ heart failure
- HTN
-rapid relief of dyspnea d/t pulmonary edema by decreasing preload
True or False: furosemide works in pt’s with low GFR
True (unlike thiazides, such as HCTZ)
What is the average time of onset for furosemide to begin working?
- 5 mins (IV)
- 30 mins (IM)
- 45 mins (PO)
What are side effects of furosemide (a loop diuretic)?
- hypokalemia
- hyponatremia
- hypocalcemia (increases risk of kidney stones)
- hypomagnesemia
- hypochloremic metabolic alkalosis (b/c of K+ loss, the cells take H+ from serum to replace it)
- hyperuricemia
- ototoxicity
True or False: furosemide is a sulfa drug
True, use ethacrynic acid in pts with sulfa allergies
What are three indications for use of captopril?
- HTN
- HFrEF
- diabetic nephropathy
What is the half-life of captopril?
-relatively short (1.7hrs)
What are the major side effects of ACEi’s?
- cough (d/t increased bradykinin)
- angioedema
- altered taste (especially captopril)
What two things make enalapril special among ACEi’s?
- prodrug available in IV form
- can be used for stroke prophylaxis
What is the dosing benefit of benazepril and lisinopril?
–longer half-life permits 1x daily dosing (unlike captopril w/ a relatively short half-life)
What are three K+ sparing diuretics?
- amiloride and triamterene (Na+ channel blockers)
- spironolactone (aldosterone antagonist)
What is the mechanism of action of triamterene and amiloride?
-blocks ENaC in the collecting duct
What is the mechanism of action of spironolactone?
-aldosterone receptor antagonist
What is the mechanism of action of thiazides?
-blocks Na+/Cl- cotransporter in the DCT
What is the mechanism of action of loop diuretics?
-blocks Na+/K+/2Cl- cotransporter in the Loop of Henle
Can HCTZ be used in pt’s with low GFR?
No
What is an off-label use of HCTZ in regards to calcium?
-Tx of calcium nephrolithiasis, because thiazides actively pull calcium out of the tubule lumen
What are side effects of HCTZ?
- hypokalemia
- hypomagnesemia
- hyponatremia
- hypochloremic alkalosis
Is HCTZ a sulfa drug?
Yes
Why would chlorthalidone be a better thiazide to use than HCTZ?
chlorthalidone has a longer half-life (50hrs)
What long-acting thiazide diuretic do cardiologists prefer as an adjunct diuretic in CHF?
-metolazone
What is the initial set-up for a patient w/ Acute Decompensated Heart Failure?
- seated position
- pulse ox +/- O2
- get BP
- continuous cardiac monitoring
- 2 IV’s
- monitor urine output
What is the pharmacological treatment of Acute Decompensated Heart Failure?
-increase diuretics
1) loop diuretic first
2) add K+ sparing diuretic next (ex: amiloride)
3) if more diuresis is needed, use a thiazide
Can you use amiloride or triamterene in pt’s with a low GFR?
No, you should avoid the K+ sparing diuretics in pt’s with a GFR < 45 mL/min
What is the mechanism of action of spironolactone?
-blocks the aldosterone receptor in the collecting duct
What is a major side effect of amiloride?
-hyperkalemia
What is a major clinical application of using spironolactone in post-MI patients?
–reduces fibrosis in HFrEF and post-MI heart failure
Is spironolactone slow-acting or fast-acting?
slow
What are some side effects of spironolactone?
- hyperkalemia
- amenorrhea, hirsutism
- gynecomastia, impotence
Is eplerenone a more selective or less selective aldosterone receptor antagonist than spironolactone?
MORE selective
-can be used to Tx hyperaldosteronism
