Pharmacology: Katzung Drugs used in heart failure Flashcards
Why are diuretics used to treat hear failure?
Because they reduce fluid retention and blood volume.
Which diuretics are commonly used in heart failure?
Furosemide, Hydrochlorothiazide, Spirinolactone.
What is the MOA of furosemide?
Furosemide inhibits the Na/K/2Cl transporter in the TALH. This creates a powerful diuretic action. It also has a vasodilating effect on the pulmonary vessels.
What are the clinical applications for furosemide?
(1) Acute/chronic heart failure
(2) acute pulmonary edema
(3) other edematous conditions
(4) hypercalcemia
What adverse effects are associated with furosemide?
(1) Ototoxicity
(2) hypovolemia
(3) hypokalemia
(4) hypocalcemia
What is the MOA for hydrochlorothiazide?
Hydrochlorothiazide inhibits the Na/Cl transporter in the distal tubule. This reduces preload and edema by a modest diuretic action.
What are the clinical applications for Hydrochlorothiazide?
(1) Mild chronic heart failure
(2) Chronic renal stones
(3) Nephrogenic diabetes insipidus
(4) Hypertension
What are the adverse effects associated with hydrochlorothiazide?
(1) hypokalemia
(2) Hyponatremia
(3) metabolic alkalosis
(4) hyperglycemia
(5) Hyperlipidemia
(6) hyperuricemia
(7) hypercalcemia.
What is the MOA of spirinolactone?
Spirinolactone is an antagonist of the Aldosterone receptor in the kidney. Causes diuresis be preventing up regulation of Na channels for Na reabsorption.
What angiotensin inhibitors are used to treat heart failure?
Captopril, Benazepril, enalapril,
Losartan, Candesartan,
Why are angiotensin inhibitors used to treat hear failure?
They reduce afterload, salt, and water retention.
What is the MOA of ACE inhibitors like captopril?
Captopril and other ACE inhibitors block angiotensin converting enzyme thus preventing the conversion of Angiotensin I to angiotensin II. Decrease in angiotensin II decreases vascular tone and aldosterone secretion.
What are the clinical applications for the ACE inhibitors?
(1) Heart failure
(2) Hypertension
(3) Diabetes
What are the adverse effects associated with the ACE inhibitors?
CAPTOPRIL
Cough Angioedema contraindicated in Pregnancy metalic Taste hypOtension Potassium increased Rash Increased renin Lower angiotensin II
Why are positive inotropic agents used to treat heart failure?
Positive inotropic agents are used to treat heart failure when is particularly severe and an increase in cardiac output is necessary to maintain perfusion
What positive inotropic agents are used to treat heart failure?
Digoxin (cardiac glycoside)
dobutamine (sympathomimetic)
What is the MOA of Digoxin?
Digoxin inhibits the Na+/K+ ATPase. This increases intracellular Na+ which decreases Ca expulsion. Increase intracellular Ca causes increased cardiac contractility.
What are the clinical applications for digoxin?
(1) heart failure
(2) Nodal arrythmias
What are the adverse effects associated with digoxin?
(1) Arrythmogenic!!!
(2) Nausea/vomiting
(3) diarrhea
(4) visual changes (rare)
What is the MOA of dobutamine?
Dobutamine is a beta 1 selective sympathomimetic the increases cAMP and thus increases the force of contraction.
What are the clinical applications for dobutamine?
(1) Acute heart failure
What are the adverse effects associated with dobutamine?
Arrythmias.
Why are beta blockers used to treat Heart failure?
beta blockers are used to treat heart failure because they decrease excess sympathetic stimulation.
Which beta blockers are used to treat heart failure?
Carvedilol
Metoprolol
bisoprolol
What is the mechanism of action for Carvedilol, metoprolol, and bisoprolol?
They are beta receptor blockers, however, their effect on heart failure is poorly understood. It is possible that they decrease remodeling.
Why are vasodilators used to treat heart failure?
Vasodilators reduce preload and afterload.
Which vasodilators are used to treat heart failure?
Nitroprusside
Hydralazine + isosorbide dinitrate
Nesiritide
What is the MOA of Nitroprusside?
Nitroprusside causes massive powerful vasodilation which reduces preload and after load.
What are the clinical applications for Nitroprusside?
Acute severe decompensated heart failure
What are the adverse effects associated with Nitroprusside?
(1) Excessive hypotenison
(2) thioscyanate and cyanide toxicity
What is the MOA of Hydralazine and isosorbide dinitrate in the treatment of heart failure?
The MOA is poorly understood
What are the clinical applications for Hydralazine and isosorbide dinitrate in the treatment of heart failure?
Hydralazine and isosorbide dinitrate are used for the treatment of chronic heart failure in African Americans.
What adverse effects are associated with the use of Hydralazine and isosorbide dinitrate?
(1) headache
(2) Tachycardia
What is the MOA of Nesiritide in the treatment of heart failure?
Nesiritide is an atrial peptide vasodilator and diuretic.
What are the clinical uses for Nesiritide?
Acute severe decompensated heart failure
What adverse effects are associated with nesiritide?
(1) renal damage
(2) hypotension.
How is digoxin eliminated?
60% renal excretion
40% hepatic metabolism
What interactions are important to consider with digitalis therapy?
(1) Quinidine reduces digoxin clearance
(2) Digitalis toxicity is increased by hypokalemia, hypomagnesemia, and hypercalcemia therefore care should be taken with loop and thiazide diuretics.
What are the three steps to treating digitalis intoxication?
(1) correction of potassium or magnesium deficiency
(2) Antiarrythmic drugs (lidocaine or phenytoin)
(3) Digoxin antibodies
To what class of drugs do inamrinone, milrinone, and theophylline belong to?
They are Phosphodiesterase inhibitors
What is the MOA of inamrinone, milrinone, and theophylline?
They inhibit phosphodiesterase which decreases the breakdown of cAMP. The result in increased cardiac intracellular Ca.
