Flashcards in Pharm: CHF drugs Deck (23):
What is acutely decompensated CHF?
Acute CHF superimposed on the setting of chronic CHF
What are the treatment objectives for acute CHF?
Early recognition and treatment
- Reduce pulmonary congestion: loop diuretics, venodilators, nesiritide
--Increase contractility: beta blockers, phosphodiesterase inhibitors
--Reduce afterload: nitroprusside
Why are diuretics useful for acute CHF?
Reduced preload and pulmonary venous pressure
What diuretics are used to treat acute CHF?
What is the major effect of nitrates?
Dilation of venous capacitance vessels
What is Niseritide and what is it used for clinically?
Niseritide is a recombinant form of BNP
Used to treat CHF by inducing vasodilation and natriuresis
What inotropic agents are used to treat CHF?
Beta agonists: dobutamine, dopamine, isoproterenol and norepinephrine
Phosphodiesterase inhibitors: inamrinone, milrinone
*These drugs increase cAMP levels
What are the actions of cAMP in cardiac muscle?
Opens L-type Ca2+ channels
Increased reuptake of Ca into SR
Increased pacemaker current
Increased rate of conduction
Why are vasodilators beneficial for CHF patients?
Reduced afterload due to reduced systemic vascular resistance allows for increased SV and CO
Are Calcium channel blockers used for CHF patients?
No. Contraindicated for CHF due to negative inotropic effects
What are the non-pharmacological therapies for acute CHF?
PCI/surgical therapy: revascularization and/or valve repair
Intra-aortic balloon pump
Ventricular assist devices
What are the treatment objectives for chronic CHF?
Early recognition of ventricular dysfunction
Prevent ventricular remodeling
Decrease symptoms: decrease congestion, increase CO
What drugs prevent ventricular remodeling?
ACE inhibitors, ARB's, LCZ696
Aldosterone antagonists (spironolactone)
What is the mechanism of action of digitalis glycosides?
Inhibit the Na/K ATPase pump which increase the Na inside the cell, this leads to increased activity of the Na/Ca exchanger, bringing more Ca into the cell and more Ca stored in the SR
What are the mechanical effects of digitalis glycosides?
-increased velocity of shortening, force of contraction, ventricular emptying
-Decreased ESV and EDV
What are the systemic effects of digitalis glycosides?
Increased renal perfusion
Decreased sympathetic tone
What are the side effects of digitalis?
VERY NARROW THERAPEUTIC WINDOW
Causes DADs and abnormal automaticity, arrhythmias
What is the difference in vasodilator drugs used for acute versus chronic CHF?
Acute CHF drugs (nitroprusside, nitroglycerin) are given IV and have rapid onset of action
Chronic CHF drugs (ACEi's, ARBs, hydralazine, minoxidil, prazosin, LCZ696) are given orally and have slower onset of aciton
What is the mechanism of action for ACE inhibitors preventing ventricular remodelling?
1) Ang II is a cardiomyocyte growth factor and fibroblast mitogen
2) Inhibit RAA system
3) Decreased wall stress
What is LCZ696?
A combination of valsartan (ARB) and sacubitril (Neprilysin inhibitor)
Valsartan blocks the AT1a receptor on cardiac and vascular smooth muscle
Sacubitril causes vasodilation and reduced ECF volume via sodium excretion
How are beta blockers useful for chronic CHF treatment?
Increased survival due to reduced LV deterioration
Mechanism: reduced HR and blocking deleterious effects of chronic sympathetic stimulation
What specific beta blockers are used for chronic CHF therapy?