Drugs for Heart Failure Flashcards
•impaired ability of the ventricle to fill with or eject blood
HEART FAILURE
•inability of the heart to pump blood to meet the metabolic demands of the body
HEART FAILURE
•formerly called CHF
HEART FAILURE
HEART FAILURE
•common cause:
–Left systolic dysfunction secondary to CAD (~70%)
•primary manifestations: HF
–dyspnea
–fatigue
–fluid retention
–pulmonary congestion
•Left Ventricular Failure
–pulmonary edema
•Left Ventricular Failure
–dyspnea, orthopnea
•Left Ventricular Failure
–systemic congestion
•Right Ventricular Failure
–peripheral edema
•Right Ventricular Failure
–jugular venous distention
•Right Ventricular Failure
–due to NE → increased HR (can only increase O2 demand)
•tachycardia & increased contractility
–increased preload → increased SV (leads to congestion)
•Frank-Starling mechanism
–to redistribute blood flow (increases afterload)
•vasoconstriction
–changes in cardiac muscle mass, size, shape, structure, function
•ventricular hypertrophy & remodelling
GOALS OF PHARMACOLOGIC INTERVENTION
•To alleviate symptoms, slow disease progression, and improve survival
•6 classes of drugs:
- 1) inhibitors of the renin-angiotensin system
- 2) ß-adrenoreceptor blockers
- 3) diuretics
- 4) direct vasodilators
- 5) inotropic agents
- 6) aldosterone antagonists
BENEFICIAL EFFECTS OF DRUGS FOR HF
- Reduction of the load on the myocardium
- Decreased extracellular fluid volume
- Improved cardiac contractility
- Slowing the rate of cardiac remodeling
•Agents of choice in HF
ACE INHIBITORS
•Block ACE (conversion of angiotensin I to II)
ACE INHIBITORS
•Diminish the rate of bradykinin inactivation
ACE INHIBITORS
•Decrease vascular resistance, venous tone, BP
ACE INHIBITORS
•Reduce preload and afterload -> increased cardiac output
ACE INHIBITORS
•Indicated in patients with all stages of left ventricular failure
ACE INHIBITORS
•Should be taken on an empty stomach
ACE INHIBITORS
•Pro-drugs that require activation by hydrolysis via hepatic enzymes (except ______)
ACE INHIBITORS
Captopril
• are adequately but incompletely absorbed following oral administration
ACE INHIBITORS
•Monopeptide, orally active compounds that are extremely potent competitive antagonists of the AT1 receptor
ARBs
•Advantage of more complete blockade of angiotensin action
ARBs
•Do not affect bradykinin levels
ARBs
•Similar actions with ACEIs but not therapeutically identical
ARBs
•Alternative to the ACEIs
ARBs
•All require only once-daily dosing
ARBs
only ARB that undergoes extensive first-pass effect, along with conversion to its active metabolite
Losartan:
•All are highly protein-bound
ARBs
•All have large Vd (except ______)
candesartan
•Ability to prevent the myocardial changes because of the chronic inactivation of the sympathetic nervous system –decreasing HR and inhibiting the release of renin
BETA-BLOCKERS
•Prevent direct deleterious effects of NE on the cardiac muscle fibers -> decreasing remodeling, hypertrophy, and cell death
BETA-BLOCKERS
is recommended for all patients with heart disease except those who are at high risk but have no symptoms and those who are in acute HF
BETA-BLOCKERS
nonselective ß-adrenoreceptor antagonist that also blocks alpha-adrenoreceptors
•Carvedilol:
long-acting ß1-selective antagonist
•Metoprolol:
•Reduce morbidity and mortality associated with HF
Carvedilol and Metoprolol
•Treatment should be started at low doses and gradually titrated to effective doses based on patient tolerance
Carvedilol and Metoprolol
•Additional benefit of antihypertensive action
Carvedilol and Metoprolol
•Relieve pulmonary congestion and peripheral edema
DIURETICS
•Useful in reducing the symptoms of volume overload (e.g., orthopnea, PND)
DIURETICS
•Decrease plasma volume -> decreased venous return to the heart (preload) -> decreased cardiac workload and oxygen demand
DIURETICS
•Decrease afterload by reducing plasma volume decreased BP
DIURETICS
relatively mild diuretics and lose efficacy if patient creatinine clearance is less than 50 mL/min
•Thiazide diuretics:
used for patients who require extensive diuresis and those with renal insufficiency; most commonly used diuretics in HF
•Loop diuretics:
–Overdoses can lead to profound hypovolemia
DIURETICS
•Dilation of venous blood vessels leads to a decrease in cardiac preload by increasing the venous capacitance
DIRECT VASODILATORS
reduce systemic arteriolar resistance and decrease afterload
•Arterial dilators
commonly used venous dilators for patients with congestive HF
•Nitrates:
if the patient is intolerant of ACEIs or ß-blockers, or if additional vasodilator response is required
•Hydralazine+ ISDN:
enhance cardiac muscle contractility -> increased cardiac output
INOTROPIC DRUGS
•Positive inotropic agents
–Result of an increased cytoplasmic Ca concentration that enhances the contractility of cardiac muscle
INOTROPIC DRUGS
•Positive inotropic agents
•Digitalis or digitalis glycosides (digitalis/foxglove plant)
I. DIGITALIS GLYCOSIDES
•Group of chemically similar compounds that can increase the contractility of the heart muscle
I. DIGITALIS GLYCOSIDES
•Influence Na and Ca ion flows in the cardiac muscle -> increased contraction of AV myocardium (positive inotropic action)
I. DIGITALIS GLYCOSIDES
•Narrow therapeutic index
I. DIGITALIS GLYCOSIDES
most widely used agent digitalis glycoside
•Digoxin:
•Digoxin (Lanoxin®)
DIGITALIS GLYCOSIDES
•Digitalis purpurea, Digitalis lanata
DIGITALIS GLYCOSIDES
•inhibit Na+/K+ - ATPase pump
DIGITALIS GLYCOSIDES
•Increases the force of cardiac contraction -> decreased EDV -> increased efficiency of contraction (EF) -> improved circulation -> reduced sympathetic activity -> reduced peripheral resistance -> decreased HR
Digoxin
•Increased vaga ltone -> decreased HR -> diminished myocardial oxygen demand
Digoxin
•Slows down AV conduction velocity (use in AF)
Digoxin
•Severe LVSD after initiation of ACEI and diuretic therapy
Digoxin
•HF with atrial fibrillation
Digoxin
•Only digitalis glycoside available in the US
Digoxin
•Very potent, with a narrow margin of safety
Digoxin
•Long half-life of ~36 hours
Digoxin
•Mainly eliminated intact by the kidney, requiring dose adjustment based on CrCl
Digoxin
•Large Vd: accumulates in muscle
Digoxin
•Dosage based on lean BW
Digoxin
•Loading dose regimen is used when acute digitalization is needed
Digoxin
•Cardiac: arrhythmia (slowing of AV conduction associated with atrial arrhythmias)
Digoxin
GI: anorexia, N/V
Digoxin
•CNS: headache, fatigue, confusion, blurred vision, alteration of color perception, halos on dark objects
Digoxin
PREDISPOSING FACTORS OF DIGOXIN TOXICITY
- Hypothyroidism
- Hypoxia
- Renal failure
- Myocarditis
MANAGEMENT OF DIGOXIN TOXICITY
- Discontinuation of cardiac glycoside therapy
- Determination of serum K levels
- Oral K supplementation (if indicated)
- Close monitoring of digoxin levels in renal insufficiency -> dose adjustments
- Administration of antiarrhythmic drugs
- Digoxin immune Fab
•Dobutamine and dopamine
II. BETA-ADRENERGIC AGONISTS
•Intravenous inotropic agent administered at the hospital
II. BETA-ADRENERGIC AGONISTS
–250 mg/20 mL vial
–250 mg/250 mL pre-mix (1:1)
–500 mg/250 mL pre-mix (2:1)
•Dobutamine and dopamine
•Positive inotropic effect and vasodilation
II. BETA-ADRENERGIC AGONISTS
•Dobutamine and dopamine
•Treatment of acute HF
II. BETA-ADRENERGIC AGONISTS
•Dobutamine and dopamine
III. PHOSPHODIESTERASE INHIBITORS
II. PHOSPHODIESTERASE INHIBITORS
•Inamrinone (formerly Amrinone)
•Milrinone
•Long-term treatment = higher risk of mortality
II. PHOSPHODIESTERASE INHIBITORS
•Inamrinone (formerly Amrinone)
•Milrinone
•Short-term IV milrinone: not associated with increased risk of mortality; symptomatic benefit in refractory HF
II. PHOSPHODIESTERASE INHIBITORS
•Inamrinone (formerly Amrinone)
•Milrinone
•Direct antagonist of aldosterone -> prevents salt retention, myocardial hypertrophy, hypokalemia
ALDOSTERONE ANTAGONISTS (Spironolactone)
•Reserved for the most advanced cases of HF
ALDOSTERONE ANTAGONISTS (Spironolactone)
•AEs: GI disturbances (e.g., gastritis, peptic ulcer); CNS effects (lethargy, confusion); endocrine abnormalities (e.g., gynecomastia, decreased libido, menstrual irregularities)
ALDOSTERONE ANTAGONISTS (Spironolactone)
•Competitive antagonist of aldosterone at mineralocorticoid receptors
ALDOSTERONE ANTAGONISTS (Eplerenone)
•Lower incidence of endocrine-related SE due to reduced affinity for glucocorticoid, androgen, and progesterone receptors
ALDOSTERONE ANTAGONISTS (Eplerenone)
•Reduces mortality in patients with LVSD and HF after acute MI
ALDOSTERONE ANTAGONISTS (Eplerenone)
At risk for developingHF. No identified structural or functional abnormality; no signs and symptoms.
Stage A
Developed structural heart diseasethat is strongly associated with the development of HF, but without signs and symptoms.
Stage B
SymptomaticHF associated with underlying structural heart disease
Stage C
Advanced structural heart disease and markedsymptoms of HF at rest despite maximal medical therapy
Stage D
No limitation of physical activity. Ordinary physicalactivity does not cause undue fatigue, palpitation, or dyspnea
Class I
Slight limitation of physical activity. Comfortableat rest, but ordinary physical activity results in fatigue, palpitation, or dyspnea
Class II
Marked limitation of physicalactivity. Comfortable at rest, but less than ordinary activity results in fatigue, palpitation, or dyspnea
Class III
Unable to carry on anyphysical activity without discomfort. Symptoms at rest. If any physical activity is undertaken, discomfort is increased.
Class IV
Stageof heart failurebased on structure and damage to heart muscle
ACC/AHAStages of Heart Failure
Severity based on symptoms and physical activity
NYHA Functional Classification