CIS: DRUGS USED IN HEART FAILURE Flashcards
Inotropic Agents
- Cardiac glycosides (e.g., digoxin)
- Bipyridines
- Inamrinone
- Milrinone
- Beta-adrenergic receptor agonists
- Dobutamine
- Dopamine
Agents Without Positive Inotropic Effects
- Diuretics
- Angiotensin converting enzyme (ACE) inhibitors
- Angiotensin Receptor Blockers (ARBs)
- Vasodilators
- Beta-adrenergic receptor blockers
- Natriuretic peptide
Heart Failure
- Major contributor to morbidity and mortality worldwide
- Five million cases of heart failure in the United States
- Variety of causes and classifications
- This CIS is limited to discussion of low-output failure due to systolic dysfunction
- Heart failure occurs when cardiac output is inadequate to provide the oxygen needed by the body
heart failure therapies are focused on
heart failure due to reduced ejection fraction from systolic dysfunction
Compensatory Changes Associated with Heart Failure
Increase sympathetic discharge increase force increase rate increase preload increase afterload
Increase ang II
remodeling
increase afterload and preload
Drug Therapy of Heart Failure
•Historic focus on end-point components
- Volume overload (congestion) treated with diuretics
- Myocardial dysfunction (heart failure) treated with positive inotropes
- Stabilize hemodynamic decompensationand reduce symptoms
- Do NOT improve survival
Drug Therapy of Heart Failure
•Current therapies target organs other than the heart
- Renin-angiotensin-aldosterone system
- Sympathetic nervous system
- Goals are to reduce preload and afterload, and reduce maladaptive cardiac remodeling
- ACE inhibitors, ARBs, aldosterone antagonists, and certain β-blockers have been shown to reduce mortality
A 58 y/o caucasianmale is admitted with a chief complaint of increasing shortness of breath and a recent 17 pound weight gain. Two weeks prior to admission, he noted the onset of dyspnea on exertion after one flight of stairs, orthopnea, and ankle edema. Since then, his symptoms have increased. He notes episodic bouts of paroxysmal nocturnal dyspnea and has only been able to sleep in a sitting position. He also notes a productive cough, nocturia(2-3 times/night) and mild, dependent edema.
History •Long history of heartburn •10-year history of osteoarthritis managed with various NSAIDs •Depression •Hypertension •Strong family history of diabetes Physical exam •Dyspnea, cyanosis, and tachycardia •BP –160/100 mmHg •Pulse –90 bpm •5’11’’, 172 lbs •Respiratory rate –28 breaths/min •Chest examination reveals inspiratory crackles and wheezes bilaterally •S3 gallop is heard on cardiac examination •Neck vein distention is noted •3+ pitting edema of the extremities Current medications •Hydrochlorothiazide •Ibuprofen –600 mg QID •Ranitidine (Zantac) •Citalopram (Celexa)
Which class of diuretics are the most efficacious for reducing volume overload and are an appropriate choice for this patient?
Loop diuretics
furosemide
torsemide
bumetanide
ethacrynic acid
Loop Diuretics
- Prototypes: furosemideand ethacrynicacid
- MOA: inhibit the luminal Na+/K+/2Cl-cotransporter(NKCC2) in the TAL of the loop of Henle
•Results in: ↓ intracellular Na+, K+, Cl-in TAL ↓ back diffusion of K+ and positive potential ↓ reabsorption of Ca2+and Mg2+ ↑ diuresis
- Ion transport is virtually nonexistent
- Relieve the “congestive” aspect of CHF
- Improve symptoms, but not mortality
Loop Diuretics
Indications
- Edema
- Heart failure
- Hypertension
- Acute renal failure
- Hypercalcemicstates
Loop Diuretics
Adverse effects
- Hypokalemia
- Alkalosis
- Hypocalcemia
- Hypomagnesemia
- Hyperuricemia
- Ototoxicity
- Sulfonamide hypersensitivity (not all)
- May worsen renal function
He is prescribed furosemide and an additional agent to control his blood pressure and edema. He returns 2 weeks later with controlled blood pressure but with a swollen tongue and a nagging cough. Which agent was most likely given that resulted in these symptoms?
Which is an appropriate replacement therapy in this situation to control blood pressure and edema in combination with furosemide?
enalapril
losartan (dont get the bradykinin effects so you dont get the cough)
Angiotensin II:
•Arterial vasoconstrictor •Increases retention of sodium and water •Increases aldosterone secretion •Promotes catecholamine release from the adrenal medulla •Promotes arrhythmias •Promotes vascular and cardiac hypertrophy and remodeling •Stimulates myocyte death
ACE inhibitors and ARBs reduce
mortality
The patient is now stable on furosemide and losartan. A third drug is prescribed that has been shown to reduce symptoms and improve survival in patients with HF. You inform your patient that his symptoms may temporarily get worse upon initiation of this drug, but that dramatic improvement should be apparent after 3-6 months of therapy. Which drug was most likely prescribed?
metoprolol
Beta Receptors in HF
- Compensatory sympathetic hyperactivationin patients with HF initially increases CO
- Chronic stimulation of causes downregulationand desensitization of beta receptors, reducing responsiveness of myocardium
- High dose β-blocker therapy can antagonize the supportive effects of catecholaminesand worsen heart failure
- Treatment only initiated in stable patients
always start with a stable pt and increase dose, also let them know they could get worse for a time
Beta Blockers Improve
LVEf and reduce mortality
Rationale for β-blocker Use in HF
- Beta blockade upregulates myocardial β1 receptor density; inotropic and chronotropic responsiveness of myocardium is improved
- Circulating levels of vasoconstrictors (e.g., NE, renin, endothelin) are reduced
- Beneficial remodeling
- Reduces myocardial O2requirement
- Improve survival after myocardial infarction
all drugs that reduce mortality in heart faiulre have been shown to have a beneficial effect on
heart remodeling
Aldosterone antagonist (spironolactone, eplerenone
- Reduces mortality and hospitalizations
- Beneficial at a variety of LVEF reductions in various HF classes
- May be especially useful after MI
- Monitor for adequate renal function and normal plasma [K+]
may have benefical remodeling on heart