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Pharmacology CHF


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What is the definition of CHF?
⬢ reduction in cardiac output and ejection fraction ⬢ blood supply to tissues is insufficient to meet the ooxygen demands of the body
What is ejection fraction?
⬢ a measurement of the heart's efficiency ⬢ can be used to estimate the function of the left ventricle
What are 2 ways to get an measurement of ejection fraction?
1. using a catheter 2. echocardiogram
List 3 general causes of CHF
1. Systolic Dysfunction 2. Diastolic Dysfunction 3. Increased workload (increased preload & afterload)
What are common causes of CHF? (7)
⬢ hypertension (#1) ⬢ a-fib ⬢ congenital heart disease ⬢ coronary artery disease ⬢ endocarditis ⬢ malfunction of valves ⬢ myocardial infarction
What are symptoms of CHF?
⬢ decreased exercise tolerance ⬢ edema ⬢ rales ⬢ shortness of breath ⬢ tachycardia
What are some of the body's compensatory mechanisms due to CHF?
⬢ increased sympathetic activity (increased HR, SV, preload, afterload) ⬢ fluid retention (decreased cardiac output, increased renin, angiotensin II, aldosterone) ⬢ myocardial hypertrophy
What are the pharmacological treatments that can be used to treat CHF? (8)
⬢ ACE inhibitors ⬢ ARBs ⬢ Aldosterone antagonist ⬢ Beta-blockers ⬢ Digoxin ⬢ Diuretics ⬢ Positive inotrope (dopamine, dobutamine) ⬢ Vasodilators (to decrease afterload)
What is the goal of pharmacological treatment?
⬢ block compensatory neurohormonal activity caused by decreased cardiac output ⬢ prevent/minimize sodium & water retention ⬢ eliminate or minimize symptoms of HF ⬢ preserve cardiac function
What are indications to use diuretics to treat CHF?
⬢ used in either an acute or chronic state ⬢ use for excessive sodium & water retention ⬢ use for signs & symptoms of systemic and pulmonary congestion
What is the primary goal of diuretics in treatment of CHF?
decrease edema and pulmonary congestion
What lab level will be elevated in an acute decompensated CHF state?
BNP level > 200
What is the MOA of diuretics of loop diuretics?
⬢ work on the ascending loop of Henle ⬢ induce prostaglandin-mediated increase in renal blood flow, which leads to natriuretic effect
What are the doses for the loop diuretics in CHF treatment?
⬢ Furosemide: 20-40 mg BID, max of 400 mg ⬢ Bumetadine: 0.5-2 mg daily, max of 10 mg ⬢ Torsemide: 10-20 mg daily, max of 200 mg
What are drugs the interact with the loop diuretics?
⬢ Probenecid (gout medication) and NSAIDs ⬢ both drugs competively inhibit loop diuretics
What is a thiazide-like diuretic that can be used in combination with loop diuretics?
What is the MOA of Digoxin?
⬢ positive inotrope (increases cardiac contractility) ⬢ decreases renal absorption (works on Na/K/ATPase pump in the kidneys)
What type of patients are put on digoxin?
⬢ used in symptomatic patients who on optimal ACE-I, Beta-blocker, diuretic ⬢ used as a 3rd/4th line drug
What is the dosing of Digoxin with CHF patients?
⬢ 0.125 mg PO (optimal dose in patients with CHF) ⬢ 0.5 mg IV (in acute setting)
What is the therapeutic range of digoxin?
0.6 - 1 ng/dl
What receptors are affected by Dobutamine (Dobutrex)?
⬢ Dobutamine is a B1 and B2 receptor agonist ⬢ has some effect on alpha-1 ⬢ net vascular effect is vasodilation (B2) ⬢ positive inotrope (B1)
What is the dosing of Dobutamine (Dobutrex)?
⬢ 2.5 - 5 mcg/kg/min ⬢ progressively increase to 20 mcg/kg/min if necessary
What is MOA of dopamine?
directly stimulates adrenergic receptors by causeing norepinephrine release
What receptors are affected by dopamine?
⬢ has positive inotropic activity ⬢ works on B1, B2, A1, and D1
What drug is a mixed vasodilator?
⬢ Nitroprusside ⬢ mixed dilators act on both arteries and veins
What is the MOA of Nitroprusside?
⬢ acts on smooth muscle to increase synthesis of nitric oxide ⬢ increases cardiac index & decreases venous pressure ⬢ no direct inotropic effects
What is adverse effect of being on a Nitroprusside drip for over 12 hours?
⬢ cyanide toxicity ⬢ thiocyanate can prevent cyanide toxicity
What is the dosing of Nitroprusside?
⬢ initiate 0.1 - 0.25 mcg/kg/min ⬢ increase up to 3 mcg/kg/min ⬢ taper dose (do not stop abruptly
What is first-line medication in treatment of CHF?
ACE inhibtior
What is the MOA of ACE inhibitors?
⬢ blocks production of angiotensin II and reduces breakdown of bradykinin ⬢ decreases sympathetic stimulation ⬢ decreases production of aldosterone ⬢ decreases vasoconstriction (afterload)
What are benefits of using ACE inhibitors in CHF?
⬢ decreased mortality ⬢ decreased hospitalization ⬢ symptom improvement ⬢ should be used in all patients with left ventricular dysfunction
What should be monitored when administering an ACE inhibitor?
monitor serum Cr, blood pressure, and K+
What are adverse effects of ACE inhibitors that would cause discontinuation of therapy?
cough and angioedema
List drugs and dosages of ACE inhibitors for CHF patients
⬢ Captopril 6.25 mg TID, Target = 50 mg TID ⬢ Enalapril 2.5 mg BID, Target = 10 mg BID ⬢ Lisinopril 2.5 mg QD, Target = 20 mg QD ⬢ Ramipril 2.5 mg BID, Target = 10 mg QD * start low and go up to target dose
What is the MOA for nitroglycerin?
⬢ increase cGMP in smooth muscle and acts as a vasodilator, producing a reudction in afterload ⬢ may inhibit the ventricular remodeling process
What would be a good alternative for a CHF patient who cannot take ACE inhibitors?
Imdur 30-60 mg QD (a nitrate) with Hydralazine 25 mg BID (a vasodilator)
What is the MOA of beta blockers?
⬢ blocks effect of norepinephrine on heart and vascular system ⬢ decreases mortality and hospitalizations and improves symptoms
True/False: Carvedilol also blocks alpha 1
Carvedilol also blocks alpha 1 and decreases afterload The correct answer is: True
True/False: Beta-blockers should be used in place of an ACE inhibitor in treating CHF
Beta-blockers should be given in addition to ACE inhibitor therapy The correct answer is: False
What needs to be monitored when a patient is given a beta blocker?
⬢ Heart rate and systolic BP ⬢ monitor for dizziness, edema, and fatigue
List the 3 beta-blockers indicated to use for CHF and their dosages
⬢ Carvedilol: 3.125 mg BID; target 25 mg BID (< 85 kg), 50 mg BID (> 85 kg) ⬢ Metoprolol XL: 12.5 mg QDl target 200 mg QD ⬢ Bisoprolol: 1.25 mg QD, target 10 mg QD
When should a CHF patient be given an ARB?
give as an alternative to patients who cannot tolerate ACE inhibitors
List 4 ARBs and their dosages when treating CHF
⬢ Losartan 25 mg QD, max of 100 mg QD ⬢ Valsartan 80 mg QD, max of 320 mg QD ⬢ Irbesartan 150 mg QD, max of 300 mg QD ⬢ Candesartan 8 mg QD, max of 32 mg QD
What drug can be used as an add-on in patients with class III & IV CHF?
Spironalactone 25 mg QD
What is the MOA of Spironalactone?
⬢ blocks aldosterone in kidneys, heart, and vasculature ⬢ decreases potassium and magnessium loss ⬢ decreases sodium retention by working on the renin/aldosterone system
What should be monitored on patients on Spironalactone?
SCr, K+, Edema

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