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Thursday, February 20, 2020

MED | PLE Pharmacology Review - Congestive Heart Failure (CHF) Drugs Mnemonics



So as I was studying for the 2019 Physician Licensure Examination or PLE, I made it a point to make drafts of some of the things I learned that I can immediately recall from the notes and tables I got during my review period.

Writing this here somehow enabled me to at least aggregate what I know and identify the weak areas that I still need to be familiar with to better prepare myself for the Pharmacology part of the PLE. Please take note that I was just an average performing student in school, but at this moment, I tried to catch up on the lessons and at the same time, aimed to be helpful to others given the limited knowledge and resources that I have.

Today's topic is about drugs used in congestive heart failure (CHF).

Side note:
  • Left-sided heart failure will usually present with orthopnea, pulmonary congestion and paroxysmal nocturnal dyspnea
  • Right-sided heart failure will come with symptoms of bipedal edema, neck vein engorgement, and hepatomegaly.
Some points to remember:
  • Because the heart is failing, cardiac output is decreased relative to the requirement of the body.
  • So the goals is to either
    • Push the heart to contract stronger (positive inotropes)
    • To lower the resistance the heart must pump against (also called afterload) for less stress (vasodilators)
    • Use other drugs to help alleviate accompanying heart failure symptoms
Enlisted below are the drugs used in congestive heart failure (CHF). Please do note that I only included what I feel are important or must-knows, given that I only have a limited amount of time. Take these with a grain of salt.

POSITIVE INOTROPES 

1. Cardiac Glycoside (DIGOXIN)

MOA: inhibits Na-K ATPase, increases contractility
Side effects: narrow therapeutic index, arrhythmia, yellow halos
Note: arrhythmogenesis risk increases with HYPOKALEMIA (from use of loop diuretics or thiazides), HYPOMAGNESEMIA, HYPERCALCEMIA

Mnemonics: Narrow Therapeutic Index Drugs


2. Beta-agonist (DOPAMINE, DOBUTAMINE)

Note: useful in ACUTE heart failure, not recommended in CHRONIC heart failure due to arrhythmogenic effects


3, PDE inhibitors (MILRINONE)

MOA: inhibits phosphodiesterase breakdown, increases cAMP, vasodilation
Side effects: bronchospasm, HYPOKALEMIA
Note: acts as an "ino-lator" (inotropes + vasodilator), increases morbidity and mortality in CHRONIC heart failure patients


VASODILATORS

1, NITROGLYCERIN, NITROPRUSSIDE - for ACUTE severe heart failure WiTH CONGESTION

2. HYDRALAZINE, ISOSORBIDE DINITRATE - reduces mortality in African Americans
Note: ISDN should not be taken with PDE inhibitor Sildenafil to prevent severe hypotension


OTHER IMPORTANT DRUGS

1. Ace inhibitors (-PRILS) and ARBs (-SARTANS) - FIRST LINE for CHRONIC heart failure
Note: Valsartan usually combined with SACUBITRIL (when activated, inhibits neprilysin, an enzyme that degrades BP-lowering peptides, in effect, lowering the BP)

2. Diuretics - first line for ACUTE and CHRONIC heart failure (systolic and diastolic)
  • FUROSEMIDE - loop diuretic, used to immediately address pulmonary congestion and severe bipedal edema, WOF hypokalemia
  • SPINOROLACTONE - K-sparing diuretic, acts as an non-selective aldosterone antagonist via competitive inhibition at the DCT, reduced mortality in CHRONIC CHF when added to loop diuretics

3. Beta blockers (-OLOLs) - slows progression of CHRONIC CHF, NOT useful in ACUTE CHF

4. Brain Natriuretic Peptide (BNP) analog (NESIRITIDE) - for ACUTE DECOMPENSATED heart failure
Note: BNP is secreted by the cardiomyocytes in response to ventricule stretch from increased ventricular blood volume

Mnemonics: Drugs that Improve Survival in chronic Heart Failure


I guess that's it. If I ever committed any mistake here, please let me know. I am no expert on these matters. Just like you, I've gone through the strenuous, anxiety-inducing days of the review. I just jotted down what I learned from my Topnotch lecturers and reviewer notes. Hope this  shor review  on CHF drugs has helped you in some way.

Don't be scared. Carry on. :)

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