MED | PLE Pharmacology Review - Antiarrhythmic Heart Drugs Mnemonics

Now, let's talk about the anti-arrhythmic heart drugs which might appear as one of the choices in the Physician Licensure Exam (PLE). I will be making this post as short as I can so as to supplement what you have learned in your review with what I can recall during my review.

Take note that this post does not serve to act as your sole source of review information. I might be wrong with some of what I'm saying here, so if you think I have committed mistake, please let me know via the comments section below. There's just so much to learn with so little time.

Antiarrhythmic drugs can be divided into four (4) classes depending on the channel that is being affected:

Singh-Vaughan Williams Classification

Class 1: Sodium (Na) channel blockers
Class 2: Beta blockers
Class 3: Potassium channel blockers

Class 4: Calcium channel blockers

For some mnemonics about the Singh-Vaughan Williams Classification:

I hope it wasn't too much of a headache to try to memorize the mnemonic NaBePoCa.

Remember that arrhythmia could either be due to abnormal automaticity where areas other than the natural pacemaker (SA node) take over in dictate the heart rate or due to abnormal conduction through erratic impulses.

Here are the mnemonics for the different classes of anti-arrhythmic drugs.

Class 1 Antiarrhythmics drugs

Since they're all anti-arrhythmic drugs, we should be reminded that the amount and administration of these if left unchecked can also cause arrhythmias. Notable differentiating side effects of Class 1 anti-arrhythmic drugs are as follows:

Side effects of Class 1A antiarrhythmic drugs:

• Quinidine- - cinchonism (tinnitus, headache, vertigo)
• Procainamide - lupus-like syndrome
• Disopyramide - antimuscarinic effects (decreased salivation and gastric secretions)

Side effects of Class 1B antiarrhythmic drugs: agranulocytosis (Tocainide), CNS stimulation, CVS depression

• MUST-KNOW: Lidocaine is used in digitalis-induced arrhythmias

Side effects of Class 1C antiarrhythmic drugs: increased arrhythmias, CNS stimulation

• MUST-KNOW: Flecainide is contraindicated in post-MI settings

Class 2 Antiarrhythmics drugs

Notable side effects of Class 2 anti-arrhythmic drugs are as follows: cardiac depresssion, bronchospasm, AV block

• MUST-KNOW: Esmolol can be used for SVT and acute perioperative and thyrotoxic arrhythmias

Class 3 Antiarrhythmics drugs

Notable side effects of Class 3 anti-arrhythmic drugs are as follows: 

• Sotalol and Dofetilide - Torsade de pointes 
• Amiodarone - as mentioned above (note: of all anti-arrhythmic drugs, Amiodarone is the most efficacious0

Class 4 Antiarrhythmics drugs

Side effects of Class 4 antiarrhythmic drugs include: pretibial edema, flushing, constipation, gingival hyperplasia, cardiac depression

Non-DHPs like Diltiazem and Verapamil are useful in SVT migraines too.

Note: Dihydropyridine CCBs like Nifedipine and Amlodipime are not used as antiarrhythmic drugs because these facilitate, not terminate, compensatory sympathetic discharges.

I hope I was able to help you with this topic, kahit kaunti. I apologize if this isn't too deep a dive for your review. Good luck on your PLE!

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  short review  on CHF drugs has helped you in some way.

Don't be scared. Carry on. :) Check out this brief PLE Pharmacology review on Anti-arrhythmic drugs.