Class 1A
What is the MOA for Class 1 anti-arrhythmic drugs?
What is...by blocking Na+ channels they raise the threshold for AP, and slow the rate of depolarization in cardiac muscles.
What is the MOA of Class 1B anti-arrhythmic drugs?
What is...They bind to both open and inactivated Na+ channels and block their fxn, especially when there is an increased frequency of firing.
Class 1C drugs the most/least potent K+/Na+ channel blocker.
What is... Most; Na+
Class III anti-arrhythmic drugs: generics
What are... Amiodarone, Dronedarone, Ibutilide, and Dofetilide
What drug is considered a mixed class? Why is this?
Rate control drugs: name(s) and Doses
What is...Digoxin.
Loading dose: 1mg total; administer 0.5mg, then 0.25mg Q6h x 2. Only 0.5mg in ESRD.
Maintenance dose: 0.125-0.375mg PO/IV daily
What is the specific MOA for Class 1A anti-arrhythmic drugs?
What is...moderate blocking effect on Na+ channel, mainly open ones, These decrease the phase 0 upstroke. This all leads to a decrease in myocardial conduction velocity. Also have a K+ channel blocking effect.
How do Class 1B drugs affect the ERP?
Why is there no change in ERP with Class 1C drugs?
What is... this is because the potent Na+ channel blockers decrease the phase 0 upstroke of ventricular cells, which results in suppression of premature ventricular contraction.
Name the drugs in these categories: Non-specific bb, specific beta-1, and beta and alpha-1 receptor blockade.
specific beta-1 blockers: atenolol, metoprolol (Lopressor and Torpor XL).
beta and alpha-1 receptor blockade: labetolol and carvedilol (Coreg)
Why would we substitute Amiodarone for Dronedarone? Why do we use Amiodarone before Dronedarone?
What is...it has a shorter half-life and it does not have iodine in it leading to decreased iodine toxicity. However, it is far less effective.
Stroke prevention Drugs: Name(s) and Doses **Except Warfarin - know target INR
Aspirin: 81mg
Rivaroxaban: Dosing based on renal fxn:
CrCl >50ml/min dose: 20mg daily with meals
CrCl 15-50ml/min dose: 15mg daily with meals
CrCl <15ml/min contraindicated
Dabigatran: Dosing based on renal fxn:
CrCl >30ml/min dose: 150mg po BID
CrCl 15-30ml/min dose: 75mg po BID
CrCl <15ml/min contraindicated
Apixaban: 5mg PO BID
Change to 2.5mg PO BID if have 2 of these:
Scr >1.5mg/dL, >80yo, wt <60kg
Edoxaban: Dosing based on renal fxn:
CrCl >95ml/min contraindicated (reduced efficacy)
CrCl >50-95ml/min dose: 60mg po daily
CrCl 15-50ml/min dose: 30mg po daily
CrCl <15ml/min contraindicated
Warfarin: INR = 2-3
What are the 2 outcomes of Class 1A drugs during a full AP?
What are the 3 Class 1B anti-arrhythmic drugs?
What are... Lidocaine, Mexiletine, and Phenytoin
What are the Class 1C anti-arrhythmic drugs?
What are...Encainide, Propafenone, and Flecainide
MOA for Beta 1 Blockers (Class II anti-arrhythmic drugs).
What is...Act on both SA and AV nodes to decrease phase 4 in pacemaker cells which prolongs ERP (due to Na+ current and HCN channel), and thus, decreasing the rate of automaticity.
Why/how does Amiodarone have such an effect on the thyroid gland?
When do you initiate a lower dose of Digoxin? What are the doses? Also, what level of Digoxin is optimal?
What is...At age >65, CrCl <50ml/min, or IBW <70kg.
You lower the dose to 0.125mg daily, or every other day depending on severity.
Optimal blood level: 0.8-1.2ng/ml
What are the main contraindications and DIs for Class 1A agents?
What are...contraindicated in those with QT prolongation.
DI with drugs that predispose pts to have QT prolongation-leading to TdP.
What are two other preparations of lidocaine?
What are... local anesthetic for ocular surfaces and as a local anesthetic for dental procedures.
Class 1C drugs can worsen a pre-existing arrhythmia, so when can we use these?
What is... approved only for life-threatening conditions like paroxysmal supraventricular arrhythmia.
K+ channels play a major role in regulating the normal plateau phase (via K+ efflux) of an AP. So What is the MOA for Class III drugs and how do they play a role in the plateau phase? How does this affect ERP?
What is... K+ channel blockers prevent the K+ efflux, decreasing their rate of outward flow. This results in a longer plateau phase and prolonged re-polarization. This increases ERP.
What main drug has ophthalmic toxicity when used long term and what signs/symptoms does this produce? What are other drugs that are associated with ocular toxicity?
What is...Amiodarone. Sx/s: corneal deposits or keratopathy, and optic neuropathy. Other drugs: Quinidine and Disopyramide (Class 1A).
What are the two main beta blockers we choose for A-fib and what are the two non-DHP CCBs?
What are... metoprolol succinate and carvedilol, and Diltiazem and Verapamil.
Which drugs are in Class 1A and what is each one's main effect, and contraindication(s)?
What are... Quinidine - Na+ blocking and anticholinergic effect. Contraindicated in pts with atrial flutter.
Disopyramide - Severe anticholinergic effects. Contraindicated in those with uropathy and glaucoma.
Procainamide - Has to be acetylated to N-acetylprocainamide (active metabolite) in liver.
Why do the Class 1B drugs have unwanted ____ effects and what effects do these pts experience?
What is...CNS.
Their effect on Na+ channels in CNS because they can cross the BBB which leads to dizziness and seizures.
What is...mortality
Adverse effects with Class III includes:
What is...Prolongation of plateau duration giving rise to early to early after depolarization (EAD) which results in TdP.
When do we not use Non-DHP CCB for rate control in A-fib?
What is...in decompensated HF or LVEF <40
Rhythm control drugs: Name(s) and doses
Amiodarone (PO): Loading dose: 10g - 1.2-1.8g/day in divided doses. 400mg BID x1 week, then 600mg daily x1 week, then 400mg daily x 4-6 weeks, then maintenance dose: 100-200mg/daily
Dronedarone: 400mg BID with meals
Dofetilide: Dosing is adjusted based on renal fxn.
CrCl >60ml/min dose: 500mcg BID
CrCl 40-59ml/min dose: 250mcg BID
CrCl 20-39ml/min dose: 125mccg BID
CrCl <20ml/min contraindicated
Sotalol: Avoid with HF. Renal dosing:
CrCl >60ml/min dose: 80mg BID
CrCl 40-60ml/min dose: 80mg daily
CrCl <40ml/min contraindicated