Flashcards in Antiarrhythmic Drugs Deck (49)
1. Antiarrhythmic effect is on the what?
2. Used for what?
3. Used for it’s effect on?
1. AV node
2. ventricular rate control in atrial fibrillation and flutter
3. positive inotrope effect in CHF
1. Digoxin_____ the electrical conduction through the AV node
2. Stimulates the ____________ nervous system and increases ______ ______
Slows AV conduction and prolongs the AV nodal refractory period. What does this cause on the EKG? 3
1. Increased PR interval
2. Downward sloping ST segment depression
3. Shortened QT interval
Dig is used to slow ventricular rates in Afib and A flutter. What is the downside to this? 2
Slows rates (for rate control)!!!
1. Does NOT convert rhythms (afib/flutter) to sinus!
2. Does not work well for slowing ventricular rates during exercise!
3. Steady State?
4. Theuropeutic range?
1. Slow onset
2. Need a loading dose period
3. May take a week to achieve steady state
4. Monitor serum blood levels periodically
Therapeutic range 0.8 – 2 ng/mL
AF and concomitant LVSD is 0.5-1 ng/mL
Who has increased mortality on Dig?
Higher levels in pts with LVSD = higher mortality
AF and concomitant LVSD is 0.5-1 ng/mL
Digoxin toxicity can be caused by
1. Declining renal function
2. Electrolyte disturbances
3. Drug interactions
Many meds may increase serum digoxin concentrations
What electrolyte disturbances can cause dig toxicity? 3
What drug interactions may increase serum dig concentrations? 2
2. hypomagnesemia and
can predispose the myocardium to the toxic effects of digoxin
Signs and symptoms of digoxin toxicity
1. Heart block
2. AV junctional tachycardia
3. Ventricular arrhythmias
4. Visual disturbances
5. Blurred vision, yellow/green halos
8. GI: N/V/D and anorexia
Why is adenosine used?
Used to convert PSVT to SR
1. Activates _______ channels by increasing the outward ________ current
2. __________ the membrane potential and __________ spontaneous SA node depolarization
3. _______ automaticity and conduction in the SA and AV nodes
4. Half life?
4. 10 seconds
1. 2nd or 3rd degree heart block
2. sick sinus syndrome in the absence of a pacemaker
1. What kind of drug is atropine?
2, What does it enhance and how? 2
3. What does it block? 2
4. Used for the treatment of what?
5. May induce what?
1. Parasympatholytic drug
--sinus nodal automaticity and
--AV nodal conduction through direct vagolytic action
--parasympathetic neuroeffector sites
4. Used for the treatment of symptomatic bradycardia
5. May induce tachycardia
1. Angle closure glaucoma
2. Obstructive uropathy (think BPH)
4. Bowel obstruction or altered bowel transit time
Class 1 blocks what?
What are the sub classes?
sodium channel blockers
1. Class Ia (intermediate onset/offset)
2. Class Ib (fast onset/offset)
3. Class Ic (slow onset/offset)
Class Ia (intermediate onset/offset)
are which drugs?
1. Disopyramide (Norpace)
2. Procainimide (Pronestyl)
3. Quinidine (Quinidex)
Class Ib (fast onset/offset) are which drugs?
2. Mexiletine (Mexitil)
3. Phenytoin (Dilantin)
Class Ic (slow onset/offset) are which drugs? 2
1. Flecainide (Tambocor)
2. Propafenone (Rythmol)
3 classes of sodium channel blockers are categorized how? 2
1. Subdivided by the rate of sodium channel dissociation
2. Variable rates of binding and dissociating from the sodium channel receptor
1. What kind of drugs are Class Ia?
2. What are they used to treat? 2
3. They have anticholinergic effects that can lead to?
4. WHat do you need to prescribe with this?
5. Major complication?
6. Which drug is IV only?
1. These drugs are proarrhythmic
Used to treat atrial and ventricular rhythms
3. Ex: Quinidine and Disopyramide increase automaticity of the SA and AV nodes
4. Need to have a Beta blocker or Calcium channel blocker on board to prevent tachyarrhythmias in afib/flutter pts
6. Procainimide IV only
What are the drugs for Class Ib?
1. What is lidocaine used for?
2. Exerts most of it’s effects on what?
3. Particularily useful for what?
4. Administered how?
5. Toxicity causes? 2
1. Used for ventricular arrhythmias (VT, VF)
2. ischemic or infarcted tissue of the ventricles
3. VT/VF associated with AMI
4. IV only
5. Toxicity: seizures and respiratory arrest
What is mexiletine?
Oral analog of Lidocaine used for ventricular arrhythmias
What are the Class Ic drugs? 2
1. Flecainide (Tambocor) mainly used for what?
2. When can we not use it? 4
1. Mainly used for rhythm control in afib/flutter
---FDA approved to use for ventricular arrhythmias but is not very effective for these and has a high incidence of adverse effects
Cannot use if any hx of structural heart disease
3. valvular disorders,
Propafenone (Rhythmol) is used for what?
Cannot be used in what situations?
Used for atrial arrhythmias such as afib/flutter
Cannot be used if hx of structural heart disease
Beta blockers are used for?
1. Used for suppression of ventricular and supraventricular arrhythmias
2. Slow AV nodal conduction and SA nodal rates
3. Negative inotropic agents
4. Decrease myocardial oxygen consumption
Review of beta blocker SE
5. Erectile dysfunction
8. Worsening CHF (in some patients…end stage or in acute decompensated state)
What are Class III drugs?
(what does it block and what are the drugs 4?)
POTASSIUM CHANNEL BLOCKERS
1. Amiodarone (Cordarone)
2. Dofetilide (Tikosyn)
3. Ibutilide (Corvert)
4. Sotalol (Betapace)