antiarrhythmics Flashcards
1
Q
Phase 0 modulators
A
- Local anesthetics/Na channel blockers
- Slows Na influx, depolarization, and conduction
- Divided into class 1 a, b, and c
- Widens the QRS primarily and the QT somewhat
1
Q
SE of Quinidine
A
prorrhythmic, prolongs QT which can lead to torsades
2
Q
SE of Procainamide
A
Proarrhythmic, can have poor compliance, lupus like syndrome
3
Q
Class 1A
A
Quinidine and Procainamide
- Blocks primarily Na channels and some K
- Has moderate effect on phase 0
- MOA: slows conduction velocity in ventricle and increases action potential duration
- Broad spectrum (flutter, afib, VT)
5
Q
Class 1B
A
Lidocaine (IV) and Mexelitine (PO)
- Blocks ONLY Na channels
- Has no effect on phase 0 and somehow shortens duration of AP without decreasing refractory period.
- Use: Only works in Ventricular arrhythmias when heart too fast. NOT for AV or atrial.
6
Q
Class 1C
A
Flecainide and Propafenone
- MOA: Blocks Na and K for a longer period of time so much longer QRS. Both tonic and rate dependent block.
- Use: Afib and flutter primarily. Also WPW
- SE: Proarrhythmic
6
Q
Class 3: Classic drugs
A
Drugs that prolong repolarizaiton
Amiodarone, Sotalol, Dronedarone
8
Q
Class 2: Beta adrenergic blockers
A
Propanolol, atenolol, timolol (PO) and Esmolol (IV)
- MOA: Depending on drug block beta 1 and/or beta 2 to slow AV conduction (beta receptors are on the Ca channels in pacemaker cells. phase 4)
- Use: AV re-entry rhythms and sinus tachycardias (sympathetic)
- Use caution with other drugs that lengthen AV conduction (CCB, digitalis), asthmatics, and diabetics
- can protect the V from the A in flutter and SVT.
- can break junctional rhythms
9
Q
Amiodarone
A
Class 3
- MOA: Blocks Na, K, Ca, and beta.
- Widely used. Can also be used for SVT, post-MI arrhythmia, and in HEART FAILURE
- 3 month HL
- Signs of toxicity include corneal cholesterol deposits, blue skin tone, and thyroid, liver, and lung toxicity
10
Q
Sotalol
A
Class 3
- Blocks K channels and beta receptors
- Used for a fib, flutter, and VT
11
Q
Dronedarone
A
- Class 3 that is similar to amiodarone but has less thyroid toxicity and a short HL (24hrs)
- Used to prevent recurrence of afib/flutter rather than conversion
- SE: bradycardia, Torsades(QT prolonged), is metabolized by same enzyme that affects antifungals and ABX
- CONTRAINDICATED in HF
12
Q
Class 3: New drugs
A
Dofetilide
- genetically engineered (cardiac selective/Ikr)
- MOA: blocks K channels only in the heart to prolong action potential duration
- Used primarily for afib and is ok for long term use in MI or HF pts
- first two doses usually given in hospital and monitored
- Risk of torsades (1-6%)
13
Q
Class 4: Ca channel blockers
A
Verapamil and Diltiazem
- blocks Ca channels which have effects much like a beta blocker when treating arrhythmia (slows conduction in AV, increases AV refractory period, prolongs repolarization phase in AV
- Use caution with other drugs that slow AV conduction. can cause hypotension
13
Q
Atropine in arrhythmia
A
treatment for vagal bradycardia
14
Q
Adenosine
A
- stops AV conduction to terminate re-entry SV arrhythmias
- has a 10 second HL
