Antarhythmics Flashcards
Antiarrhythmic Medications Info
- Suppress dysrhythmias
a. Work c depressing automaticity by decreasing conduction
b. Increasing refractoriness to premature stimulation
c. Some meds work c atrial vs venticular - Classified by their effect on the cardiac electrical conduction system
- Classifications are divided into 4 main categories
Electrical Conduction
- Properties of cardiac tissue
a. Automaticity
b. Contractility
c. Conductivity
d. Excitability - Any antiarrhythmic can become a proarrhythmic
Mechanism of Action
- Each class works in a different to suppress the arrhythmia
- Class 1 Rx are membrane stabilizing agents which act on the Na+ channels
- 3 subgroups in class 1 bc the agents have cellular repolarization & action potential duration
Class 1
A. Na+ channel blockers
B. Ventricular dysrhythmias
C. Tx life threatening arrhythmias
D. Fallen out of use due to S.E.
Class 2
- Class 2 are Beta blockers which reduce or block SNS stimulation to the heart & transmission of impulses in the cardiac conduction system
- Affect mostly slow tissue
- Tx Atrial & Ventricular
Name 2 Class 1 medications
- Procainamide
2. Lidocaine
Name 1 class 2 medication
- Propranolol
Class 2 Contraindication
- Bradycardia
- Cardiogenic shock
- Asthma
Class 2 Adverse Effects
- Hypotension
- Bradycardia
- Bronchospasm
Class 3
- K+ channel blocker
- Class 3 agents increase the action potential duration
- Tx Atrial & ventricular dysrhythmias
Name 1 class 3
- Amiodarone*
Class 3 Contraindication
- Bradycardia
- Heart block
- Cardiogenic shock
- Pregnancy
Class 3 Rx Interaction
- Digoxin
2. Warfarin
Class 3 Adverse Effects
- Hypotension
- Bradycardia
- GI upset
- QT prolongation
- Pulmonary fibrosis
Class 4
- Class 4 CCB & block the slow channels, Reduces rigitity of atriols & veinules
- Used for atrial dysrhythmias
Name 2 class 4 CCB
- Diltiazem
2. Verapamil
Class 4 Contraindication
- Heart block
- Bradycardia
- CHF
- Hypotension
- Pregnancy
Class 4 Adverse Effects
- Hypotension
- CHF
- Edema
- Dizziness/fatigue/Headache
- Avoid IV Beta Blockers c IV CCB
Class 4 RN Implication/Teaching
- Potent Drugs
- Thorough drug Hx & Rx interactions
- Monitor BP & HR
- Monitor EKG
- Monitor K+ levels
- No skipping doses
- Withhold if HR less than 60
Amiodarone
- K+CB
2. Used only for life threatening Atrial or Ventricular dysrhythmias
Amiodarone Adverse Effects
- Bradycardia
- Arrhythmias
- HF
- Heart Block
- Hepatic failure
- pulmonary tox/Resp distress
Amiodarone Rx interaction
- BB
- CCB
- Digoxin
- Grapefruit juice
Amiodarone Monitored Labs
- ALT
- AST
- T3 & T4
Amiodarone Contraindications
- Heart block
2. Cardiogenic shock