Dysrhythmia drugs

Question 1

Types of dysrhythmias

Answer 1

A-fib
V-fib
SVT
Torsades de pointes

Question 2

Vaughan Williams Classification

Answer 2

System used to classify dysrhythmias drugs based on electrophysiological effect of drug on AP

Question 3

All Classes

Answer 3

"Spring break Panama City!" 
Class 1: Sodium channel blockers
Class 2: Beta blockers
Class 3: Potassium channel blockers 
Class 4: Calcium channel blockers

Question 4

Classes 1 and 3 MOA

Answer 4

1. Na channel blockers, 2. K channel blockers

Affect muscles of ventricles

Question 5

Classes 2 and 4 MOA

Answer 5

2. Beta blockers, 4. Ca channel blockers

Target SA and AV nodes of heart

Question 6

Amiodarone

Answer 6

Class 3: K channel blocker
In every crash cart/for emergencies
Super long 1/2 life (25-110 d)
Inhibits adrenergic stimulation
Unique: blocks K, Na, Ca channels; blocks A and B receptors
Drug:drug interactions: CYP3A4 inhibitors no grapefruit juice!)
Lots of AEs, FDA requires med guide: “BITCH”, QT prolongation

Question 7

“BITCH”

Answer 7

Amiodarone (Class 3: K channel blocker) 
Lots of AEs, FDA requires med guide: 
B: Blue tint to skin
I: Interstitial lung disease 
T: Thyroid toxicity
C: Cornea disease w/halos 
H: HTN, hepatotoxicity
Plus QT prolongation

Question 8

Class 4

Answer 8

Non-DHP Ca channel blockers
Work on heart and vascular smooth muscle
Incl Verapamil, Diltiazem

Question 9

Class 2

Answer 9

Beta blockers
Reduce/block SNS stimulation
Slow HR
Incl Esmolol

Question 10

Adenosin

Answer 10

Misc dysrhythmia drug
Pos inotropic (+ contractility), neg chronotropic (- HR), neg dromotropic (- conductivity)
IV tx for SVT - slows then stops heart to reset! Pt will flatline for 10 sec. Eek!
Super short 1/2 life (10 sec)
AE: competes w/Theophylline (tx for asthma and COPD)

Question 11

Digoxin

Answer 11

Misc dysrhythmia drug
Pos inotropic (+ contractility), neg chronotropic (- HR), neg dromotropic (- conductivity)
AE: bradycardia; narrow therapeutic index so need to monitor: levels, electrolytes, HR, other AE to catch toxicity before worsened dysrhythmias; hypokalemia may precipitate toxicity