Tox

Question 1

Discuss changes seen in the ECG with fast sodium channel blockade

Answer 1

• wide QRS
• Right axis deviation of the terminal QRS (dominant terminal R)
• Bradycardia (although tachycardia secondary to other cuases is more common)
• VT and VF

Question 2

List agents that cause fast sodium channel blockade

Answer 2

TCA

Class 1A antidysrhythmics 
-progainamide 
-quinidine 
Class 1c antidysrhtyhmuic agents 
-flecanide 

Local anaethetics

• bupivacaine
• ropivacaine

Phenothazines 
Diltiazem 
Hydroxychlooquie 
Propanalol
Quinine

Question 3

Discuss effect of k+ efflux blocakde

Answer 3

• Prolongation of QT

- Torsades de pointes

Question 4

Discuss agents with K blocking potentional

Answer 4

Antipsychotics

Class1a, c and 3 antidysrhythmics

TCA

Antidepressants 
Antihistamines 
Choloroquine 
Quinine 
Fluoroquinolones 
Macrolides 
Methadone