Class 1 Anti-Arrhythmic Drugs Flashcards
What are the Class 1A drugs?
Quinidine
Procainamide
Disopyramide
MOA for Class 1A drugs?
Block Na+ AND K+ channels!!
With Class 1A drugs blocking Na+ and K+ channels, that will ____ the slope of phase ___ and prolong action potential duration
Decrease slope of phase 0
Class 1A drugs effect the ECG how?
Prolong QRS interval and QT interval
– block Na+ and K+ channels
Class 1A drugs are not usually used clinically anymore. What main adverse effect can be caused by them?
Torsade de Pointes = Prolong the QT interval
What specific adverse effect can be seen with Procainamide?
- Class 1A
= SLE-like syndrome and torsade de pointes
What specific adverse effect can be seen with Quinidine?
- Class 1A
= Cinchonism (tinnitus, hearing loss, delirium and psychosis) due to the drug being made of cinchona bark
– and torsade de pointes
What drug causes Cinchonism and what is that?
Quinidine (Class 1A)
= tinnitus, hearing loss, delirium, psychosis
What specific adverse effect is seen with Disopyramide?
- Class 1A
= Atropine - like effects and torsade de pointes
Procainamide, Quinidine and Disopyramide can block which channels?
Na+ AND K+
– Class 1A drugs
What are the Class 1B drugs?
Lidocaine
Mexiletine
MOA for Class 1B drugs?
Block Na+ channels
Class 1B drugs cause slow conduction and dissociate from Na+ channels with?
Fast Kinetic = no effect on conduction in normal tissue
How is Lidocaine given and why?
- Class 1B
= IV due to extensive 1st pass metabolism
What is the least toxic of all Class 1 drugs?
Lidocaine
- Class 1B
