Section 3: Pharmacology Flashcards
Vaughn Williams Classification
SoBePoCa
Class I
Sodium Channel Blockers
Do Class I increase or decrease the speed of depolarization?
Decrease speed of depolarization
Class I Action Potential Trend
1a- shift
1b- shorter
1c- tilt
Class Ia
moderate Na channel blocking, prolongs refractory, dec conduction velocity
class 1b
weak Na channel blocking, dec action potential, shorten refractory
class 1c
strong na channel blocker, dec conduction velocity, little effect on refractory
class II
beta blocking
what effect do class II have on sympathetic tone
dec sympathetic tone
class III
potassium channel blocking
what do class III drugs do
inc action potential duration
class IV drugs
calcium channel blockers
what do calcium channel blockers do/affect
affect SA and AV nodes, slow automaticity, and conduction time
what do class V drugs do
increase parasympathetic effects via unknown/various methods
Class Ia Drug Examples
Double Quarter Pounder
- Disopyramide, Quinidine, and Procainamide
Background on 1a drugs
1A (a)- does it All
effective in A and V
moderately effective for most tachyarrythmias
severe side effects
can cause torsades- monitor QRS width and QT prolongation
procainamide - affects pathways
can enhance av conduction
Class 1b drug examples
Lettuce, Pickle, Tomato, Mustard
-lidocaine, phenytoin, tocainide, mexiletine
background on 1b drugs
less likely than 1a to be proarrythmic
used and ok at treating v
CNS side effects
lidocaine used for short term IV therapy
class 1 c drug examples
Enjoy More Fries Please
- Encainide (bad), muncizine, flecainide, propafenone
background on 1c drugs
similar effects on a and v
not commonly used
proarrythmic for SHD and ischemic patients
can be used for A and life threatening V
not for patients with structural heart disease
Class II drug examples
(the -olols)
- atenolol, cavedilol, metopropolol, labetalol, nadolol, timolol
class II drugs background
dec automaticity in sa node causing slower hr
less effective at suppressing arrythmia
NOT good for COPD or asthma
class III drug examples
(A Big Dog Is Scary)
Amiodarone, Bretylium, Dofetilide, Ibutilide, Sotalol
Sotalol
decrease DFT, inc pacing threshold
- defib threshold, how much energy it takes to shock out of VT/VF
