Antiarrythmics Flashcards
Sodium channel blockers (class I)
slow or block conduction(esp in depol cells).
dec slope of phase 0 depol.
State dependent (selectively depress tissue that is frequently depol)
Class 1a list
Quinidine, Procainamide, Disopyramide
“The Queen Proclaims Diso’s Pyramid.”
Class I MOA
increase: AP duration, effective refractory period in ventricular action potential, QT interval
Class I use
atrial and ventricular arrhythmias (esp. re-entrant and ectopic SVT and VT)
Class I ADR
thrombocytopenia, torsades de pointes due to inc QT interval
quinidine ADR
cinchonism (HA, tinnitus)
procainamide ADR
reversible SLE-like sx
disopyramide ADR
heart failure
Class 1b list
Lidocaine, Mexiletine
Phenytoin can be classified here
Class 1b MOA
dec AP duration.
preferentially affect ischemic or depol. Purkinje and ventricular tissue
Class 1b use
acute ventricular arrhythmias (esp post MI)
digitalis-induced arrhythmias
Class 1b ADR
CNS stimulation/depression, CV depression
Class 1C list
flecinide, propafenone
Class 1c MOA
significantly prolongs ERP in AV node and accessory bypass tracts.
no effect on ERP in Purkinje and ventricular tissue.
minimal effect on AP duration
Class 1C use
SVTs, including afib
only as last resortin refractory VT
Class 1C contraindications
proarrhythmic, esp post-MI (contraindictated)
structural and ischemic heart disease
Antiarrhythmics Class II (BB) list
metoprolol, propranolol, esmolol, atenolol, timolol, carvedilol
BB MOA
dec. SA and AV nodal activity by dec cAMP, Ca currents.
Suppress abnormal pacemakers by dec slope of phase 4
AV node particularly sensitive, inc. PR interval.
BB use
SVT, ventricular rate control for afib and atrial flutter
BB ADR
impotenence; exacerbation of COPD and asthma; bradycardia/AV block/HF; sedation, sleep alterations; may mask sx of hypoglycemia
Metoprolol ADR
dyslipidemia
Propanolol ADR
exacerbate vasospasm in prinzmetal angina
BB contraindications
pheochromocytoma, cocaine toxicity
cause unopposed a1-agonism if given alone
BB OD tx
saline, atropine, and glucagon
Antiarrhythmics Class III (KCl channel blockers) list
amiodarone, ibutilide, dofetilide, sotalol
“AIDS”
KCl channel blockers MOA
increased: AP duration, ERP, QT interval
KCl channel blockers use
afib, atrial flutter
Amiodarone, sotalol use
ventricular tachycardia
Sotalol ADR
torsades de pointes, excessive B blockade
Ibutilide ADR
torsades de pointes
Amiodarone ADR
check PFTS, LFTS, TFTS*
pulmonary fibrosis, hepatotox, thyroidism, corneal deposits, blue/gray skin deposits resulting in photodermatitis, neuro effects, constipation, bradycardia/heart block/HF
Why is amiodarone special?
lipophilic, has class I-IV effects
Antiarrhythmics Class IV (Ca channel blockers) list
verapamil, diltiazem
Ca Channel blockers MOA
dec conduction velocity
inc ERP, PR interval
Ca channel blockers use
prevention of nodal arrhythmias (eg SVT)
rate control in afib
Ca channel blockers ADR
constipation, flushing, edema, HF/AV block/sinus node depression
Other antiarrythmics
adenosine, MG
adenosine MOA
inc K+ out of cells –> hyperpolarizing the cell and dec Ica
Adenosine use
dx/terminating certain forms of SVT (very short acting)
Adenosine antagonists
theophylline, caffeine
Adenosine ADR
flushing, hypotension, chest pain, sense of impending doom, bronchospasm
Mg2+ use
effective in torsade de pointes and digoxin toxicity
