Anti-Arrhythmics Flashcards
(21 cards)
Quinidine
Class: Class IA antiarrhythmic
Mech: Block inward K rectifying channel (slow rate) at normal concentrations; blocks sodium channels (fast rate) at high concentrations which prolongs prolongs effective refractory period and prolongs AP duration. Also has alpha-adrenergic blockade, M2 blockade, vagal inhibition
Thera: Chronic A-flutter/fib, SVT, VT
Tox: diarrhea, nausea, fever, hepatitis, QT prolongation (TdP)
Misc: Numerous drug interactions with CYP2D6
Procainamide
Class: Class IA antiarrhythmic
Mech: Block inward K rectifying channel (slow rate) at normal concentrations; blocks sodium channels (fast rate) at high concentrations which prolongs prolongs effective refractory period and prolongs AP duration.
Thera: Chronic A-flutter/fib, SVT, V-fib
Tox: Drug-induced lupus, QT prolongation (TdP), hypotension
Disopyramide
Class: Class IA antiarrhythmic
Mech: Block inward K rectifying channel (slow rate) at normal concentrations; blocks sodium channels (fast rate) at high concentrations which prolongs prolongs effective refractory period and prolongs AP duration.
Thera: Chronic A-flutter/fib, SVT, VT
Tox: Prominent anticholinergic action (constipation, dry mouth, glaucoma), QT prolongation (TdP)
Lidocaine
Class: Class IB Antiarrhythmic
Mech: Block Na channel in inactivated state, no action on atrial tissue (therefore cannot be used for atrial arrhythmias
Thera: Emergency VT/VF, digitalis toxicity
Tox: Tremor, nausea, seizures
Mexiletine
Oral version of lidocaine but has some renal toxicity
Tocainide
Same as lidocaine except not available in the US bc of fatal bone marrow aplasia and pulmonary fibrosis
Flecainide, Propafenone, moricizine
Class: Class IC
Mech: Most potent Na channel blocks (greatly prolonging Na recovery), IKr channel blockade as well
Thera: chronic A-fib/flutter, paroxysmal SVT due to structural heart disease
Tox: Worsened HF, MI, proarrhythmic in ischemic tissue(MI thing)
Flecainide=blurry vision
Propafenone=brady, bronchospasm
Propanolol
Class: Class II (nonselective beta blocker)
Mech: Decrease SA, AV node activity (decrease phase 4 depolarizaiton)
Thera: A-fib/flutter, SVTs (exercise induced, digitalis induced), PVC, MI
Tox: Hypotension, bronchospasm, bradycardia
Misc: All beta blockers are contraindicated in WPW syndrome and avoid sudden withdrawal bc may cause an MI
Carvedilol
Class: Class II (nonselective beta blocker)
Mech: Decrease SA, AV node activity (decrease phase 4 depolarizaiton)
Thera: A-fib/flutter, SVTs (exercise induced, digitalis induced), PVC, MI, CHF
Metoprolol, Acebutolol,
Class: Class II B1 selective blocker
Same as above
Acebutolol has some sympathomimetic
Esmolol
IV with short half life and is useful in treatment of SVT in acute setting where short duration is desired
Class III antiarrhythmics
Mech: K channel blockade which prolongs refractoriness
Thera: A-fib/flutter, paroxysmal SVT, VT
Tox: Photosensitivity (blue-gray skin) numerous drug interactions, TdP, pulmonary fibrosis, peripheral neuropathy, hepatic dysfunction
Sotalol
Class III
Mech: Blocks IKs, non-selective B-blocker
Thera: Preferred drug for A-fib over Quinidine
Tox: EADs, TdP, slow HR, decrease AV conduction
Ibutilide
Class III
IV dose for Afib/flutter
Dofetilide
Class III
Mech: IKr blocker, maintain sinus rhythm after cardioversion, and converts chronic AFib
DO NOT use for ventricular arrhythmias or paroxysmal AFib
Amiodarone
Class III
Mech: Thyroxine analog that mimics all classes (decease Na, Ca, K, alpha, beta) with long half life of 80 days
Thera: Useful against almost all arrhythmias except digitalis toxicity and not during pregnancy.
Tox: QT prolongation (TdP), pulmonary fibrosis, peripheral neuropathy, hepatic dysfunction, corneal microdeposits, photosensitivity
Dronedarone
Less effective but fewer side effects than amiodarone but still causes QT prolongation, nausea, diarrhea
Verapamil
Diltiazam
Class: Class IV
Mech: Blockade of L-type calcium channels slowing the SA and AV node activity and prolonging AV refractoriness
Thera: Prevent or terminate reentrant SVTs, slow ventricular rate during a-flutter/fib
Tox: Hypotension, brady, constipation, dizziness, increased serum digoxin levels and becomes additive with digoxin and B blockers in terms of AV block
Contraindicated in WPW
Adenosine
Mech: Adenosine receptors in atria, sinus node, AV node, activates K current, shortening AP hyperpolarizing tissue, and slowing down automaticity and AV conduction
Thera: A-fib, paroxysmal SVT
Tox: Sedation, dyspnea, hypotension
Magnesium
Thera: Prevents recurrent TdP and some digitalis-induced arrhythmias
Misc: Alternative to amiodarone for shock-refractory cardiac arrest
Cardiac glycosides (digoxin)
Mech: Na/K pump inhibitor which slows AVN conduction and activity
Thera: A-fib/flutter, chronic SVT
Tox: May cause DAD arrhythmias
Misc: low therapeutic index
