Antiarrhythmic Drugs Flashcards
1A
Quinidine, Procainamide, Disopyramide
MOA: Na+ (phase 0) and K+ (phase 3) channel blockers on atrial and ventricular myocardial cells
EKG: increase QRS, QT
CA: (SV)
AE: Quinidine arrhythmias, cinchonism, SA/AV block, GI effects, thrombocytopenia purpura; Procainamide reversible lupus-like syndrome, arrhythmias, CNS effects, anticholinergic effects, heart block; Disopyramide negative inotrope, strong antimuscarinic effects, peripheral vasoconstriction
TCo: Quinidine heart block, Torsade de Pointes, uncompensated heart failure, myocarditis, myocardial damage; Procainamide heart block, SLE, Torsade de Pointes, hypersensitivity; Disopyramide heart block, Torsades de Pointes, heart failure
1B
Lidocaine, Mexiletine
MOA: Na+ (phase 0) channel blockers of atrial and ventricular myocardial cells
EKG: increase QRS, decrease QT (insignificant)
CA: (V) acute Tx of ventricular arrhythmias from MI or cardiac manipulation
AE: Lidocaine drowsiness, slurred speech, agitation, little risk of arrhythmias, toxic dose is convulsions/coma; Mexiletine mainly CNS and GI
1C
Flecainide, Propafenone
MOA: potent Na+ (phase 0) channel blockers on atrial and ventricular myocardial cells
EKG: increase QRS
CA: (SV) rhythm control agent in A-fib
AE: Flecainide negative inotrope, CNS/GI effects, life-threatening arrhythmias; Propafenone beta-blocking activity > bronchospasm, aggrevation of heart failure, severe life threatening arrhythmias
TCo: Flecainide heart failure; Propafenone COPD, asthma, heart failure
Beta-blockers (class 2)
Metoprolol (B1), Propanolol (B1/2), Esmolol (B1)
MOA: antagonist of beta receptors at nodal cells (SA/AV)
EKG: increase PR
CA: (S or catecholamine induced V), rate control agents in A-fib
AE: airway constriction (propanolol), bradycardia, CNS effects (fatigue, sexual dysfunction) which mask signs of hypoglycemia in diabetics
TCo: pts taking CCBs, 2nd/3rd degree heart block, or severe left ventricular dysfunction
Potassium Channel Blockers (class 3)
Amiodarone, Sotalol, Dofetilide
MOA: K+ channel blockers at the atrial and ventricular myocardial cells
EKG: Amiodarone increase QRS, QT, PR; Sotalol increase QT, PR; Dofetilide increase QT
CA: (SV) Amiodarone acute ventricular arrhythmias, rate/rhythm control of A-fib; Sotalol life threatening ventricular arrhythmias, maintain sinus rythm in A-fib; Dofetilide conversion to maintenace of sinus rythm in A-fib
AE: Amiodarone interstital pulmonary fibrosis
TCo:
CCBs (class 4)
Diltiazem, Verapamil
MOA: antagonist of L-type cardiac Ca2+ channels at nodal cell (mainly AV), and inhibit vascular calcium channels
EKG: increase PR
CA: (S) rate control in A-fib
AE: constipation, negative inotropic effects
TCo: pts taking B-blocker, 2nd/3rd degree heart block or severe left ventricular dysfunction
Digoxin
MOA: vagomimetic actions on nodal cells (mainly AV)
EKG: increase PR
CA: (S) rate control agent in A-fib plus heart failure pts
AE: nausea, vomiting, anorexia, headache, fatigue, confusion, alteration of color perception, blurred vision
TCo: diastolic heart failure, uncontrolled HTN, bradyarrhythmias, non-responders/intolerant pts
Nucleoside
Adenosine
MOA: agonist at P1 receptors causing hyperpolarization by inhibiting cAMP mediated Ca2+ influx (mainly AV node)
EKG: increase PR
CA: (S) first line drug in abolishing acute supraventricular arrhythmias
AE: flushing, burning chest pain, hypotension, bronchoconstriction in asthmatics
TCo: COPD, asthma
Functional Ca2+ Antagonist
Magnesium
MOA: inhibit effects of calcium in all myocardial cells
EKG: increase PR, QRS
CA: (SV) Tx Torsades de Pointes, digitalis-induced arrhythmias and prophylaxis of arrhythmias in acute MI
Muscarinic Antagonist
Atropine
MOA: decreases vagal tone (SA/AV nodal cells)
EKG: varies
CA: (SV) Tx bradyarrhythmias
AE: antimuscarinic effects
TCo: tachyarrhythmias
