[INCOMPLETE] Antiarrhythmic drugs Flashcards
Class I antiarrhythmic agents act on which ion channels?
Na+ channels
Class II antiarrhythmic act on which receptors?
Beta-receptors
Class III antiarrhythmic agents act on which ion channels?
K+ channels
Class IV antiarrhythmic agents act on which ion channels?
Ca2+ channels
Which class of antiarrhythmic agents act on Na+ channels?
Class I
Which class of antiarrhythmic agents act on Beta-receptors?
Class II
Which class of antiarrhythmic agents act on K+ channels?
Class III
Which class of antiarrhythmic agents act on Ca2+ channels?
Class IV
What effect do group IA antiarrhythmic agents have on AP duration?
Prolong AP duration
What effect do group IB antiarrhythmic agents have on AP duration?
Slightly shorten AP duration in ischemic tissue
What effect do group IC antiarrhythmic agents have on AP duration?
No effect on AP duration
Group IA antiarrhythmic agents dissociate with what kinetics?
Intermediate kinetics
Group IB antiarrhythmic agents dissociate with what kinetics?
Rapid kinetics
Group IC antiarrhythmic agents dissociate with what kinetics?
Slow kinetics
What is the group IA antiarrhythmic agent prototype?
Procainamide
Procainamide is the prototype of which class of antiarrhythmic agent?
Group IA
Group IA antiarrhythmic agents have what effects on Purkinje fiber action potentials?
Slow upstroke of AP, prolong AP duration, increase refractory period
Group IA antiarrhythmic agents cause what changes seen on EKG?
QRS prolongation, QT prolongation
What are the common side effects of group IA antiarrhythmic agents?
Torsades de pointe (more likely in hypokalemic patients), lupus-like syndrome, thrombocytopenia
What effect does hyperkalemia have on cardiac toxicity of class I antiarrhythmic agents?
Exacerbates cardiac toxicity by increasing blockade of NA+ channels
Group IA antiarrhythmic agents are contraindicated in patients that are taking what drugs?
Drugs that cause hypokalemia or prolong AP duration (increased risk of Torsade de Pointes)
Procainamide is given to patients in which form?
IV only
What is the group IB prototype antiarrhythmic agent?
Lidocaine
Lidocaine and mexiletine belong to which class of antiarrhythmic agents?
Group IB
Lidocaine is given to patients in which form?
IV only
Mexiletine is given to patients in which form?
Oral only
Class IB antiarrhythmic agents have what effects on Purkinje fiber action potentials?
Little effect on normal tissue due to rapid dissociation; slow upstroke of AP, shortened AP duration in ischemic tissue
Group IB antiarrhythmic agents cause what changes on EKG?
Slight shortening of QT interval
What are the common side effects of group IB antiarrhythmic agents?
Restlessness, tremor, convulsions, respiratory/cardiovascular depression
Group IB antiarrhythmic agents are contraindicated in patients taking which drugs?
Drugs that decrease seizure threshold or cause hyperkalemia
What is the group IC prototype antiarrhythmic agent?
Flecainide
Flecainide is the prototype for which class of antiarrhythmic agent?
Group IC
Group IC antiarrhythmic agents have what effects on Purkinje fiber action potentials?
Slow upstroke of AP without AP prolongation
Group IC antiarrhythmic agents cause what changes on EKG?
Increase QRS duration
What are the major side effects of group IC antiarrhythmic agents?
Exacerbation of heart failure, increase mortality post acute MI, can cause cardiac arrest in patients with prolonged QRS
What are the uses of group IC antiarrhythmic agents?
Treatment of supraventricular arrhythmias in patients without structural or ischemic alterations of the heart
What are the uses of group IB antiarrhythmic agents?
Treatment of ventricular arrhythmias caused by acute ischemia or digoxin toxicity
What are the uses of group IA antiarrhythmic agents?
Treatment of all types of arrhythmias, especially in acute phase of myocardial infarction