Antiarrhythmics Flashcards
Class 1 MOA
Membrane stabilizing or anesthetic effect on the cells of the myocardium
Class 1 indications
Arrhythmia, local anesthesia
Class 1 restrictions
Not for people with hyperkalemia
Class 1A indication and considerations
Arrhythmia, increase AP, QT, and ERP interval
Class 1A ex
Disopyramide, procainamide (SE: lupus), quinidine (SE: cinchonism)
Class 1A general side effects
Thrombocytopenia
Class 1B indications
Arrhythmia, post myocardial infections
Class 1B considerations
Decrease AP duration, effect ischemic tissue
Class 1B ex
Mexiletine (SE: GI upset), lidocaine (SE: CNS depression), phenytoin (SE: hirsutism)
Class 1C considerations
Used as last resort, no effect on AP duration
Class 1C ex
Propafenone, flecainide
Class 1C restrictions
Not for post myocardial infarction
Class 3 indications
Arrhythmia
Class 3 considerations
Increase AP duration, ERP, and QT interval
Class 3 ex
Amiodarone (LFT, dirty drug), ibutilide, dofetilide, sotalol (beta blocker), dronedarone
Class 4 indications
SVT, subarachnoid hemorrhage
Class 4 considerations
Decrease conduction velocity, increase PR interval, and ERP
Class 4 ex
Verapmil, dilitazem, nimodipine
Class 4 side effects
Cardiovascular, constipation, swelling in lower limbs
Adenosine MOA
Slows AV conduction
Adenosine indications
Bradycardia, flushing, dyspnea
Adenosine interactions
Caffeine and theophylline decrease effects, dipyridamole increases effects
Lidocaine indications
Ventricular arrhythmia, anesthetic
Lidocaine side effects
Paresthesias, seizures, respiratory depression, drowsy
Lidocaine interactions
Anesthetic effect increase with epinephrine
Magnesium sulfate MOA
Muscle relaxant
Magnesium sulfate indications
Preterm labor contractions, preeclampsia
Magnesium sulfate side effects
Warm feeling, low blood pressure, less deep tendon reflexes, decreased respiratory rate, decreased urine output, paralytic ileus
Magnesium sulfate antidote
Calcium gluconate
Atrial flutter
Type of arrhythmia, rapid contraction of the atria at a rate too fast for the ventricles to pump efficiently
Atrial fibrillation
Type of arrhythmia, irregular and rapid atrial contraction, resulting in a quivering of the atria and causing an irregular and inefficient ventricular contraction
PVCs
Type of arrhythmia, beats originating in the ventricles instead of the SA node in the atria, causing the the ventricles to contract before the atria, and resulting in a decrease in the amount of blood pumped to the body
Ventricular tachycardia
Thyme of arrhythmia, a rapid heartbeat of usually more than 100 bpm, usually originating in the ventricles
Ventricular fibrillation
Type of arrhythmia, rapid, disorganized contractions of the ventricles, resulting in the inability of the heart to pump any blood to the body, which will result in death unless treated immediately
Class 1A MOA
Prolong action potential, produce moderate slowing of cardiac conduction
Disopyramide MOA
Decreases depolarization of myocardial fibers, prolongs the refractory period, and increased the action potential duration of cardiac cells
Qunidine MOA
Depresses myocardial excitability, decreasing the pulse rate and correcting the heartbeat
Class 1B MOA
Shorten the action potential duration, and selectively depress cardiac conduction
Lidocaine antiarrhythmic MOA
Decreases diastolic depolarization, decreases automaticity of ventricular cells and raises the threshold of the ventricular myocardium
Class 1C MOA
Slight effect on repolarization, and profound slowing of conduction
Flecainide MOA
Depresses fast sodium channels, decreases the height and rate of rise of action potentials and slows conduction of all areas of the heart
Propafenone MOA
Direct membrane stabilizing effect on the myocardial membrane, prolongs the refractory period
Class 2 MOA
Beta blockers, indirectly block calcium channels and block catecholamine caused arrhythmias, and also have membrane stabilizing effects
Class 3 MOA
Prolongation of repolarization
Amiodarone MOA
Acts directly of the cardiac cell membrane, prolonging the refractory period and repololarization and increasing the ventricular fibrillation threshold
Inutilice MOA
Prolonging the action potential, producing a mild slowing of the sinus rate and AV conduction
Class 4 MOA
Depressing depolarization, lengthening phase 1 and 2 of repolarization
Verapmil MOA
Inhibit the movement of calcium through channels across the myocardial cell membranes and vascular smooth muscle, and slows conduction through the SA and AV nodes
Antiarrhythmics use
Premature ventricular contractions (PVCs), ventricular tachycardia, premature atrial contractions, paroxysmal atrial tachycardia, other atrial arrhythmias (atrial fibrillation or flutter), tachycardia when rapid, but short term control of ventricular rate is desirable
Propanolol use
Myocardial infarction
Antiarrhythmics general side effects
Lightheadedness, weakness, somnolence, hypotension, arrhythmias, bradycardia, urinary retention, local inflammation
Who is at the highest risk for proarrhythmic effect
People that are given excessive dosages, when pre-existing arrhythmia is life threatening or when the drug is given IV
Antiarrhythmics contraindications
Pregnancy and lactation, 2nd or 3rd degree AV block (if there is no pacemaker), severe heart failure, aortic stenosis, hypotension and cardiogenic shock
Quinidine contraindications
Myasthenia gravis, systemic lupus erythematosus
Amiodarone pregnancy cat
D
Antiarrhythmics precautions
Hepatic disease, electrolyte disturbances, renal impairment, pregnancy (cat B or C), lactation, children
Disopyraminde precautions
Heart failure, myasthenia gravis, urinary retention, glaucoma, men with prostate enlargement
Quinidine precautions
Heart failure
Flecainide precautions
Heart failure
Disopyramide interactions
Clarithromycin and erythromycin and quinidine increase serum disopyramide levels, flouroquinolones and thioridazine and ziprasidone increase risk of life threatening arrhythmias, rifampin decreases disopyramide serum levels,
Quinidine interactions
Cholinergic cause failure to terminate paroxysmal supraventricular tachycardia, cimetidine increases serum quinidine levels, hydantoins decrease therapeutic effect of quinidine, nifedipine decreases quinidine action and serum level, and cholinergic blocking drugs have an additive vagolytic effect
Lidocaine interactions
Beta blockers increase lidocaine levels, and cimetidine decreases lidocaine clearance with possible toxicity
Flecainide interactions
Amiodarone and cimetidine increase serum flecainide levels, disopyramide and verapmil May increase negative inotropic properties, increased serum level of beta blockers, which also results in increased serum levels of flecainide, and additive negative inotropic effects, local anesthetics increase risk of CNS reactions, anticoagulants increase prothrombin time and increase plasma anticoagulant levels, increased serum digoxin level, and increased serum theophylline level
Propafenone interactions
Quinidine and SSRIs increase serum propafenone levels,
When to withhold oral antiarrhythmics
When pulse rate is above 120 or below 60
Antiarrhythmics elderly considerations
Greater risk for side effects, such as, additional arrhythmias, aggravation of existing arrhythmias, hypotension and heart failure
Signs of cinchonism
Tinnitus, hearing loss, headache, nausea, dizziness, vertigo, and lightheadedness
Class 2 ex
Beta blockers (acebutolol, propanolol)
