Class 1 anti-dysrhythmic medications and cardiac glycosides (CV) Flashcards
Anti-dysrhythmics: General overview
-Classified as the Vaughan Williams classification
-Cardiac Action Potential in relation to NSR
Class I antidysrhythmic effects
-Membrane-stabilizing drugs
-Fast sodium channel blockers
Class Ia anti dysrhythmic drugs
-Disopryramide
-Quinidine
-Procainamide
-“mide” & “dine”; DQP
Class Ia anti dysrhythmic MOA
-Blocks Na+ channels
-Delays repolarization and prolongs action potential duration
-Affects phase 0
Class Ia anti-dysrhythmic effects
-Depress myocardial excitability, inotropic effect & ectopic foci stimulation
-Prolong refractory period
Class Ia anti-dysrhythmic indications
-Atrial fibrillation
-Premature contractions & ventricular tach
-Wolff-Parkinson-White syndrome
Class Ia anti-dysrhythmics: procainamide adverse effects
-Agranulocytosis
-SLE-like syndrome
Class Ia anti-dysrhythmic adverse events: quinidine
-Prolonged QT
-Anorexia
-Bitter taste, blurred vision, tinnitus
Class Ib anti-dysrhythmic drugs
-Lidocaine
-Mexiletine
-Phenytoin
Class Ib anti-dysrhythmic MOA
-Block Na+ channels
-They accelerate repolarization and decrease the action potential duration
Class Ib anti-dysrhythmic effects
-Decrease ventricular excitability
Class Ib anti-dysrhythmic indications
Ventricular dysrhythmias only:
-PVC, v-tach, v-fib
Class Ib anti-dysrhythmic adverse events: Lidocaine
-Bradycardia
-Metallic taste
Class Ic anti-dysrhythmic MOA
-Block Na+ channels
-Suppresses re-entry
-“C” suppress
Class Ic anti-dysrhythmic drugs
-Flecainide
-Propafenone
-PF
Class Ic anti-dysrhythmic effects
-Depression of conduction in the bundle of his-Purkinje system
-Have minimal effect on atrial conduction
-Flecainide: Reserved for the most serious dysrhythmias
Class Ic anti-dysrhythmic indications
-V-Tach, SVT, A fib, atrial flutter
-Wolff-Parkinson-White syndrome
Class Ic anti-dysrhythmic adverse events: Flecainide
-Dyspnea, dizziness
-Palpitations
-Visual disturbances
-N/V, diarrhea, weakness
Class Ic anti-dysrhythmics: propafenone (effect, indications & adverse effects)
-Prodysrythmic effect, angina, tachycardia, AV block
-Dizziness, dyspnea, fatigue
Class II anti-dysrhythmics: beta-blocker drugs
-Metoprolol
-Esmolol
-Acebutalol
-“lols”
Class II anti-dysrhythmics: beta blockers MOA
-Reduces spontaneous depolarization
-Block impulse transmission
-Affects phase 4
Class II anti-dysrhythmic: beta blocker effects
-Blocks beta-adrenergic heart stimulation
-Decrease atrial stimulation & ventricular contraction rate
-Decrease CO & BP
Class II anti-dysrhythmics: beta blockers indications
-SVT
-Ventricular dysrhythmias
Class II anti-dysrhythmics: beta blocker adverse effects
-AV block , HF
-Hyperglycemia, mask the symptoms of hypoglycemia
-Bronchospasm, wheezing, dry mouth
-Erectile dysfunction
Class III anti-dysrhythmic drugs
-Amiodarone
-Dronedarone
-Sotalol
-Ibutilide
-AIDS
Class III antidysrhythmic MOA
-Increase action potential duration by prolonging repolarization in phase 3
-Prescribed for difficult to treat dysrhythmias
Class III anti-dysrhythmic effects
-Prolongs the refractory period & myocardial action potential
-Blocks both alpha and beta adrenergic stimulation
Class III anti-dysrhythmic indications
-V-Tach or V-Fib
-Atrial fibrillation and flutter resistant to other drugs
Class III anti-dysrhythmic adverse events (amiodarone)
-Pulmonary toxicity, thyroid disorders
-Bradycardia, hypotension
-SA node dysfunction, AV block, ataxia, QT prolongation, torsades de pointes
-Omitting, constipation
-Photosensitivity, visual disturbances
-abn Liver function tests, jaundice
-Hyperglycemia or hypoglycemia
-Toxic epidermal necrolysis, vasculitis, blue-grey colouring of the skin
Class III anti-dysrhythmics: Ibutilide: Adverse events
-V-Tach, ventricular extra systoles, tachycardia, AV block
-Hypotension, headache, nausea
Class III anti-dysrhythmic sotalol: Adverse events
-Chest pain, palpitations, dyspnea, bradycardia
-Fatigue, dizziness, weakness
Class IV anti-dysrhythmic drugs
-Diltiazem
-Verapamil
Class IV anti-dysrhythmic MOA
-Inhibit calcium channels and reduces the influx of calcium ions during action potentional
-Depression of phase 4 depolarization
Class IV anti-dysrhythmic effects
-Prolong AV refractory period
-Reduce AV conduction
-Reduce rapid ventricular conduction caused by atrial flutter
Class IV anti-dysrhythmic indications
-SVT
-Rate control for A-fib and flutter
Class IV anti-dysrhythmic adverse events
-Constipation
-Bradycardia, heart block
-Hypotension, dizziness, dyspnea
Unclassified anti-dysrhythmic: Adenosine MOA
-Slows the conduction time through the AV node
Unclassified anti-dysrhythmic indications: Adenosine
-When SVT has failed with verapamil
-Pt has co-existing conditions such as HF, hypotension, or LV dysfunction
Unclassified anti-dysrhythmic: Adenosine contraindications
-2nd or 3rd degree heart block
-Sick sinus syndrome
-Atrial flutter or atrial fib
-V-Tach
Unclassified anti-dysrhythmic: Adenosine nursing considerations
Patients feel impending doom when administered, must be monitored with accessible airway, expect asystole prior to return to rhythm
Cardiac glycosides: Digoxin MOA for conduction
Decrease in rate of conduction and a prolonged refractory period between the SA and AV node
Cardiac glycosides: Digoxin MOA for contractility
-Increases contractility d/t the inhibition of the Na+-K+ adenosine triphosphatase pump leaving more sodium and calcium available enhancing contractility
Cardiac glycosides: Digoxin effects
-Positive inotropic effect
-Negative chronotropic & dromotropic effect
-Reduction in heart size during diastole
-Decrease in venous BP and vein engorgement
Cardiac glycosides: Digoxin effects cont’d
-Increase in coronary circulation
-Promotion of tissue perfusion and diuresis
-Decrease in dyspnea, cough, and cyanosis
Cardiac glycosides: Digoxin indications
-A fib and systolic HF
Cardiac glycosides: Digoxin contraindications
-2nd or 3rd degree heart block, a fib, v tach or fibrillation, HF resulting from diastolic dysfunction
-Subaortic stenosis
-Reduced kidney function
Cardiac glycosides: Digoxin adverse effects (CV)
-Bradycardia, tachycardia, HTN
Cardiac glycosides: Digoxin adverse effects (CNS)
-Headache, fatigue, confusion, convulsion
Cardiac glycosides: Digoxin adverse events (visual)
-Coloured vision, halo vision
Cardiac glycosides: Digoxin adverse events (GI)
-Anorexia
-N/V
-Diarrhea
Digoxin toxicity
-Toxic is > 2.0 g/L
-Low potassium and magnesium levels or decrease in kidney function may increase potential for toxicity
-Digoxin toxicity treatment may be to hold medication, treat the symptoms, or administer antidote which is digoxin immune Fab
Digoxin drug to drug interactions
-Amiodarone, quinidine, verapamil (increase digoxin levels)
Digoxin drug to food interactions
-Bran (decreases oral absorption of digoxin)
Digoxin drug to natural health product interactions
-Ginseng (increases digoxin levels)
-St. John’s Wart (reduces digoxin levels)
-Hawthorne (increases digoxin effects)
-Licorice (increase risk for digoxin toxicity due to potassium loss)
Digoxin use in pediatrics
-HF
-A one decimal point placement error will result in a 10-fold dosage error
-Watch for worsening heart failure: Increased fatigue, sudden weight gain, respiratory distress
Anti-dysrhythmics and cardiac glycosides: Nursing considerations & patient teaching
-All anti-dysrhythmics can cause dysrhythmias
-Grapefruit juice: Amiodarone, Class Ia’s - Disopyramide, and quinidine
Anti-dysrhythmics and cardiac glycosides: Prodysrhythmias clinical significance
-Antidysrhythmic drugs may cause life-threatening dysrhythmias
-Risk increases in presence of:
-Severe LV dysfunction
-Digoxin and class IA, IC, and III antidysrhythmia drugs
Anti-dysrhythmics and cardiac glycosides: Prodysrhythmias treatment
-First several days of drug therapy represent the vulnerable period for development of prodysrhythmias
-Many oral antidysrhythmia drug regimens are initiated in a monitored hospital setting
