Antidysrhythmics

Antidysrhythmics


Action: Antidysrhythmics are divided into four classes and miscellaneous antidysrhythmics:

» Class I increases the duration of action potntial and effective refractory period and reduces disparity in the refractory period between a normal and infarcted myocardium; further subclasses include Ia, Ib, Ic

» Class II descreases the rate of SA node discharge, increases recovery time slow conduction throutgh the AV node, and decreases heart rate, which decreases O2 consumption in the myocardium

» Class III increases the duration of action potential and the effective refractory period

» Class IV inhibits calcium ion influx across the cell membrane during cardiac depolarization; decreases SA node discharge, decreases conducton velocity through the AV node

» Miscellaneous antidysrhythmics include those such as adenosine, which slows conduction through the AV node, and digoxin, which decreases conduction velocity and prolongs the effective refractory period in the AV node

Uses: These products are used for PVCs, tachycardia, hypertention, atrial fibrillation, angina pectoris.

Side effects / Adverse reactions: Side effects and adverse reactions vary widely among products.

Contraindications: Contraindications vary widely among products.

Precautions: Precautions vary widely among products.

Interactions: Interactions vary widely among products; check individual monographs for specific information.

Possible nursing diagnoses:
» Decreased cardiac output [uses]
» Altered tissue prefusion: cardiopulmonary [uses]
» Diarrhea [adverse reactions]
» Impaired gas exchange [adverse reactions]

Nursing Considerations


Assess:
» ECG continuously to determine drug effectiveness, PVCs, or other dysrhythmias
» IV infusion rate to avoid causing nausea, vomiting
» For dehydraton or hypovolemia
» B/P continuouslyfor hypotension, hypertension
» I/O ratio
» Serum potassium
» Edema in feet and legs daily

Evaluate:
» Therapeutic response, including decrease in B/P in hypertnsion; decreased B/P, edema, moist rale in CHF

Teach patient/family:
» To comply with dosage scadule, even if patient is feeling better
» To report bradycardia, dizziness, confusion, depression, fever

Selected Generic Names


Class 1
moricizine

Class 1a
disopyramide
procainamide
quinidine

Class 1b
lidocaine
mexiletine
phenytoin
tocainide

Class 1c
flecainide
indecainide
propafenone

Class 2
acebutolol
esmolol
propranolol
sotalol

Class 3
amiodarone
bretylium
ibutilide

Class 4
verapamil

Miscellaneous
adenosine
atropine
digoxin

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