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(^354) CHAPTER 19 Cardiac Circulatory Medications
Classes Actions Examples/Side Effects
Class I
Sodium channel
blockers
IA Slows conduction;
prolongs repolarization
IB Slows conduction and
shortens repolarization
IC Prolongs conduction
with little to no effect
on repolarization
Class II Reduces calcium entry;
Beta blockers decreases conduction
velocity, automaticity,
and recovery time
(refractory period)
Class III Prolongs repolarization
Prolong during ventricular
repolarization dysrhythmias. Prolongs
action potential duration.
Class IV Blocks calcium influx;
Calcium channel slows conduction velocity,
lockers decreases myocardial
contractility (negative
inotropic), and increases
refraction in the AV node
Table 19-3. Classes and actions of antidysthythmic drugs.
Procainamide (Pronestyl, Procan)
(less cardiac depression than quinidine,
abdominal pain/cramping, nausea, diarrhea,
vomiting, flushing, rash, pruritus, lupus-like
syndrome with rash).
Quinidine sulfate, polygalactorate, gluconate
(Quinidex, Cadioquin) (nausea, vomiting,
diarrhea, confusion, and hypotension).
Lidocaine (Xylocaine) (cardiovascular
depression, bradycardia, and hypotension;
dizziness, lightheadedness, and confusion)
Flecainide (Tambocor) (nausea, vomiting,
diarrhea, confusion)
Esmolol (Brevibloc) (Generally well
tolerated, with transient and mild side effects)
Propranolol HCl (Inderal)
(Decreased sexual ability, drowsiness, diffi-
culty sleeping, unusual tiredness/weakness)
Adenosine (Adenocard) (Facial flushing,
shortness of breath/dyspnea)
Amiodarone HCl (Cordarone) (Corneal
microdeposits are noted in almost all
patients treated for >6 months [can lead to
blurry vision], hypotension, nausea, fever,
bradycardia, constipation, headache,
decreased appetite, nausea, vomiting,
numbness of fingers/toes, photosensitivity,
muscular incoordination;
Bretylium tosylate (Bretylol) (Transitory
hypertension followed by postural and supine
hypotension in 50% of patients observed as
dizziness, lightheadedness, faintness, vertigo)
Verapamil HCl (Calan) (Constipation,
dizziness, lightheadedness, headache,
asthenia [loss of strength, energy])
Diltiazem (Cardizem) (Peripheral edema,
dizziness, lighheadedness, headache, brady-
cardia, asthenia [loss of strength, weakness],
nausea, constipation, flushing, altered EKG)