Class
Description
Onset and Duration
Indications
Contraindications
Adverse Reactions
Drug Interactions
How Supplied
Dosage and Administration
Special Considerations
Calcium channel blocker (class IV antidysrhythmic)
Verapamil is used as an antidysrhythmic and antianginal agent. It works by inhibiting the movement of calcium ions across cell membranes. The slow calcium ion current blocked by verapamil is more important for the activity of the SA and AV nodes than for many other tissues in the heart. By interfering with this current, calcium channel blockers achieve some selectivitv of action. Verapamil decreases atrial automaticity, reduces AV conduction velocity, and prolongs the AV nodal refractory period. In addition, verapamil depresses mvocardial contractility, reduces vascular smooth muscle tone, and dilates coronary arteries and artericles in normal and ischemic tissues.
PSVTs
Atrial flutter with a rapid ventricular response
Atrial fibrillation with a rapid ventricular response
Hypersensitivity
Sick-sinus syndrome (unless the patient has a functioning pacemaker)
Second- or third-degree heart block
Hypotension
Cardiogenic shock
Severe congestive heart failure
WPW with atrial fibrillation or flutter
Patients receiving intravenous beta blockers
Wide-complex tachycardias (ventricular tachycardia can deteriorate into ventricular fibrillation when calcium channel blockers are given)
Dizziness
Headache
Nausea and vomiting
Hypotension
Bradycardia
Complete AV block
Peripheral edema
Verapamil increases serum concentration of digoxin.
Beta-adrenergic blockers may have additive negative inotropic and chronotropic effects.
Antihypertensives may potentiate hypotensive effects.
Pregnancy safety: Category C.
Closely monitor patient's vital signs.
Be prepared to resuscitate.
AV block or asystole may occur as a result of slowed AV conduction.