Verapamil (Calan/Isoptin)

Question 1

Classification

Answer 1

Calcium Channel Blocker

Question 2

Mechanism of Action

Answer 2

• Inhibits influx of calcium across the cell membrane
• Slows conduction, prolongs refractory period in the AV node
• Decreases myocardial O2 demand
• Decreases inotropy
• Dilates coronary and systemic arteries
• Decreases automaticity of the SA node

Question 3

Indications

Answer 3

• Narrow complex SVT unresponsive to adenosine and not requiring cardioversion
• Rapid atrial fibrillation/atrial flutter

Question 4

Contraindications

Answer 4

• Hypersensitivity
• Hypotension
• Sick sinus syndrome
• Second or third-degree heart block
• WPW
• Patients taking beta-blockers

Question 5

Adverse Effects

Answer 5

• Hypotension, bradycardia, heart block, asystole, dizziness, headache, nausea, vomiting

Question 6

Administration

Answer 6

• 2.5-5 mg slow IVP over 2-3 minutes. If no response, repeat 5-10 mg slow IVP every 15-30 minutes to a max of 30 mg
• Not for peds

Question 7

Special Considerations

Answer 7

• May cause severe hypotension in patients with V-tach, therefore should only be given to patients with SVT, known with certainty to be supraventricular based on narrow complex
• May have synergistic effect if adminsitered to patients on beta-blockers
• In older patient, administer slower over 3 minutes.