Calcium Channel blockers (CCBs)

Question 1

What are the indications of Calcium Channel Blockers?

Answer 1

1) HTN
2) IHD
3) Supraventricular arrhythmias

Question 2

What is the Method of Action of CCBs?

Answer 2

Reduces Ca2+ ion into the muscle cells, reducing depolarization and therefore muscle contraction. So in the

Heart: suppresses conduction across the AV node > slowed ventricular contraction & afterload > decreased myocardial oxygen demand

Vascular Smooth muscles: causes Vasodialation > decreased blood pressure.

Question 3

What are the 2 classes of CCBs and what does each specifically target?

Answer 3

1) Dhydroprirdine (DHP)- targets vasculature

2) Non-Dhydroprirdine (Non-DHP)- mostly targets the heart
- Verapamil is more cardioselective
- Diltiazem has some effects on vasculature

Question 4

Non - Dhydroprirdine include?

Answer 4

Verapamil & Diltiazem

Question 5

Dhydroprirdines (DHPs) include?

Answer 5

“Pines”

Amlodipine
Nifedepine
Nimodipine

Question 6

What are the side effects of Amlodipine & Nifedepine?

Answer 6

Ankle swelling
Flushing
Headache
Palpitations

Question 7

What are the side effects of Verapamil & Diltiazem?

Answer 7

Constipation
Bradycardia
Heart block
heart failure

Question 8

What are the contraindications of Verapamil & Diltiazem?

Answer 8

AV nodal conduction delay (as they can cause a complete heart block)

use with caution in: impaired left ventricular function

Question 9

What are the contraindications of Amlodipine & Nifedepine?

Answer 9

Unstable angina (as Vasodialation causes a reflex increase in contractility and therefore myocardial oxygen demand)

Aortic Stenosis (can cause collapse)

Question 10

What drug interacts with Non-DHP CCBs?

Answer 10

Beta blockers. Do NOT prescribe Non - Dhydropridines with Beta blockers!

Question 11

How do you prescribe Amlodipine?

Answer 11

Stable angina / HTN:
5 mg OD (if necessary, increase to 10 mg OD)