CALCIUM CHANNEL BLOCKER

Question 1

CALCIUM CHANNEL BLOCKER - examples of non-DHP CCB

Answer 1

Diltiazem

Verapamil

Question 2

CALCIUM CHANNEL BLOCKER - examples of DHP CCB

Answer 2

Amlodipine

Nifedipine

Question 3

CALCIUM CHANNEL BLOCKER - indications (and which CCB is usually used in each indication)

Answer 3

Hypertension (usually amlodipine)

Stable angina (all CCB)

SVT and AF (diltiazem and verapamil)

Question 4

CALCIUM CHANNEL BLOCKER - which CCB is usually given in HTN

Answer 4

amlodipine

Question 5

CALCIUM CHANNEL BLOCKER - which CCB is usually given in stable angina

Answer 5

any CCB can be given

Question 6

CALCIUM CHANNEL BLOCKER - which CCB is usually given in SVT and AF

Answer 6

diltiazem or verapamil

Question 7

CALCIUM CHANNEL BLOCKER - MOA on the:
1- vascular smooth muscles
2- heart
3 - pacemaker cells of heart

Answer 7

CCB decrease intracellular [Ca2+] in vascular and cardiac cells

Vascular smooth muscles (hypertension)

• enhances production of NO (potent dilator)
• this causes relaxation of the vascular (arteriole) smooth muscles
• reduced PVR = reduced BP

Heart (stable angina)

• CCBs relax coronary vessels
• improves oxygen delivery to heart
• reduces oxygen demand of the heart

Heart (pacemaker cells) (SVT + AF)

• CCBs supresses cardac conduction
• reduces myocardial contractility = reducing HR

Question 8

CALCIUM CHANNEL BLOCKER - adverse effects of DHP CCB

Answer 8

Amlodipine and nifedipine 
→ ankle swelling 
→ flushing 
→ headache 
→ palpitation

Question 9

CALCIUM CHANNEL BLOCKER - adverse effects of non-DHP CCB

Answer 9

Verapamil
Common = constipation

Less common, but more serious
→ Bradycardia
→ Heart block
→ Cardiac failure

Diltiazem can cause any of the CCB effects

Question 10

CALCIUM CHANNEL BLOCKER - interactions

Answer 10

Non-dihydropyridine CCB should NOT be used with beta blockers (unless under close supervision)

Why? Taken together may cause HF, bradycardia and even systole

Question 11

CALCIUM CHANNEL BLOCKER - contraindications with DHP CCB (avoid)

Answer 11

Amlodipine and nifedipine should be:
→ avoided in patients with unstable angina
→ avoided in patients with severe aortic stenosis

REMEMBER - AAA
Amlodipine = aortic stenosis and angina (unstable)

Question 12

CALCIUM CHANNEL BLOCKER - contraindications with non-DHP CCB (caution and avoid)

Answer 12

Verapamil and diltiazem should be:
→ caution in poor left ventricular function (e.g.- heart failure)
→ avoided in AVN conduction delay

Question 13

CALCIUM CHANNEL BLOCKER - difference between non-DHP and DHP

Answer 13

DHP (amlodipine and nifedipine) have a more potent action on the blood vessels (specifically arterioles) than on the heart - this is why they are preferred in the treatment of hypertension

non-DHP verapamil has a more potent action on the heart than on the blood vessels - this is why they are preferred in the treatment of arrhythmias and stable angina (note: all CCBs can be used in stable angina but these are preferred)

non-DHP diltiazem has equal effects on both the heart and the blood vessels