Calcium Channel Blockers

Question 1

Voltage-gated calcium channelsare activated by?

Answer 1

Membrane depolarisation

Question 2

Voltage-gated calcium channels function

Answer 2

Allow selective diffusion of calcium ions in response to changes in cellular membrane potential down their gradient

Question 3

L-type calcium channels are present where?

Answer 3

Vascular smooth muscle and ventricular myocytes etc

Question 4

For cardiovascular disease, we look at what type of calcium channels?

Answer 4

L-type

Question 5

L-type calcium channels are responsible for what? In skeletal, smooth and cardiac muscle

Answer 5

Excitation-contraction

Question 6

Calcium channel blockers function

Answer 6

Decrease phase o up-slope
Therefore prolonging the overall cycle
Therefore slowing down the heart rate

Question 7

Calcium channel blocker classes

Answer 7

Dihydropyridines
Non-dihydropyridines

Question 8

Examples of Dihydropyridines

Answer 8

Amlodipine and felodipine

Question 9

Examples of non-Dihydropyridines

Answer 9

Phenylalkylamine- verapamil
Benzothiazepine - dilitiazem

Question 10

Non- Dihydropyridines aren’t vascular selective. Why?

Answer 10

Mainly work on the heart
Also reduce activity in vascular SMCs

Question 11

Dihydropyridines are selective for vascular SMCs , therefore?

Answer 11

Have for lower effects on cardiac conduction

Question 12

Clinical uses of calcium channel blockers

Answer 12

Hypertension
Angina
Vascular spasm
Arrhythmia

Question 13

Role of calcium channel blockers in hypertension

Answer 13

Joint first line treatment for hypertension: usually amlodipine
CCB may not be sufficient and may require additional treatments

Question 14

Other first line option treatments for CCB in hypertension are?

Answer 14

ACE inhibitors or angiotensin receptor blockers

Question 15

Role of calcium channel blockers in angina: reduce pain?

Answer 15

By: reducing metabolic requirements of myocardium or improving blood supply

Question 16

CCB in joint first-line treatment for angina usually? And other options?

Answer 16

Usually amlodipine

Other= beta-blockers

Question 17

Angina describe

Answer 17

Chest pain arising from myocardial ischaemia
Underlying coronary artery disease (spasm) leading to inadequate Blood supply for myocardial metabolic requirements

Question 18

Role of CCB in vascular spasm

Answer 18

CCB as vasodilators → often first-line

Question 19

Example of vascular spasm
Explain what it is

Answer 19

Rynaud syndrome
= construction of digital arteries often by vasospams
= affected areas initially turn White (lack of blood) then blue (lack of oxygenated blood)
When good flow restored, Digits are red

Question 20

In raynaud syndrome affected areas initially turn?

Answer 20

= affected areas initially turn White (lack of blood) then blue (lack of oxygenated blood)

=) associated with “pins and needles” and pain due to lack of oxygenated blood

Question 21

Treatment for vascular spasms

Answer 21

Avoid precipitants (especially cold)
CCB as vasodilators

Question 22

Role of CCB in arrhythmias
Which class of CCB? And mechanism

Answer 22

Non-dihydropyridine CCB: decrease calcium influx at phase 0
At SAN and AV node
→ therefore slows down the cycle and reduced heart rate

Question 23

If you decrease phase o slope in cardiac cycle, what effect does this have?

Answer 23

Prolonged overall cycle → slowing down the HR

Question 24

Clinical term for irregular or abnormal heart’ rhythm?

Answer 24

Arrhythmia

Question 25

Adverse effects of CCB

Answer 25

Symptoms of low bp: dizziness, palpitations, flushing especially postural hypotension
Ankle oedema
Constipation

Question 26

Adverse effects of CCB: non-dihydropyridines

Answer 26

Lower heart rates