Calcium Channel Blockers Flashcards
Give 3 examples of non-rate limiting CCBs a.k.a dihydropyridines?
- Amlodipine
- Felodipine
- Nifedipine
(they all end in -dipine)
What are non-rate limiting CCBs known as?
Dihydropyridine CCBs
e.g. amlodipine and felodipine
Give 2 examples of rate-limiting CCBs?
- Verapamil
- Diltiazem
What is important to note when prescribing diltiazem?
Should be prescribed by brand
What is the mechanism of action of CCBs?
They inhibit the influx of calcium ions into vascular smooth muscle, therefore decreasing intracellular calcium, which reduces contractility, conductivity, and oxygen demand of the heart
What are the routes of delivery of CCBs?
- PO
- IV
What CCBs can be given IV?
- Verapamil
- Nicardipine
Why are some CCBs available in a modified release preparation?
As some have short half lives
What are the indications for non-rate limiting CCBs?
dihydropyridines
- Prophylaxis in stable angina
- Hypertension
When are CCBs first line in hypertension?
In those who are >55 or Afro-Caribbean
Why are CCBs first line in Afro-Caribbean?
As low-renin hypertension for which CCBs are effective is common in this ethnic group
What are the indications for rate-limiting CCBs?
dialtazem and verapamil
- SVT
- Prophylaxis and treatment of angina
- Hypertension
What can diltiazem cream be used for?
Haemorrhoids
What are the cautions/contraindications for CCBs?
in terms of conditions
- Unstable angina
- Severe aortic stenosis
- Recent MI (within 1 month)
What might CCBs interact with?
- Other anti-hypertensives
- Digoxin
- Theophylline
- Anti-epileptics
What might happen if CCBs are given with digoxin?
Increased plasma digoxin concentration
What might happen if CCBs are given with theophylline?
Increased plasma theophylline concentration
What might happen if CCBs are given with anti-epileptic drugs?
Reduced effect of dihydropyridine CCBs
non-rate limiting
What are the common side effects of CCBs?
- Headache
- Flushing
- Abdominal pain
- Hypotension
- Tachycardia
- Fatigue
- Peripheral oedema
- Cold peripheries
What are the less common side effects of CCBs?
- Bradycardia, heart block and heart failure in patients with poor LV function
- Impotence
What CCB causes impotence?
Felodipine
What might happen to the side effects of flushing, hypotension, dizziness, and ankle swelling with CCBs?
May settle down after couple of weeks then resolve
What patient counselling is required with CCBs?
- Lifestyle measures
- Food interactions
- Compliance in angina
What should be discussed regarding lifestyle measures with CCBS?
Discuss reduction of other cardiovascular risk factors
What should be discussed regarding food interactions with CCBs?
Do not consume grapefruit or its juice as this may interact
Why should people not consume grapefruit with CCBs?
Grapefruit inhibits the CYP3A4 system, which increases the bioavailability of the calcium channel blocker and increases its anti-hypertensive effect
What should be discussed regarding compliance with CCBs in angina?
If you have angina and stop taking CCB, may worsen
