Calcium channel antagonists Flashcards
What are common indications for the use of calcium channel blockers?
- Hypertension
- Stable angina
- SVTs - AF, SVT, Flutter
What is the mechanism of action of CCBs?
Decrease calcium entry into vascular and cardiac cells, reducing intracellular calcium concentration. This causes relaation and vasodilatation in arterial smooth muscle, lowering arterial pressure. In the hear, they reduce myocardial contractility by suppressing cardiac conduction, particularly across the AV node, slowing ventricular rate
How does reduction in myocardial contractility affect oxygen demand?
Reduces myocardial oxygen demand, preventing angina
What are the two classes of CCBs?
- Dihydropyridines
- Non-Dihydropyridines
What are examples of dihydropyridines?
- Nifedipine
- Amlodipine
- Felodipine
What are examples of non-dihydropyridines?
- Verapamil
- Diltiazem
Where do dihydropyridines act?
Primarily on vascular smooth muscle
Where do non-dihydropyridines act?
On the heart
What are contraindications for CCBs?
- Aortic stenosis
- Bradyarrythmias
- Heart Failure
- Recent MI
What are adverse effects of CCBs?
- Flushing
- Dizziness
- Hypotension
- Ankle swelling (note this is not due to oedema)
- Headache
- Gum hyperplasia
- Verapamil/diltiazem - worsening HF/brady, constipation
