Calcium Channel Blockers (CCBs) (cont.)

For what conditions are calcium channel blockers used?

Calcium channel blockers are approved for treating:

• high blood pressure,
  
  
• angina,
  
  
• abnormal heart rhythms (for example, atrial fibrillation, paroxysmal supraventricular tachycardia) and subarachnoid hemorrhage.

They are also used for treating other conditions such as:

• high blood pressure in the pulmonary arteries (pulmonary hypertension),
  
  
• Raynaud's phenomenon, cardiomyopathy (disease of the heart's muscle), and
  
  
• preventing migraine headaches.

Are there any differences among calcium channel blockers?

Although calcium channel blockers have a similar mechanism of action, they differ in their ability to affect heart muscle vs. arteries, and they differ in their ability to affect heart rate and contraction. These differences determine how they are used and their side effects.

For example:

• verapamil (Covera-HS, Verelan PM, Calan), and diltiazem (Cardizem LA, Tiazac) reduce the strength and rate of the heart's contraction and are used in treating abnormal heart rhythms; and
  
  
• amlodipine (Norvasc) has very little effect on the heart rate and contraction. Therefore, amlodipine is not used for treating abnormal heart rhythm, but it is preferred when heart failure is present and dilation of arteries is desired.