Calcium Channel Blockers to Control Heart Rate

Most of the information below about calcium channel blockers comes from this source.1


Calcium channel blockers relax blood vessels and reduce the heart’s workload. They do just what their name implies, preventing calcium from entering the heart and arteries. That lowers blood pressure, increases blood and oxygen to the heart, and slows electrical activity.

Common Side Effects

The most common side effects include:

  • Lightheadedness
  • Flushing
  • Headache

Serious Side Effects

If you experience any of these serious side effects, contact your doctor immediately.

  • Blurred vision
  • Difficulty breathing or swallowing
  • Extreme tiredness
  • Fainting
  • Fever
  • Flu-like symptoms
  • Loss of appetite
  • Nausea
  • Pain in the upper right part of the stomach
  • Rash
  • Slow heartbeat
  • Swelling of the hands, feet, ankles, or lower legs
  • Unusual bleeding or bruising
  • Yellowing of the skin or eyes

Drug Interactions

Tell your doctor about all prescription and over-the-counter medications you’re taking, as well as vitamins, herbs, and nutritional supplements to ensure there are no interactions with this class of drugs.

You should also avoid grapefruit juice and grapefruit as it can interact with the drug and affect how your body uses it.


Calcium channel blockers include diltiazem (Cardizem®, Tiazac®, and others), verapamil (Calan®, Covera-HS®, Calan SR®, Verelen®, VerelenPM®, and Isoptin®), amlodipine (Norvasc®), nifedipine (Procardia®), nisoldipine (Sular®), felodipine, isradipine, and nicardipine.