Calcium channel blockers are drugs used to lower blood pressure. They work by slowing the movement of calcium into the cells of the heart and blood vessel walls, which makes it easier for the heart to pump and widens blood vessels. As a result, the heart doesn't have to work as hard, and blood pressure lowers.
Examples of calcium channel blockers include:
- Norvasc (amlodipine)
- Plendil (felodipine)
- DynaCirc (isradipine)
- Cardene (nicardipine)
- Procardia XL, Adalat (nifedipine)
- Cardizem, Dilacor, Tiazac, Diltia XL (diltiazem)
- Sular (Nisoldipine)
- Isoptin, Calan, Verelan, Covera-HS (verapamil)
Side Effects of Calcium Channel Blockers
Potential side effects from taking a calcium channel blocker include:
- Dizziness or lightheadedness
- Low blood pressure
- Heart rhythm problems
- Dry mouth
- Edema (swelling of ankles, feet, or lower legs)
- Skin rash
- Constipation or diarrhea
- Gastroesophageal reflux disease (GERD)
Guidelines for Calcium Channel Blockers
Before taking a calcium channel blocker, tell your doctor:
- About any medical conditions you have, including any heart or blood vessel disorders, kidney or liver disease
- About every medication you are taking, including any over-the-counter or herbal medications; certain drugs may interact with calcium channel blockers.
How Should I Take Calcium Channel Blockers?
Most calcium channel blockers can be taken with food or milk; however, ask your doctor. Follow the label directions on how often to take it. The number of doses you take each day, the time allowed between doses, and how long you need to take the medicine will depend on the type of medication prescribed and on your condition. Avoid grapefruit juice while taking these medications, because grapefruit prevents the breakdown of the drug in the body.
Be sure to see your doctor on a regular basis to make sure the medicine is working as it should and isn't causing any intolerable side effects. Your doctor may want to change the dosage if the drug isn't having the intended effect.
Interactions With Calcium Channel Blockers
- Grapefruits and grapefruit juice can affect the action of many of the calcium channel blockers. Ask your doctor or pharmacist whether your calcium channel blocker is affected by grapefruit juice.
- Do not drink alcohol while taking a calcium channel blocker. Alcohol interferes with the effects of the drug and increases the side effects.
- Taking other blood pressure medications in combination with a calcium channel blocker may cause a sudden drop in blood pressure. Discuss with your doctor the best way to take the medication if you are taking other drugs.