Hypertension/High Blood Pressure Health Center

Font Size

High Blood Pressure and Calcium Channel Blockers

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)
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 particularly.
Dry mouth.
Edema (swelling of ankles, feet, or lower legs).
Headache.
Nausea.
Fatigue.
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?

Take your calcium channel blocker with food or milk. 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.

While taking a calcium channel blocker, your doctor may tell you to take and record your pulse daily. Your doctor will tell you how rapid your pulse should be. If your pulse is slower than advised, contact your doctor about taking your medication that day.

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.

WebMD Medical Reference

Reviewed by Robert J Bryg, MD on March 06, 2009