Calcium Channel Antagonist Side Effects

Normally, calcium entry into blood vessel walls causes contraction of the vessels and triggers a rise in blood pressure. Calcium channel antagonists, also known as calcium channel blockers, prevent calcium from getting into blood vessel cells. As a result, blood vessel walls relax to keep your blood pressure from getting too high. Since calcium channel blockers -- CCBs -- relax blood vessels all over your body, side effects occur along with the desired results of therapy.

Side effects usually dissipate with continued use, but about 10 percent of patients need to stop taking the medication because of unwanted and intolerable effects, states "Braunwald's Heart Disease, a Textbook of Cardiovascular Medicine."

Headaches

A headache, one of the most common complaints related to therapy with CCBs, results from dilated blood vessels in your head and brain. Conversely, if you have pre-existing headaches resulting from constricted blood vessels, the CCBs may relieve your headaches by relaxing the vessels. Indeed, this class of drug reportedly provides relief for some migraine sufferers, although, according to the "American Family Physician," research does not provide an indication for CCBs for this purpose.

After about two to three weeks of CCB use, headaches as a side effect should subside. If they do not, talk to your doctor about options for relief or alternative medications.

Ankle Swelling

When blood vessels in the legs dilate, more blood accumulates there due to gravity, especially in the presence of poor circulation. The fluid component of the blood can leak through the walls of the veins, leading to swelling of your lower legs, ankles and feet. You may receive a prescription of a diuretic with your calcium channel blocker, since diuretics help eliminate this extra fluid. If you experience swelling, let your doctor know since, according to MedlinePlus, many causes exist for this side effect, including other medications. Elevation, exercise and adherence to a low-sodium diet help relieve swelling.

Flushing

Flushing, a feeling of warmth accompanied by redness of the skin, also occurs due to increased blood flow. Most patients notice this in their face and neck. Flushing usually improves after a few weeks, as well.

Interaction with Grapefruit

MayoClinic.com warns that taking some types of calcium channel blockers with grapefruit or grapefruit juice inhibits your liver's ability to eliminate CCBs. As a result, excess medication builds up in your body, leading to increased side effects and possibly dangerous reduction of your blood pressure.

Gingival Hyperplasia

Although gingival hyperplasia occurs more often with anticonvulsants and cyclosporine, calcium channel blockers can rarely cause this overgrowth of oral gum tissue. The gums appear thickened or swollen with the overgrowth causing movement or even loss of teeth. The exact mechanism remains unknown but fortunately, gingival hyperplasia may resolve partially or completely after stopping the medication, according to the Nov. 4, 2008 issue of "Journal of Clinical Hypertension." Talk to your doctor immediately if you experience gum swelling or any other side effect while taking CCBs.