What are Calcium Antagonists?

Calcium antagonists are better known by their alternate name: calcium channel blockers (CCBs). They are a large group of medications used to treat conditions like high blood pressure, arrhythmias, angina or severe chest pain, some types of congestive heart failure, and occasionally pulmonary hypertension. Less commonly, CCBs are employed for treatment of migraines or bipolar disorder, though these tend to be off-label uses. They’re principally found effective, though helpfulness may vary, because they inhibit the movement of calcium into the blood vessels and the heart. This relaxes and widens (dilates) blood vessels, which allows blood to flow with greater ease, improving blood vessel and circulatory function.

Significant research suggests calcium antagonists aren’t always the drugs of choice to treat the above-mentioned conditions, and they may not be first-line treatment for high blood pressure. They may be second or third choices for many patients because they usually don’t control blood pressure conditions as well as other medications. They also lack some protective features common among drugs like beta blockers or angiotensin-converting enzyme (ACE) inhibitors.

For example, they don’t tend to prevent repeat heart attacks in patients who have already suffered one myocardial infarction, and they may not protect the kidneys, as do ACE inhibitors, from additional complications like diabetes. On the other hand, some populations seem to benefit more from CCBs. Calcium antagonists might particularly be used with people of African descent, since these drugs seem more effective in this subgroup. There are also plenty of reasons why CCBs are a good choice, including if other drugs like beta blockers or ACE inhibitors are not effectively managing a condition.

Numerous calcium antagonists exist and doctors may make decisions on which ones to use depending on treatment goals and patient response to other medications. Individual CCBs don’t treat all conditions with the same efficacy. Some generic names for drugs in this group include verapamil, diltiazem, amlodipine, nicardipine, felodipine, nisoldipine, nifedipine, and isradipine. The medications may have different brand names depending on country of issue and age of the drug. Specific dosage of each of these medicines depends on the individual drug and condition treated.

Though side effects are individualized to each of the calcium antagonists, there is a predictable accompanying group of adverse effects. CCBs may cause swelling or edema in the ankles and legs, they can be associated with reduction in libido and erectile dysfunction, and they can result in other symptoms like constipation, stomach upset, drowsiness, dizzy sensations, and low blood pressure. Certain CCBs may also be contraindicated if congestive heart failure is evident because they may worsen it.

All of these medications have interactions with other drugs, and patients need to fully review all drugs taken with a physician, as well as all medical conditions before accepting a prescription for CCBs. CCBs can lower serum concentration of other medicines and this should be carefully evaluated. It’s particularly important to avoid consuming grapefruit juice with any of the calcium antagonists because this may interfere with drug absorption.