What are calcium channel blockers?

Calcium channel blockers are also called calcium antagonists or calcium blockers. They're medications that may decrease the heart's pumping strength and relax blood vessels. They may be used to treat high blood pressure, angina (AN'jih-nah or an-JI'nah) (chest pain or discomfort caused by reduced blood supply to the heart muscle) and some arrhythmias (abnormal heart rhythms). They include such drugs as verapamil (veh-RAP'ah-mil), diltiazem (dil-TI'ah-zem), and nifedipine (ni-FED'ih-peen). They're usually not prescribed for people with heart failure or other structural damage to the heart.

A National Heart, Lung, and Blood Institute panel recommends to physicians that "short-acting nifedipine should be used with great caution (if at all), especially at higher doses, in the treatment of high blood pressure, angina, and myocardial infarction (mi"o-KAR'de-al in-FARK'shun)."

The American Heart Association cautions that if patients are concerned about possible adverse effects of high doses of short-acting nifedipine, they should not stop taking their medication. They should consult their doctors about possible alternatives based on a full evaluation of their condition.