Calcium-channel blockers (CCBs) are drugs used to treat high blood pressure, angina, and an irregular heartbeat, according to the Mayo Clinic. This class of drugs works by preventing calcium from entering cells. Through various complex biochemical reactions, this calcium block results in decreased blood pressure and a widening of blood vessels. CCBs are divided into three different groups by Cardiovascular Pharmacology Concepts: dihydropyridines, diltiazem, and verapamil.
Dihydropyridines
Dihydropyridines have a greater effect in the small muscles of the blood vessels than in the larger muscles of the heart, according to Patient UK. These drugs are used to treat high blood pressure and chest pain. These drugs also lead to an increased heart rate, which can be beneficial in patients experiencing heart failure. Dihydropyridines are rarely used in cases of abnormal heartbeat. Side effects of this class of CCBs include flushing, edema, severely low blood pressure levels, and headache. Some dihydropyridines include amlodipine, lacidipine, lercanidipine, nifedipine, nicardipine, and felopdipine.
Diltiazem
Diltiazem is classified as a benzothiazepine, and according to Cardiovascular Pharmacology Concepts, it shares some of the features of both dihydropyridines and the drug verapamil. Diltiazem has the ability to decrease heart rate and increase the diameter of blood vessels. Therefore, this drug can lower blood pressure and also decrease the workload of the heart.
Diltiazem is not recommended in patients with heart failure. The drug causes a decreased heart rate and can worsen the heart failure. Patients with high blood pressure and heart failure should consider other CCBs, such as the dihydropyridines.
Verapamil
Verapamil focuses on the cells of the heart. This drug is commonly used to treat high blood pressure, chest pain, and cases of irregularly fast heartbeat. Verapamil is effective in treating heart conditions because it targets specialized cells in the heart, according to Cardiovascular Pharmacology Concepts. These cells usually control the heart rate. When these cells are blocked by verapamil, the heart slows down. Since the drug slows down the heart, it should not be used in patients who are suffering from heart failure. Verapamil might exacerbate the heart failure in the patient and lead to fatal complications.
