How Do Calcium Channel Blockers Work?

Calcium channel blockers (CCBs) also known as calcium channel antagonists are drugs widely used for treating hypertension (high blood pressure) and other cardiovascular diseases such as angina, coronary diseases, and arrhythmias. CCBs are of two different types-dihydropyridines and nondihydropyridines.

CCBs work by blocking the entry of calcium into the cells through voltage-gated calcium channels present in the muscles of the heart and blood vessels. Calcium is crucial for the conduction of electrical signals in the heart, which stimulates the contraction of the muscles so that the heart pumps the blood to the body. Calcium that enters the cells also contracts the muscles in the heart and arteries.

Therefore, CCBs reduce blood pressure as the free flow of blood increases due to the widening of the arteries. They decrease the conduction of electrical impulses and are used to correct abnormal heart rhythms. They also reduce the force of contraction of the heart muscles, thus reducing the oxygen demand of the muscle.

CCBs are used to treat:

• Hypertension (high blood pressure)
• Pulmonary hypertension (a type of high blood pressure that affects arteries in the lungs and in the heart)
• Preeclampsia (a pregnancy complication characterized by high blood pressure)
• Arrhythmia (irregular heartbeat)
• Cardiomyopathy (a disease of the heart muscle that makes it harder for your heart to pump blood to the rest of your body)
• Angina (chest pain that is caused because of poor blood flow and reduced oxygen supply)
• Coronary artery disease (decrease in blood supply to the heart because of damage of blood vessels)
• Raynaud’s syndrome (excessive constriction of small arteries causing numbness in fingers, toes, and other areas under the skin as response to cold)
• Subarachnoid hemorrhage (bleeding in the space between the brain and the outer layers that cover the brain)
• Migraine

Common side effects of CCBs include:

• Nausea and vomiting
• Heartburn
• Headache
• Dizziness
• Tiredness
• Bleeding of the gums
• Skin rash
• Diarrhea
• Constipation
• Edema (accumulation of fluid) in legs, ankles, or feet
• Weight gain

Serious side effects of CCBs may include:

• Hypotension (low blood pressure)
• Arrhythmias (irregular heartbeat)
• Trouble breathing

The information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of CCBs drugs include:

• Amlodipine/atorvastatin (Caduet)
• Amlodipine/celecoxib (Consensi)
• Clevidipine (Cleviprex)
• Dilatrate
• Diltiazem (Cardizem, Cardizem CD, Cardizem LA, Cartia XT, Dilacor, Dilacor XR, Dilt-CD, Diltazem, Diltazem CD, Diltia XT, Diltiaz, Diltiaz CD, Diltiaz SR, Diltiazem CD, Diltiazem SR, Taztia XT, Tiazac)
• Dilzem
• Felodipine (Cabren, Cardioplen XL, Neofel XL, Felendil XL, Felogen XL, Felotens XL, Keloc SR, Neofel XL, Plendil, Renedil, Vascalpha)
• Isradipine
• Nicardipine (Cardene IV, Cardene SR)
• Nifedipine (Adalat, Adalat CC, Afeditab CR, Nifediac CC, Nifedical XL, Procardia, Procardia XL)
• Nimodipine (Nimotop, Nymalize)
• Nisoldipine (Sular)
• Verapamil (Calan, Calan SR, Covera HS, Isoptin, Isoptin IV, Isoptin SR, Verap, Verapamil SR, Verelan, Verelan PM)