In the sixties, drugs known as Calcium Antagonist Blockers or Calcium Channel Blockers (CCBs) were introduced into cardiovascular medicine and have since become one of the most commonly prescribed drugs in the treatment of heart diseases.
Calcium Channel blockers are used for treating
- Angina Pectoris
- Cardiac Arrhythmias
- Left Ventricular Diastolic Dysfunction
- Raynaud’s phenomenon
- Esophageal Spasm
CCBs can also be used after a heart attack if the patient cannot tolerate beta blocking drugs.
The main function of a Calcium Channel Blocker is to reduce the blood pressure. They do so by disrupting the calcium conduction of calcium channels.Hence they are employed in Hypertensive emergencies when there is an urgent need to reduce the blood pressure in order to prevent or limit target organ damage.This action makes it one of the best options for usage upon people with hypertension.
The heart needs Oxygen to pump blood and when the heart works harder it will need more Oxygen. When the supply of Oxygen to the heart becomes inadequate, Angina (heart pain) occurs. CCBs reduce the pressure in the arteries by dilating it, thus making it easier for the heart to pump blood and reducing the need for Oxygen. CCBs are also capable of slowing the rate of heart beat. Thus they are used for the treatment of abnormally rapid heart rhythms.
Common Calcium Channel Blockers used are:
- Nimodipine (Nimotop)
- Felodipine (Plendil)
- Nisoldipine (Sular)
- Isradipine (Dynacirc)
- Nifedipine (Adalat,Procardia)
- Nicardipine (Cardene) and
- Clevidipine (Cleviprex)
Drug interactions must be considered while treating patients with Comorbid conditions ( presence of one or more diseases along with the heart disorder ) as they may have to be administered more than one drug.
Most interactions of CCB occur with Verapamil or Diltiazem because these drugs reduce the elimination of a number of drugs by the liver leading to potentially toxic levels in the blood stream. One should be careful not to consume grapefruit juice two hours prior or after four hours after administration of CCBs known to interact with it, as it may elevate certain serum concentrations of Felodipine, Verapamil, Nisoldipine, Nifedipine, Nicardipine and Amlodipine.
CCBs need not always be beneficial. Though it has many advantages, it has certain negative characteristics too.
Common side effects of CCBs include:
- Low blood pressure,
- Edema(swelling of the legs with fluids) ,
- Drowsiness and dizziness
Calcium Antagonists like Diltiazem and Verapamil are not generally given to people with heart failure because they tend to further depress cardiac function by reducing the ability of the heart to pump blood. Most Calcium Channel Blockers decrease the force of contraction of myocardium which is called the negative inotropic effect. This makes it unsuitable for treatment on individuals with Cardiomyopathy. Calcium Channel Blockers can also lead to sexual dysfunction.
Calcium Channel Blockers are also not known to prevent recurrent heart attacks. These are also not that effective in preventing kidney failure caused by high blood pressure or diabetes, unlike the ACE inhibitors. But their effectiveness in the treatment of patients with hypertension and as drug which can rein in heart disease makes them a well considered alternative in cardiac treatments.