Calcium channel blockers were first identified in the lab of German pharmacologist Albrecht Fleckenstein in 1964. These drugs disrupt the movement of calcium; they are most commonly used as anti-hypertensive drugs in order to decrease blood pressure in patients who are hypertensive. They are often used with elderly patients to reduce stiffness of large vessels. They are also used to alter heart rate and prevent vasospasm, which is a prolonged constriction of major arteries in the body. Recently, some are being used as migraine preventers and powerful painkillers.
In the body's tissues, the concentration of calcium ions outside of cells is thousands of times higher than the concentration inside of cells. Embedded in the membrane of some cells are calcium channels. When these cells receive a certain signal, the channels open, letting calcium rush into the cell. The resulting increase in intracellular calcium has different effects in different types of cells. Calcium channel blockers prevent or reduce the opening of these channels and thereby reduce these effects
CCBs used as medications primarily have three effects:
• By acting on smooth muscle they reduce contraction of the arteries and cause an increase in arterial diameter, known as vasodilation.
• By acting on cardiac muscles (myocardium), they reduce the force of contraction of the heart
• By slowing down the conduction of electrical activity within the heart, they slow down the heart beat.
These effects cause an overall decrease in blood pressure, since it depends on the force of contraction and resistance of the arteries.
However, these drugs are associated with several side-effects and prolonged use of them can lead to complications. Therefore CCB’s are usually are not used alone but are part of a combination of drugs used for the treatment. Side effects of these drugs may include but are not limited to:
• Dizziness, headache, redness in the face
• Fluid build up in the legs and ankle edema
• Slow heart rate
• Constipation
• Gingival overgrowth