Calcium channel blockers lower the blood pressure by preventing the entrance of calcium into the muscles of the heart and the blood vessel walls. According to a study published in the journal "Advances in Physiology Education" in December 2003, calcium serves as an initiator of smooth muscle contraction within the blood vessels. When smooth muscles contract, the blood vessel caliber decreases, thereby increasing the pressure within its lumen, the blood vessel channel. With the use of calcium channel blockers, the smooth muscles relax, causing a decrease in the blood pressure reading. Examples of calcium channel blockers include nifedipine, amlodipine and felodipine.
Relief From Chest Pain
Calcium channel blockers may relieve chest pains in patients experiencing this symptom. The contraction of the smooth muscles of the blood vessels of the heart causes a decrease in the blood supply to the heart muscles. The decreased blood supply results in ischemia, or damage in the cardiac muscles resulting from a relative drop in blood supply. Ischemia causes a patient to perceive chest pain. With the administration of a calcium channel blocker, the smooth muscles of the cardiac blood vessels relax, thereby reestablishing the blood flow into the heart muscles and relieving the chest pain.
Tocolytic Agent for Preterm Labor
Tocolytic agents are special medications that inhibit the onset of labor by slowing down the contraction of the uterine muscles. According to RHL, the World Health Organization Health Library, calcium channel blockers may also serve as tocolytic agents for preterm labor. The uterine muscles are mainly composed of smooth muscles. Smooth muscles are involuntary muscles found in hollow organs such as the stomach, the small and large intestines, the blood vessel walls and the uterus. With the administration of calcium channel blockers, the smooth muscles of the uterus relax, thereby preventing labor.
Calcium Channel Blocker Overdose
Accidental or intentional intake of more than the recommended dosage of a specific calcium channel blocker may result in calcium channel blocker overdose. Calcium channel overdose results in slurred speech, weakness, confusion, dizziness, palpitations and an irregular or slow heartbeat, nausea and shortness of breath. Patients who manifest symptoms of calcium channel overdose should never be treated and managed at home. Never induce vomiting in a patient with this condition unless you are instructed to do so by a qualified health care professional.
Bipedal Edema
The regular intake of calcium channel blockers, even in the recommended dose, may result in the development of bipedal edema -- the swelling of both lower extremities. A study published in 2002 in "Kidney International," the official journal of the International Society of Nephrology, notes that edemas induced by calcium channel blockers are almost always very disturbing to the patient. To resolve the bipedal edema, discontinuing the intake of calcium channel blocker and switching to an alternative antihypertensive medication is necessary.
References
- "Advances in Physiology Education"; Smooth Muscle Contraction and Relaxation; R. Clinton Webb; December 2003
- MayoClinic.com: Calcium Channel Blockers
- RHL: Tocolytics for Preterm Labor
- MedlinePlus: Calcium Channel Blocker Overdose
- "Kidney International"; Role of calcium channel blockers in the future, in view of the INSIGHT Study; Talma Rosenthal; 2002
