Blood pressure lowering medications work to counter the effects of the high force of blood pressure in blood vessels which, over time, creates health problems such as an increased risk for strokes, heart attacks, heart failure, or kidney failure. Blood pressure pills are categorized into different classes based on how they work in the body.
Function
According to the American Heart Association, to understand how blood pressure pills work, it is important to know that blood pressure is caused by both the amount of blood pumped by the heart and how easily the blood vessels can be widened. Therefore, to lower blood pressure, medications must either decrease the amount of blood being pumped by the heart and/or open the blood vessels so blood flows more easily through them.
Types
The National Heart Lung and Blood Institute reports some of the more common classes of blood pressure lowering drugs to be diuretics, beta blockers, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, calcium channel blockers, alpha blockers, peripheral adrenergic blockers and vasodilators. Depending on the severity of the high blood pressure, two or more medications from different classes may be needed to lower blood pressure, according to the MayoClinic.com.
Effects
Diuretics, or water pills, work by removing excess salt and water through the kidneys which results in less fluid carried by blood vessels, says the AHA.
Beta-blockers reduce nerve impulses to the heart and blood vessels which causes a slower heart rate and decreased force of blood passing in the blood vessels.
Angiotensin converting enzyme inhibitors and angiotensin receptor blockers work by different mechanisms to inhibit a hormone called angiotensin II which acts to tighten blood vessels. The result is more relaxed and open blood vessels.
Calcium channel blockers prevent calcium from entering into the muscle cells of blood vessels, which opens the vessels.
Alpha blockers decrease signals from the nervous system that normally stimulate blood vessels to contract. This results in more relaxed and open blood vessels which let blood flow more easily.
The peripheral adrenergic blockers prevent natural chemicals in the brain, called neurotransmitters, from conveying information to blood vessels to tighten, says the AHA. This allows blood vessels to be more open which reduces blood pressure.
Vasodilators directly relax the muscle in blood vessels which widens the blood vessels and lessens pressure to ease blood flow, reports the National Heart Lung and Blood Institute.
Considerations
When taking blood pressure medications, the potential for side effects should be considered. According to FamilyDoctor.org, a website produced by the American Academy of Family Physicians, some of the more common side effects of blood pressure lowering medications include head pain, lightheadedness, stomach problems such as nausea or vomiting, weakness, sleepiness, increased or decreased weight, nervousness, chest pain, abnormal heart rhythm, cough, flu type symptoms, and rash. If serious or troublesome side effects occur, treatment can be adjusted by the doctor.
Warnings
According to the AHA, these medications are life saving and should not be stopped and no change in the prescribed dosage should be made without first consulting a doctor. It is also important to tell the doctor about any other medications or herbal preparations being taken due to the potential drug interactions which can decrease effectiveness of these medications. These medications may cause fetal injury and should be avoided during pregnancy, according to the FDA.
