Besides a lifestyle change, the main method of treating hypertension is through the use of drugs collectively known as antihypertensives. There are many antihypertensives, and exactly which drug is prescribed by a physician will depend on the exact characteristics of the patient.
These are some of the more common categories of antihypertensives:
- Diuretics
A diuretic is any drug which causes the person ingesting it to urinate more. Not all diuretics do this in the same way, but they all share this basic property. The beneficial effect of diuretics on hypertension is due to the fact that in increasing the rate of urination, diuretics allow the person taking them to eliminate excess fluid and salt from the bloodstream, hence lowering blood pressure and reducing the amount of work that the heart has to do.
- Adrenergic receptor antagonists
This class of drugs includes beta- and alpha-blockers. These drugs have the effect of blocking epinephrine-mediated sympathetic actions. In other words, they inhibit the effect of the ‘fight-or-flight’ response, such as increased heart rate and dilation of blood vessels. In doing this they lower blood pressure and reduce the amount of work that the heart has do to.
Recent studies have suggested that adrenergic receptor antagonists such as beta- and alpha-blockers may not in fact be as effective a treatment for hypertension as once thought, and so these drugs are typically not prescribed as a first-line treatment for hypertensive people.
- Calcium channel blockers
Calcium channel blockers prevent calcium in the body from entering muscle cells found in artery walls. This causes the muscles, which includes the heart itself, to contract less. Because the output of the heart is therefore less, this has the effect of lowering blood pressure.
- Angiotensin-converting enzyme inhibitors
Angiotensin-converting enzymes, or ACEs, work on a hormone in the blood. They convert this substance, known as angiotensin, into a form which is a vasoconstrictor. Vasoconstrictors narrow arteries in the body, which (obviously) increases blood pressure and forces the heart to work harder. These drugs inhibit the action of the enzyme, reducing the production of the vasoconstrictor.
- Angiotensin II receptor antagonists
These drugs also concern the hormone angiotensin. Specifically, they block receptors from being affected by the form of angiotensin that is made by ACEs, and which is a vasoconstrictor.
- A possibility for the future: high blood pressure vaccines?
At the present time there is nothing commercially available that resembles a vaccine to inoculate people against high blood pressure, but studies have been done trialing a high blood pressure vaccine that appear to be very promising. It is likely however, that such a vaccine would be prescribed not for people who are yet to develop high blood pressure, but rather for those who are already suffering from it. The idea behind this is while other drugs would be taken in pill form to lower blood pressure; the vaccine would be administered as an injection, and would prevent blood pressure from rising in the event that a patient for whatever reason stops taking their pills.