Hypertension is a vascular disease that is characterised by consistently elevated average blood pressure readings recorded over a period of time. A person is considered to have hypertension if the average systolic blood pressure is 160mmHg or over and the diastolic is over 90mmHg.
Hypertension is categorized into three parts, Essential, Secondary and Malignant hypertension. Essential hypertension often presents without any accompanying symptoms and it is often not related to any overt disease process. The underlying cause of this type of hypertension seems to be age-related changes in the nervous system, cardiovascular and endocrine system.
Secondary hypertension arises as a consequence of other conditions, such as pregnancy, atherosclerosis and renal disease.
The third type of hypertension develops fast and reaches critical levels and can cause major complications, such as cerebral oedema. This is called malignant hypertension. A condition that precipitates the latter form of hypertension is hypertensive crisis associated with the use of antidepressants such as monoamine oxidase inhibitors and eclampsia.
Chronic hypertension results from damage to the walls of the blood vessels. Arteries and arterioles thicken in response to the high pressure and vasoconstriction, leading to the narrowing of the lumen. Accounting for these changes are hypertrophy and hyperplasia of the vascular smooth muscles.
Also, other layers of the wall will undergo fibrosis. The damage to vessels wall induces an inflammatory response that increases the permeability of the endothelial walls. Sodium, water, calcium, plasma proteins and other substances from the blood permeate the vascular wall, further execrating the thickening. The major consequence of untreated hypertension is damage to some organs and tissues.
Atherosclerosis, myocardial infarction or heart attack, heart failure, renal failure, stroke, impaired mobility and generalised oedema are all associated with chronic hypertension. Some of the risk factors include age, ethnicity, size and weight and other existing conditions like cardiovascular disease and diabetes.
Overall management of hypertension involves a combination of managing modifiable risk factors such as a change in diet, increase in physical activity and reduction in weight. Pharmacological therapies are used depending on the severity of the condition.
Below is a list of medications used in the management of hypertension
ACE Angiotensin-converting enzyme is an enzyme in the body that cause a generalised vessel constriction. When there is vasoconstriction, blood pressure rises, ACE inhibitors decrease the production of Angiotensin, thereby decreasing blood pressure. Example of ACE inhibitors include:
- Benazepril hydrochloride (Lotensin)
- Captopril (Capoten)
- Enalapril Maleate (Vasotec)
- Fosinopril sodium (Monopril)
- Lisinopril (Prinivil, Zestril)
Angiotensin II receptor blockers can also be used, they prevent angiotensin II from binding to the receptors in the blood vessels. This also lowers the BP, examples include; Azilsartan (Edarbi), Candesartan (Atacand) and Eprosartan mesylate (Teveten) to name a few.
Alpha blockers cause the blood vessels to dilate, thereby reducing blood pressure. These medications are also used to treat prostate enlargement in men. Alpha blockers include doxazosin mesylate (Cardura), prazosin hydrochloride (Minipress). Vasodilators are also used to dilate the blood vessels to reduce BP.
The beta blockers lower the BP by acting directly on the heart, beta blockers reduce the heart rate and the force of contraction. They also reduce blood volume, examples include:
- Acebutolol (Sectral)
- Atenolol (Tenormin)
- Bisoprolol fumarate (Zebeta)
- Carvedilol (Coreg) — Combined alpha/beta blocker
- Esmilol (Brevibloc)
CALCIUM CHANNEL BLOCKERS
Calcium increases the strength and force of contraction in the heart and blood vessels. Blocking its entry into the smooth muscle stops this process. Calcium channel blockers lower blood pressure by relaxing blood vessels and reducing the heart rate. Examples of calcium channel blockers include:
Diuretics increase urine output, which reduces sodium and fluid in the body. This can help the blood pressure because it reduces the over blood volume. Diuretics alone can sometimes be used to treat mild hypertension, although they are commonly used in combination with other medications. Examples of diuretics include:
- Bumetanide (Bumex)
- Chlorthalidone (Hygroton)
- Chlorothiazide (Diuril)
- Ethacrynate (Edecrin)
- Furosemide (Lasix)
- Hydrochlorothiazide HCTZ (Esidrix, Hydrodiuril, Microzide)
One main side effects of diuretics to note is a loss of potassium, potassium is needed for proper muscular contraction. A deficiency in potassium can cause fatigue weakness, leg cramps, and cardiac issues. To prevent that from happening potassium-sparing diuretics can be used.
Sun, Z. (2015). Ageing, arterial stiffness, and hypertension. Hypertension, 65(2), 252-256.
Disclaimer; This article is purely for educational purposes and should not be used as a diagnostic tool, if hypertension is suspected, see your doctor.