Hypertension, describing abnormally high blood pressure, is a physiological condition where the walls of arteries are undergoing too much force in a continuous manner.

Causes, symptoms and complications

The causes of hypertension remain unclear, but many factors have been ascertained to worsen the condition or increase the probability of incidence. These factors are:

  • Age
  • Ethnicity and family history
  • Obesity
  • Physical inactivity
  • Smoking and drinking habits
  • Diet
  • Mental stress

The medical standards for diagnosis of hypertension are blood pressures of 130/90 mmHg (systolic/diastolic) or higher outside physical exertion, compared to a normal level of 120/80 mmHg. If the blood pressure reaches a level of 180/120, 130 over 90 mmHg (systolic over diastolic) or higher outside physical exertion, compared to a normal level of 120 over 80 mmHg. If the blood pressure reaches a level of 180 over 120, then the condition becomes a hypertensive crisis and requires immediate treatment.

Symptoms of hypertension are not always clear or visible, but hypertension can cause damage over a long period. The potential complications are:

  • Kidney disease
  • Higher chance of strokes
  • Higher chance of heart attacks
  • Aneurysm


There are a wide range of treatments depending on the severity of the condition and the combination with drugs already taken for other conditions. The most common hypertension drugs can however be classified into 5 categories.


Diuretics are often the first line of treatment against hypertension. By facilitating the release of salts (such as sodium ions) from the body, it triggers the secretion of larger volumes of urine, thus decreasing the blood volume and consequentially the blood pressure.

Angiotensin-converting enzymes inhibitors (ACE)

These inhibitors block enzymes that convert angiotensin I to angiotensin II. Angiotensin II is a hormone that elevates blood pressure by narrowing arterioles (vasoconstriction) and decreasing urine output.

Angiotensin Receptors blockers

These compounds block the angiotensin II receptors, blocking the effects of this hormone.

Calcium-channel blockers

Calcium is normally higher in the blood than in cells, and entry of calcium into cells through these channels cause cellular responses. Blocking one type of calcium channel in the heart lowers calcium levels in the heart cells, reducing the strength of heart contractions, lowering blood pressure. Blocking another type of calcium channel lowers calcium levels in smooth muscles of the arterioles, causing the arterioles to widen (vasodilatation), lowering blood pressure.


These block the beta-receptors for epinephrine on the heart, reducing heart rate and lowering blood pressure.