Hypertension is a very common condition and the most important risk factor for the occurrence of cardiovascular events. The hyperactivity of the renin-angiotensin-aldosterone system is considered a cardiovascular risk factor in subjects with
essential hypertension. The intrinsic vascular abnormality in which the renin-angiotensin-aldosterone system is clearly the milieu for the development of the pathologic changes in blood vessel walls is one of the causes of the establishment of
hypertension. Many drugs with different mechanisms of action have been used for the treatment of
hypertension and its vascular complications. Nevertheless, the utilities of many drugs are limited by their adverse effects. Continuous research in the search for new pharmacological agents for the treatment of
hypertension has led to the development of
angiotensin II receptor type AT1 blockers. The most important functions mediated by AT1 receptors include: vasoconstriction, induction of the production and release of
aldosterone, renal reabsorption of
sodium, cardiac cellular growth, proliferation of vascular smooth muscle, increase of peripheral noradrenergic action and the central activity of the sympathetic nervous system, stimulation of
vasopressin release, and inhibition of
renin release from the kidney. The
angiotensin II receptor type AT1 blockers inhibit the interaction of
angiotensin II with its AT1 receptor. These agents lower blood pressure without producing
cough as a side effect since, unlike the
angiotensin-converting enzyme inhibitors they do not influence the levels of
bradykinin or
substance P. Hence, these drugs are suitable for the treatment of hypertensive patients who require
therapy with a drug blocking the effect of
angiotensin-converting enzyme but cannot use
angiotensin-converting enzyme inhibitors due to
cough as a side effect.