Centrally acting antihypertensive drugs: re-emergence of sympathetic inhibition in the treatment of hypertension.

Central regulation of the sympathetic nervous system plays an important role in the maintenance of blood pressure. In a subset of patients with essential hypertension, sympathetic activation may contribute to the development and maintenance of hypertension. Unlike the first generation of centrally active antihypertensive drugs, the second generation may be superior because of its selectivity to I1-imidazoline receptor and selective binding to the vasomotor center. Lack of a2 effects differentiates moxonidine from clonidine with respect to monoxidine"s superior side-effect profile (little or no sedation or dry mouth). Clinical trials show that moxonidine is as effective as angiotensin-converting enzyme inhibitors (eg, enalapril and captopril), b-blockers (e.g., atenolol), calcium-channel blockers (e.g., long-acting nifedipine), and diuretics (eg, hydrochlorothiazide) in lowering blood pressure and that it has superior tolerability. Thus, central modulation of the sympathetic nervous system has re-emerged as an exciting target for blood pressure reduction. Given the multiple adverse effects of sympathetic stimulation in various disease processes, including congestive heart failure, moxonidine may be the next therapeutic option for the management of hypertension and the prevention of target organ dysfunction.