Centrally Acting Antihypertensive Agents in the Treatment of Hypertension

Abstract

Centrally acting antihypertensive agents stimulate α 2 -adrenergic receptors and/or imidazoline receptors on adrenergic neurons situated within the rostral ventrolateral medulla and in so doing variably reduce sympathetic outfl ow. Centrally acting agents also stimulate peripheral α 2 -receptors, which for the most part is of marginal clinical signifi cance with the medication doses used in clinical practice. Central α-agonists have an extended usage history, starting with α-methyldopa, which has seen its use dramatically decline, in part, because of signifi cant dose-dependent side effects as well as the arrival of more mechanistically attractive classes of antihypertensive medications. Patients with resistant hypertension requiring multidrug therapy, such as those with chronic kidney disease, are commonly responsive to these drugs as are patients with sympathetically mediated forms of hypertension. Perioperative hypertension is typically responsive to clonidine -a clinical circumstance where the anestheticand analgesia-sparing properties of this compound may offer further clinical benefi ts. Clonidine can be used adjunctively with other more traditional therapies in systolic forms of heart failure, particularly when hypertension exists. Sustained-release moxonidine, however, is associated with early mortality and morbidity when used in the patient with heart failure. Escalating doses of drugs in this class often give rise to salt and water retention in which case diuretic therapy becomes a needed adjunctive therapy.