Hypertension centrally acting agents

General note In resistant (refractory) hypertension centrally acting agents (selective and non-selective) and alpha-blockers may be required to control BR... 

Primary pulmonary hypertension and cardiac valve disorders have been associated with other centrally acting weight loss agents that cause release of serotonin from nerve terminals although sibutramine has not been associated with these effects in premarketing clinical studies, patients should be informed of the potential for these side effects and monitored closely for their occurrence... 

FIGURE 37 Clonidine, a centrally acting antiadrenergic agent, is used in treating hypertension. 

Methyldopa is a centrally acting antiadrenergic agent that canses central alpha-adrenergic stimnlation, which inhibits sympathetic cardioaccelerator and vasoconstrictor centers rednces plasma renin activity and rednces standing and snpine BP. It is indicated in the treatment of hypertension. 

Methyldopa (Aldomet) is a centrally acting antihypertensive agent. It is a prodrug that exerts its antihypertensive action via an active metabolite. Although used frequently as an antihypertensive agent in the past, methyldopa s significant adverse effects limit its current use in the United States to treatment of hypertension in pregnancy, where it has a record for safety. 

Agents acting via oq-ARs to elicit changes in blood pressure induce a characteristic biphasic hemodynamic profile an initial, transient hypertensive response (by which peripherally located arterial oq-ARs constrict vascular smooth muscle) is followed by a longer-lived, centrally mediated attenuation of sympathetic outflow (culminating in a sustained drop in blood pressure). For this reason, oq-AR agonists are used to treat high blood pressure in some populations of hypertensive patients. 

As discussed above, agents acting via o -ARs to elicit changes in blood pressure induce a characteristic biphasic hemodynamic profile consisting of a transient hypertensive response followed by the sustained, centrally localized o -AR-mediated drop in blood pressure. As with the a2A-AR, mice null for the o ij-AR (a2B-AR / ) have documented the role of the a2B-AR subtype in modulating the pressor, or increased, blood pressure responses following a2-agonist activation of peripheral mechanisms (11). Control studies demonstrated that a2B-... 

Although a large number of p-blockers have been investigated in the clinic, their mode of action in hypertension is still unknown.60 it is unclear whether all agents act by the same or the same combination of effects and whether all the observed effects are due to p-adrenergic receptor antagonism. The role of renin continues to be argued without new conclusions.60 The central depressor effects have been reviewed.69 It has... 

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