Drug withdrawal and rebound hypertension: Differential action of the central antihypertensive drugs moxonidine and clonidine

Abstract
To examine the antihypertensive action of the centrally acting antiadrenergic drugs moxonidine and clonidine, systolic and diastolic blood pressure as well as heart rate were monitored by radio telemetry in spontaneously hypertensive rats (SHR) with established high blood pressure. Increasing doses were administered with regular rat chow for 6–8 day periods. Moxonidine reduced (p1-receptors, whereas clonidine would interact not only with I1-receptors but also with alpha2-adrenoceptors, and most probably also with the vagal activity. In view of our previous studies demonstrating a rise in blood pressure and heart rate after a hypercaloric dietary intake, the selective I1-receptor agonist moxonidine appears particularly appropriate for treating overweight hypertension associated with an enhanced sympathetic outflow of the brain. Of importance in this respect is that a moxonidine-induced reduction in sympathetic outflow was not associated with a gain in body weight but resulted in reduced caloric intake.