Beta-adrenoceptor stimulating and blocking agents in essential hypertension: single and combined therapy with terbutaline and metoprolol.

Single and combined therapy with terbutaline (10 mg/day) and metoprolol (200 mg/day) was assessed over 8 weeks in a double-blind parallel study in a total of 36 patients with essential hypertension grade I-II according to WHO criteria at rest and during exercise. Blood pressure was comparably reduced with metoprolol and terbutaline (I) and metoprolol alone (II) at rest as well as during exercise. Under terbutaline (III), only diastolic blood pressure decreased during exercise. The responder rates (greater than or equal to 10% reduction in diastolic blood pressure) at rest were 58% in I, 63% in II and significantly lower in III at 42%. Heart rate was not affected in I and III but decreased significantly with metoprolol. While therapy with metoprolol resulted in an increase of noradrenaline and a fall of plasma renin activity after 8 weeks, these parameters remained unchanged in I and III. Therapy was well tolerated in all groups. Terbutaline in the chosen dosage slightly decreased diastolic blood pressure and did not increase heart rate. Metoprolol is an effective antihypertensive agent resulting in a heart rate decrease. Under combined therapy, there is no additional blood pressure decrease, but the heart rate remains unaffected.