Hormonal and blood pressure responses to tilting in beta-blocked essential hypertension treated with felodipine or prazosin.
A study was carried out of 22 patients with essential hypertension who were treated with metoprolol (100 mg/day) and placebo for 4 weeks. Felodipine (n = 11) or prazosin (n = 11) were then added in increasing doses (felodipine 5, 10, 20 mg bid; prazosin 1, 2, 4 mg bid) for 2 weeks until a diastolic blood pressure of less than or equal to 90 mm Hg was achieved. Acute haemodynamic and hormonal responses to 80 degrees tilting (measurements after 4 minutes' tilt) were obtained immediately prior to randomisation to felodipine or prazosin, and after 6 to 8 weeks of treatment. At randomisation, 80 degrees tilt produced no change in blood pressure and only a small increase in pulse rate. There was no significant change in the plasma renin-angiotensin system, vasopressin or adrenaline concentrations. Plasma noradrenaline concentration rose in response to 80 degrees tilt. Following substitution of felodipine (n = 11) or prazosin (n = 11) for placebo, and continuation of metoprolol, blood pressure fell. 80 degrees tilt caused no change in the plasma renin-angiotensin system, vasopressin or adrenaline concentration. Plasma noradrenaline concentration rose in response to tilt, as before. Felodipine is an effective antihypertensive agent when used with metoprolol.(ABSTRACT TRUNCATED AT 250 WORDS)
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000328:Adult; D000368:Aged; D000804:Angiotensin II / Q000097:blood; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects*; D002395:Catecholamines / Q000097:blood; D015736:Felodipine; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009568:Nitrendipine / Q000031:analogs & derivatives* / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011674:Pulse / Q000187:drug effects; D012083:Renin / Q000097:blood; D014667:Vasopressins / Q000097:blood
D000319:Adrenergic beta-Antagonists; D000959:Antihypertensive Agents; D002395:Catecholamines; D014667:Vasopressins; D000804:Angiotensin II; D009568:Nitrendipine; D012083:Renin; D015736:Felodipine; D011224:Prazosin