Responses of catecholamines and blood pressure to beta-blockade in diuretic-treated patients with essential hypertension.
Twenty patients (mean age 49 +/- 4 (SEM) yr) with mild to moderate essential hypertension were studied during placebo conditions, following 6 weeks of chlorthalidone monotherapy and 6 to 28 weeks of combined beta-blocker-chlorthalidone treatment, or vice versa. Compared to chlorthalidone therapy alone, addition of a beta-blocker to this diuretic caused a further blood pressure reduction in 11 patients (Responders); in 9 patients addition of a beta-blocking agent failed to further reduce blood pressure (Non-responders). Supine and upright plasma renin, aldosterone, norepinephrine and epinephrine levels and catecholamine excretion rates were always comparable between Responders and Non-responders. In both groups plasma and urinary norepinephrine or epinephrine values were not significantly altered following addition of a beta-blocker; heart rate and plasma renin activity were decreased in both groups to a similar extent. It is concluded that the antihypertensive mechanism of beta-blockers given to diuretic treated patients with essential hypertension is independant of renin and not associated with changes in plasma or urinary catecholamines.
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000328:Adult; D001794:Blood Pressure / Q000187:drug effects*; D002395:Catecholamines / Q000378:metabolism*; D002752:Chlorthalidone / Q000627:therapeutic use; D004232:Diuretics / Q000627:therapeutic use*; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D012083:Renin / Q000097:blood; D014882:Water-Electrolyte Balance / Q000187:drug effects
D000319:Adrenergic beta-Antagonists; D002395:Catecholamines; D004232:Diuretics; D012083:Renin; D002752:Chlorthalidone