title: Effects of metoprolol on blood pressure and plasma renin activity in thiazide-resistant hypertensive patients.
abstract: Twenty patients with mild to moderate hypertension whose blood pressures were not adequately controlled by a thiazide diuretic were treated for 4 wk with metropolol. Normotension (diastolic pressure less than 90 mm Hg) or reduction in diastolic pressure of at least 10 mm Hg was achieved in 12 of the patients 1 wk after metoprolol (200 mg/day) was added to the hydrochlorothiazide (100 mg/day) regimen. In  the other 8 patients, pressure reduction was attained with larger doses (300 to 400 mg/day) of metoprolol. After 1 wk of combined therapy, heart rate decreased by 11% (p less than 0.001) and plasma renin activity (PRA) decreased 48% (p less than 0.001). The individual changes in mean blood pressure did not correlate with either the premetoprolol PRA level (r = 0.14) or the changes in PRA after metoprolol (r = 0.03) but did correlate with steady-state metoprolol plasma levels (r = 0.61, p less than 0.01). Pressure and heart rate reductions were sustained during the last 3 wk of combined therapy but the PRA decrease did not persist; levels gradually rose to near control by the fourth week. Urinary sodium excretion was not consistently changed on metoprolol therapy.
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000187:drug effects*; D003404:Creatinine / Q000097:blood; D004351:Drug Resistance; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006852:Hydrochlorothiazide / Q000627:therapeutic use*; D006973:Hypertension / Q000188:drug therapy / Q000503:physiopathology*; D008297:Male; D008790:Metoprolol / Q000627:therapeutic use*; D008875:Middle Aged; D011412:Propanolamines / Q000627:therapeutic use*; D012083:Renin / Q000097:blood*; D012964:Sodium / Q000652:urine
chemical_list: D011412:Propanolamines; D006852:Hydrochlorothiazide; D012964:Sodium; D003404:Creatinine; D012083:Renin; D008790:Metoprolol