Double-blind placebo-controlled trial of terazosin effect on blood pressure and urinary output of dopamine in hypertensive patients.
In a parallel, double-blind study, 12 untreated hypertensive patients received terazosin (2-4 mg/day for 4 weeks), and 12 received placebo during the same period. Systolic and diastolic blood pressure decreased significantly in the terazosin group, from 150 +/- 5.0 mmHg systolic and 99.6 +/- 2.0 diastolic before treatment, to 134.0 +/- 7.0 systolic and 85.6 +/- 3.0 mmHg diastolic at week 4 of treatment. No significant blood pressure changes occurred in the placebo group. Blood pressure decrease showed a positive correlation (r = .62 and r = .52 for systolic and diastolic blood pressure, respectively) with the patient's age (P less than .05). Total plasma cholesterol decreased 18% in the terazosin group (P less than .05) and 9% in the placebo group (P greater than .05). Urinary dopamine excretion decreased significantly from 692.8 +/- 180.0 to 330.5 +/- 52.0 micrograms/24 hours in the terazosin group (P less than .05) and showed a nonsignificant increase in the placebo group. Compared with 22 age- and sex-matched healthy volunteers, urinary dopamine excretion in the hypertensive group before treatment was not statistically different (779.3 +/- 83.1 micrograms/24 hours). Dopamine excretion was higher in untreated hypertensive men and in male healthy volunteers compared with women. The decrease of urinary dopamine excretion observed under terazosin treatment could be due to a decrease of kidney dopamine synthesis or release induced by blood pressure reduction, or secondarily to the blockade of kidney alpha 1-receptors, modulating dopamine excretion. No significant changes were observed in urinary excretion of noradrenaline and adrenaline.
Department of Pharmacology, J.M. Vargas School of Medicine, Vargas Hospital, Caracas, Venezuela.
E
E
Romero
M
M
Angeli
M
M
Velasco
E
E
Azar
O
O
Bueno
G
G
Lema
N
N
Morales
Y
Y
Nuchi
C
C
Rasines
A
A
Wagner
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects*; D004298:Dopamine / Q000652:urine*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000503:physiopathology* / Q000652:urine; D008297:Male; D008875:Middle Aged; D011224:Prazosin / Q000031:analogs & derivatives* / Q000494:pharmacology; D014554:Urination / Q000187:drug effects
D000317:Adrenergic alpha-Antagonists; C041226:Terazosin; D004298:Dopamine; D011224:Prazosin