Natriuretic effect of barnidipine, a long-acting dihydropyridine calcium channel blocker, in patients with essential hypertension.
OBJECTIVE
To evaluate the effect of barnidipine hydrochloride, a long-acting dihydropyridine calcium channel blocker on urinary sodium excretion in patients with essential hypertension.


METHODS
Twelve patients (2 males, 10 females) with mild to moderate essential hypertension.


METHODS
A single-blinded study. After the control (placebo) period, 10 to 15 mg barnidipine hydrochloride was administered for 7 days, followed by a post-treatment (placebo) period. Daily changes in blood pressure, urinary volume, and urinary electrolyte excretions were evaluated. Plasma levels of atrial natriuretic peptide (ANP) and aldosterone were also determined in each period. Daily sodium intake was kept at 120 mEq.


RESULTS
Blood pressure decreased from 161 +/- 4/92 +/- 2 mmHg to 146 +/- 4/85 +/- 2 mmHg (p<0.05) after 7-day-treatment with barnidipine. Barnidipine significantly increased urinary sodium excretion; the change was evident on the first day of administration (control period 41 +/- 3 mEq/day, and first day 59 +/- 3 mEq/day, p < 0.05). Drug discontinuation transiently decreased sodium excretion to 35 +/- 3 mEq/day. Cumulative sodium balance after 7-day-treatment reached 47 +/- 19 mEq. Urine volume, potassium excretion, and creatinine excretion did not change during the treatment period. The plasma levels of ANP tended to increase, but those of aldosterone did not change with barnidipine.


CONCLUSIONS
Barnidipine administration for a week decreased the blood pressure and made the sodium balance negative by increasing the urinary sodium excretion in patients with essential hypertension. The natriuretic effect of this drug could contribute at least in part to its antihypertensive effect.
Ohya
Y
Y
Second Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Abe
I
I
Ohta
Y
Y
Onaka
U
U
Fujii
K
K
Kagiyama
S
S
Fujishima-Nakao
Y
Y
Fujishima
M
M
D000328:Adult; D000368:Aged; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000652:urine; D008297:Male; D008875:Middle Aged; D009318:Natriuresis / Q000187:drug effects*; D009543:Nifedipine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D016037:Single-Blind Method
D002121:Calcium Channel Blockers; C050699:mepirodipine; D009543:Nifedipine