This study investigated the significance of measuring plasma level of
thiobarbituric acid reactive substance (
TBARS) in patients with
hypertension and compared the clinical effects of
benidipine hydrochloride (CAS 91599-74-5, Coniel) and
amlodipine besylate (CAS 111470-99-6) on plasma
TBARS. At first, blood pressure and plasma
TBARS were measured in 85 untreated patients (48 males and 37 females, 68 years old on average) with at least one risk factor of
cardiovascular disease to investigate factors which had influence on plasma
TBARS. As the result, plasma
TBARS was significantly higher in those with
hypertension, which was also true when adjusted for other factors (r = 0.359, p< 0.01). Among these patients,
benidipine hydrochloride at the dose of 4 mg/day was administered to 49 patients with
hypertension or
angina pectoris. All patients stratified for each factor showed significantly decreased plasma
TBARS after
benidipine hydrochloride treatment. Second, 40 untreated patients with
essential hypertension were randomly assigned to the
amlodipine group (5-7.5 mg/day) or
benidipine group (4-8 mg/day) to compare the plasma
TBARS levels. Plasma
TBARS levels were significantly decreased in both groups. The
amlodipine group showed a positive correlation between the decrease in plasma
TBARS level and those in both diastolic and systolic blood pressures
after treatment. On the other hand,
benidipine hydrochloride decreased plasma
TBARS to a greater degree than both diastolic and systolic blood pressures. These findings suggest that patients with
hypertension have high plasma
TBARS, and
benidipine hydrochloride decreases not only blood pressure but also oxidative stress in the clinical practice.