Single Administration of Captopril and Combined Use with Beta-Blocker and/or Thiazide Diuretic in the Treatment of Essential Hypertension

Abstract

Thirty-four patients with essential hypertension at WHO stage I or II were divided into three groups. Group I consisted of 22 cases who displayed normal renin activity (NR) or low renin activity (LR) and who received a single administration of captopril. Group II consisted of 6 cases given beta-blockers after administration of captopril. Group III consisted of 6 cases in whom beta-blocker was replaced with thiazide diuretics after administration of captopril alone. Blood pressure decreased significantly by captopril treatment alone in group I of the NR and LR subgroups (except for the diastolic blood pressure [DBP] of the NR subgroup) and fell below the target blood pressure (SBP of 165 mmHg and DBP of 95 mmHg) in 86% of the NR subgroup and 73% of the LR subgroup. Combined treatment with captopril and beta-blocker in Group II did not decrease blood pressure any lower than with captopril alone treatment and achieved the target blood pressure in only 50% of the patients. In group III, combined treatment with captopril and thiazide achieved the target blood pressure in 100% of the patients. Plasma renin activity (PRA) was increased by captopril but reduced by captopril in combination with beta-blocker. However, when beta-blocker was replaced with thiazide, PRA increased. The serum sodium concentration was significantly reduced in the LR subgroup after a single administration of captopril, but there was no other variation.

Combination of β Adrenergic Receptor Block and Renin–Angiotensin System Inhibition Diminished the Angiotensin II-Induced Vasoconstriction and Increased Bradykinin-Induced Vasodilation in Hypertension

“… 30 However, and in agreement with our results, it has described that treatment with captopril and a β-blocker is not very effective and might be associated with little change in the vascular reactivity to Ang-II in SHR. 31 In addition, in patients with primary hypertension, the propranolol treatment might be associated with reduction in heart rate, 32 and captopril has shown a positive chronotropic effect by using isolated dog heart. 33 In our study and in a similar way, propranolol showed the bradycardic effect which was avoided by the combination with captopril ( Table 1 ).…”