One year antihypertensive treatment with enalapril once daily: clinical and biochemical effects
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N Gadsbøll1, A Leth, S Rasmussen
1Department of Medicine C, Glostrup Hospital, University of Copenhagen, Denmark.
Insights
Enalapril combined with hydrochlorothiazide effectively lowers blood pressure in patients with moderate essential hypertension. This combination therapy provides sustained renin-angiotensin system blockade for up to one year.
Area of Science:
- Cardiology
- Pharmacology
- Nephrology
Background:
- Moderate essential hypertension often requires combination therapy for adequate blood pressure control.
- Hydrochlorothiazide (HCTZ) monotherapy may be insufficient for some patients.
- The renin-angiotensin system plays a crucial role in blood pressure regulation.
Purpose of the Study:
- To evaluate the antihypertensive efficacy of enalapril administered once daily.
- To assess enalapril's effectiveness in achieving sustained blockade of the renin-angiotensin system.
- To determine the safety and tolerability of enalapril in combination with HCTZ.
Main Methods:
- A study involving 15 patients with moderate essential hypertension inadequately controlled on HCTZ.
- Patients received escalating doses of enalapril (10-40 mg) once daily in combination with HCTZ.
- Blood pressure, plasma renin activity, and angiotensin concentrations were monitored over 1 year.
Main Results:
- Once-daily enalapril significantly reduced supine and erect blood pressure, with effects persisting for 24 hours and throughout 1 year of combination therapy.
- Blood pressure was significantly lower 6 hours post-enalapril compared to 24 hours post-enalapril, sometimes reaching hypotensive levels.
- Enalapril effectively blocked the renin-angiotensin system, indicated by decreased angiotensin II and increased renin and angiotensin I levels, with no detectable bradykinin.
Conclusions:
- Combination therapy with HCTZ and enalapril administered once daily is a rational, simple, and effective treatment for moderate essential hypertension.
- Sustained blockade of the renin-angiotensin system is achieved with this combination therapy.
- This regimen offers a valuable therapeutic option for patients whose hypertension is not adequately controlled by HCTZ alone.
Abstract:
The purpose of the study was to evaluate the antihypertensive effect of enalapril administered once daily (q.d.), and to assess the effectiveness of enalapril in achieving sustained blockade of the renin-angiotensin system. The study population comprised 15 patients with uncomplicated, moderate essential hypertension whose blood pressure (BP) was not adequately controlled on hydrochlorothiazide (HCTZ) monotherapy. Enalapril 10-40 mg q.d. produced a significant fall in supine and erect BP (24 h after enalapril) that persisted during 1 year of combination therapy with HCTZ and enalapril. Blood pressure 6 h after enalapril was significantly lower than BP measured 24 h after enalapril, and occasionally at hypotensive levels. Plasma angiotensin II concentration fell significantly after enalapril with reciprocal increases in the plasma concentrations of renin and angiotensin I. The blockade of the renin-angiotensin system was maintained throughout the study. Bradykinin could not be detected in venous blood at any time during the study. We conclude that combination therapy with HCTZ and enalapril once daily is a rational, simple, and effective treatment in patients with moderate essential hypertension.