September 1, 1980Clinical Pharmacology & Therapeutics
Dose response in captopril therapy of hypertension
Why the study?
What is the dose-response relationship of captopril for blood pressure reduction and renin-angiotensin-aldosterone system modulation in hypertensive patients?
Population
21 hypertensive patients
Design
Cohort
Authors
Discussion
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Implication
75 mg daily captopril was associated with BP reduction without further benefit at higher doses; leaves open confirmation in randomized trials.
Key Points
- To determine the dose-response relationships of blood pressure and biochemical markers of the renin-angiotensin-aldosterone system during long-term captopril therapy.
- Evaluated 21 patients with hypertension undergoing long-term captopril therapy.
- Administered captopril in biweekly doubling doses starting at 25 mg three times daily (75 mg/day) until blood pressure control was achieved or a maximum of 600 mg/day was reached.
- Recumbent and standing systolic and diastolic blood pressure fell significantly at a daily dose of 75 mg captopril.
- Increasing the daily dose beyond 75 mg did not induce further significant hypotensive effects.
- Biochemical evidence of in vivo ACE inhibition (increased plasma renin activity and angiotensin I, decreased angiotensin II and aldosterone) occurred at doses of 75 to 150 mg/day, whereas pretreatment renin poorly predicted blood pressure response.
Structured PICO
What is the dose-response relationship of captopril for blood pressure reduction and renin-angiotensin-aldosterone system modulation in hypertensive patients?
P
Population
21 hypertensive patients
I
Intervention
Captopril given in biweekly, doubling doses starting with 25 mg 3 times a day until control of blood pressure was achieved or a total daily dosage of 600 mg was reached
O
Outcome
Dose-response curves of blood pressure (recumbent and standing systolic and diastolic) and biochemical components of the renin-angiotensin-aldosterone system (PRA, PA I, PA II, PAC)surrogate
Captopril effectively lowers blood pressure and inhibits ACE at a daily dose of 75 mg, with higher doses providing no additional significant hypotensive benefit.
Cite This Study
Lijnen et al. (1980) studied this question.