Blood pressure lowering efficacy of angiotensin converting enzyme (ACE) inhibitors for primary hypertension.
BACKGROUND
ACE inhibitors are widely prescribed for hypertension so it is essential to determine and compare their effects on blood pressure (BP), heart rate and withdrawals due to adverse effects (WDAE).


OBJECTIVE
To quantify the dose-related systolic and/or diastolic BP lowering efficacy of ACE inhibitors versus placebo in the treatment of primary hypertension.


METHODS
We searched CENTRAL (The Cochrane Library 2007, Issue 1), MEDLINE (1966 to February 2007), EMBASE (1988 to February 2007) and reference lists of articles.


METHODS
Double-blind, randomized, controlled trials evaluating the BP lowering efficacy of fixed-dose monotherapy with an ACE inhibitor compared with placebo for a duration of 3 to 12 weeks in patients with primary hypertension.


METHODS
Two authors independently assessed the risk of bias and extracted data. Study authors were contacted for additional information. WDAE information was collected from the trials.


RESULTS
Ninety two trials evaluated the dose-related trough BP lowering efficacy of 14 different ACE inhibitors in 12 954 participants with a baseline BP of 157/101 mm Hg. The data do not suggest that any one ACE inhibitor is better or worse at lowering BP. A dose of 1/8 or 1/4 of the manufacturer's maximum recommended daily dose (Max) achieved a BP lowering effect that was 60 to 70% of the BP lowering effect of Max. A dose of 1/2 Max achieved a BP lowering effect that was 90% of Max. ACE inhibitor doses above Max did not significantly lower BP more than Max. Combining the effects of 1/2 Max and higher doses gives an estimate of the average trough BP lowering efficacy for ACE inhibitors as a class of drugs of -8 mm Hg for SBP and -5 mm Hg for DBP. ACE inhibitors reduced BP measured 1 to 12 hours after the dose by about 11/6 mm Hg.


CONCLUSIONS
There are no clinically meaningful BP lowering differences between different ACE inhibitors. The BP lowering effect of ACE inhibitors is modest; the magnitude of trough BP lowering at one-half the manufacturers' maximum recommended dose and above is -8/-5 mm Hg. Furthermore, 60 to 70% of this trough BP lowering effect occurs with recommended starting doses. The review did not provide a good estimate of the incidence of harms associated with ACE inhibitors because of the short duration of the trials and the lack of reporting of adverse effects in many of the trials.
Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, 2176 Health Sciences Mall, Vancouver, British Columbia, Canada, V6T 1Z3. bsheran@ti.ubc.ca
Balraj S
BS
Heran
Michelle My
MM
Wong
Inderjit K
IK
Heran
James M
JM
Wright
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D016032:Randomized Controlled Trials as Topic
D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents