Quarter-Dose Antihypertensive Therapy—Meta-Analysis

Especially in combination, quarter-dose medication regimens may provide a safe and effective alternative for blood pressure-lowering therapy, according to a meta-analysis in Hypertension.

A literature review identified 42 randomized trials of quarter-dose therapy with major classes of antihypertensive drugs. Comprising a total of 20,284 patients, all studies included at least one quarter-dose arm and one placebo and standard-dose monotherapy arm. On average, the studies were published 17 years ago. Data were pooled for meta-analysis of safety and efficacy outcomes.

On analysis of 36 comparisons with placebo, quarter-dose therapy was associated with a 4.7/2.4 mm Hg reduction in blood pressure. With dual quarter-dose therapy, based on six comparisons with placebo, the reduction in blood pressure was 6.7/4.4 mm Hg. In a single placebo-controlled study, quadruple quarter-dose therapy reduced blood pressure by 22.4/ 13.1 mm Hg.

Analysis of 37 comparisons of single quarter-dose therapy versus standard monotherapy suggested a blood pressure increase of +3.7/+2.6 mm Hg. Data from seven comparisons of dual quarter-dose therapy versus monotherapy showed no significant difference. In one study, quadruple quarter-dose therapy reduced blood pressure by 13.1/7.9 mm Hg. Adverse events of single and dual quarter-dose therapy were no different from placebo, and less frequent than with standard-dose monotherapy.

For many patients, combinations of antihypertensive drugs are needed to achieve good blood pressure control with minimal side effects. The new meta-analysis suggests potential clinical advantages of quarter-dose antihypertensive regimens.

Based on just two trials, quadruple quarter-dose combinations may significantly increase efficacy. The authors conclude, “This review suggests a potentially broader clinical role for low-dose blood pressure-lowering drugs” [Bennett A, et al. Efficacy and safety of quarter-dose blood pressure-lowering agents: a systematic review and meta-analysis of randomized controlled trials. Hypertension 2017; 70:85–93].

July 2017 (Vol. 9, Number 6)