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Blood pressure lowering efficacy of alpha blockers for primary hypertension

  • Review
  • Intervention

Authors


Abstract

Background

Alpha blockers are occasionally prescribed for hypertension so it is important to determine and compare their effects on blood pressure (BP), heart rate and withdrawals due to adverse effects (WDAE).

Objectives

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

Search methods

We searched CENTRAL (The Cochrane Library 2009, Issue 1), MEDLINE (1950 to April 2009), EMBASE (1980 to April 2009) and reference lists of articles.

Selection criteria

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

Data collection and analysis

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.

Main results

Only 10 trials evaluated the dose-related trough BP lowering efficacy of 4 different alpha blockers in 1175 participants with a baseline BP of 155/101 mm Hg. The data do not suggest that any one alpha blocker is better or worse at lowering BP. The best but unsatisfactory estimate of the trough BP lowering efficacy for alpha blockers is -8/-5 mmHg.

Authors' conclusions

Based on the limited number of published RCTs, the BP lowering effect of alpha blockers is modest; the estimate of the magnitude of trough BP lowering of -8/-5 mmHg is likely an overestimate. There are no clinically meaningful BP lowering differences between different alpha blockers. The review did not provide a good estimate of the incidence of harms associated with alpha blockers because of the short duration of the trials and the lack of reporting of adverse effects in many of the trials.

摘要

背景

α腎上腺素受體拮抗劑對於原發性高血壓的降血壓療效

在治療原發性高血壓的降血壓藥物中,α腎上腺素受體拮抗劑有時會使用的藥物,因此決定與比較α腎上腺素受體拮抗劑在降血壓的療效、對心率的影響、以及因副作用所導致的停藥事件,是有其重要性。

目標

量化α腎上腺素受體拮抗劑治療原發性高血壓的劑量性,在降低收縮壓和/或舒張壓的療效,並與安慰劑做對照。

搜尋策略

我們蒐集下列資料庫CENTRAL (The Cochrane Library 2009, Issue 1),MEDLINE (1950年至2009年4月),EMBASE資料庫 (1980年至2009年4月) 和文章內的參考文獻。

選擇標準

蒐集隨機雙盲對照試驗,以固定單獨使用α腎上腺素受體拮抗劑治療原發性高血壓病患與安慰劑相比,持續時間約為3至12週,評估其降壓療效的研究。

資料收集與分析

兩位作者各自獨立評估風險的偏差並擷取資料。同時與原始研究的作者進行了聯繫,獲得更多訊息。也收集因副作用所導致的停藥事件的資料。

主要結論

只有10個試驗總共1175受試者中 (基礎血壓155/101毫米汞柱) 評估4種不同的α阻斷劑與劑量相關之降壓療療效。這些資料並未顯示任何α阻斷劑種類在降低血壓方面,有哪一種比較好或比較壞的效果。α阻斷劑最好降低血壓功效約是−8/−5毫米汞柱,其效果並不理想。

作者結論

基於隨機對照試驗發表的數量有限,得知α阻斷劑其降血壓作用的降低效果約為−8/−5毫米汞柱血壓,屬於中度降壓效果,此數據可能是高估的。不同的α阻斷劑其降低血壓的效果,是沒有臨床顯著的差異。。這篇回顧並未提供一個確切使用α阻斷劑後,不良反應的發生率的估計資料,主因於此回顧性研究受試時間太短且缺乏藥物不良反應回報的設計

翻譯人

本摘要由臺北榮民總醫院許富舜翻譯。

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。

總結

α阻斷劑具有適度降壓效應,這類藥物有時被用來降低高血壓。本類藥物包括doxazosin(商品名:Cardura),prazosin(Minipress)和terazosin(Hytrin)。我們想了解此類藥物可降低血壓的效果,以及是否有個別藥物效果間之差異。在現有的科學文獻檢索中,我們找到10個相關試驗研究,評估4種不同的α阻斷劑的降血壓效果 (總共有1175人納入研究),α阻斷劑降血壓效果及影響似乎中等程度。結果顯示α阻斷劑減少收縮壓8個單位及舒張壓5個單位。資料顯示沒有任何其中一種α阻斷劑在降低血壓有比較其他α阻斷劑有好與壞的差異。由於缺乏完整的報告有多少參與者因藥物不良反應退出了研究,以及這些試驗持續時間較短,所以本篇研究未能提供一個估計的此類藥物不良反應的資料。

Plain language summary

Alpha blockers have a modest BP lowering effect

The class of drugs called alpha blockers is sometimes used to lower elevated blood pressure. This class includes drugs such as doxazosin (brand name: Cardura), prazosin (Minipress) and terazosin (Hytrin). We asked how much this class of drugs lowers blood pressure and whether there is a difference between individual drugs within the class. The available scientific literature was searched to find all the trials that had assessed this question. We found only 10 trials studying the blood pressure lowering ability of 4 different alpha blockers in 1175 participants. The blood pressure lowering effect was modest. There was an 8-point reduction in the upper number that signifies the systolic pressure and a 5-point reduction in the lower number that signifies the diastolic pressure. No alpha blocker drug appears to be any better or worse than others in terms of blood pressure lowering ability. Due to incomplete reporting of the number of participants who dropped out of the trials due to adverse drug reactions, as well as the short duration of these trials, this review could not provide an estimate of the harms associated with this class of drugs.

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