How should patients treated with alpha-blockers be followed? Insights from an ambulatory blood pressure monitoring database

Abstract

Objective: Adrenergic alpha-antagonists have been suggested to confer lesser protection, compared to diuretics, when used as first agents for hypertension. While differences in clinic blood pressure may be partly responsible, this inferiority is unexpected in light of the metabolic advantages of alpha-blockade. The aim of this study was to evaluate the relationship between use of alpha-blockers and blood pressure dipping.

Methods: A database of a 24-h ambulatory monitoring service was cross-sectionally evaluated for associations between antihypertensives and dipping. There were 681 treated subjects during a 3-year period (age 63 +/- 14, 57% female).

Results: Overall, 78 of 681 treated hypertensive subjects used alpha-blockers (11%). Nine per cent of dippers and 16% of nondippers were treated with alpha-blockade, odds ratio 2.0. Whereas clinic, 24-h, and awake blood pressures were similar in alpha-blocker users and nonusers, sleep blood pressure was significantly higher in the former group. Furthermore, significantly fewer subjects given alpha-blockers had a controlled sleep blood pressure. Among alpha-blocker nonusers sleep blood pressure was the best controlled category, whereas in alpha-blocker users manual blood pressure had the highest rate of control. Generally, accounting for covariates of alpha-blockade (age, gender, diabetes, total number of medications) did not influence the above-mentioned trends. Finally, a limited negative dose-response relationship between alpha-blockade and dipping magnitude was also noticed.

Conclusions: We found a significant negative association between adrenergic alpha-blockade and the magnitude of sleep-related blood pressure decline. Awaiting results from interventional studies, this may suggest a need to perform ambulatory monitoring in patients given alpha-blocking agents (or at least supine and standing measurements), and may partially clarify the inferiority of doxazosin in the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT).