| Summary: | Background: Beta blockers are a class of drug commonly prescribed for treatment of hypertension. Although the long-term goal of antihypertensive treatment is reduction of mortality and morbidity, the reduction of blood pressure (BP) is often used by clinicians to evaluate the effectiveness of treatment. Our goal was to quantify the BP lowering efficacy of all beta blockers. The magnitude of BP lowering efficacy of each beta blocker provides valuable information to assist clinical decision making.
Methods: We searched the three major databases (MEDLINE, EMBASE and CENTRAL) and other sources for randomized, double blind, placebo controlled trials (DBRCT) of beta blocker mono therapy studies in primary hypertensive patients. Study duration had to be between 3 to 12 weeks. We used the RevMan program, version 5.2, to generate pooled BP, heart rate and pulse pressure estimates.
Results: Included in our review were 96 DBRCTs that examined the dose related BP lowering efficacy of 20 mono-therapy beta blockers in 9,803 primary hypertensive patients. In patient with mild to severe hypertension, the estimates of BP lowering efficacy (SBP/DBP) for beta blockers separated by subclasses were -10/-7 mmHg for non-selective beta blockers, -5/-4 mmHg for dual receptor blockers, -8/-4 mmHg for partial agonists and -10/-8 mmHg for beta-1 blockers. Baseline BP and time of measurement (peak or trough) influenced the BP lowering effect. None of the beta blocker subclasses showed a convincing graded dose response BP lowering effect. Doses higher than twice the recommended starting dose provided little or no additional BP lowering effect. Beta blockers overall had little or no effect on pulse pressure. Beta blockers showed a graded dose response effect in reducing heart rate and different beta blockers subclasses lowered heart rate by different amounts. The review findings were limited by a high risk of loss of blinding bias and publication bias.
Conclusion: Different subclasses of beta blockers lowered BP and heart rate by different amounts. None of the beta blockers subclasses showed a graded dose response blood pressure lowering effect. Beta blockers overall have little or no effect on pulse pressure in comparison to other antihypertensive drug classes. === Medicine, Faculty of === Anesthesiology, Pharmacology and Therapeutics, Department of === Graduate
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