Carvedilol , within the recommended dose range , did not show a significant dose response effect for SBP or DBP .
Carvedilol had little or no effect on pulse pressure ( -1 mm Hg ) and did not change BP variability .
Due to the larger sample size from the two unpublished studies , carvedilol provided a better estimate of BP lowering effect than labetalol .
Doses higher than the recommended starting dose did not provide additional BP reduction .
Higher doses of dual receptor blockers caused more bradycardia than lower doses .
Based on indirect comparison with other classes of drugs , the blood pressure lowering effect of dual alpha- and beta-receptor blockers is less than non-selective , beta1 selective and partial agonist beta blockers , as well as thiazides and drugs inhibiting the renin angiotensin system .
Dual blockers also had little or no effect on reducing pulse pressure , which is similar to the other beta-blocker classes , but less than the average reduction of pulse pressure seen with thiazides and drugs inhibiting the renin angiotensin system .
Patients taking dual receptor blockers  were not more likely to withdraw from the study compared to patients taking placebo
BACKGROUND Drugs with combined alpha and beta blocking activity are commonly prescribed to treat hypertension .
However , the blood pressure ( BP ) lowering efficacy of this class of beta blockers has not been systematic ally review ed and quantified .
OBJECTIVES To quantify the dose-related effects of various types of dual alpha and beta adrenergic receptor blockers ( dual receptor blockers ) on systolic and diastolic blood pressure versus placebo in patients with primary hypertension .
Clinical evaluation of labetalol alone and combined with chlorthalidone in essential hypertension: A double-blind multicentre controlled study
Summary In a multicentre , double-blind , crossover , placebo-controlled study , the antihypertensive effect of labetalol 100 mg and chlorthalidone 10 mg , given alone or in combination , has been assessed in 32 hypertensive patients . The combination had a greater effect in reducing blood pressure than did its separate components . This was particularly evident after exercise . Heart rate increased during chlorthalidone therapy , decreased during labetalol therapy , and a summation effect was observed during treatment with the combination . In most cases additivity was observed , as no interaction between the single components was observed , except for heart rate after exercise , and for diastolic blood pressure in the upright position . No interaction was observed either in the biochemical indices or in the clinical side-effects
Carvedilol , within the recommended dose range , did not show a significant dose response effect for SBP or DBP .
Carvedilol had little or no effect on pulse pressure ( -1 mm Hg ) and did not change BP variability .
Due to the larger sample size from the two unpublished studies , carvedilol provided a better estimate of BP lowering effect than labetalol .
Doses higher than the recommended starting dose did not provide additional BP reduction .
Higher doses of dual receptor blockers caused more bradycardia than lower doses .
Based on indirect comparison with other classes of drugs , the blood pressure lowering effect of dual alpha- and beta-receptor blockers is less than non-selective , beta1 selective and partial agonist beta blockers , as well as thiazides and drugs inhibiting the renin angiotensin system .
Dual blockers also had little or no effect on reducing pulse pressure , which is similar to the other beta-blocker classes , but less than the average reduction of pulse pressure seen with thiazides and drugs inhibiting the renin angiotensin system .
Patients taking dual receptor blockers  were not more likely to withdraw from the study compared to patients taking placebo
BACKGROUND Drugs with combined alpha and beta blocking activity are commonly prescribed to treat hypertension .
However , the blood pressure ( BP ) lowering efficacy of this class of beta blockers has not been systematic ally review ed and quantified .
OBJECTIVES To quantify the dose-related effects of various types of dual alpha and beta adrenergic receptor blockers ( dual receptor blockers ) on systolic and diastolic blood pressure versus placebo in patients with primary hypertension .