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Due to the larger sample size from the two unpublished studies , carvedilol provided a better estimate of BP lowering effect than labetalol .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 .
[Effect on lipids, lipoproteins and apoproteins of labetalol prescribed in doses of 400 mg/day in hypertensive patients. Double-blind versus placebo study].
The effects of labetalol on plasma lipoprotein metabolism were evaluated in a 3-month double-blind drug versus placebo study conducted on 30 consenting hypertensive patients , 15 of whom had normal plasma lipid levels and 15 , minor type II hyperlipoproteinaemia ; 20 patients received labetalol 400 mg/day and 10 the placebo .  All patients remained in stable nutritional status throughout the study . Full clinical examination and blood sampling were carried out 30 days before , and on days 0 , 30 and 90 of treatment . Whole blood was collected after 12 hours ' fasting and immediately centrifuged prior to determination of plasma lipids ( total cholesterol and triglycerides , by enzymatic assay ) , lipoprotein lipids ( HDL , HDL2 , HDL3 , LDL , VLDL separated by ultracentrifugation in density gradient ) , apoproteins A1 and B ( by laser immunonephelometry ) and post-heparin lipoprotein lipase activity ( PHLA ) . Significant changes in heart rate and systolic and diastolic blood pressures were noted in patients under labetalol but not in patients under placebo .  Lipid and apolipoprotein levels were similar in both groups on day 0 , and no significant variation in lipids , lipoprotein lipids and apolipoproteins were observed after 30 and 90 days of treatment with either labetalol or the placebo . At the end of treatment PHLA was unmodified in the group under placebo and raised in the group under labetalol ( p = 0.05 ) . The absence of changes in blood lipid values was found both in patients with normal lipidemia and in those with hyperlipidaemia . This study confirms that labetalol in doses of 400 mg/day has notable anti-hypertensive activity and , as previously reported and in contrast with other beta-blocking agents , is devoid of any adverse effect on lipid metabolism
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 .