Felodipine, metoprolol and their combination compared with placebo in isolated systolic hypertension in the elderly

Blood pressure lowering efficacy of beta-blockers as second-line therapy for primary hypertension

BACKGROUND

Beta-blockers are one of the more commonly prescribed classes of anti-hypertensive drugs, both as first-line and second-line.

OBJECTIVES

To quantify the effect on systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate and withdrawals due to adverse effects of beta-blocker therapy when given as a second-line drug in adult patients with primary hypertension.

SEARCH STRATEGY

CENTRAL (The Cochrane Library 2009, Issue 2), MEDLINE (1966-Aug 2009), EMBASE (1988-Aug 2009) and bibliographic citations of articles and reviews were searched.

SELECTION CRITERIA

Double-blind, randomized controlled trials comparing a beta-blocker in combination with a drug from another class of anti-hypertensive drugs compared with that drug alone for a duration of 3 to 12 weeks in patients with primary hypertension were included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted the data and assessed trial quality of each included study.

MAIN RESULTS

20 double-blind RCTs evaluated the BP lowering efficacy of beta-blockers as second-line drug in 3744 hypertensive patients (baseline BP of 158/102 mmHg; mean duration of 7 weeks). The BP reduction from adding a beta-blocker as the second drug was estimated by comparing the difference in BP reduction between the combination and monotherapy groups. A reduction in BP was seen with adding a beta-blocker to thiazide diuretics or calcium channel blockers at doses as low as 0.25 times the manufacturer's recommended starting dose. The BP lowering efficacy of beta-blockers as a second drug was 6/4 mmHg at 1 times the starting dose and 8/6 mmHg at 2 times the starting dose. Beta-blockers reduced heart rate by 10 beats/min at 1 to 2 times the starting dose. Beta-blockers did not statistically significantly increase withdrawals due to adverse effects but this was likely due to the lack of reporting of this outcome in 35% of the included RCTs.

AUTHORS' CONCLUSIONS

Addition of a beta-blocker to diuretics or calcium-channel blockers reduces BP by 6/4mmHg at 1 times the starting dose and by 8/6 mmHg at 2 times the starting dose. When the blood pressure lowering effect of beta-blockers from this review was compared to that of thiazide diuretics from our previous review (Chen 2009), second-line beta-blockers reduce systolic BP to the same extent as second-line thiazide diuretics, but reduce diastolic BP to a greater degree. The different effect on diastolic BP means that beta-blockers have little or no effect on pulse pressure whereas thiazides cause a significant dose-related decrease in pulse pressure. This difference in the pattern of BP lowering with beta-blockers as compared to thiazides might be the explanation for the fact that beta-blockers appear to be less effective at reducing adverse cardiovascular outcomes than thiazide diuretics, particularly in older individuals.

Blood pressure lowering efficacy of diuretics as second-line therapy for primary hypertension

BACKGROUND

Diuretics are widely prescribed for hypertension not only as a first-line drug but also as a second-line drug. Therefore, it is essential to determine the effects of diuretics on blood pressure (BP), heart rate and withdrawals due to adverse effects (WDAEs) when given as a second-line drug.

OBJECTIVES

To quantify the additional reduction in systolic blood pressure (SBP) and diastolic blood pressure (DBP) of diuretic therapy as a second-line drug in patients with primary hypertension

SEARCH STRATEGY

CENTRAL (The Cochrane Library 2008, Issue 2), MEDLINE (1966-July 2008), EMBASE (1988-July 2008) and bibliographic citations of articles and reviews were searched.

SELECTION CRITERIA

Double-blind, randomized, controlled trials evaluating the BP lowering efficacy of a diuretic in combination therapy with another class of anti-hypertensive drugs compared with the respective monotherapy (without a diuretic) for a duration of 3 to 12 weeks in patients with primary hypertension.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted the data and assessed trial quality.

MAIN RESULTS

Fifty-three double-blind RCTs evaluating a thiazide in 15129 hypertensive patients (baseline BP of 156/101 mmHg) were included. Hydrochlorothiazide was the thiazide used in 49/53 (92%) of the included studies. The additional BP reduction caused by the thiazide as a second drug was estimated by comparing the difference in BP reduction between the combination and monotherapy groups. Thiazides as a second-line drug reduced BP by 6/3 and 8/4 mmHg at doses of 1 and 2 times the manufacturer's recommended starting dose respectively. The BP lowering effect was dose related. The effect was similar to that obtained when thiazides are used as a single agent. Only 3 double-blind RCTs evaluating loop diuretics were identified. These RCTs showed a BP lowering effect of a starting dose of about 6/3 mmHg.

AUTHORS' CONCLUSIONS

Thiazides when given as a second-line drug have a dose related effect to lower blood pressure that is similar to when they are added as a first-line drug. This means that the BP lowering effect of thiazides is additive. Loop diuretics appear to have a similar blood pressure lowering effect as thiazides at 1 times the recommended starting dose. Because of the short duration of the trials and lack of reporting of adverse events, this review does not provide a good estimate of the incidence of adverse effects of diuretics given as a second-line drug.

Candesartan and hydrochlorothiazide in isolated systolic hypertension

AIM

We investigated the efficacy and safety of daily candesartan 8/16mg and hydrochlorothiazide 12.5 mg as monotherapy and in combination in older patients with systolic hypertension.

METHODS

The study used a double-blind randomized placebo-controlled crossover design. Treatment phases were of 6 weeks duration. For inclusion, patients were aged 55-84 years with sitting systolic blood pressure (SBP) 160-210 mmHg and diastolic blood pressure (DBP) < 95 mmHg. Nineteen patients (11 male, eight female, median age 68 years) completed the study.

MAJOR FINDINGS

Compared with the placebo phase, clinic and ambulatory SBP was significantly reduced with both dose-adjusted candesartan and fixed-dose hydrochlorothiazide as monotherapy, the effect of candesartan being greater than that of hydrochlorothiazide. In combination, the effects of the two drugs were additive. Both drugs were well tolerated either as monotherapy or in combination.

CONCLUSION

Both candesartan and a low dose of hydrochlorothiazide are effective and well-tolerated antihypertensive agents in isolated systolic hypertension with additive effects in combination. Candesartan was more effective than hydrochlorothiazide, although it is possible that dose adjustment only of candesartan could have enhanced its relative effectiveness.

Should beta blockers be used in the treatment of hypertension in the elderly?

The lack of benefit and the potential negative side effects of beta blockers are overstated, especially in the elderly. This emphasis has led to recommendations by some investigators that these agents not be used in the management of hypertension in this age group. There are numerous reasons why these recommendations should not be followed. The use of beta blockers in the elderly hypertensive has resulted in a reduction in strokes and congestive heart failure. In addition, it should be emphasized that elderly patients are more likely to have silent coronary artery disease or sustain myocardial infarctions. There is abundant evidence that beta blockers are effective therapy in reducing mortality once a myocardial infarction has occurred. In fact, there is a clear reduction in sudden cardiac death. Furthermore, national statistics document that elderly patients have a prevalence of congestive heart failure that varies from 6%-10%. Multiple studies have now documented that beta blockers are additive to angiotensin-converting enzyme inhibitors in reducing mortality for congestive heart failure. Thus, elderly hypertensive patients may benefit from the use of beta blockers, especially if there is evidence of ischemic heart disease, cardiac arrhythmias, or congestive heart failure.

Low-dose diuretic and/or dietary sodium restriction when blood pressure is resistant to ACE inhibitor

AIM

To compare the efficacy of indapamide (1.25 mg daily) and low-salt diet (<100 mmol/day) separately and in combination in essential hypertensive patients with inadequate BP response to perindopril.

DESIGN AND METHODS

Randomized double-blind, double-dummy, crossover design. The randomized treatments were indapamide 1.25 mg daily, sodium chloride 80 mmol daily, the combination of indapamide and sodium chloride and placebo. All patients received perindopril 4 mg daily and maintained a low-sodium diet.

RESULTS

19 patients entered and 17 completed the study. Prior to randomization, average clinic sitting blood pressure was 162/101 mm Hg and average 24-h urine sodium excretion was 157 mmol/day. Compared to the phase in which patients received perindopril with sodium repletion, clinic and ambulatory BPs were significantly reduced (p<0.01) in all the other phases. Indapamide had a greater effect on BP than dietary sodium restriction, and in combination their effects were additive. The effect of indapamide on ambulatory BP persisted throughout 24 h, but the effect of the low-salt diet was predominantly observed during waking hours.

CONCLUSIONS

In hypertensives with BP resistant to the angiotensin converting enzyme (ACE) inhibitor perindopril, the diuretic indapamide had greater additional efficacy and longer duration of action than dietary sodium restriction. In combination they had additive effects on BP.

Lacidipine, hydrochlorothiazide and their combination in systolic hypertension in the elderly

OBJECTIVE

To compare with placebo the efficacies of once-daily administrations of lacidipine and hydrochlorothiazide separately and in combination to elderly patients with systolic hypertension.

DESIGN AND METHODS

Nineteen elderly subjects (five men and 14 women, median age 71 years, range 62-79 years) participated in the study, which had a randomized double-blind crossover design. For each subject there were four treatment phases, each of duration 4 weeks. The initial treatments in each phase were 2 mg lacidipine once a day and 25 mg hydrochlorothiazide once a day, separately and in combination, and placebo. Doses of each agent could be doubled after 2 weeks in each phase if the patient's goal systolic blood pressure had not been achieved. The numbers of subjects administered the higher dose of each treatment were 13 for placebo, 14 for lacidipine, 11 for hydrochlorothiazide and eight for lacidipine plus hydrochlorothiazide.

RESULTS

End-of-phase mean clinic blood pressures were 164/85 mmHg with placebo, 159/82 mmHg with lacidipine, 157/84 mmHg with hydrochlorothiazide and 152/82 mmHg with lacidipine plus hydrochlorothiazide. Systolic blood pressure was significantly reduced during all active treatment phases compared with placebo and that for the lacidipine plus hydrochlorothiazide phase was also significantly less than those for both of the other active treatment phases. There was no difference between sitting and standing blood pressure for any phase. Factorial analysis of the main effects of treatment indicated that the effects of lacidipine and hydrochlorothiazide on clinic blood pressure were additive and also that heart rate was higher when hydrochlorothiazide had been administered. Ambulatory blood pressure monitoring confirmed the pattern of the responses of blood pressure and showed that administration of hydrochlorothiazide had a significantly greater effect on systolic blood pressure and a longer duration of action than did administration of lacidipine. There was no difference in the frequency of adverse effects among any of the phases.

CONCLUSIONS

In treating elderly systolic hypertensives the diuretic hydrochlorothiazide is a more effective antihypertensive agent with a longer duration of action than is the calcium channel antagonist lacidipine. In combination the effects of these two drugs on blood pressure are additive.

Management of isolated systolic hypertension

Isolated systolic hypertension (ISH) [systolic blood pressure (SBP) > or = l60mm Hg with diastolic blood pressure (DBP) <90mm Hg] is the commonest form of hypertension in the elderly, and accounts for about 60% of all hypertensive conditions in the population aged over 65 years. It is associated with a significantly increased risk of cardiovascular and cerebrovascular morbidity and mortality. The landmark Systolic Hypertension in the Elderly Program (SHEP) study, published in 1991, has shown that lowering the SBP in elderly patients with ISH results in a significant reduction in cardiovascular events. These results have had a major impact on clinical practice in hypertension. On theoretical grounds, considering the pathophysiological mechanisms of ISH in the elderly, any drug which lowers total peripheral resistance and/or arterial stiffness should reduce SBP effectively in these patients. This effect has been observed in outcome studies and short term clinical trials using a variety of drugs from the 4 major antihypertensive classes: diuretics, beta(1)-blockers, calcium channel antagonists and ACE inhibitors. Other drugs, including alpha antagonists, may also be effective. In general, there is compelling evidence to support active treatment of any individual with an SBP > or = 160mm Hg. As in essential hypertension, the maximum benefit is gained by aggressive treatment of those individuals at highest risk because of coexisting cardiovascular risk factors. In these people, an SBP of 140 to 159mm Hg should be considered to be an indication for active management. Initial management should be by manipulation of lifestyle factors such as bodyweight, salt and alcohol intake and aerobic exercise. Drug therapy, generally well tolerated in low doses, should be considered if SBP remains > or = 160mm Hg, or > or = 140mm Hg in the presence of multiple risk factors. The choice of initial drug therapy should be influenced by the particular clinical situation. If there are no coexisting contraindications or co-indications for particular drugs, it is reasonable to begin treatment with a low dose of a thiazide-like diuretic, as used in the SHEP study. However, in short term treatment trials calcium channel antagonists and ACE inhibitors have been shown to lower SBP effectively and can be used in the appropriate clinical context. Beta-blockers appear to be less effective as monotherapy in ISH. Combination therapy is frequently required and can be effective and well tolerated if carefully chosen.

Mono- and combination therapy with felodipine or enalapril in elderly patients with systolic hypertension

Using a randomised double-blind crossover design with Latin square allocation of treatments in 20 subjects (7 male, 13 female-ages: 61-87 years) with systolic hypertension, we investigated the efficacy and tolerability of once daily felodipine (extended release) 5-20 mg, enalapril 5-20 mg and their combination compared with placebo in four treatment phases each of 6 weeks duration. During each phase, doses were titrated to achieve a predose clinic supine systolic blood pressure of 140 mmHg or to a predetermined maximum dose. In both the felodipine and combination phases, predose supine and standing systolic and diastolic pressures were significantly reduced compared with the placebo phase (decrease in supine pressure: -13/-5 and -18/-7, respectively). Only predose supine diastolic pressure was significantly reduced (-3 mmHg) compared to placebo in the enalapril phase. In combination the effects of the two drugs on predose blood pressure were additive. There was a 40-60% increase in reported symptoms in the felodipine and combination phases compared with the placebo and enalapril phases. Thus, in elderly subjects with systolic hypertension, felodipine effectively reduces blood pressure throughout the dose interval but with vasodilator adverse effects. In contrast, enalapril is well tolerated but is less effective in reducing blood pressure throughout the whole dose interval.

The place of combination therapy in the treatment of hypertension in 1993

"Step Care" fell into disuse following the advent of the ACE inhibitors and calcium antagonists. This was partly because the potency of these agents encouraged their use in monotherapy, and partly because of dissatisfaction with ritual treatment using multiple drugs. However monotherapy too has its problems, not the least of which is ritual increase in the dose of the first drug prescribed, leading to prolonged treatment with high doses and hence an increase in side effects. It is therefore important to consider changing to an alternative drug rather than automatically increasing the dose, or adding a second drug. Combination therapy still has a major place in the treatment of hypertension. It is necessary in patients with severe hypertension, with clinical manifestations of target organ damage, or with associated conditions that often help the doctor to choose a rational combination. Even in patients with uncomplicated mild hypertension, the achievement of goal blood pressure requires combination therapy in around half the cases. By choosing two drugs from appropriate classes of agent, it is possible to add the primary actions of drugs acting through different mechanisms, while opposing the homeostatic compensations that limit the fall in blood pressure. Effective combinations therefore maximise hypotensive efficacy while minimising side effects. Effective combinations for the treatment of classical and of systolic hypertension, are discussed.