Nitrendipine and enalapril combination therapy in mild to moderate hypertension: assessment of dose-response relationship by a clinical trial of factorial design

Combination therapy in hypertension

Hypertension is recognized as a major risk factor for cardiovascular and renal diseases and represents the leading cause of mortality worldwide. In spite of proven benefits of hypertension treatment, blood pressure control rates are poor, even in high-income countries with virtually full-access to therapies. Nearly 75% of hypertensive patients do not achieve adequate control with monotherapy, thus needing combination treatment. Strategies to improve blood pressure control include the prompt shift from monotherapy to combination therapy, the initial treatment with a two-drug combination, and the use of fixed-dose combinations in a single pill. Currently, preferred combinations include a renin-angiotensin blocker, either an angiotensin-converting enzyme inhibitor or an angiotensin-receptor blocker plus a calcium channel blocker or a diuretic. Some patients will also require a triple combination to achieve blood pressure control.

Combinations of inhibitors of the renin-angiotensin system with calcium channel blockers for the treatment of hypertension: focus on perindopril/amlodipine

BACKGROUND

Combination antihypertensive therapy with an inhibitor of the renin-angiotensin system (RAS) and a calcium channel blocker (CCB) is a rational approach to achieve blood pressure (BP) goals in patients with hypertension, and may provide additional cardiovascular protection compared to other strategies in special populations. This article reviews the rationale for, and evidence supporting, the use of newer fixed-dose combinations of RAS inhibitors and CCBs, with particular emphasis on perindopril/amlodipine.

METHODS

A literature search was performed in Medline and EMBASE databases to identify articles published up to May 2010 describing the impact of combination treatment with angiotensin receptor blocker (ARB)/CCB or angiotensin-converting enzyme (ACE) inhibitor/CCB based antihypertensive strategies on BP or clinical outcomes.

FINDINGS

A substantial body of evidence supports the BP-lowering efficacy of RAS inhibitor/CCB combination therapy in patients with hypertension. RAS inhibitors and CCBs represent two different and complementary mechanisms of actions; their use in combination is associated with effective BP lowering with favourable tolerability and fewer adverse metabolic effects than some other combination therapies. Currently, intervention studies demonstrating the impact of ARB/CCB combinations on cardiovascular mortality and morbidity are lacking. However, evidence from large outcome trials supports the use of ACE inhibitor/CCB combinations for reducing the risk of cardiovascular and renal events, particularly in high-risk patients. There is also evidence that the benefits of ACE inhibitor/CCB combinations may extend beyond those solely associated with brachial BP lowering, by an additional impact on central BP haemodynamics.

CONCLUSIONS

RAS inhibitor/CCB combination therapy is an effective antihypertensive therapy. Strong evidence supports the antihypertensive efficacy of ACE inhibitor/CCB combinations with cardioprotective and renoprotective properties. In particular, evidence suggests that fixed-dose perindopril/amlodipine effectively decreases BP and currently is the only RAS inhibitor/CCB combination proven to decrease all-cause and cardiovascular mortality as well as major cardiovascular events, and thus is a valuable option for the management of hypertension, especially in high-risk patients.

Effectiveness and tolerability of fixed-dose combination enalapril plus nitrendipine in hypertensive patients: results of the 3-month observational, post-marketing, multicentre, prospective CENIT study

BACKGROUND AND OBJECTIVE

Monotherapy with any class of antihypertensive drug effectively controls blood pressure (BP) in only about 50% of patients. Consequently, the majority of patients with hypertension require combined therapy with two or more medications. This study aimed to evaluate the effectiveness (systolic BP [SBP]/diastolic BP [DBP] control) and tolerability of the fixed-dose combination enalapril/nitrendipine 10 mg/20 mg administered as a single daily dose in hypertensive patients.

METHODS

This was a post-authorization, multicentre, prospective, observational study conducted in primary care with a 3-month follow-up. Patients throughout Spain with uncontrolled hypertension (> or =140/90 mmHg for patients without diabetes mellitus, or > or =130/85 mmHg for patients with diabetes) on monotherapy or with any combination other than enalapril + nitrendipine, or who were unable to tolerate their previous antihypertensive therapy, were recruited. Change from previous to study treatment was according to usual clinical practice. BP was measured once after 5 minutes of rest in the sitting position. Therapeutic response was defined as follows: 'controlled' meant controlled BP (<140/90 mmHg for nondiabetic patients, or <130/85 mmHg for diabetic patients); 'response' meant controlled BP, or a decrease in SBP of > or =20 mmHg and in DBP of > or =10 mmHg. The main laboratory test parameters were documented at baseline and after 3 months. Patients aged >65 years, with diabetes, with isolated systolic hypertension (ISH; SBP > or =140 mmHg for patients without diabetes, SBP > or =130 mmHg for patients with diabetes) and who were obese (body mass index [BMI] > or =30 kg/m2) were analysed separately.

RESULTS

Of 6537 patients included, 5010 and 6354 patients were assessed in effectiveness and tolerability analyses, respectively. In the tolerability analysis population, there were 3023 men (47.6%) and 3321 women (52.4%). The mean (+/- SD) age of the tolerability analysis group was 62.8 (+/- 10.7) years. A total of 71.1% of the patients presented at least one clinical cardiovascular risk factor other than hypertension, with the most frequent being dyslipidaemia (42.3%), obesity (29.2%) and diabetes (23.9%). After 3 months of treatment, SBP and DBP showed mean (+/- SD) decreases of 26.5 (+/- 14.4) mmHg and 14.9 (+/- 9.0) mmHg, respectively, and 73.0% of patients responded to treatment while 40.9% achieved BP control (70.8%/36.1% in 2658 patients aged >65 years; 61.7%/46.8% in 1521 patients with diabetes; 55.3%/44.2% in 731 patients with ISH; 72.0%/36.4% in 1762 obese patients). Adverse events were reported in 10.8% of patients (n = 689). During the follow-up period, ten patients died and seven patients had serious adverse events; in no case was a causal relationship attributed to the study product.

CONCLUSIONS

The rate of SBP/DBP control achieved demonstrates the effectiveness of the fixed-dose enalapril/nitrendipine 10 mg/20 mg combination administered as a single daily dose in patients with essential hypertension not adequately controlled with monotherapy or with any combination other than enalapril + nitrendipine. The proportion and type of adverse events reported were as expected and have already been described for both components of the enalapril/nitrendipine 10 mg/20 mg combination. These results confirm the effectiveness of a strategy based on a fixed-dose enalapril/nitrendipine 10 mg/20 mg combination in reducing BP and achieving BP control goals.

Blood pressure responder rates versus goal rates: which metric matters?

Reducing blood pressure (BP) to guideline-recommended goals associated with reductions in cardiovascular risk is central to effective hypertension management. In addition to measuring BP reduction, clinical trials of antihypertensive agents should assess the percentage of patients responding to treatment. The Food and Drug Administration's defined rate of response required for drug approval is a reduction in diastolic BP (DBP) to <90 mmHg and/or a DBP reduction of > or = 10 mmHg. Consequently, some patients may be counted as responders even if they have not reached DBP <90 mmHg. An antihypertensive agent's effectiveness may be better assessed by the proportion of patients who achieve recommended BP goals. This article analyzes the frequency of response rates versus goal rates as endpoints in randomized trials since January 2001. Data showed that goal rates, especially combined systolic BP (SBP)/DBP goal rates, are consistently lower than response rates in studies evaluating both endpoints. Goal rates incorporating both SBP and DBP, or having a focus on SBP for individuals >50 years of age, provide the most clinically relevant information and are a more clinically relevant metric of an agent's ability to reduce BP than DBP alone.

Blood pressure lowering efficacy of angiotensin converting enzyme (ACE) inhibitors for primary hypertension

BACKGROUND

ACE inhibitors are widely prescribed for hypertension so it is essential to determine and compare their effects on blood pressure (BP), heart rate and withdrawals due to adverse effects (WDAE).

OBJECTIVES

To quantify the dose-related systolic and/or diastolic BP lowering efficacy of ACE inhibitors versus placebo in the treatment of primary hypertension.

SEARCH STRATEGY

We searched CENTRAL (The Cochrane Library 2007, Issue 1), MEDLINE (1966 to February 2007), EMBASE (1988 to February 2007) and reference lists of articles.

SELECTION CRITERIA

Double-blind, randomized, controlled trials evaluating the BP lowering efficacy of fixed-dose monotherapy with an ACE inhibitor compared with placebo for a duration of 3 to 12 weeks in patients with primary hypertension.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias and extracted data. Study authors were contacted for additional information. WDAE information was collected from the trials.

MAIN RESULTS

Ninety two trials evaluated the dose-related trough BP lowering efficacy of 14 different ACE inhibitors in 12 954 participants with a baseline BP of 157/101 mm Hg. The data do not suggest that any one ACE inhibitor is better or worse at lowering BP. A dose of 1/8 or 1/4 of the manufacturer's maximum recommended daily dose (Max) achieved a BP lowering effect that was 60 to 70% of the BP lowering effect of Max. A dose of 1/2 Max achieved a BP lowering effect that was 90% of Max. ACE inhibitor doses above Max did not significantly lower BP more than Max. Combining the effects of 1/2 Max and higher doses gives an estimate of the average trough BP lowering efficacy for ACE inhibitors as a class of drugs of -8 mm Hg for SBP and -5 mm Hg for DBP. ACE inhibitors reduced BP measured 1 to 12 hours after the dose by about 11/6 mm Hg.

AUTHORS' CONCLUSIONS

There are no clinically meaningful BP lowering differences between different ACE inhibitors. The BP lowering effect of ACE inhibitors is modest; the magnitude of trough BP lowering at one-half the manufacturers' maximum recommended dose and above is -8/-5 mm Hg. Furthermore, 60 to 70% of this trough BP lowering effect occurs with recommended starting doses. The review did not provide a good estimate of the incidence of harms associated with ACE inhibitors because of the short duration of the trials and the lack of reporting of adverse effects in many of the trials.

Hypertension‐Related Morbidity and Mortality in African Americans—Why We Need to Do Better

Almost one third of adults in the United States have hypertension. Prevalence data among different racial or ethnic groups indicate that a disproportionate number of African Americans have hypertension compared with non-Hispanic whites and Mexican Americans. Earlier onset of high blood pressure and greater severity of hypertension contribute to a greater burden of hypertensive target organ damage in African Americans and may be a factor in the shorter life expectancy of this population compared with white Americans. There is a clear need for improved management of hypertension in African Americans via therapeutic lifestyle interventions and pharmacotherapy. While there is some evidence that particular antihypertensive agent classes provide blood pressure-lowering advantages over others, there is no support for withholding agents of any one class. When given as monotherapy, diuretics and calcium channel blockers may be relatively more effective in lowering blood pressure in African Americans than beta blockers, angiotensin-converting enzyme inhibitors, and angiotensin II receptor blockers. However, when combined with a diuretic, African Americans respond as well to these agents as other racial groups. Combination therapy using antihypertensive agents with differing modes of action provides additive antihypertensive efficacy and is well tolerated. Recent guidelines recommend combination therapy as the standard of care for patients with significant blood pressure elevation, especially those with diabetes mellitus and renal disease. These comorbidities are more common in African Americans and indicate the potential need for initial therapy with more than one agent or a combination of agents in one pill.

Estudio doble ciego de la eficacia y la seguridad de la combinación a dosis fija de 10mg de enalapril/20mg de nitrendipino en comparación con el incremento de dosis de amlodipino en pacientes con hipertensión esencial no controlada con 5mg de amlodipino

INTRODUCTION

Combined therapy or dose-tiration are acceptable second-line therapeutic options after a first treatment failure.

MATERIAL AND METHODS

This double blind clinical trial compared the fixed dose combination of enalapril 10 mg/nitrendipine 20 mg (E/N) with amlopidine 10 mg (A) in 323 hypertensive patients not previously controlled with amlodipine 5 mg.

RESULTS

After 6 weeks of treatment, the E/N and A groups had similar percentages of blood pressure normalization (55% versus 60.2%; p = 0.4588). The adverse events related with the treatment were significantly less frequent with E/N than with a (19.8% versus 37%; p = 0.0029), especially due to a lower incidence of malleolar edema in E/N (11.1% versus 33.6%; p < 0.0001).

CONCLUSION

Combining the efficacy and tolerability data, treatment with E/N permitted control of blood pressure of 2.8 patients per every patient with adverse events, while this rate for A was 1.6 to 1.

Combination therapy as first-line treatment for hypertension

With the cut-off point between "normal" and "high" blood pressure (BP) being pushed increasingly downward, especially for patients with multiple cardiovascular risk factors, most hypertensives need more than one antihypertensive agent to reach their target BP. In this article, we examine the rationale for combining drugs from different classes that have synergistic or additive effects and properties that might offset one another's adverse hemodynamic and/or metabolic reactions. We suggest circumstances in which the initiation of therapy with a fixed two-drug combination might be preferable to the usual practice of starting with monotherapy followed by upward titration and addition of other agents, and we briefly review the existing fixed drug combinations. We end with the intriguing and provocative notion of the future "polypill," a fixed combination of agents addressing various components of the metabolic syndrome as well as other coexisting common risk factors in both high-risk patients with conditions requiring polypharmacy and in healthy, asymptomatic individuals.

Comparison of the antihypertensive effects of the fixed dose combination enalapril 10 mg/nitrendipine 20 mg vs losartan 50 mg/hydrochlorothiazide 12.5 mg, assessed by 24-h ambulatory blood pressure monitoring, in essential hypertensive patients

Fixed combinations of calcium channel blockers and angiotensin converting enzyme inhibitors represent an alternative to diuretic-based combination therapy. The aim of the present study was to compare the antihypertensive efficacy of the combination enalapril 10 mg/nitrendipine 20 mg (E/N) vs losartan 50 mg/hydrochlorothiazide 12.5 mg (L/H), assessed by 24-h ambulatory blood pressure monitoring. This multicentre, double-blind, parallel study included 97 hypertensive patients (office diastolic blood pressure (DBP) 90-109 mmHg and daytime DBP > 85 mmHg). After a 2- to 3-week period of single-blind placebo, they were randomized to receive double-blind treatment with E/N (n = 48) or L/H (n = 49) for a 4-week period. The primary outcome measure was the difference in 24-h DBP reduction between treatments from randomization to the end of the double-blind period. Secondary efficacy variables included differences in 24-h systolic (S) BP reduction, daytime, night-time and office SBP and DBP reduction, proportion of responders and controlled patients, trough-to-peak ratio and smoothness indexes. Safety was assessed by the proportion of patients with adverse events and the detection of laboratory abnormalities. No significant differences were observed in the primary outcome measure. The group receiving E/N tended to show greater reductions in most measures (24 h, daytime and office SBP and DBP) and higher BP control rates, but only the difference in the rate of office SBP control (< 140 mmHg) reached statistical significance (42.2 vs 22.4%; P = 0.048). The trough-to-peak ratios and smoothness indexes were similar in both groups. The incidence of adverse events related to the treatment was 27.1% (95% CI 14.5-39.6%) in E/N-treated patients and 14.3% (95% CI 4.5-45.8%) in the L/H group, but differences were not significant. The kind of event more frequently observed were flushing and headache in E/N, and dizziness and asthenia in L/H; all observed adverse events were mild. We conclude that E/N and L/H have a similar antihypertensive efficacy, assessed by office or ambulatory blood pressure monitoring. E/N achieved a significantly higher office SBP control rate, but this was accompanied by an apparently higher proportion of mild adverse events.

The role of calcium antagonists in chronic kidney disease

PURPOSE OF REVIEW

To review goals of antihypertensive treatment in chronic kidney disease in the context of what role calcium antagonists play toward reducing progression of kidney disease.

RECENT FINDINGS

All recently published guidelines recommend a blood pressure goal of less than 130/80 mmHg in patients with chronic kidney disease. Use of calcium antagonists is not recommended as part of the initial armamentarium. Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers, when used in concert with diuretics reduce blood pressure as well as both proteinuria and the rate of decline in the glomerular filtration rate. The evidence for calcium antagonists in this regard is more divergent. Dihydropyridine calcium antagonists, e.g. amlodipine, felodipine, help achieve blood pressure goals and reduce stroke risk. When used with a renin-angiotensin system blocker they do not detract from the benefits of this blockade on slowing progression of kidney disease. Non-dihydropyridine calcium antagonists, e.g. verpamil or diltiazem, decrease proteinuria and in studies with 5 to 6 years follow-up preserve kidney function similarly to angiotensin-converting enzyme inhibitors. The reason for this outcome difference between calcium antagonists is partial preservation of renal autoregulation compared to its obliteration by the dihydropyridine subclass.

SUMMARY

Use of calcium antagonists is safe and necessary to achieve blood pressure goals in people with chronic kidney disease. While both subclasses are safe and necessary to achieve blood pressure goals, dihydropyridine calcium antagonists fail to significantly slow the progression of kidney disease among patients with established nephropathy and macroalbuminuria when compared to agents that block the renin-angiotensin system.

Fixed-Dose Combination Enalapril/Nitrendipine

The fixed-dose combination of enalapril 10mg with nitrendipine 20mg combines an ACE inhibitor with a calcium channel antagonist (CCA) and is indicated for the treatment of patients with mild-to-moderate hypertension whose blood pressure (BP) is inadequately controlled with enalapril or nitrendipine monotherapy. In randomised, double-blind clinical trials, enalapril/nitrendipine 10/20 mg/day was significantly more effective than its individual components in reducing diastolic BP (DBP) in patients with mild-to-moderate hypertension inadequately controlled with enalapril 10 mg/day or nitrendipine 20 mg/day. The fixed-dose combination was similar in efficacy at reducing DBP to amlodipine 10 mg/day in patients who failed to achieve BP control with amlodipine 5 mg/day, and to losartan/hydrochlorothiazide 50/12.5 mg/day in patients who received the combinations as first-line therapy. Enalapril/nitrendipine 10/20 mg produced a consistent antihypertensive effect that persisted for the entire 24-hour dosage interval as shown by ambulatory BP monitoring. Enalapril/nitrendipine 10/20 mg was well tolerated in clinical trials where it was administered to patients with mild-to-moderate hypertension for up to 12 weeks. The adverse events were those expected of ACE inhibitors and CCAs and included cough, headache and flushing. Evidence from clinical trials, including a pooled analysis, suggests that the incidence of oedema may be significantly lower with the fixed-dose combination than with CCA monotherapy. In conclusion, enalapril/nitrendipine 10/20 mg is a well tolerated fixed-dose combination of two established antihypertensive agents administered once daily that effectively lowers BP throughout the 24-hour dosage interval. Importantly, the fixed-dose combination may have a lower incidence of oedema than CCA monotherapy. Enalapril/nitrendipine 10/20 mg provides an additional treatment option for patients with mild-to-moderate hypertension for whom combination therapy is appropriate.

[Theoretical model of a cost-effectiveness analysis of combined enalapril-nitrendipine therapy for treating hypertension]

OBJECTIVE

Cost-effectiveness analysis of combined enalapril-nitrendipine therapy (E/N), as second-line therapy for light or moderate hypertension.

DESIGN

Theoretical model of cost-effectiveness, based on the norms of hypertension treatment in primary care, the considered view of a panel of experts and the direct costs of health resources and purchase of medication.

SETTING

Spanish National Health system.

PARTICIPANTS

Simulation of 1000 patients with hypertension, with a time horizon of one year.

INTERVENTIONS

After a prior failure of the first-line treatment with either enalapril or nitrendipine, an evaluation was made of the possibilities of increasing dosage of the first-line treatment, changing the drug or administering the E/N combination.

MAIN MEASUREMENT

The likelihoods, in the primary care context, of controlling diastolic pressure, of abandonment and of using the two strategies or not were measured, as were the use of health resources in each situation, and costs of resource use and of medication.

RESULTS

The cost-effectiveness quotient of the combined E/N treatment was consistently more efficient than the increase in dose or change to another drug. This was so, whether the treatment was started with enalapril (301.06 euros vs 337.97 euros and 588.42 euros) or with nitrendipine (331.5 euros vs 469.88 euros and 579.76 euros).

CONCLUSIONS

Combined therapy (E/N) is, on the basis of the assumptions made in the model, an efficient therapy option. Therefore, it can be recommended for prescription.