Evaluation of the efficacy and tolerability of the combination delapril plus indapamide in the treatment of mild to moderate essential hypertension: a randomised, multicentre, controlled study

Which thiazide to choose as add-on therapy for hypertension?

Combined therapy is required in the majority of patients with hypertension to achieve blood pressure (BP) targets. Although different antihypertensive drugs can be combined, not all combinations are equally effective and safe. In this context, the combination of a renin angiotensin system inhibitor with a diuretic, usually a thiazide, particularly hydrochlorothiazide (HCTZ) or thiazide-like diuretics, such as chlorthalidone or indapamide, is recommended. However, not all diuretics are equal. Although HCTZ, chlorthalidone, and indapamide as add-on therapy effectively reduce BP levels, the majority of studies have obtained greater BP reductions with chlorthalidone or indapamide than with HCTZ. Moreover, there are data showing benefits with chlorthalidone or indapamide beyond BP. Thus, chlorthalidone seems to have pleiotropic effects beyond BP reduction. Moreover, compared with placebo, chlorthalidone has small effects on fasting glucose and total cholesterol, and compared with HCTZ, chlorthalidone achieves significantly lower total cholesterol and low-density lipoprotein cholesterol levels. Similarly, indapamide has demonstrated no negative impact on glucose or lipid metabolism. More importantly, although head-to-head clinical trials comparing the effects of indapamide or chlorthalidone with HCTZ are not available, indirect comparisons and post hoc analyses suggest that the use of chlorthalidone or indapamide is associated with a reduction in cardiovascular events. Despite this, the most frequent diuretic used in clinical practice as add-on therapy for hypertension is HCTZ. The purpose of this review is to update the published data on the efficacy and safety of HCTZ, chlorthalidone, and indapamide as add-on therapy in patients with hypertension.

Efficacy and tolerability of delapril plus indapamide versus lisinopril plus hydrochlorothiazide combination treatments in mild to moderate hypertension: a multicenter, randomized clinical study

BACKGROUND

Several studies have shown that antihypertensive monotherapy is commonly insufficient to control blood pressure (BP) in hypertensive patients and that concomitant use of ≥2 drugs is necessary in ∼50% of these patients. The combination of an angiotensin-converting enzyme (ACE) inhibitor and a diuretic, delapril plus indapamide (D + I), has been shown to be effective and tolerable, with no interaction between the 2 components. Another widely used combination of ACE inhibitor and diuretic is lisinopril plus hydrochlorothiazide (L + H).

OBJECTIVES

The aims of this study were to confirm the antihypertensive efficacy and tolerability of the fixed combination of D + I in mild to moderate hypertension, and to compare its therapeutic efficacy and tolerability with that of L + H.

METHODS

The antihypertensive efficacy and tolerability of a fixed combination of D + I (30-mg + 2.5-mg tablets once daily) or L + H (20-mg + 12.5-mg tablets once daily) in patients with mild to moderate hypertension were compared in a multinational, multicenter, randomized, 2-armed, parallel-group study. Eligible patients were aged 18 to 75 years and had a diastolic blood pressure (DBP) 95 to 115 mm Hg and a systolic blood pressure (SBP) ≤180 mm Hg, both measured in the sitting position. After a single-blind, placebo run-in period of 2 weeks, patients were randomized to receive 1 of the 2 treatments for a 12-week period. The primary efficacy end point was the BP normalization rate (ie, the percentage of patients with a sitting DBP ≤90 mm Hg) after 12 weeks of treatment. Secondary end points were as follows: (1) the responder rate (ie, the percentage of patients whose sitting DBP was reduced by ≥10 mm Hg from baseline or had a DBP ≤90 mm Hg after 12 weeks of treatment), (2) the percentage of patients with a DBP ≤85 mm Hg, and (3) changes in sitting SBP and DBP after 4, 8, and 12 weeks of treatment.

RESULTS

A total of 159 hypertensive patients (88 women, 71 men) were randomized to receive D + I (44 women, 36 men; mean [SD] age, 53 [(11)] years) or L + H (44 women, 35 men; mean [SD] age, 55 [(10)] years). No significant between-group differences were found in any of the primary or secondary end points of the study. Both combinations induced a significant reduction in sitting DBP and SBP from baseline (P<0.001 for both groups at week 12), without significant differences between the groups. Five mild to moderate adverse drug reactions (ADRs) occurred in each treatment group. No patient dropped out of the study because of an ADR.

CONCLUSION

This study showed no difference between D + I and L + H interms of antihypertensive efficacy or tolerability in patients with mild to moderate hypertension.

Efficacy and safety of delapril/indapamide compared to different ACE-inhibitor/hydrochlorothiazide combinations: a meta-analysis

The main objective of this meta-analysis was to compare the efficacy of the combination of delapril and indapamide (D+I) to different angiotensin-converting enzyme inhibitor (ACEi) plus hydrochlorothiazide (HCTZ) combinations for the treatment of mild-to-moderate hypertension. A secondary objective was to examine the safety of these two combinations. Studies comparing the efficacy of D+I to ACEi+HCTZ combinations in hypertensive patients and published on computerized databases (1974–2010) were considered. Endpoints included percentage of normalized patients, of responders, change in diastolic and systolic blood pressure (DBP/SBP) at different time-points, percentage of adverse events (AEs), and percentage of withdrawal. Four head-to-head randomized controlled trials (D+I-treated, n = 643; ACEi+HCTZ-treated, n = 629) were included. Meta-analysis indicated that D+I-treated patients had a higher proportion with normalized blood pressure (P = 0.024) or responders (P = 0.002) compared to ACEi+HCTZ-treated patients. No difference was observed between treatments on absolute values of DBP and SBP at different time-points. Although the rate of patients reporting at least one AE was similar in both groups (10.4% versus 9.9%), events leading to study withdrawal were lower in the D+I group versus the ACEi+HCTZ group (2.3% versus 4.8%, respectively; P = 0.018). This meta-analysis suggests that treatment with D+I could provide a higher proportion of normalized or responder patients with good tolerability compared to ACEi+HCTZ combinations.

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.

Delapril plus indapamide: a review of the combination in the treatment of hypertension

Although many data indicate that the management of hypertension has improved over the last two decades, there is still a large proportion of hypertensive individuals who do not receive adequate management of their blood pressure (BP). Combination therapy with two or more antihypertensive agents from different drug classes is increasingly being recognised as the most effective means of achieving target BP values by pharmacological means, particularly in the large number of patients in whom monotherapy proves to be ineffective. Use of an angiotensin-converting enzyme (ACE) inhibitor combined with a diuretic is a well established antihypertensive combination that is very effective because of the different, yet synergistic, mechanisms of actions of agents from these two drug classes. Delapril is a potent antihypertensive ACE inhibitor, and indapamide is a thiazide-like diuretic with additional antihypertensive properties. The combination of delapril and indapamide provides renoprotective effects, and indapamide is also cardioprotective. Use of these two drugs together is therefore a rational selection for combination therapy, and one that has consistently demonstrated lowering of BP to target values with a level of efficacy that is at least as good as other combinations of ACE inhibitors and diuretics. This combination has also been found to provide favourable effects on haemodynamic parameters, including left ventricular mass index and ejection fraction. Furthermore, combining an ACE inhibitor and a thiazide-type diuretic has been associated with a decreased risk of stroke and is recommended for patients with cerebrovascular disease, a setting in which the combination of delapril and indapamide has therapeutic potential. Because of the additive mechanisms of delapril and indapamide, the dose required for an effective antihypertensive effect is relatively low, and the combination is well tolerated at such doses. In particular, metabolic effects normally associated with diuretics are rare at the therapeutic dose of indapamide used in combination with delapril, making the combination suitable for patients with metabolic disorders in whom diuretic therapy would otherwise not be recommended. Delapril 30 mg and indapamide 2.5mg have been combined in a fixed combination, offering the convenience of a one-tablet-per-day antihypertensive drug regimen for most patients, which, along with good tolerability, helps to address the issue of noncompliance.

Fixed-Drug Combinations as First-Line Treatment for Hypertension

As combinations of drugs from different classes that have synergistic or additive effect and properties to cancel out each others' untoward hemodynamic and metabolic effects become more and more widely used, their use as first-line therapy for the treatment of newly diagnosed hypertensive patients is growing in popularity as well. The possibility to begin therapy with a fixed 2-drug combination may be preferable to starting with monotherapy followed by upward titration and addition of other agents. More and more combinations are coming out on the market and proving their effectiveness in randomized controlled trials and in large multicenter studies. One suggestion is the "polypill," a fixed combination of multiple agents that address various components of the metabolic syndrome and coexisting common risk factors in both high-risk patients with conditions requiring polypharmacy, and in healthy asymptomatic individuals.

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.