Low-dose antihypertensive therapy with 1.5 mg sustained-release indapamide: results of randomised double-blind controlled studies. European study group

Pharmacokinetics and Drug-Drug Interaction of Allisartan Isoproxil and Indapamide Sustained-Release Formulation

Allisartan isoproxil (AI) is an angiotensin II type 1 receptor blocker and be converted into the active substance EXP3174 in vivo. We evaluated the drug-drug interactions of AI and an indapamide sustained-release (Ind SR) preparation, as well as the pharmacokinetic characteristics and safety of AI and Ind SR in healthy subjects. The trial was set up in 6 sequences and 3 cycles, and each cycle contained a 7-day washout period. Subjects received 3 different trial drugs (A, AI; B, Ind SR; C, AI + Ind SR) during 3 different cycles. Twenty-four subjects were enrolled in the clinical trial. Of these, 22 completed the study, 2 subjects dropped out due to adverse events (AEs). For subjects given AI alone or combined with Ind SR, the pharmacogenetic parameters Cmax and the geometric mean ratio of steady state (combined/single) of EXP3174 was 130%. The geometric mean ratio of area under the concentration-time curve over the dosing interval at steady state (combined/single use) was 144.5%. Therefore, the combination of Ind SR had an impact on the pharmacokinetics of AI. Then, the results indicated that the AI combination had no effect on the pharmacokinetics of Ind SR. Serious AEs did not occur. The AEs in this clinical trial were the same as those for AI and Ind SR. Combined administration resulted in 2 cases (2 subjects) of Grade 3 hypotension and 1 case of Grade 3 hypotension with AI alone. Considering that this trial included healthy volunteers, the risk of hypotension was expected to be manageable.

Incidence of severe hypokalaemia in patients taking indapamide

BACKGROUND

Diuretics are commonly used for the treatment of hypertension. Yet, hypokalaemia is a well-recognised adverse effect. We conducted a retrospective study to evaluate the incidence of severe hypokalaemia, defined as requiring hospitalisation, among patients on indapamide.

METHODS

We searched a territory-wide database, Clinical Data Analysis and Reporting System of the Hong Kong Hospital Authority. We traced all hypertensive patients who had been prescribed indapamide in 2007-2016 and all admissions due to hypokalaemia in 2007-2018. Factors associated with hospitalisation were studied using multivariable logistic regression.

RESULTS

During the period studied, 62,881 patients were started on indapamide and 509 (0.8%) were hospitalised for hypokalaemia. 53% of these hospitalisations occurred within the first year of treatment, and half of those in the first year occurred during the first 16 weeks. Female sex (adjusted OR, 1.75; 95%CI, 1.45-2.12) and immediate-release formulation (adjusted OR, 1.41; 95%CI, 1.14-1.75) were associated with hospitalisation. In the multivariable model, advanced age was not a significant predictor. There were no deaths during hospitalisation and the median length of hospital stay was one day.

CONCLUSIONS

In this large population-based study with 147,319 person-years of follow-up, severe hypokalaemia requiring hospitalisation was uncommon among hypertensive patients on indapamide. The risk is higher in women and in the initial weeks and months after starting therapy. The use of the sustained-release formulation reduces the risk. We conclude that using indapamide to treat hypertension is safe, even in the elderly, especially if the sustained-release formulation is used and electrolytes are monitored periodically.

Diuretic-induced hypokalaemia: an updated review

Diuretic-induced hypokalaemia is a common and potentially life-threatening adverse drug reaction in clinical practice. Previous studies revealed a prevalence of 7%-56% of hypokalaemia in patients taking thiazide diuretics. The clinical manifestations of hypokalaemia due to diuretics are non-specific, varying from asymptomatic to fatal arrhythmia. Diagnosis of hypokalaemia is based on the level of serum potassium. ECG is useful in identifying the more severe consequences. A high dosage of diuretics and concomitant use of other drugs that increase the risk of potassium depletion or cardiac arrhythmias can increase the risk of cardiovascular events and mortality. Thiazide-induced potassium depletion may cause dysglycaemia. The risk of thiazide-induced hypokalaemia is higher in women and in black people. Reducing diuretic dose and potassium supplementation are the most direct and effective therapies for hypokalaemia. Combining with a potassium-sparing diuretic or blocker of the renin-angiotensin system also reduces the risk of hypokalaemia. Lowering salt intake and increasing intake of vegetables and fruits help to reduce blood pressure as well as prevent hypokalaemia.

Severe Electrolyte Disturbances Complicated by Seizures and Acute Kidney Injury Within 10 Days of Starting Indapamide

Indapamide is one of the most effective and well-known anti-hypertensive medications. Electrolyte disturbances have been classically recognized as a typical side effect profile of indapamide. The most common electrolyte imbalance described with indapamide was hypokalemia; however, hyponatremia is being increasingly reported. In this case, we report a unique form of severe electrolytes derangement (hyponatremia, hypokalemia, hypophosphatemia, and hypocalcemia), which was complicated by seizures, rhabdomyolysis, and acute kidney injury that occurred within only 10 days of indapamide initiation. The patient was admitted to the medical intensive care unit for prompt electrolyte replacement and close monitoring. With the discontinuation of indapamide and the prompt replacement of the deficient electrolytes, the patient's condition has improved dramatically, and he was discharged in a good state of health. Electrolyte disturbances are expected to be seen with indapamide usage, and it might be associated with severe consequences like arrhythmias and seizures. This case report would raise awareness and add to the importance of closely following patients after prescribing indapamide.

Redefining diuretics use in hypertension: why select a thiazide-like diuretic?

Diuretics are listed in hypertension guidelines as one of three equally weighted first-line treatment options. In order to differentiate between antihypertensives, a lot of discussion has been directed at side effect profiles and as a result, has created a perhaps disproportionate fear of the metabolic effects that can be associated with diuretics. Data, however, show that the risk of a clinically meaningful change in laboratory parameters is very low, whereas the benefits of volume control and natriuresis are high and the reductions in morbidity and mortality are clinically significant. Moreover, as clinically significant differences in safety and efficacy profiles exist among diuretics, several international guidelines have started making a distinction between thiazides (hydrochlorothiazide) and thiazide-like (chlorthalidone, indapamide) diuretics; and some of them now recommend longer acting thiazide-like diuretics. In time, pending more data, chlorthalidone and indapamide may need to be subdivided further into separate classifications.

[Chronic obstructive pulmonary disease concurrent with hypertension: Evaluation of the therapeutic effect of prolonged-release indapamide]

AIM

To provide a rationale for the clinical efficacy and safety of prolonged-release indapamide used in the combination therapy of patients with chronic obstructive pulmonary disease concurrent (COPD) concurrent with hypertension.

SUBJECTS AND METHODS

Sixty-five patients (50 men and 15 women) with Stages I-IV COPD and grades 1-3 elevated blood pressure (BP) in whom prior antihypertensive therapy had proved insufficiently effective were examined.

RESULTS

Prolonged-release indapamide demonstrated a high efficacy in achieving and maintaining goal BP, in normalizing its daily profile, and in reducing increased variability and the rate of morning rise in BP, without negatively affecting the clinical manifestations of COPD, pulmonary ventilatory function, and serum potassium levels. The drug was shown to have additional pleiotropic effects in lowering the activity of inflammatory markers (high-sensitivity C-reactive protein, intercellular adhesion molecules-1) and the level of endothelial dysfunction markers (endothelin-1, sP-selectin). Another commonly clinically used diuretic hydrochlorothiazide was chosen as a compared drug.

CONCLUSION

The high antihypertensive efficacy and additional pleiotropic properties of prolonged-release indapamide that exerts no negative effect on the clinical manifestations of COPD, bronchial patency, and serum potassium levels demonstrate that it is expedient to incorporate prolonged-release indapamide into the combination therapy of patients with COPD concurrent with hypertension.

Evidence-based diuretics: focus on chlorthalidone and indapamide

Thiazide and thiazide-like diuretics are cornerstone treatments for hypertension. However, unlike chlorthalidone (CTD) and indapamide (IDP), hydrochlorothiazide (HCTZ) lacks evidence for reducing morbidity and mortality as monotherapy compared with placebo or control. Despite this fact, HCTZ is prescribed much more frequently than CTD or IDP. We believe that all hypertension guidelines should follow the National Institute for Health and Excellence (NICE) and make IDP and CTD first choice 'thiazide-like diuretics.' This article will focus on the available evidence pertaining to HCTZ versus CTD and IDP. We will review the pharmacological differences between these three diuretics, as well as the clinical trial data and important side effects.

Development and experimental design of a novel controlled-release matrix tablet formulation for indapamide hemihydrate

CONTEXT

Development, experimental design and in vitro in vivo correlation (IVIVC) of controlled-release matrix formulation.

OBJECTIVE

Development of novel oral controlled delivery system for indapamide hemihydrate, optimization of the formulation by experimental design and evaluation regarding IVIVC on a pilot scale batch as a confirmation of a well-established formulation.

MATERIALS AND METHODS

In vitro dissolution profiles of controlled-release tablets of indapamide hemihydrate from four different matrices had been evaluated in comparison to the originator's product Natrilix (Servier) as a direction for further development and optimization of a hydroxyethylcellulose-based matrix controlled-release formulation. A central composite factorial design had been applied for the optimization of a chosen controlled-release tablet formulation.

RESULTS

The controlled-release tablets with appropriate physical and technological properties had been obtained with a matrix: binder concentration variations in the range: 20-40w/w% for the matrix and 1-3w/w% for the binder. The experimental design had defined the design space for the formulation and was prerequisite for extraction of a particular formulation that would be a subject for transfer on pilot scale and IVIV correlation.

CONCLUSIONS

The release model of the optimized formulation has shown best fit to the zero order kinetics depicted with the Hixson-Crowell erosion-dependent mechanism of release. Level A correlation was obtained.

Treatment of Hypertensive Patients With Diabetes and Microalbuminuria With Combination Indapamide SR/Amlodipine: Retrospective Analysis of NESTOR

BACKGROUND

Combination treatments for hypertension most often include a renin-angiotensin-aldosterone system (RAAS) inhibitor. However, systolic blood pressure (SBP) remains difficult to control. Non-RAAS-inhibiting strategies such as calcium channel blocker/thiazide-like diuretic combinations may offer effective alternatives.

METHODS

Hypertensive diabetic patients with microalbuminuria were included in this retrospective, post-hoc analysis of the Natrilix SR Versus Enalapril Study in Hypertensive Type 2 Diabetics With MicrOalbuminuRia (NESTOR) trial if they were uncontrolled on monotherapy (indapamide slow release (SR) 1.5 mg or enalapril 10mg) and had been given add-on amlodipine 5 mg. Patients uncontrolled with monotherapy/amlodipine 5mg were uptitrated to 10 mg.

RESULTS

After 52 weeks, supine SBP/diastolic BP (DBP) decreased from baseline by 26±13/14±9 mm Hg in the indapamide SR/amlodipine group (n = 135) and by 21±14/11±9 mm Hg in the enalapril/amlodipine group (n = 156) (P = 0.006 for ΔSBP). In the amlodipine 10mg subgroup, SBP/DBP decreased from baseline by 26±13/13±9 mm Hg in the indapamide SR/amlodipine group (n = 62) and by 20±13/12±8 mm Hg in the enalapril/amlodipine group (n = 77) (P = 0.02 for ΔSBP). Treatment with indapamide SR/amlodipine was well tolerated. Few patients experienced edema, with no between-group differences. As expected with diuretics, slight changes in kalemia and in uricemia were observed in the indapamide SR/amlodipine group. Changes in fasting glucose, lipids, natremia, and creatinine clearance were similar between groups.

CONCLUSIONS

Indapamide SR/amlodipine results in superior SBP reduction with a safety profile in line with that of its components and tolerability equivalent to that of an angiotensin-converting enzyme inhibitor/amlodipine strategy.

Head-to-head comparisons of hydrochlorothiazide with indapamide and chlorthalidone: antihypertensive and metabolic effects

Hydrochlorothiazide (HCTZ) has often been contrasted with chlorthalidone, but relatively little is known about HCTZ versus indapamide (INDAP). This systematic review retrieved 9765 publications, and from these, it identified 14 randomized trials with 883 patients comparing HCTZ with INDAP and chlorthalidone on antihypertensive potency or metabolic effects. To make fair comparisons, the dose of the diuretic in each arm was assigned 1 of 3 dose levels. In random effects meta-analysis, INDAP and chlorthalidone lowered systolic blood pressure more than HCTZ: -5.1 mm Hg (95% confidence interval, -8.7 to -1.6); P=0.004 and -3.6 mm Hg (95% confidence interval, -7.3 to 0.0); P=0.052, respectively. For both comparisons, there was minimal heterogeneity in effect across trials and no evidence for publication bias. The HCTZ-INDAP contrast was biased in favor of greater HCTZ potency because of a much greater contribution to the overall effect from trials in which the HCTZ arm had a higher dose level than the INDAP arm. For the HCTZ-INDAP comparison, no single trial was responsible for the overall result nor was it possible to detect significant modifications of this comparison by duration of follow-up, high- versus low-bias trials, or the presence or absence of background medications. There were no detectable differences between HCTZ and INDAP in metabolic adverse effects, including effects on serum potassium. In conclusion, these head-to-head comparisons demonstrate that, like chlorthalidone, INDAP is more potent than HCTZ at commonly prescribed doses without evidence for greater adverse metabolic effects.

Blood pressure-lowering efficacy of monotherapy with thiazide diuretics for primary hypertension

BACKGROUND

Hypertension is a modifiable cardiovascular risk factor. Although it is established that low-dose thiazides reduce mortality as well as cardiovascular morbidity, the dose-related effect of thiazides in decreasing blood pressure has not been subject to a rigorous systematic review. It is not known whether individual drugs within the thiazide diuretic class differ in their blood pressure-lowering effects and adverse effects.

OBJECTIVES

To determine the dose-related decrease in systolic and/or diastolic blood pressure due to thiazide diuretics compared with placebo control in the treatment of patients with primary hypertension. Secondary outcomes included the dose-related adverse events leading to patient withdrawal and adverse biochemical effects on serum potassium, uric acid, creatinine, glucose and lipids.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2014, Issue 1), Ovid MEDLINE (1946 to February 2014), Ovid EMBASE (1974 to February 2014) and ClinicalTrials.gov.

SELECTION CRITERIA

We included double-blind, randomized controlled trials (RCTs) comparing fixed-dose thiazide diuretic monotherapy with placebo for a duration of 3 to 12 weeks in the treatment of adult patients with primary hypertension.

DATA COLLECTION AND ANALYSIS

Two authors independently screened articles, assessed trial eligibility, extracted data and determined risk of bias. We combined data for continuous variables using a mean difference (MD) and for dichotomous outcomes we calculated the relative risk ratio (RR) with 95% confidence interval (CI).

MAIN RESULTS

We included 60 randomized, double-blind trials that evaluated the dose-related trough blood pressure-lowering efficacy of six different thiazide diuretics in 11,282 participants treated for a mean duration of eight weeks. The mean age of the participants was 55 years and baseline blood pressure was 158/99 mmHg. Adequate blood pressure-lowering efficacy data were available for hydrochlorothiazide, chlorthalidone and indapamide. We judged 54 (90%) included trials to have unclear or high risk of bias, which impacted on our confidence in the results for some of our outcomes.In 33 trials with a baseline blood pressure of 155/100 mmHg, hydrochlorothiazide lowered blood pressure based on dose, with doses of 6.25 mg, 12.5 mg, 25 mg and 50 mg/day lowering blood pressure compared to placebo by 4 mmHg (95% CI 2 to 6, moderate-quality evidence)/2 mmHg (95% CI 1 to 4, moderate-quality evidence), 6 mmHg (95% CI 5 to 7, high-quality evidence)/3 mmHg (95% CI 3 to 4, high-quality evidence), 8 mmHg (95% CI 7 to 9, high-quality evidence)/3 mmHg (95% CI 3 to 4, high-quality evidence) and 11 mmHg (95% CI 6 to 15, low-quality evidence)/5 mmHg (95% CI 3 to 7, low-quality evidence), respectively.Direct comparison of doses did not show evidence of dose dependence for blood pressure-lowering for any of the other thiazides for which RCT data were available: bendrofluazide, chlorthalidone, cyclopenthiazide, metolazone or indapamide.In seven trials with a baseline blood pressure of 163/88 mmHg, chlorthalidone at doses of 12.5 mg to 75 mg/day reduced average blood pressure compared to placebo by 12.0 mmHg (95% CI 10 to 14, low-quality evidence)/4 mmHg (95% CI 3 to 5, low-quality evidence).In 10 trials with a baseline blood pressure of 161/98 mmHg, indapamide at doses of 1.0 mg to 5.0 mg/day reduced blood pressure compared to placebo by 9 mmHg (95% CI 7 to 10, low-quality evidence)/4 (95% CI 3 to 5, low-quality evidence).We judged the maximal blood pressure-lowering effect of the different thiazides to be similar. Overall, thiazides reduced average blood pressure compared to placebo by 9 mmHg (95% CI 9 to 10, high-quality evidence)/4 mmHg (95% CI 3 to 4, high-quality evidence).Thiazides as a class have a greater effect on systolic than on diastolic blood pressure, therefore thiazides lower pulse pressure by 4 mmHg to 6 mmHg, an amount that is greater than the 3 mmHg seen with angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs) and renin inhibitors, and the 2 mmHg seen with non-selective beta-blockers. This is based on an informal indirect comparison of results observed in other Cochrane reviews on ACE inhibitors, ARBs and renin inhibitors compared with placebo, which used similar inclusion/exclusion criteria to the present review.Thiazides reduced potassium, increased uric acid and increased total cholesterol and triglycerides. These effects were dose-related and were least for hydrochlorothiazide. Chlorthalidone increased serum glucose but the evidence was unclear for other thiazides. There is a high risk of bias in the metabolic data. This review does not provide a good assessment of the adverse effects of these drugs because there was a high risk of bias in the reporting of withdrawals due to adverse effects.

AUTHORS' CONCLUSIONS

This systematic review shows that hydrochlorothiazide has a dose-related blood pressure-lowering effect. The mean blood pressure-lowering effect over the dose range 6.25 mg, 12.5 mg, 25 mg and 50 mg/day is 4/2 mmHg, 6/3 mmHg, 8/3 mmHg and 11/5 mmHg, respectively. For other thiazide drugs, the lowest doses studied lowered blood pressure maximally and higher doses did not lower it more. Due to the greater effect on systolic than on diastolic blood pressure, thiazides lower pulse pressure by 4 mmHg to 6 mmHg. This exceeds the mean 3 mmHg pulse pressure reduction achieved by ACE inhibitors, ARBs and renin inhibitors, and the 2 mmHg pulse pressure reduction with non-selective beta-blockers as shown in other Cochrane reviews, which compared these antihypertensive drug classes with placebo and used similar inclusion/exclusion criteria.Thiazides did not increase withdrawals due to adverse effects in these short-term trials but there is a high risk of bias for that outcome. Thiazides reduced potassium, increased uric acid and increased total cholesterol and triglycerides.

Indapamide lowers blood pressure by increasing production of epoxyeicosatrienoic acids in the kidney

Diuretics are widely used in the treatment of hypertension, although the precise mechanisms remain unknown. Epoxyeicosatrienoic acids (EETs), cytochrome P450 (P450) epoxygenase metabolites of arachidonic acid, play critical roles in regulation of blood pressure. The present study was carried out to investigate whether EETs participate in the antihypertensive effect of thiazide diuretics [hydrochlorothiazide (HCTZ)] and thiazide-like diuretics (indapamide). Male spontaneously hypertensive rats (SHRs) were treated with indapamide or HCTZ for 8 weeks. Systolic blood pressure, measured via tail-cuff plethysmography and confirmed via intra-arterial measurements, was significantly decreased in indapamide- and HCTZ-treated SHRs compared with saline-treated SHRs. Indapamide increased kidney CYP2C23 expression, decreased soluble epoxide hydrolase expression, increased urinary and renovascular 11,12- and 14,15-EETs, and decreased production of 11,12- and 14,15-dihydroxyeicosatrienoic acids in SHRs. No effect on expression of CYP4A1 or CYP2J3, or on 20-hydroxyeicosatetraenoic acid production, was observed, suggesting indapamide specifically targets CYP2C23-derived EETs. Treatment of SHRs with HCTZ did not affect the levels of P450s or their metabolites. Increased cAMP activity and protein kinase A expression were observed in the renal microvessels of indapamide-treated SHRs. Indapamide ameliorated oxidative stress and inflammation in renal cortices by down-regulating the expression of p47phox, nuclear factor-κB, transforming growth factor-β1, and phosphorylated mitogen-activated protein kinase. Furthermore, the p47phox-lowering effect of indapamide in angiotensin II-treated rat mesangial cells was partially blocked by the presence of N-(methylsulfonyl)-2-(2-propynyloxy)-benzenehexanamide (MS-PPOH) or CYP2C23 small interfering RNA. Together, these results indicate that the hypotensive effects of indapamide are mediated, at least in part, by the P450 epoxygenase system in SHRs, and provide novel insights into the blood pressure-lowering mechanisms of diuretics.

Evidence-based diuretic therapy for improving cardiovascular prognosis in systemic hypertension

Diuretics are among the most commonly prescribed cardiovascular (CV) medications. The strength of evidence supporting the effectiveness of diuretics in lowering blood pressure and for preventing major adverse CV events in patients with hypertension varies considerably among diuretic classes and even among agents within the same class. Unfortunately, common prescribing habits among American physicians, including specialists in CV diseases, are not in line with the existing evidence regarding diuretic therapy for improving CV prognosis. In conclusion, although hydrochlorothiazide is the standard diuretic used for hypertension, the outcomes data suggest that chlorthalidone, indapamide, and possibly even the aldosterone receptor blockers (spironolactone and eplerenone) may be superior agents.

Treating hypertension by rational use of diuretics: results of the Russian ARGUS-2 Study

OBJECTIVE

Insufficient use of diuretics in combination antihypertensive therapy is a main cause of poor blood pressure (BP) control in Russia. The objective of the ARGUS-2 study was to demonstrate that a rational use of a thiazide-like diuretic, indapamide sustained release (SR), alone or in combination, improves BP control in patients with arterial hypertension difficult to control due to isolated systolic hypertension (ISH), diabetes mellitus (DM), chronic nephropathy, or metabolic syndrome.

METHODS

The open-label, non-comparative, 3-month study without preliminary washout included 1438 hypertensive patients (mean age: 57.3 +/- 10.7 years, mean BP: 158.8 +/- 14.2/93.4 +/- 10.0 mmHg), with difficult-to-control arterial hypertension and who had never been treated with diuretics previously. Throughout the study, patients received indapamide SR 1.5 mg OD. BP control was defined as <140/90 mmHg for all patients and <130/80 mmHg for those with diabetes mellitus or chronic nephropathy.

RESULTS

Indapamide SR was given as initiation monotherapy to 13.7% of the patients, as substitutive monotherapy to 6.8% of the patients uncontrolled by a previous monotherapy, as additive therapy to 31.9% of the patients uncontrolled by previous monotherapy, and as additive therapy to 47.6% uncontrolled by previous combination therapy without a diuretic. Among included patients 75.7% received also an ACE inhibitor or an angiotensin II receptors blocker, 43.9% a calcium channel blocker, and 32.8% a beta-blocker. In 3 months after indapamide SR administration, average BP level decreased to 131.8 +/- 9.7/80.5 +/- 6.9 mmHg and 84.5% of the study population achieved BP control. BP was controlled in 91.9% of patients with ISH (n = 477), 74.8% of those with diabetes (n = 214), 75.6% of those with chronic nephropathy (n = 82), and 85.1% of patients with metabolic syndrome (n = 745). No case of hypokalemia was reported.

CONCLUSION

The study demonstrates the value of including the thiazide-like diuretic indapamide SR in a combined antihypertensive regimen to control BP in hypertensive patients with added cardiovascular risk factors whose hypertension is difficult to treat. Methodological limitations of this study are its open-label design and the possibility of a change in concomitant antihypertensive treatment during the study.

Treatment of hypertension in patients 80 years of age or older

BACKGROUND

Whether the treatment of patients with hypertension who are 80 years of age or older is beneficial is unclear. It has been suggested that antihypertensive therapy may reduce the risk of stroke, despite possibly increasing the risk of death.

METHODS

We randomly assigned 3845 patients from Europe, China, Australasia, and Tunisia who were 80 years of age or older and had a sustained systolic blood pressure of 160 mm Hg or more to receive either the diuretic indapamide (sustained release, 1.5 mg) or matching placebo. The angiotensin-converting-enzyme inhibitor perindopril (2 or 4 mg), or matching placebo, was added if necessary to achieve the target blood pressure of 150/80 mm Hg. The primary end point was fatal or nonfatal stroke.

RESULTS

The active-treatment group (1933 patients) and the placebo group (1912 patients) were well matched (mean age, 83.6 years; mean blood pressure while sitting, 173.0/90.8 mm Hg); 11.8% had a history of cardiovascular disease. Median follow-up was 1.8 years. At 2 years, the mean blood pressure while sitting was 15.0/6.1 mm Hg lower in the active-treatment group than in the placebo group. In an intention-to-treat analysis, active treatment was associated with a 30% reduction in the rate of fatal or nonfatal stroke (95% confidence interval [CI], -1 to 51; P=0.06), a 39% reduction in the rate of death from stroke (95% CI, 1 to 62; P=0.05), a 21% reduction in the rate of death from any cause (95% CI, 4 to 35; P=0.02), a 23% reduction in the rate of death from cardiovascular causes (95% CI, -1 to 40; P=0.06), and a 64% reduction in the rate of heart failure (95% CI, 42 to 78; P<0.001). Fewer serious adverse events were reported in the active-treatment group (358, vs. 448 in the placebo group; P=0.001).

CONCLUSIONS

The results provide evidence that antihypertensive treatment with indapamide (sustained release), with or without perindopril, in persons 80 years of age or older is beneficial. (ClinicalTrials.gov number, NCT00122811 [ClinicalTrials.gov].).

Antihypertensive efficacy of indapamide SR in hypertensive patients uncontrolled with a background therapy: the NATIVE study

OBJECTIVES

Antihypertensive monotherapy rarely achieves blood pressure (BP) control. NATIVE (NATrilix SR use in combInation antihypertensiVe thErapy) evaluated indapamide sustained release (SR) in hypertensive patients receiving background therapy.

RESEARCH DESIGN AND METHODS

Patients remaining hypertensive (systolic BP [SBP], 145-180 mmHg; diastolic BP [DBP], 95-105 mmHg) while receiving an angiotensin-converting enzyme (ACE) inhibitor (n = 709), beta-blocker (n = 629), calcium-channel blocker (CCB; n = 493), angiotensin II type 1 receptor blocker (ARB; n = 75), alpha-blocker (n = 29) or other therapy (n = 6) were enrolled, recruited by physicians from 228 centres in Pakistan. Indapamide SR 1.5 mg was administered daily for 3 months with background therapy. BP was assessed every 2 weeks, and blood glucose and total cholesterol were evaluated at baseline and study end in a patient subgroup. Adverse events were also recorded.

MAIN OUTCOME MEASURES AND RESULTS

Of 2073 enrolled patients (49% males; mean age 51 years), 1941 received indapamide SR and background therapy. SBP and DBP decreased significantly (SBP, 166 +/- 16 mmHg at baseline vs. 132 +/- 12 mmHg at 3 months; DBP, 102 +/- 8 mmHg vs. 83 +/- 6 mmHg; both p < 0.0001 vs. baseline). Patients uncontrolled with an ACE inhibitor, beta-blocker, CCB or ARB achieved an SBP/DBP decrease of 34 +/- 15/19 +/- 9, 33 +/- 17/19 +/- 10, 33 +/- 15/18 +/- 8 or 35 +/- 16/20 +/- 12 mmHg, respectively (all p < 0.0001). In all, 84% of patients achieved target SBP (< or = 140 mmHg) and 61% achieved BP normalisation (SBP < 140, DBP < 90 mmHg). The absence of placebo control may lead to an overestimation of the extent of the BP reduction achieved. Glucose and cholesterol levels were unaffected by indapamide SR. Four percent of patients experienced side-effects, which were mild-to-moderate in severity.

CONCLUSIONS

In patients with hypertension despite antihypertensive therapy, indapamide SR significantly reduced BP with a good acceptability profile. Indapamide SR may represent an effective additional therapy for patients who do not achieve BP goals with other antihypertensive agents.

The efficacy of indapamid in different cardiovascular outcome – Meta-analysis

Bevezetés: Az első vonalba tartozó vérnyomáscsökkentőktől elvárható, hogy csökkentsék a cardiovascularis morbiditást és mortalitást. A thiazid vízhajtók ez irányú hatékonyságát több metaanalízisben leírták. Az indapamid hatásosságát bár számos tanulmány vizsgálja, eddig nem készült az összes adatot összefoglaló elemzés. Célkitűzés: az indapamid hatásosságát vizsgáló összes randomizált kontrollált vizsgálat adatainak szintézise. A tanulmányok eredményeit a különböző cardiovascularis és biztonsági végpontok szerint elemezzük. Módszer: A MEDLINE adatbázisban megkerestük az összes randomizált kontrollált indapamidvizsgálatot 1995 és 2005 között. Csak a kettős vak-, párhuzamos lebonyolítású vizsgálatokat vontuk be. Az adatok metaanalízisét állandó és véletlen hatású modellekben is elvégeztük, az eredményeket Mantel–Haenzel-próbával, inverz varianciapróbával teszteltük. Eredmények: 9 vizsgálat és 10 108 beteg adatait elemeztük. 48, stroke-on átesett beteg indapamidkezelésével megelőzhető egy újabb stroke-esemény (NNT = 47,8; 95%; KI: 29,6–126,6). 5 vizsgálatban 7085 beteg adatai alapján az indapamid a szisztolés vérnyomást 7,28 (95%; KI: 6,37–8,19), a diasztolés vérnyomást 3,50 Hgmm-rel (95%; KI 2,99–4,01) nagyobb mértékben csökkentette, mint a placebo. 5 vizsgálatban 2856 beteg szisztolés vérnyomását az indapamid 1,30 Hgmm-rel (95%; KI: 0,28–2,31) nagyobb mértékben csökkentette, mint az aktív kontroll, a diasztolés vérnyomáscsökkentés esetében nem volt szignifikáns különbség. 505 beteg adatai alapján az indapamid 6,50 g/m 2 -rel (95%; KI: 0,81–12,9) nagyobb mértékben csökkenti a bal kamrai izomtömegindexet, mint az enalapril. 6206 beteg követése során a gyógyszerhez köthető mellékhatások előfordulásának gyakorisága hasonló a placebóéhoz (rr = 0,97; 95%; KI: 0,76–1,22). Következtetések: Az indapamid hatásos az újabb stroke megelőzésében, hatékonyan csökkenti a vérnyomást és a bal kamrai izomtömegindexet. A kezelés biztonságosan alkalmazható.

Pharmacoepidemiology of antihypertensive drugs in primary care setting of Bahrain between 1998 and 2000

PURPOSE

To compare pattern of antihypertensive drug utilization in 1998 with 2000 following the: (a) publication of 1999 World Health Organization/International Society of Hypertension (WHO/ISH) guidelines for drug management of hypertension; and (b) introducing new antihypertensives to the essential drug list, in primary care, Bahrain.

METHODS

Retrospective prescription-based survey carried out in seven out of 20 primary care health centers in Bahrain. A total of 9272 patients comprising 6543 with uncomplicated hypertension and 2729 with diabetic hypertension were studied.

RESULTS

Between 1998 and 2000, the prescription rate of beta-blockers and methyldopa significantly declined (p < 0.0001) while the rate of angiotensin converting enzyme (ACE) inhibitors and calcium channel blockers (CCBs) increased (p < 0.0001) in uncomplicated hypertension. However, in diabetic hypertension there was a non-significant decline in utilization of beta-blockers, CCBs, methyldopa, and diuretics whereas a significant increase in prescribing of ACE inhibitors (p < 0.0001). Inclusion of Perindopril into the essential drug list resulted in an overall increase in utilization of ACE inhibitors: use of captopril and enalapril declined while lisinopril and perindopril increased. Substitution of immediate-release (IR) indapamide by sustained-release (SR) formulation did not change the overall utilization of diuretics; however, intra-class changes were evident with a significant decline in use of thiazide diuretics and concomitant increase in use of SR indapamide by 2000.

CONCLUSIONS

The antihypertensive prescribing pattern is influenced by WHO/ISH guidelines as well as by introduction of new antihypertensives to primary care essential drug list in primary care. The choice of a drug is also influenced by presence of co-morbidity with diabetes mellitus.

An overview of the pharmacology and clinical efficacy of indapamide sustained release

The relationship between blood pressure (BP) and cardiovascular risk is clearly established; hypertension increases the rate of cardiovascular. High systolic blood pressure (SBP) may be the main parameter involved in cardiovascular morbidity and mortality. The benefit of lowering BP, particularly with diuretics has been proven in many outcome studies. Indapamide, a thiazide-type diuretic, was available for many years at a dosage of 2.5 mg in an immediate release formulation. A new sustained release (SR) formulation has been developed in order to allow the same antihypertensive efficacy with a better acceptability profile. This paper reviews the pharmacology of indapamide 1.5 mg SR from the bench to the bedside. Indapamide has a dual mechanism of action: diuretic effect at the level of the distal tubule in the kidney and a direct vascular effect, both of which contribute to the antihypertensive efficacy of the drug. The SR formulation contains a hydrophilic matrix, which delivers a smoother pharmacokinetic profile. This avoids unnecessary plasma peak concentrations, which may be associated with side effects. Indapamide SR has now been extensively used in hypertensive patients, including those at increased risk, for example elderly or diabetic patients. It has been shown to decrease BP, particularly SBP, with 24-h efficacy, allowing a once-daily dosage. Studies have demonstrated BP lowering to be at least as effective as all major therapeutic classes including the more recent antihypertensive drugs. Beyond BP decrease, indapamide SR has also been shown to protect against hypertensive target-organ damage in the heart and the kidney and to have a favorable metabolic profile. A broad evidence-base has accumulated to support the benefit of indapamide 1.5 mg SR in hypertensive patients, alone or as part of combination therapy, as recommended by the majority of guidelines.

Utilidad de indapamida retard en el tratamiento de la hipertensión arterial en población anciana de riesgo. Estudio RETARD

INTRODUCTION

It is estimated that more than 65% of the elderly population in Spain is hypertensive. This study aimed to evaluate the safety and efficacy of extended release indapamide in hypertensive patients over 60 years of age, having high cardiovascular risk and the factors that influence this effect.

MATERIAL AND METHODS

Prospective study made in 944 patients with essential HBP and age > 60 years (55.9% women) in whom treatment with extended release indapamide in single drug therapy or in combination was indicated, whether as a new drug or due to lack of efficacy of the previous therapy. The action scope was hospital out-patient clinics of Internal Medicine and follow-up time of the patients was 6 months.

RESULTS

Extended release indapamide causes a significant decrease (p < 0.05) of systolic blood pressure (SBP) (21.3 mmHg) and diastolic blood pressure (DBP) (10.8 mmHg). No significant differences were found between the results in monotherapy or combined therapy. A total of 52.7% of the patients included had 3 or more cardiovascular risk factors (RF) or had target organ lesion (TOL) and 41.1% had an associated cardiovascular disease (CVD). Those patients with greater baseline SBP and DBP were those having a greater decrease in BP. On the other hand, patients with 1 or 2 RF showed a greater decrease of the SBP in comparison with patients with 3 or more RF, TOL or associated CVD. The adverse reactions rate was 2.8%.

CONCLUSIONS

Extended release indapamide is an effective drug in the elderly population having high cardiovascular risk and is well tolerated.

The place of diuretics in preventing cardiovascular events

Low-dose diuretics are recommended for the initial choice of antihypertensive therapy in the 7th US Joint National Committee report and are accepted as an appropriate choice among other classes of drugs in the 2003 European Society of Hypertension guidelines. The rationales for the use of low-dose diuretics include the following: Renal dysfunction interfering with normal natriuresis is likely a fundamental defect in the pathogenesis of hypertension. Subtle renal insufficiency that interferes with sodium excretion is a common consequence of uncontrolled hypertension. Diuretic-based therapy has been clearly documented in placebo-controlled, randomized trials to reduce cardiovascular morbidity and mortality, particularly in the treatment of elderly hypertensives.In multiple comparative trials, diuretic-based therapy has been shown to provide equal cardiovascular protection to that provided by newer agents. Diuretics enhance the antihypertensive efficacy of all other classes of agents. As lower blood pressure goals of therapy have been found to be needed, diuretic enhancement of other agents' efficacy has become even more essential. With such low doses, side effects are minimal in degree and infrequent in appearance.

Efficacy of indapamide 1.5 mg, sustained release, in the lowering of systolic blood pressure

The relationship between the increase in blood pressure and the incidence of cardiovascular disease is well recognized today. Studies have shown that more attention should be paid to systolic blood pressure (SBP) in relation to cardiovascular risk and that therapeutic interventions should preferably focus on reducing SBP. The antihypertensive efficacy of indapamide 1.5 mg sustained release (indapamide SR), a low-dose thiazide-type diuretic, was assessed on SBP. Three randomized, double-blind, controlled studies were conducted with indapamide SR, over a period of 3 to 12 months. Elderly patients or patients with target-organ damage, hypertension and left ventricular hypertrophy (LVH) (LIVE study) or with type II diabetes with microalbuminuria (NESTOR study) showed a decrease in SBP varying from 22.7 to 31.8 mmHg. The treatment with indapamide SR resulted in a better or equivalent control of SBP than treatment with a standard dose of a true thiazide diuretic (hydrochlorothiazide), a calcium channel blocker (amlodipine), and an angiotensin-converting enzyme inhibitor (enalapril). No therapeutic escape was observed. All treatments showed good acceptability with no unexpected adverse event. In conclusion, indapamide SR is very effective in lowering SBP-a major independent cardiovascular risk factor-notably in hypertensive high-risk patients with LVH, the elderly and diabetics, when compared to major antihypertensive treatments. This SBP-lowering effect is maintained over the long term.

Use of diuretics in cardiovascular disease: (2) hypertension

Hypertension is a common condition associated with increased mortality and multiple morbidities. Evidence based management of hypertension is known to improve both the short term and the long term outcomes in patients with this condition. There are several general measures and pharmacological agents that are known to treat hypertension adequately. Diuretics, in particular low dose thiazide and thiazide-like diuretics, are widely used in the treatment of hypertension. They have excellent outcome data and high safety and low side effects profiles. In this article, the physiology, pharmacological actions, side effects, and outcome data of the use of diuretics in hypertension are reviewed. In addition, the effective use of diuretics in the management of hypertension is discussed.

Preparation of indapamide slow-release pellets

During the process of developing a slow-release formulation of indapamide, researchers created a drug-containing pellet coated with Eudragit RS100 (Rohm GMbH & Co. KG, Darmstadt, Germany) to control the rate at which the drug was released. The two main variables were the agglomerants used in the pellet preparation and the amount of Eudragit RS100 used to coat them. The optimal outcome was indicated by the greatest number of drug-containing pellets recovered through an 18- to 24-mesh sieve and a satisfactory 24-hour release curve. The kinetics of dissolution fit the Higuchi kinetics model. Stability tests of the drug pellets showed no notable changes in the rate of drug release, related substances (mean byproducts or impurities from interactions or decompositions), and drug content.

Metabolic profile of indapamide sustained-release in patients with hypertension: data from three randomised double-blind studies

OBJECTIVE

To evaluate the influence of indapamide sustained-release (SR) 1.5 mg/day, a thiazide-related sulfonamide diuretic, on serum levels of lipids (total cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol and triglycerides), glucose and uric acid, and renal function (serum urea and creatinine levels).

METHODS

Pooled data from three randomised, double-blind, controlled studies are analysed. Two of these studies were of short duration (2 and 3 months), one of which included a 9-month nonblind extension phase, and the third was a 12-month prospective study. Short- and long-term metabolic effects of the treatment could thus be analysed. All studies were conducted in patients with mild-to-moderate hypertension; the total population randomised in these studies comprised 1195 patients, of whom 505 had left ventricular hypertrophy (LVH).

RESULTS

After 2 to 3 months' treatment with indapamide SR 1.5 mg/day, there was no significant change from baseline in serum lipid levels and glucose levels. This neutral effect was maintained after 9 and 12 months of treatment. Renal function was not affected by short- or long-term indapamide SR 1.5 mg/day therapy. Serum uric acid level was slightly increased after short-term therapy, but was restored to baseline values during long-term therapy with indapamide SR 1.5 mg/day.

CONCLUSIONS

Indapamide SR 1.5 mg/day has no deleterious effect on glucose metabolism, serum levels of lipids and uric acid, or renal function. This antihypertensive agent can be considered to be an attractive therapeutic choice for all patients with mild-to-moderate hypertension, including the elderly and patients with increased cardiovascular risks, i.e. those with LVH.

Benefits of treating hypertension in the elderly: should age affect treatment decisions?

Do the benefits of treating hypertension extend equally to all age groups, particularly the very elderly? Several large controlled trials have been published in recent years that confirm the benefits of the treatment of hypertension in terms of morbidity and mortality. However, these trials included only relatively small numbers of patients aged > or = 80 years. Data regarding such patients have been extracted and subjected to meta-analysis, but with inconclusive results. Further difficulties arise as a result of the range of therapeutic agents employed. Therefore, uncertainty still surrounds the value of treating very elderly patients with hypertension. The J-curve hypothesis, i.e. that a blood pressure threshold exists below which there is an increase in the rate of cardiac events, has been a concern in treating elderly patients. Upon close examination, this appears to be spurious. The Hypertension in the Very Elderly Trial study sets out to provide conclusive evidence for the benefits or otherwise of treating hypertension in the very elderly and has just commenced. The results of this trial will not be available for some time. In the meantime, should physicians initiate or continue treatment for very elderly individuals with hypertension? If so, what regimens should be employed and should target blood pressure levels be set? At the present time, it would appear sensible to provide treatment for very elderly patients with hypertension, particularly those with evidence of complications or target organ damage. In relatively healthy individuals with mild-to-moderate hypertension, the guiding principle should be 'the lower the blood pressure the better'. Regarding the choice of therapeutic agent, a low-dose diuretic remains the first choice therapy.

Diuretics in the therapy of hypertension

Antihypertensive monopharmacotherapy with diuretics renders blood pressure (BP) values under control in a large percentage of patients suffering from essential hypertension, and it reduces cardiovascular morbidity and mortality. Diuretics are effective in adult and elderly hypertensive subjects, independently of their race. Treatments with classic (high) doses of antihypertensive diuretics, such as 25 mg hydrochlorothiazide once daily, raise the activity of the RAA system, decrease plasma potassium and magnesium concentrations, and cause untoward changes in carbohydrate metabolism and in the plasma lipid profile. These changes appear to limit the positive response of cardiovascular prognosis to antihypertensive therapy with classic doses of diuretics. Lower doses of diuretics reduce high BP to the sought extent in many patients, and they do not elicit or cause only mild unfavourable neuroendocrine and metabolic changes. When a low dose of an antihypertensive diuretic substance is used as monopharmacotherapy, it may take 12-14 weeks after the initiation of treatment for BP to attain final stable values. The following low-dose oral formulations of diuretics constitute effective once-daily monopharmacotherapies for mild-to-moderate uncomplicated essential hypertension: bendrofluazide 1.25 mg, chlorthalidone 12.5 and 15 mg, cicletanine 50 mg, cyclopenthiazide 0.125 mg, HCTZ 12.5 mg, and torasemide 2.5 and 5 mg. These formulations are safer than classically used high-dose formulations such as hydrochlorothiazide 25 and 50 mg.

Drug-Induced lipid changes: a review of the unintended effects of some commonly used drugs on serum lipid levels

Many drugs besides lipid-lowering drugs affect serum lipid levels in either a potentially harmful or beneficial way, and may therefore increase or decrease the risk of cardiovascular disease. Diuretics, beta-blocking agents, progestogens, combined oral contraceptives containing 'second generation' progestogens, danazol, immunosuppressive agents, protease inhibitors and enzyme-inducing anticonvulsants adversely affect the lipid profile. They increase total cholesterol, low density lipoprotein cholesterol and triglycerides by up to 40, 50 and 300%, respectively, and decrease high density lipoprotein cholesterol by a maximum of 50%. Conversely, alpha-blocking agents, estrogens, hormone replacement therapy, combined oral contraceptives containing 'third generation' progestogens, selective estrogen receptor modulators, growth hormone and valproic acid show mostly beneficial effects on the lipd profile. Some drugs, for example, isotretinoin, acitretin and antipsychotics, mainly elevate triglyceride levels. Adverse or beneficial effects on serum cholesterol levels do not always translate into a higher or lower, respectively, incidence of cardiovascular disease. because these drugs may influence cardiovascular risk through multiple pathways. In some cases, excessive cholesterol levels occur, for example, with protease inhibitor therapy, and several cases of pancreatitis attributable to drug-induced hypertriglyceridaemia have been reported. Some general guidelines on the management of drug-induced dyslipidaemia can be given. Replacement of the dyslipidaemia-inducing drug by an equivalent alternative therapy is preferred. However, such alternatives are often difficult to find. If there is no equivalent alternative and treatment with the dyslipidaemia-inducing drug must be initiated, monitoring of serum lipid levels is important. If drug use is expected to be long term, the existing guidelines for the management of dyslipidaemia in the general population can be applied to drug-induced dyslipidaemia. In cases of extreme hyperlipidaemia, medication use should be reassessed.

Hypertension in the Very Elderly Trial (HYVET): protocol for the main trial

A number of trials and meta-analyses have demonstrated clear benefits of blood pressure (BP) reduction in patients aged <80 years with regard to the reduction in stroke and cardiovascular events. However, a variety of studies have suggested that the positive relationship between BP and cardiovascular mortality is weakened or indeed reversed in the very elderly. Most intervention trials to date have either excluded or not recruited sufficient patients aged > or =80 years to determine whether there is a significant benefit from treatment in this age group. A meta-analysis of intervention trials that recruited patients aged > or =80 years has suggested a benefit in terms of stroke reduction but has also raised the possibility of an increase in total mortality. The benefit to risk ratio therefore needs to be clearly established before recommendations can be made for treating very elderly patients with hypertension. The Hypertension in the Very Elderly Trial (HYVET) pilot recruited 1283 patients aged > or =80 years and showed the feasibility of performing such a trial in this age group. It was a Prospective Randomised Open Blinded End-Points (PROBE) design but the main trial has additional pharmaceutical sponsorship to run a double-blind trial. Therefore, the main trial is a randomised, double-blind, placebo-controlled trial designed to assess the benefits of treating very elderly patients with hypertension. It compares placebo with a low dose diuretic (indapamide sustained release 1.5mg daily) and additional ACE inhibitor (perindopril) therapy if required. As in the pilot trial, the primary end-point is stroke events (fatal and non-fatal) and the trial is designed to determine whether or not a 35% difference occurs between placebo and active treatment. The main objective will be achieved with 90% power at the 1% level of significance. Secondary outcome measures will include total mortality, cardiovascular mortality, cardiac mortality, stroke mortality and skeletal fracture. 2100 patients aged > or =80 years are to be recruited and followed up for an average of 5 years. Entry BP criteria after 2 months of a single-blind placebo run-in period are a sustained sitting systolic BP (SBP) of 160 to 199mm Hg and a diastolic BP of 90 to 109mm Hg. The standing SBP must be >140mm Hg. The trial will be carried out in accordance with the principles of Good Clinical Practice. We describe in detail the protocol for the main trial and discuss the reasons for the changes from the pilot, the use of the drug regimen, and the BP criteria to be used in the trial.

A comparison of indapamide SR 1.5 mg with both amlodipine 5 mg and hydrochlorothiazide 25 mg in elderly hypertensive patients: a randomized double-blind controlled study

OBJECTIVE

To analyse the efficacy of indapamide sustained-release (SR) 1.5 mg in reducing blood pressure versus amlodipine 5 mg and hydrochlorothiazide 25 mg, in elderly hypertensive patients.

DESIGN

Double-blind, randomized, 12 week study using three parallel groups.

SETTING

European teaching hospitals and general practices.

PATIENTS

Randomized patients, (n = 524) including 128 patients with isolated systolic hypertension (ISH); mean age: 72.4 years; mean systolic/diastolic blood pressures (SBP/DBP): 174.5/97.9 mmHg.

MAIN OUTCOME MEASURES

Clinic systolic and diastolic blood pressure variations.

RESULTS

Indapamide SR 1.5 mg demonstrates a similar efficacy to that of amlodipine 5 mg, as well as to that of hydrochlorothiazide 25 mg (equivalence P < 0.001); the mean decreases in SBP/DBP were -22.7/-11.8 mmHg, -22.2/-10.7 mmHg and -19.4/-10.8 mmHg, respectively. In the ISH subgroup, indapamide SR 1.5 mg tends to have greater efficacy than hydrochlorothiazide 25 mg in reducing the SBP (-24.7 versus -18.5 mmHg, respectively; equivalence P = 0.117), while similar results are obtained with amlodipine 5 mg (-23 mmHg, equivalence P < 0.001). The normalization rate was relatively high for indapamide SR 1.5 mg (75.3%), when compared with amlodipine (66.9%) and hydrochlorothiazide (67.3%), especially in the subgroup of isolated systolic hypertensive patients: 84.2 versus 80.0% for amlodipine, and versus 71.4% for hydrochlorothiazide.

CONCLUSIONS

Indapamide SR 1.5 mg shows similar antihypertensive efficacy to amlodipine 5 mg and hydrochlorothiazide 25 mg in elderly hypertensive patients, while in patients with isolated systolic hypertension, indapamide SR 1.5 mg shows a similar efficacy to amlodipine 5 mg but a greater efficacy than hydrochlorothiazide 25 mg.

Clinical positioning of indapamide sustained release 1.5mg in management protocols for hypertension

Indapamide sustained release (SR) 1.5mg is a new galenic formulation that is characterised by a relatively constant plasma concentration at steady state, with only minor fluctuations during the 24-hour period. A dose-titration study of 3 doses of indapamide SR (1.5, 2 and 2.5mg) given once daily has shown that the 3 dosages are equipotent in lowering blood pressure, and have an effect similar to that of indapamide immediate-release (IR) 2.5mg; all were statistically more effective than placebo. The percentage of hypertensive patients whose serum potassium was less than 3.4 mmol/L was significantly lower after indapamide SR 1.5mg than after indapamide IR 2.5mg. Neither indapamide formulation had any significant effects on lipid profile, glucose, urea and serum creatinine; only uric acid was slightly raised during the 2-month study. In an equivalence study, indapamide SR 1.5mg and IR 2.5mg produced similar blood pressure reductions (within the equivalence limit of +/-5mm Hg), whereas the percentage of patients whose serum potassium fell to less than 3.4 mmol/L was lower in the IR 1.5mg group than in the SR 2.5mg group. Antihypertensive treatment with indapamide SR 1.5mg once daily produced reductions in blood pressure in elderly patients with systolic/diastolic or isolated systolic hypertension that were similar to reductions with amlodipine 5 mg/day. The incidence of adverse effects was very low in all studies with indapamide SR 1.5mg and very similar to that in the placebo group, confirming thereby the improvement in the efficacy: tolerance ratio with the new indapamide compound.

Concluding remarks. Pursuit of the optimal outcome in hypertension

Achieving the optimal outcome in hypertensive patients requires the selection and use of appropriate strategies to lower the blood pressure and reduce the patient's risk of cardiovascular events such as stroke and coronary heart disease. It also requires ongoing monitoring of the patient to ensure that the desirable end-points of treatment are being met, and that the heart, kidneys and other sites are being effectively protected from potential complications. Current guidelines on the treatment of hypertension continue to emphasise the use of low dose diuretics as appropriate first-line therapy whenever pharmacological intervention is indicated, except where there are positive indications (e.g. coexisting congestive heart failure or diabetic nephropathy) for other classes of drugs. Diuretics have repeatedly been shown to reduce the morbidity and mortality associated with hypertension, both in the elderly and in younger adults, and their combination with other antihypertensive agents (when clinically indicated) permits the use of lower total dosages. The thiazide-related diuretic indapamide has been reported to have a number of advantages over the thiazides, including minimal or no adverse influence on plasma lipids and glucose metabolism, or on kidney function in patients with renal insufficiency. It has also been found to produce regression of left ventricular hypertrophy, which is now accepted as an important objective of antihypertensive therapy. The recently developed sustained release (SR) formulation of indapamide allows use of a lower daily dosage of the drug, thereby improving its efficacy:safety ratio in comparison with immediate release formulations. Clinical studies have confirmed the efficacy of indapamide SR 1.5 mg daily in lowering elevated blood pressure, and this formulation can be considered an appropriate choice whenever a diuretic is indicated for the treatment of hypertension, including elderly hypertensives and, because of its metabolic 'neutrality', hypertensive patients with diabetes.