Fixed combination therapy of hypertension: focus on valsartan/hydrochlorothiazide combination (Diovan/HCT)

Combining angiotensin receptor blockers with chlorthalidone or hydrochlorothiazide - which is the better alternative? A meta-analysis

BACKGROUND

Hypertension is a disease with significant clinical and socio-economic consequences. The reduction in cardiovascular mortality and morbidity in patients treated for hypertension is directly related to the magnitude of blood pressure reduction. Diuretics have proven useful for the prevention of cardiovascular complications in addition to a long history of safety and efficacy. The main aim for this meta-analysis is to compare the efficacy of the combination of angiotensin receptor blocker (ARB) and chlorthalidone (CTLD) to the combination of ARB and hydrochlorothiazide (HCTZ) in patients with hypertension.

METHODS

A comprehensive literature search was conducted through electronic databases PubMed, MEDLINE, Scopus, PsyInfo, Cochrane, eLIBRARY.ru, http://ClinicalTrials.gov and http://www.clinicaltrialsregister.eu in July 2020 to identify studies that investigate the effect of the combination of angiotensin receptor blocker with chlorthalidone or hydrochlorothiazide on the systolic and diastolic blood pressure in patients with hypertension. Changes in systolic and diastolic blood pressure (BP) expressed as a weighted mean difference (WMD) were our primary outcomes. The random-effects method was chosen as the primary analysis and results were presented with a 95% confidence interval (CI). Sensitivity analysis was performed and bias was assessed.

RESULTS

Our search returned 2745 titles. Of them, 51 full-text articles remained to be subjected to assessment. Comparisons of ARB/HCTZ versus ARB showed changes in BP of -6.89 (-8.09, -5.69) mmHg for systolic BP and - 3.67 (-4.15, -3.19) mmHg for diastolic BP. For the ARB/CTLD versus ARB/HCTZ comparison changes were - 6.30 (-7.30, -5.29) mmHg for systolic BP and - 3.57 (-4.17, 2.98) mmHg for diastolic BP.

CONCLUSION

Our analysis suggests a small but significant favor for CTLD in blood pressure control when compared to HCTZ. We believe it should be considered as a valuable alternative for HCTZ and an option for fixed dose combinations with an ARB although further research is required.

Renal secretion of hydrochlorothiazide involves organic anion transporter 1/3, organic cation transporter 2, and multidrug and toxin extrusion protein 2-K

Hydrochlorothiazide (HCTZ) is the most widely used thiazide diuretic for the treatment of hypertension either alone or in combination with other antihypertensives. HCTZ is mainly cleared by the kidney via tubular secretion, but the underlying molecular mechanisms are unclear. Using cells stably expressing major renal organic anion and cation transporters [human organic anion transporter 1 (hOAT1), human organic anion transporter 3 (hOAT3), human organic cation transporter 2 (hOCT2), human multidrug and toxin extrusion 1 (hMATE1), and human multidrug and toxin extrusion 2-K (hMATE2-K)], we found that HCTZ interacted with both organic cation and anion transporters. Uptake experiments further showed that HCTZ is transported by hOAT1, hOAT3, hOCT2, and hMATE2-K but not by hMATE1. Detailed kinetic analysis coupled with quantification of membrane transporter proteins by targeted proteomics revealed that HCTZ is an excellent substrate for hOAT1 and hOAT3. The apparent affinities (K_m) for hOAT1 and hOAT3 were 112 ± 8 and 134 ± 13 μM, respectively, and the calculated turnover numbers (k_cat) were 2.48 and 0.79 s^-1, respectively. On the other hand, hOCT2 and hMATE2-K showed much lower affinity for HCTZ. The calculated transport efficiency (k_cat/K_m) at the single transporter level followed the rank order of hOAT1> hOAT3 > hOCT2 and hMATE2-K, suggesting a major role of organic anion transporters in tubular secretion of HCTZ. In vitro inhibition experiments further suggested that HCTZ is not a clinically relevant inhibitor for hOAT1 or hOAT3. However, strong in vivo inhibitors of hOAT1/3 may alter renal secretion of HCTZ. Together, our study elucidated the molecular mechanisms underlying renal handling of HCTZ and revealed potential pathways involved in the disposition and drug-drug interactions for this important antihypertensive drug in the kidney.

Triple Combination Therapies Based on Olmesartan: A Personalized Therapeutic Approach to Improve Blood Pressure Control

Recent epidemiological surveys have demonstrated that effective and sustained blood pressure (BP) control is achieved in a relatively small proportion of treated hypertensive patients. Indeed, treatment of hypertension represents a key strategy for preventing coronary artery disease, stroke, congestive heart failure and cardiovascular death. Several interventions have been proposed by international guidelines for ameliorating hypertension management and control, mostly including integrated and multi-dimensional pharmacological and non-pharmacological strategies. In particular, numerous evidence demonstrated that a more extensive use of combination therapy may represent a valid therapeutic option for treating hypertensive patients at different risk profile. This strategy has been definitely strengthened by the availability of single pill fixed-dose combinations. Among potential combination therapies, those based on the association of renin-angiotensin system antagonists, thiazide diuretics and calcium channel blockers are very effective in lowering BP levels and well tolerated. We will provide here an overview of clinical evidence supporting the use of triple combination therapy, with a focus on that based on olmesartan medoxomil, a thiazide diuretic (hydrochlorothiazide) and a calcium channel blocker (amlodipine besylate), which is available in multiple dosages. Finally, in view of the recognised importance of single-pill combination therapy for treating hypertension, we will examine the potential benefits of dual (fixed) combination therapy based on olmesartan medoxomil with either thiazide diuretic hydrochlorothiazide or calcium channel blocker amlodipine in terms of efficacy, safety and tolerability profile.

Triple combination therapy to improve blood pressure control: experience with olmesartan-amlodipine-hydrochlorothiazide therapy

INTRODUCTION

Effective treatment of hypertension is a key strategy for preventing and reducing the burden of hypertension-related cardiovascular diseases. In spite of these well-established concepts, hypertension remains poorly controlled, worldwide. Among the different pharmacological strategies required to improve blood pressure (BP) control, a more extensive use of combination therapy is progressively emerging as a cornerstone of a more effective treatment of hypertension. Among different drug combinations currently available for the clinical management of hypertension, those based on the association of drugs inhibiting the renin-angiotensin system, thiazide diuretics and calcium channel blockers have demonstrated to be very effective in lowering both systolic and diastolic, clinic and 24-h ambulatory BP levels with a good tolerability and safety profile.

AREAS COVERED

In the present manuscript the authors provide an overview of the evidence supporting the use of triple combination therapy with different classes of antihypertensive drugs, with a particular focus on those based on olmesartan medoxomil, a thiazide diuretic (hydrochlorothiazide) and a calcium channel blocker (amlodipine besylate).

EXPERT OPINION

Available data indicate that triple combination therapy based on olmesartan provides effective and sustained clinical and 24-h BP control in a high proportion of individuals among a broad range of hypertensive patients.

Comparison of the efficacy and safety profiles of two fixed-dose combinations of antihypertensive agents, amlodipine/benazepril versus valsartan/hydrochlorothiazide, in patients with type 2 diabetes mellitus and hypertension: a 16-week, multicenter, randomized, double-blind, noninferiority study

BACKGROUND

Hypertension is a prevalent condition that is closely associated with chronic complications in patients with diabetes. Fixed-dose combination therapy is currently recommended for the treatment of hypertension due to the advantage of reducing the pill burden. However, the effects of combination therapy may be diverse because of the different components.

OBJECTIVES

We examined blood pressure reduction and metabolic alterations after amlodipine/benazepril and valsartan/hydrochlorothiazide treatment in patients with type 2 diabetes mellitus and hypertension and microalbuminuria.

METHODS

This randomized, double-blind, parallel comparison, noninferiority clinical trial included patients with type 2 diabetes mellitus and hypertension and microalbuminuria detected within the past year. After a 2-week, placebo run-in period, patients were assigned to treatment with amlodipine/benazepril or valsartan/hydrochlorothiazide for 16 weeks. The primary end point was mean change in diastolic blood pressure. The prespecified boundary for noninferiority was 3.5 mm Hg of the mean change in diastolic blood pressure between treatments (amlodipine/benazepril minus valsartan/hydrochlorothiazide). If the upper limit of the 95% CI fell within 3.5 mm Hg, amlodipine/benazepril would be considered noninferior to valsartan/hydrochlorothiazide.

RESULTS

Of the 226 patients assessed for eligibility, 169 satisfied the inclusion/exclusion criteria and were assigned to a treatment group; 83 patients (54.2% male, mean age of 60.5 [10.0] years) in the amlodipine/benazepril group and 84 patients (64.3% male, mean age of 59.0 [10.6] years) in the valsartan/hydrochlorothiazide group received at least 1 dose of study medication and were included in the intention-to-treat population. In the per-protocol population, amlodipine/benazepril (n = 74) was noninferior to valsartan/hydrochlorothiazide (n = 78) with regard to the mean change in diastolic blood pressure (difference, -0.9 mm Hg; 95% CI, -3.5 to 1.6). The mean change in systolic blood pressure was not significantly different (2.4 mm Hg; 95% CI, -1.2 to 6.0) between study groups (P = 0.195) in the per-protocol population. However, data from the intention-to-treat population suggest that patients in the amlodipine/benazepril group may have better metabolic outcomes than those in the valsartan/hydrochlorothiazide group; specifically, a preservation of the estimated glomerular filtration rate (5.7 mL/min/1.73 m(2) [95% CI, 1.9 to 9.6]; P = 0.004) and improvements in glycosylated hemoglobin (-0.5% [95% CI, -0.7 to -0.2]; P < 0.001), fasting triglycerides (-0.4 mmol/L [95% CI, -0.7 to -0.2]; P = 0.002), HDL-C (0.07 mmol/L [95% CI, 0.01 to 0.12]; P = 0.022), and uric acid (-57.5 μmol/L [95% CI, -74.8 to -40.3]; P < 0.001). There were no significant differences in adverse effects between groups, with the exception of more respiratory disorders in the amlodipine/benazepril group than in the valsartan/hydrochlorothiazide group (17 vs 5; P = 0 .006).

CONCLUSIONS

The study results suggest that amlodipine/benazepril is noninferior to valsartan/hydrochlorothiazide with regard to blood pressure reduction and that this combination exerts beneficial effects on renal function, glucose control, HDL-C, and triglyceride levels compared with valsartan/hydrochlorothiazide. However, respiratory adverse events (particularly coughing) were more frequently reported in the amlodipine/benazepril group. ClinicalTrials.gov identifier: NCT01375322.

Real-world effectiveness of valsartan on hypertension and total cardiovascular risk: review and implications of a translational research program

The pharmacological efficacy of various monotherapy, single pill, and combination therapies of the angiotensin II receptor blocker valsartan have been established, mainly through randomized controlled trials that used similar methodological and statistical platforms and thus enabled synthesis of evidence. The real world effectiveness of valsartan has been studied extensively, but the relative lack of scientific and technical congruence of these studies render synthesis virtually impossible. To date, all have focused on blood pressure outcomes, despite evidence-based calls to grade antihypertensive treatment to patients' total cardiovascular risk. We review a T3 translational research program of seven studies involving valsartan monotherapy as well as single and separate pill combinations, and the determinants and effect on blood pressure and total cardiovascular risk outcomes. All seven studies examined not only the impact of valsartan-based regimens on blood pressure values and control, but also, within a statistical hierarchical approach, the physician- and patient-related determinants of these blood pressure outcomes. Two studies also investigated the determinants and outcomes of valsartan-based treatment on total cardiovascular risk - among the first studies to use this risk coefficient as an outcome rather than only a determinant. These seven studies included a total of 19,533 patients, contributed by 3434 physician-investigators in Belgium - a country particularly well-suited for observational effectiveness studies because of demographics and epidemiology. Each study used the same methodological and statistical platform. We summarize the impact of various valsartan regimens on such outcomes as blood pressure values and control, change in total cardiovascular risk, and reduction in risk by at least one category. We also review the results of statistical multilevel and logistic modeling of physician- and patient-related determinants on these outcomes, including the proportion of variance attributable to a physician class effect before patients enter the equation. In its different formulations, valsartan has major real-world benefits in lowering blood pressure and total cardiovascular risk within a 90-day period. It is essential to understand the physician- and patient-related determinants of blood pressure and total cardiovascular risk outcomes associated with valsartan treatment. Antihypertensive research should expand its historical focus on lowering blood pressure with an emphasis on lowering total cardiovascular research.

Compliance with the treatment of hypertension: the potential of combination therapy

Patient adherence to antihypertensive medication is vital to ensure the successful treatment of hypertension. Low levels of adherence to and persistence with prescribed therapy are major factors leading to the current poor rates of blood pressure control among patients with hypertension. There are many reasons for nonadherence to therapy including patient-, physician-, and therapy-related factors. Poor tolerability has a detrimental effect on adherence, therefore reducing the apparent effectiveness of agents with dose-dependent side effects. Various effective combination therapies are recommended by current guidelines, eg, beta-blocker plus calcium channel blocker (CCB), angiotensin receptor blocker (ARB) plus thiazide diuretic, angiotensin-converting enzyme (ACE) inhibitor plus thiazide diuretic, CCB plus thiazide diuretic, ACE inhibitor plus CCB, and ARB plus CCB, and these have the potential to increase adherence to therapy by combining a favorable tolerability profile with once-daily dosing.

Safety and tolerability of fixed-dose irbesartan/hydrochlorothiazide for rapid control of severe hypertension

This prospective, double-blind, multicenter trial compared the safety and tolerability of irbesartan/hydrochlorothiazide (HCTZ) fixed-dose combination therapy with irbesartan monotherapy in patients with severe hypertension (seated diastolic blood pressure (SeDBP) >or=110 mm Hg, mean BP 172/113 mm Hg at baseline). Patients were randomized 2:1 to 7 weeks' irbesartan/HCTZ 150/12.5 mg to 300/25 mg (n = 468) or irbesartan 150 mg to 300 mg (n = 227). The incidence of treatment-related adverse events (AEs) was similar with combination and monotherapy (11.3% and 10.1%), and most AEs were mild-to-moderate. The combined incidence of prespecified AEs was lower with irbesartan/HCTZ than with irbesartan (8.8% vs. 11.5%). There were no treatment-related serious AEs or deaths. At week 5, more patients achieved SeDBP < 90 mm Hg compared to irbesartan (47% vs. 33%; P = 0.0005). Despite more rapid and aggressive BP lowering, initial fixed-dose irbesartan/HCTZ demonstrated a comparable AE profile to irbesartan monotherapy in patients with severe hypertension.

Irbesartan/hydrochlorothiazide for the treatment of isolated systolic hypertension: a subgroup analysis of the INCLUSIVE trial

This post hoc analysis of the Irbesartan/Hydrochlorothiazide (HCTZ) Blood Pressure Reductions in Diverse Patient Populations (INCLUSIVE) trial evaluated the efficacy and safety of fixed-dose irbesartan/HCTZ in patients with isolated systolic hypertension. Adults with uncontrolled systolic blood pressure (SBP) (140-179 mm Hg; 130-179 mm Hg in type 2 diabetes) after 4 weeks or more of antihypertensive monotherapy once-daily treatment with placebo for 4-5 weeks, followed by HCTZ 12.5 mg for 2 weeks, irbesartan/HCTZ 150/12.5 mg for 8 weeks, and then irbesartan/HCTZ 300/25 mg for 8 weeks, in a prospective, multicenter, open-label, single-arm study. In patients with isolated systolic hypertension (n = 443) and the total study population (n = 736), irbesartan/HCTZ treatment for 16 weeks provided comparable mean blood pressure (BP) reductions from baseline (21.4/10.1 mm Hg vs 21.5/10.4 mm Hg; p < .001 vs baseline) and high SBP control rates (74% vs 77%). Patients with isolated systolic hypertension and concomitant type 2 diabetes experienced smaller BP reductions (17.9/8.7 mm Hg vs 22.9/10.7 mm Hg) and lower rates of SBP control (< 130 mm Hg, 47%) than those without diabetes (< 140 mm Hg, 87%). BP reductions from baseline and SBP control rates were similar across isolated systolic hypertension subgroups (> or = 65 vs < 65 years, sex, race, and metabolic syndrome status). Irbesartan/HCTZ was well tolerated, with drug-related adverse events (dizziness, < or = 3%; upper respiratory tract infection, < or = 2%) occurring with similar rates in the isolated systolic hypertension and total population. Fixed-dose irbesartan/HCTZ combination treatment provided effective and well-tolerated BP lowering in a diverse population of patients with isolated systolic hypertension.

Valsartan regulates the interaction of angiotensin II type 1 receptor and endothelial nitric oxide synthase via Src/PI3K/Akt signalling

AIMS

Valsartan, a selective angiotensin II type 1 receptor (AT1R) blocker, has beneficial effects in the cardiovascular system in part by its increase of nitric oxide (NO) bioavailability, yet the mechanisms are unclear. We investigated the molecular mechanisms underlying this effect in endothelial cells (ECs).

METHODS AND RESULTS

NO production was examined by Griess reagent assay, DAF-2 DA fluorescence staining and cGMP ELISA kits. Protein interaction was determined by western blotting and immunoprecipitation. Treating bovine or human aortic ECs with valsartan increased NO production, as evidenced by elevated level of stable NO metabolites and intracellular cGMP. Valsartan increased the phosphorylation but not the protein level of endothelial NO synthase (eNOS). Inhibition of phosphoinositide-3 kinase (PI3K)/Akt and Src pathways by specific inhibitors suppressed valsartan-induced NO release. In addition, valsartan increased the tyrosine residue phosphorylation of AT1R, which was attenuated by inhibition of Src but not PI3K activities. Valsartan also suppressed the interaction of eNOS and AT1R, which was blocked by Src or PI3K inhibition.

CONCLUSION

Valsartan-induced NO production in ECs is mediated through Src/PI3K/Akt-dependent phosphorylation of eNOS. Valsartan-induced AT1R phosphorylation depends on Src but not PI3K, whereas valsartan-induced suppression of AT1R-eNOS interaction depends on Src/PI3K/Akt signalling. These results indicate a novel vasoprotective mechanism of valsartan in upregulating NO production in ECs.

Efficacy and safety of fixed combinations of irbesartan/hydrochlorothiazide in hypertensive women: the inclusive trial

OBJECTIVE

This post hoc analysis of the Irbesartan/Hydrochlorothiazide Blood Pressure Reductions in Diverse Patient Populations (INCLUSIVE) trial evaluated the efficacy and safety of irbesartan/hydrochlorothiazide (HCTZ) in a diverse population of hypertensive women.

METHODS

INCLUSIVE was a multicenter, prospective, open-label, single-arm trial. Adult subjects had uncontrolled systolic blood pressure (SBP 140-159 mm Hg; 130-159 mm Hg for those with type 2 diabetes mellitus [T2DM]) after > or =4 weeks of antihypertensive monotherapy. Treatment was sequential: placebo (4-5 weeks), HCTZ 12.5 mg (2 weeks), irbesartan/HCTZ 150/12.5 mg (8 weeks), and irbesartan/HCTZ 300/25 mg (8 weeks). Mean changes from baseline to treatment end in SBP and diastolic blood pressure (DBP), BP goal attainment, and safety were assessed.

RESULTS

Treatment with irbesartan/HCTZ was associated with significant mean reductions in BP (intent-to-treat population, n = 370; SBP/DBP: -22.9/-10.3 +/- 14.7/8.8 mm Hg). Improvements in SBP were observed in all subgroups (p < 0.001): Caucasian (n = 207) -23.5 +/- 13.5 mm Hg; African American (n = 93) -21.0 +/- 17.2 mm Hg; Hispanics/Latino (n = 66) -23.6 +/- 14.3 mm Hg; age <65 years (n = 281) -22.5 +/- 14.7 mm Hg; age > or =65 years (n = 89) -24.3 +/- 14.5 mm Hg; T2DM (n = 97) -19.0 +/- 15.1 mm Hg; and metabolic syndrome (n = 187) -22.1 +/- 14.6 mm Hg. Overall, 82% (95% confidence interval [CI] 78%-86%) of women achieved their SBP goal, 86% (95% CI 83%-90%) achieved their DBP goal, and 76% (95% CI 71%-80%) achieved their dual SBP/DBP goal. Treatments were well tolerated in all groups.

CONCLUSIONS

Irbesartan/HCTZ treatment was effective and well tolerated in a diverse population of women whose BP was previously uncontrolled on monotherapy.

Predictors of blood pressure response to angiotensin receptor blocker/diuretic combination therapy: a secondary analysis of the irbesartan/hydrochlorothiazide blood pressure reductions in diverse patient populations (INCLUSIVE) study

The secondary analysis of the Irbesartan/Hydrochlorothiazide Blood Pressure Reductions in Diverse Patient Populations (INCLUSIVE) clinical trial investigated whether baseline demographic and clinical variables are predictive of different degrees of blood pressure reduction following an angiotensin II receptor blocker/diuretic treatment regimen. Irbesartan/hydrochlorothiazide and other angiotensin receptor blocker combinations with a diuretic have been shown to be effective in reducing systolic blood pressure in a diverse patient population previously uncontrolled on monotherapy. Ordinary least squares regression analysis was performed on the intent-to-treat population of the INCLUSIVE study to identify variables predictive of variations in blood pressure changes in response to irbesartan/hydrochlorothiazide combination therapy. Higher baseline systolic blood pressure, female sex, type 2 diabetes, and statin therapy were found to be predictive of additional blood pressure lowering with this combination. The impact of higher baseline systolic blood pressure and diabetic state on changes in systolic blood pressure were diminished in female patients compared with male patients. In conclusion, a significant correlation may exist between certain clinical/demographic characteristics and the extent of the therapeutic response with irbesartan/hydrochlorothiazide treatment.

The Role of Angiotensin II Type 1 Receptor Antagonists in Elderly Patients with Hypertension

Hypertension is a major risk factor for stroke and coronary events in elderly people and clinical trials have shown that treatment of hypertension with various drugs can result in a substantial reduction in cerebrovascular and cardiovascular events. The angiotensin II type 1 (AT1) receptor antagonists are the newest class of antihypertensive agents to be used widely in clinical practice. AT1 receptor antagonists can generally be given once-daily. They are also extremely well tolerated with minimal first-dose hypotension and an incidence of adverse effects similar to that seen with placebo. Adverse event rates are significantly lower than with other classes of antihypertensive drugs including ACE inhibitors. These factors result in improved compliance and increased rates of continuance on therapy. AT1 receptor antagonists show similar efficacy in lowering blood pressure to other classes of antihypertensive agents and their antihypertensive effect is potentiated when they are given concomitantly with low-dose thiazide diuretics. AT1 receptor antagonists are eliminated predominantly by the hepatic route but most are not subject to extensive metabolism and interactions with other drugs are uncommon. This is an advantage in the elderly, who are often receiving multiple medications which increases the risk for adverse drug interactions. Dose adjustments are not usually required in the elderly unless there is plasma volume depletion. Although plasma AT1 receptor antagonist concentrations are generally higher in the elderly than in younger subjects, this pharmacokinetic difference may be balanced by decreased activation of the circulating renin-angiotensin-aldosterone system in the elderly. Recent clinical studies in high-risk hypertensive patients with left ventricular hypertrophy or in patients with diabetic nephropathy or heart failure have demonstrated that AT1 receptor antagonists can improve clinical outcomes to a similar or sometimes greater extent than other antihypertensive agents. Many of these studies have included large numbers of older patients and have confirmed the excellent tolerability profile of these drugs. Thus, AT1 receptor antagonists should be considered as a possible first-line treatment or as a component of combination therapy in patients with type 2 diabetes mellitus and microalbuminuria or nephropathy and as an alternative or additional treatment to ACE inhibitors in patients with heart failure or left ventricular dysfunction. AT1 receptor antagonists also appear to reduce the onset of new diabetes compared with some other antihypertensive drugs. The benefits in terms of organ protection have mainly been seen in studies using higher doses of particular AT1 receptor antagonists and it is not certain at present whether these results can be extrapolated to other members of the class. As the elderly are more likely to have developed organ damage related to hypertension or to have heart failure or diabetes as concomitant conditions, AT1 receptor antagonists represent an appropriate option for many elderly patients. The main disadvantage of these drugs is the cost of the medication but this may be offset by their improved tolerability with fewer adverse reactions and thus increased compliance, resulting in better blood pressure control and fewer clinical events. Overall, AT1 receptor antagonists are well tolerated and efficacious for blood pressure-lowering when given as a single daily dose in elderly patients and have many potential benefits in high-risk hypertensive subjects.

The Efficacy and Safety of Low- and High- Dose Fixed Combinations of Irbesartan/Hydrochlorothiazide in Patients With Uncontrolled Systolic Blood Pressure on Monotherapy: The INCLUSIVE Trial

This multicenter, prospective, open-label, single-arm study determined the efficacy and safety of irbesartan/hydrochlorothiazide (HCTZ) fixed combinations in patients (n=1005), aged 18 years and older, with uncontrolled systolic blood pressure (SBP) of 140-159 mm Hg (130-159 mm Hg for type 2 diabetes mellitus) after at least 4 weeks of antihypertensive monotherapy. Treatment was sequential: placebo (4-5 weeks), HCTZ 12.5 mg (2 weeks), irbesartan/HCTZ 150/12.5 mg (8 weeks), and irbesartan/HCTZ 300/25 mg (8 weeks). Enrolled patients (n=844) were aged 57.3+/-11.2 years; 52% were women, 23% were African American, and 14% were Hispanic. Thirty percent had type 2 diabetes mellitus, 46% had metabolic syndrome, and baseline blood pressure was 154.0+/-10.3/91.3+/-8.8 mm Hg. The mean change in SBP from placebo end to the primary end point, Week 18 (intent-to-treat population, n=736) was -21.5+/-14.3 mm Hg (p<0.001). The mean change in diastolic blood pressure (DBP) was -10.4+/-8.7 mm Hg (p<0.001). The mean Week 18 SBP/DBP was 132.9+/-13.8/81.1+/-9.7 mm Hg. Overall, 77% (95% confidence interval, 74%-80%) of patients achieved SBP goal (<140 mm Hg; <130 mm Hg for type 2 diabetes mellitus); 83% (95% confidence interval, 80%-86%) achieved DBP goal (<90 mm Hg; <80 mm Hg for type 2 diabetes mellitus); and 69% (95% confidence interval, 66%-72%) achieved dual SBP/DBP goal. Treatments were well tolerated. This irbesartan/HCTZ treatment regimen achieved SBP goals in more than 75% of patients uncontrolled on monotherapy.

Antihypertensive efficacy of olmesartan medoxomil alone and in combination with hydrochlorothiazide

Angiotensin receptor blockers (ARBs) are highly effective antihypertensive agents with excellent safety profiles. ARBs have been shown to improve cardiovascular morbidity and mortality in hypertensive patients with heart failure or diabetic nephropathy. For this later class of patients, the American Diabetes Association recommends ARBs as the primary treatment option. The ARBs function by blocking the binding of angiotensin-II (A-II) to its receptor, thereby inhibiting the action of A-II. Unlike the angiotensin-converting enzyme (ACE) inhibitors, which block the production of A-II through the ACE pathway, the ARBs effectively inhibit A-II regardless of whether it is produced through ACE or some alternate enzyme pathway. This difference in action offers a distinct advantage of ARBs over ACE inhibitors. Olmesartan medoxomil, the latest addition to the ARB class, is a long-acting, safe and well-tolerated antihypertensive drug. The combination of olmesartan medoxomil with a low-dose diuretic, potentiates the blood pressure lowering effect of either agent alone and is highly effective in achieving the recommended blood pressure goals in the majority of patients treated.