Valsartan/hydrochlorothiazide: a review of its pharmacology, therapeutic efficacy and place in the management of hypertension

Unveiling Wide Spectrum Therapeutic Implications and Signaling Mechanisms of Valsartan in Diverse Disorders: A Comprehensive Review

Valsartan is an orally active non-peptide angiotensin receptor antagonist, an effective and well-tolerated anti-hypertensive drug. Besides its antihypertensive action, it has clinical implications in many other disorders, like heart failure (HF), arrhythmia, chronic kidney disease (CKD), diabetic complications (DM), atherosclerosis, etc. Besides angiotensin receptor blocking activity, valsartan reduces circulating levels of biochemical markers, such as hs-CRP, which is responsible for its anti-inflammatory and anti-oxidant activity. Moreover, valsartan also acts by inhibiting or inducing various signalling pathways, such as inducing autophagy via the AKT/mTOR/S6K pathway or inhibiting the TLR/NF-kB pathway. The current review exhaustively discusses the therapeutic implications of valsartan with specific emphasis on the mechanism of action in various disorders. The article provides a detailed spectrum of the therapeutic profile of valsartan and will likely be very useful to researchers working in the relevant research areas.

A Selective and Accurate LC-MS/MS Method for Simultaneous Quantification of Valsartan and Hydrochlorothiazide in Human Plasma

The fixed dose combination of valsartan (VAL) and hydrochlorothiazide (HCTZ) is the most commonly prescribed medicine for the effective treatment of hypertension. In this study, a simple sensitive and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous quantitation of VAL and HCTZ in human plasma by using irbesartan (IRB) and hydroflumethiazide (HFMZ) as their specific internal standards (ISs). HLB cartridge-based solid-phase extraction was used for the extraction of analytes and ISs. The chromatographic separation was achieved on Lichrocart RP Select (125 × 4 mm), 5 nm with the mobile phase composition of acetonitrile: 10 mM ammonium acetate buffer: 95:05, v/v, at flow rate of 0.5 mL/min. The turbo ion electrospray ionization in negative mode was used as ion source for the sample ionization. The precursor to product ion transitions were 434.10 > 179.10 (VAL), 295.70 > 204.90 (HCTZ), 427.10 > 192.90 (IRB), and 329.90 > 302.40 (HFMZ) for detection and quantification of analytes and their ISs. The retention times of VAL and HCTZ were 1.90 min and 2.30 min, respectively. The range for the calibration curves of VAL and HCTZ were 50.2–6018.6 ng/mL and 1.25–507.63 ng/mL, respectively, with good linearity having correlation coefficient values of ≥0.995 for both VAL and HCTZ. All validation parameter results (selectivity, precision and accuracy, matrix effects and stabilities) were within the acceptable range as per USFDA guideline for bioanalytical method validation. The intra-day and inter-day accuracy data for VAL were within the range of 105.68–114.22% and 98.41–108.16%, respectively, whereas for HCTZ they were 87.01–101.18% and 95.16–99.37%, respectively. The ion suppression effects produced for VAL and ion enhancement effects produced for HCTZ were insignificant according to the proposed sample cleanup procedure. The developed LC-MS/MS method was successfully applied to bioequivalence study on healthy volunteers.

The Bioequivalence Between Valsartan Oral Solution and Suspension Formulations Developed for Pediatric Use

The bioequivalence of valsartan 160 mg oral solution compared to suspension was assessed in a single-dose, open-label, randomized, 2-period, 2-way crossover study in 82 healthy adults. The participants were randomly assigned (1:1) to receive a single dose of the solution or suspension formulation in each of the two treatment periods. Serial blood samples for pharmacokinetic evaluation were collected up to 48 hours post-dose. The pharmacokinetic parameters were estimated by noncompartmental methods and analyzed as per bioequivalence criteria of statistical analysis. The peak plasma concentration of valsartan was reached with median time of 1 and 3 hours with solution and suspension formulation, respectively. Compared to suspension formulation, the mean peak plasma concentration with solution formulation was higher by 32% (90%CI, 1.27-1.38) while the geometric mean ratios (1.09) and the associated 90%CIs (1.05-1.13) of both the areas under the concentration time-curves (from time zero to the last quantifiable concentration and from time zero to infinity) were contained in the required range of 0.80 to 1.25. No new safety signals were observed with either of the formulations.

Development and Validation of a UPLC-DAD Method for the Simultaneous Quantification of Eight Antihypertensive Drugs in the Pharmaceutical Matrix

BACKGROUND

Hypertension is a critical health problem; it is a prevalent risk factor for cardiovascular disease. Many treatments to combat hypertension are available, however many patients are resistant to the standard therapeutic approaches. The association of two or more substances in a fixed-dose combination is effective and tolerated as a substitute for the standard therapeutic approach.

OBJECTIVE

The new ultra performance liquide chromatography method was developed and validated to assay a combination of eight antihypertensive drugs including a diuretic: hydrochlorothiazide, dihydropyridine calcium channel blocker: Amlodipine and angiotensin II type 1 receptor blockers (sartans): valsartan, candesartan, eprosartan, olmesartan, losartan, and irbesartan in the pharmaceutical matrix.

METHODS

Chromatographic separation was performed on an Acquity® UPLC C18 1.7 µm 2.1 × 100 mm column, with a gradient of buffer solution and acetonitrile, in the proportion of (80:20 v/v).

RESULTS

Good resolution was obtained, and an optimal analysis time of less than 5 min was achieved. The method was validated according to the International Conference on Harmonization guidelines following the classical approach and accuracy profile, and it is shown to be suitable for intended applications. The method was successfully used for quality control laboratories and the determination of these drugs combinations in pharmaceutical dosage forms.

Patient characteristics do not predict the individual response to antihypertensive medication: a cross-over trial

BACKGROUND

International guidelines on hypertension management do not agree on whether patient characteristics can be used for the first choice of treatment of uncomplicated essential hypertension.

OBJECTIVE

We wanted to identify predictive patient characteristics to the response of two different classes of antihypertensive drugs in patients with newly diagnosed hypertension in primary care.

METHODS

We conducted a prospective, open label, blinded endpoint cross-over trial in 120 patients with a new diagnosis of hypertension from 10 family practices. Patients received 4 weeks of 12.5 mgr hydrochlorothiazide once daily and 4 weeks of 80 mgr valsartan once daily, each followed by a 4-week washout. The sequence of drugs was randomized. Age, sex and menopausal state were recorded at run in and 24 h ambulatory blood pressure, office blood pressure, plasma renin concentration, NT-proBNP, potassium, estimated glomerular filtration rate, urinary albumin, body mass index and waist circumference at each regimen change. The difference in systolic blood pressure response between both study drugs, calculated from mean daytime ambulatory blood pressures, was the main outcome measure.

RESULTS

Ninety-eight patients (52% female; median age 53 years) were eligible for per-protocol-analysis. None of the studied variables were predictive for the difference in systolic blood pressure response. Individual systolic blood pressure responses ranged from an increase by 18 mmHg to a decrease of 39 mmHg.

CONCLUSION

In a relevant group of primary care patients with newly diagnosed hypertension, we were unable to detect predictors of treatment response. This study rather supports the United States and European guidelines than the United Kingdom and Dutch guidelines on hypertension.

Simultaneous determination of telmisartan and amlodipine in dog plasma by LC-MS-MS

A simple, rapid and sensitive method was established for the simultaneous determination of telmisartan and amlodipine in dog plasma by a HPLC-MS-MS analysis. The plasma sample preparation was a simple deproteinization by the addition of three volumes of methanol/acetonitrile mixture followed by centrifugation. The analytes and internal standard diphenhydramine were separated on a Zorbax SB-C18 column with a mobile phase of acetonitrile : water (45 : 55, v/v) at a flow rate of 0.2 mL/min with an operating temperature of 25°C. Detection was carried out by electrospray ionization in positive-ion multiple reaction monitoring mode. The calibration plots in dog plasma were linear over the ranges of 0.5-2,000 ng/mL for telmisartan and 0.5-500 ng/mL for amlodipine. The lower limit of quantification was 0.5 ng/mL for two analytes. The intra- and interday precisions (RSD%) were within 9.0%. The average recoveries of analytes were >85.0%. The method was successfully applied to the pharmacokinetic study of the two compounds after oral administration of telmisartan-amlodipine combination preparation to dogs.

Simultaneous determination of amlodipine, valsartan and hydrochlorothiazide by LC-ESI-MS/MS and its application to pharmacokinetics in rats

Polypill is a fixed-dose combination that contains three or more active ingredients used as a single daily pill to achieve a large effect in preventing cardiovascular disease with minimal adverse effects. A novel and accurate liquid chromatography tandem mass spectrometry method using electrospray ionization mode has been developed and validated for the simultaneous determination of amlodipine (AMD), valsartan (VAL) using losartan (LOS) as an internal standard (IS), and hydrochlorothiazide (HCT) using furosemide (FSD) as an IS. The separation was carried on Aquasil C₁₈ (50 mm×2.1 mm, 5 µm) reversed phase column using acetonitrile and water containing 0.1% formic acid (50:50, v/v) as the mobile phase. The method was validated in terms of linearity, accuracy and precision over the concentration range of 1–1000 ng/mL. The intra and inter-day precision and accuracy, stability and extraction recoveries of all the analytes were in the acceptable range. This method can be successfully applied to the pharmacokinetic study of AMD, VAL and HCT when given as a polypill.

Bioanalytical method development and validation for determination of metoprolol tartarate and hydrochlorothiazide using HPTLC in human plasma

A simple, sensitive, rapid and economic chromatographic method has been developed for determination of metoprolol tartarate and hydrochlorothiazide in human plasma using paracetamol as an internal standard. The analytical technique used for method development was high-performance thin-layer chromatography. HPTLC Camag with precoated silica gel Plate 60F254 (20 cm×10 cm) at 250 µm thicknesses (E. Merck, Darmstadt, Germany) was used as the stationary phase. The mobile phase used consisted of chloroform: methanol: ammonia (9:1:0.5v/v/v). Densitometric analysis was carried out at a wavelength of 239 nm. The rf values for hydrochlorothiazide, paracetamol and metoprolol tartarate were 0.13±0.04, 0.28±0.05, 0.48±0.04, respectively. Plasma samples were extracted by protein precipitation with methanol. Concentration ranges of 200, 400, 600, 800, 1000, 1200 ng/mL and 2000, 4000, 6000, 8000, 10000, 12000 ng/mL of hydrochlorothiazide and metoprolol tartarate, respectively, were used with plasma for the calibration curves. The percent recovery of metoprolol tartarate and hydrochlorothiazide was found to be 77.30 and 77.02 %, respectively. The stability of metoprolol tartarate and hydrochlorothiazide in plasma were confirmed during three freeze-thaw cycles (-20 ºC) on a bench for 24 hours and post-preparatively for 48 hours. The proposed method was validated statistically and proved suitable for determination of metoprolol tartarate and hydrochlorothiazide in human plasma.

Development of an HPLC-UV Method for the Analysis of Drugs Used for Combined Hypertension Therapy in Pharmaceutical Preparations and Human Plasma

A simple, rapid, and selective HPLC-UV method was developed for the determination of antihypertensive drug substances: amlodipine besilat (AML), olmesartan medoxomil (OLM), valsartan (VAL), and hydrochlorothiazide (HCT) in pharmaceuticals and plasma. These substances are mostly used as combinations. The combinations are found in various forms, especially in current pharmaceuticals as threesome components: OLM, AML, and HCT (combination I) and AML, VAL, and HCT (combination II). The separation was achieved by using an RP-CN column, and acetonitrile-methanol-10 mmol orthophosphoric acid pH 2.5 (7 : 13 : 80, v/v/v) was used as a mobile phase; the detector wavelength was set at 235 nm. The linear ranges were found as 0.1-18.5  μ g/mL, 0.4-25.6  μ g/mL, 0.3-15.5  μ g/mL, and 0.3-22  μ g/mL for AML, OLM, VAL, and HCT, respectively. In order to check the selectivity of the method for pharmaceutical preparations, forced degradation studies were carried out. According to the validation studies, the developed method was found to be reproducible and accurate as shown by RSD ≤6.1%, 5.7%, 6.9%, and 4.6% and relative mean error (RME) ≤10.6%, 5.8%, 6.5%, and 6.8% for AML, OLM, VAL, and HCT, respectively. Consequently, the method was applied to the analysis of tablets and plasma of the patients using drugs including those substances.

Telmisartan or valsartan alone or in combination with hydrochlorothiazide: a review

The aim of this review was to compare telmisartan and valsartan in the treatment of hypertension. PubMed searches were conducted to identify randomized trials (n = 14) comparing the two agents, alone or combined with hydrochlorothiazide. With one exception, all studies with blood pressure reduction as primary endpoint showed significantly greater reductions with telmisartan than with valsartan. Other studies showed that telmisartan was associated with greater improvements in metabolic measures and inflammatory markers than valsartan. These findings suggest that pharmacologic differences between telmisartan and valsartan may translate into clinically relevant differences between the two drugs in the management of hypertension.

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.

Simultaneous determination of related substances of telmisartan and hydrochlorothiazide in tablet dosage form by using reversed phase high performance liquid chromatographic method

Objective:

Telmisartan is a potent, long-lasting, nonpeptide antagonist of the angiotensin II type-1 (AT₁) receptor that is indicated for the treatment of essential hypertension. Hydrochlorothiazide is a widely prescribed diuretic and it is indicated for the treatment of edema, control of essential hypertension and management of diabetes insipidus. In the current article a new, accurate, sensitive, precise, rapid, reversed phase high performance liquid chromatography (RP-HPLC) method was developed for determination of related substances of Telmisartan and Hydrochlorthiazide in tablet dosage form.

Materials and Methods:

Simultaneous determination of related substances was performed on Kromasil C₁₈ analytical column (250 × 4.6 mm; 5μm pertical size) column at 40°C employing a gradient elution. Mobile phase consisting of solvent A (solution containing 2.0 g of potassium dihydrogen phosphate anhydrous and 1.04 g of Sodium 1- Hexane sulphonic acid monohydrate per liter of water, adjusted to pH 3.0 with orthophosphoric acid) and solvent B (mixture of Acetonitrile: Methanol in the ratio 80:20 v/v) was used at a flow rate of 1.0 ml min^–1. UV detection was performed at 270 nm.

Results:

During method validation parameter such as precision, linearity, accuracy, specificity, limit of detection and quantification were evaluated, which remained within acceptable limits.

Conclusions:

HPLC analytical method is linear, accurate, precise, robust and specific, being able to separate the main drug from its degradation products. It may find application for the routine analysis of the related substances of both Telmisartan and Hydrochlorthiazide in this combination tablets.

Economic impact of switching from valsartan to other angiotensin receptor blockers in patients with hypertension

BACKGROUND

The approaching availability of lower-cost generic angiotensin receptor blockers (ARBs) may affect formulary policies for patients maintained on the ARB valsartan.

OBJECTIVE

Estimate the economic impact of switching from valsartan (including valsartan-based single-pill combinations) to other ARBs without apparent medical reasons.

RESEARCH DESIGN AND METHODS

Patients with essential hypertension and at least 6 months of continuous valsartan treatment free of hospitalization, cardiovascular events, renal events or ARB-associated adverse events were identified from the MarketScan administrative claims database from January 1, 2004 to March 31, 2008. Those who subsequently switched to a different ARB with at least a 5% copayment decrease (switchers) were matched to those who did not switch (maintainers) according to propensity score quintiles and selected baseline characteristics. Refills were not required after the index fill for the switched-to ARB or maintained valsartan. Matched switchers and maintainers were compared in terms of medication discontinuation, healthcare resource use and costs during the 6 months following the index fill.

RESULTS

A total of 99,926 valsartan maintainers and 2150 switchers (with a mean copayment decrease of $16.5 per month) were identified and matched. After matching, switching from versus maintaining valsartan was associated with an 8% higher risk of medication discontinuation (p < 0.008), 19.1 additional outpatient visits/100 patients (p = 0.002) and 9.3 additional hypertension-related inpatient days/100 patients (p = 0.030). Concurrently, switching from versus maintaining valsartan was associated with higher total medical costs by $748/patient (p < 0.001), driven largely by higher costs for hypertension-related medical services by $492/patient (p = 0.004).

LIMITATIONS

Exact reasons for switching were not available and the study assessed only the short-term impacts of switching.

CONCLUSIONS

Hypertension patients maintained on valsartan who switched to a different ARB with a lower copayment experienced substantial increases in medication discontinuation, healthcare resource use and costs compared to those who maintained valsartan treatment.

Valsartan plus hydrochlorothiazide for first-line therapy in hypertension

Goal blood pressure levels are only being achieved in approximately a third of hypertensive patients, which suggests that there is a need for new and/or improved approaches to the treatment of hypertension. The majority of patients with hypertension require combination therapy to control their blood pressure. The use of a combination of drugs with complementary mechanisms of action may provide greater efficacy and tolerability compared with monotherapy, and may allow more rapid achievement of target blood pressure. Moreover, the use of single-pill combinations has the potential to increase adherence and persistence, and reduce costs. The single-pill combination of valsartan plus hydrochlorothiazide was recently approved by the US FDA for first-line use in hypertensive patients who are likely to need multiple drugs to achieve their blood pressure goals. The focus of this article is on those randomized, double-blind trials in which this combination was administered as first-line therapy in patients with essential hypertension.

Position of fixed‐dose combinations containing an AT1‐receptor blocker and a thiazide diuretic

Treatment of hypertension remains a difficult task despite the availability of different types of medications lowering blood pressure by different mechanisms. In order to reach the target blood pressures recommended today combination therapy is required in most patients. The co-administration of two drugs with different impacts on the cardiovascular system markedly increases the antihypertensive effectiveness without altering adversely tolerability. Fixed low-dose combinations are becoming a valuable option not only as second-line, but also as first-line therapy. In this respect the co-administration of thiazide diuretic with an AT(1)-receptor blocker is particularly appealing. The diuretic-induced decrease in total body sodium activates the renin-angiotensin system, thus rendering blood pressure maintenance angiotensin II-dependent. During blockade of the renin-angiotensin system low doses of thiazides generally suffice, allowing the prevention of undesirable metabolic effects. Also, blockade of the AT(1)-receptor, particularly when angiotensin II production is enhanced in response to diuretic therapy, is expected to be beneficial, since angiotensin II seems to contribute importantly to the pathogenesis of cardiovascular and renal complications of 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.

Combination antihypertensive therapy with valsartan and hydrochlorothiazide in Chinese patients with mild-to-moderate hypertension

OBJECTIVES

To compare the efficacy and safety of valsartan (VAL)/HCTZ 80/12.5 mg with VAL 80 mg in Chinese patients with mild-to-moderate essential hypertension not adequately controlled with VAL 80 mg alone.

RESEARCH DESIGN AND METHODS

This was a multicenter, double-blind, double-dummy, randomized, active-controlled, parallel-group trial. Patients (1175) with mild-to-moderate essential hypertension (mean sitting diastolic blood pressure [MSDBP] > or = 95 and < 110 mmHg) from 26 centers in China received VAL 80 mg o.d. for 4 weeks, 864 patients whose MSDBP remained > or = 90 and < 110 mmHg were randomized (1:1) to receive VAL80/HCTZ12.5 mg (n = 429) or VAL80 mg (n = 435) for 8 weeks.

MAIN OUTCOME MEASURES

The efficacy variable was changed from baseline to endpoint in trough MSDBP. The secondary efficacy variables were changed in mean sitting systolic blood pressure (MSSBP), response rate, and control rate.

RESULTS

Significant reductions in MSDBP and MSSBP from baseline to endpoint were observed in both groups. There were significantly greater reductions in MSDBP (8.4 mmHg vs. 6.2 mmHg) and MSSBP (10.2 mmHg vs. 6.7 mmHg), higher response (64.2% vs. 52.5%) and control rates (53.9% vs. 40.9%) in the VAL80/HCTZ12.5 group as compared with the VAL80 group at endpoint (p < 0.001). VAL80/HCTZ12.5 was equally effective in both age subgroups (> or = 65 and < 65 years) and was well tolerated. There were no deaths and the two serious adverse events reported were unrelated to study medication.

CONCLUSION

In Chinese patients with mild-to-moderate essential hypertension not adequately controlled by VAL 80 mg alone, VAL80/HCTZ12.5 mg combination was well tolerated and showed additional BP reduction. The limitations of this study were the inability to include an HCTZ arm as a control group and the short trial duration.

Economic benefits of treating high-risk hypertension with angiotensin II receptor antagonists (blockers)

Hypertension is one of the leading risk factors for cardiovascular disease and represents a major health and economic burden. Most patients with high- or very high-risk hypertension have multiple cardiovascular risk factors with or without accompanying subclinical organ damage or established cardiovascular or renal disease. Patients with severe hypertension or with moderate hypertension and one to two additional risk factors have absolute 10-year risks of cardiovascular disease of 21-30% and 15-20%, respectively. Current European treatment guidelines recommend that antihypertensive therapy be initiated rapidly and aggressively in patients with high-risk hypertension. Most patients require two or more antihypertensive agents to achieve the strict blood pressure target of <130/80 mmHg. This article reviews the existing cost-effectiveness data on the use of angiotensin II receptor antagonists (blockers) [ARBs] in patients with high-risk hypertension. Aggressive ARB treatment of patients in the early (microalbuminuric) stages of diabetic nephropathy has a significant renoprotective effect, delaying the onset of overt (proteinuric) nephropathy. By slowing the progression of these patients to end-stage renal disease, substantial cost savings can be made. There is a paucity of cost-effectiveness data regarding the use of fixed-dose ARB plus thiazide diuretic combination therapies. Longitudinal cost-benefit studies of this attractive and efficacious first-line treatment option are needed.

Maximising antihypertensive effects of angiotensin II receptor blockers with thiazide diuretic combination therapy: focus on irbesartan/hydrochlorothiazide

BACKGROUND

Evidence-based guidelines for the management of hypertension are now well established. Studies have shown that more than 60% of patients with hypertension will require two or more drugs to achieve current treatment targets.

DISCUSSION

Combination therapy is recommended as first-line treatment by the JNC-7 guidelines for patients with a blood pressure > 20 mmHg above the systolic goal or 10 mmHg above the diastolic goal, while the International Society of Hypertension in Blacks recommends combination therapy when BP exceeds targets by > 15/10 mmHg. Current European Society of Hypertension-European Society of Cardiology guidelines also recommend the use of low-dose combination therapy in the first-line setting. Furthermore, JNC-7 recommends that a thiazide-type diuretic should be part of initial first-line combination therapy. Thiazide/diuretic combinations are available for a variety of classes of antihypertensive, including ACE inhibitors, angiotensin receptor blockers (ARBs), beta blockers and centrally acting agents. This article focuses on clinical data investigating the combination of an ARB, irbesartan, with the diuretic, hydrochlorothiazide.

CONCLUSIONS

These data indicate that the ARB/HCTZ combination has greater potency and a similar side effect profile to ARB monotherapy and represents a highly effective approach for attaining goal BP levels using a therapeutic strategy that very effectively lowers BP, is well tolerated and minimises diuretic-induced metabolic effects.

Determination of hydrochlorothiazide in human plasma by liquid chromatography/tandem mass spectrometry

In this study, a fast and sensitive liquid chromatography/tandem mass spectrometry method for determination of hydrochlorothiazide in human plasma was developed and validated. The analyte and irbesartan, used as the internal standard, were precipitated and extracted from plasma using methanol. Analysis was performed on a Phenomenex Kromasil C(8) column with water and methanol (27:73, v/v) as the mobile phase. Linearity was assessed from 0.78 to 200 ng/mL in plasma. The analytical method proved to be applicable in a pharmacokinetic study after oral administration of 12 mg hydrochlorothiazide tablets to 20 healthy volunteers.

Valsartan in the treatment of heart attack survivors

Survivors of myocardial infarction (MI) are at high risk of disability and death. This is due to infarct-related complications such as heart failure, cardiac remodeling with progressive ventricular dilation, dysfunction, and hypertrophy, and arrhythmias including ventricular and atrial fibrillation. Angiotensin (Ang) II, the major effector molecule of the renin–angiotensin–aldosterone system (RAAS) is a major contributor to these complications. RAAS inhibition, with angiotensin-converting enzyme (ACE) inhibitors were first shown to reduce mortality and morbidity after MI. Subsequently, angiotensin receptor blockers (ARBs), that produce more complete blockade of the effects of Ang II at the Ang II type 1 (AT₁) receptor, were introduced and the ARB valsartan was shown to be as effective as an ACE inhibitor in reducing mortality and morbidity in high-risk post-MI suvivors with left ventricular (LV) systolic dysfunction and and/or heart failure and in heart failure patients, respectively, in two major trials (VALIANT and Val-HeFT). Both these trials used an ACE inhibitor as comparator on top of background therapy. Evidence favoring the use of valsartan for secondary prevention in post-MI survivors is reviewed.

A liquid chromatography/tandem mass spectrometry method for the simultaneous quantification of valsartan and hydrochlorothiazide in human plasma

A rapid and sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed and validated for simultaneous quantification of valsartan and hydrochlorothiazide in human plasma. After a simple protein precipitation using acetonitrile, the analytes were separated on a Zorbax SB-Aq C18 column using acetonitrile-10mM ammonium acetate (60:40, v/v, pH 4.5) as mobile phase at a flow rate of 1.2 mL/min. Valsartan and hydrochlorothiazide were eluted at 2.08 min and 1.50 min, respectively, ionized using ESI source, and then detected by multiple reaction monitoring (MRM) mode. The precursor to product ion transitions of m/z 434.2-350.2 and m/z 295.9-268.9 were used to quantify valsartan and hydrochlorothiazide, respectively. The method was linear in the concentration range of 4-3600 ng/mL for valsartan and 1-900 ng/mL for hydrochlorothiazide. The method was successfully employed in a pharmacokinetic study after an oral administration of a dispersible tablet containing 80 mg valsartan and 12.5 mg hydrochlorothiazide to each of the 20 healthy volunteers.

Lack of pharmacokinetic interactions of aliskiren, a novel direct renin inhibitor for the treatment of hypertension, with the antihypertensives amlodipine, valsartan, hydrochlorothiazide (HCTZ) and ramipril in healthy volunteers

Aliskiren is a novel, orally active direct renin inhibitor that lowers blood pressure alone and in combination with existing antihypertensive agents. As aliskiren does not affect cytochrome P450 enzyme activities, is minimally metabolised, and is not extensively protein bound, the potential for drug interactions is predicted to be low. Four open-label studies investigated the pharmacokinetic interactions between aliskiren 300 mg and the antihypertensive drugs amlodipine 10 mg (n = 18), valsartan 320 mg (n = 18), hydrochlorothiazide 25 mg (HCTZ, n = 22) and ramipril 10 mg (n = 17) in healthy subjects. In each study, subjects received multiple once-daily doses of aliskiren and the test antihypertensive drug alone or in combination in two dosing periods separated by a drug-free washout period. Plasma concentrations of drugs were determined by liquid chromatography and mass spectrometry methods. At steady state, relatively small changes in exposure to aliskiren were observed when aliskiren was co-administered with amlodipine (AUC(tau) increased by 29%, p = 0.032), ramipril (C(max,ss) increased by 31%, p = 0.043), valsartan (AUC(tau) decreased by 26%, p = 0.002) and HCTZ (C(max,ss) decreased by 22%, p = 0.039). Co-administration with aliskiren resulted in small changes in exposure to ramipril (AUC(tau) increased by 22%, p = 0.002), valsartan (AUC(tau) decreased by 14%, p = 0.062) and HCTZ (AUC(tau) decreased by 10% and C(max,ss) by 26%, both p < 0.001). All other changes in pharmacokinetic parameters were also small, and not statistically significant. None of the observed pharmacokinetic changes was considered clinically relevant. Aliskiren inhibited plasma renin activity (PRA) and also prevented the reactive rise in PRA induced by valsartan. The most commonly reported adverse events were headache, dizziness and gastrointestinal symptoms (all mild in severity), which were similar in frequency during antihypertensive drug treatment alone and in combination with aliskiren except for an increase in dizziness during treatment with the combination of aliskiren and HCTZ. In conclusion, aliskiren shows no clinically relevant pharmacokinetic interactions and is generally well tolerated when administered in combination with amlodipine, valsartan, HCTZ or ramipril.

Hydrochlorothiazide added to valsartan is more effective than when added to olmesartan in reducing blood pressure in moderately hypertensive patients inadequately controlled by monotherapy

This study was undertaken to evaluate the effects on blood pressure of hydrochlorothiazide (HCTZ) 12.5 mg added to valsartan 160 mg or to olmesartan 20 mg in hypertensive patients. After a 2-wk placebo period, 130 patients, aged 35 to 75 y, with diastolic blood pressure (DBP) >or=99 and 110 mm Hg were randomly assigned to olmesartan 20 mg once daily or to valsartan 160 mg once daily according to a prospective, parallel-arm study design. After 4 wk of monotherapy, patients whose BP was not controlled (DBP >or=90 mm Hg) were given combination treatment with HCTZ 12.5 mg for an additional 4 wk. At the end of the placebo period and at the end of each treatment period, clinical and ambulatory BP measurements were recorded. At the end of the combination therapy period, venous blood samples were drawn 2, 4, and 24 h after drug intake for evaluation of HCTZ plasma concentrations. Both combinations induced a greater ambulatory BP reduction than monotherapy. However, mean reduction from baseline in the valsartan/HCTZ-treated patients (-21.5)-14.6 mm Hg for 24 h, -21.8/-14.9 mm Hg for daytime, and -20.4/-13.7 mm Hg for nighttime systolic blood pressure [SBP]/DBP) was greater than in the olmesartan/HCTZ-treated patients )-18.8/-12.3 mm Hg for 24 h, -19.3/-12.8 mm Hg for daytime, and 17.4/-10.6 mm Hg for nighttime SBP/DBP). The difference between the effects of the 2 treatments was significant (P<.01). In particular, compared with monotherapy, the add-on effect of HCTZ 12.5 mg was significantly greater in the valsartan group than in those treated with olmesartan; the difference was more evident for nighttime BP values. Plasma concentrations of HCTZ were significantly greater with valsartan than with olmesartan at each determination time (P<.05). These findings suggest that the addition of HCTZ 12.5 mg to valsartan 160 mg monotherapy produces a greater BP reduction than the addition of the same dose of HCTZ to olmesartan 20 mg monotherapy.

A review of the efficacy of fixed-dose combinations olmesartan medoxomil/hydrochlorothiazide and amlodipine besylate/benazepril in factorial design studies

In order to adequately control hypertension, the majority of patients will require treatment with more than one antihypertensive agent. Fixed-dose combination therapy offers several advantages, including improved efficacy, tolerability, and treatment compliance. Certain combinations have benefits in specific patient populations, such as the elderly or those with comorbidities. In this review, we evaluate the BP-lowering efficacy of olmesartan medoxomil/hydrochlorothiazide (HCTZ) and amlodipine besylate/benazepril in similarly designed, randomized, placebo-controlled studies in similar patient populations. This indirect comparison showed that both combinations significantly improve both systolic and diastolic BP compared with monotherapy with the individual agents or placebo; it also demonstrated that the combinations were well tolerated. Both combination therapies significantly improved response rates, but olmesartan medoxomil/HCTZ achieved the highest control rates compared with the individual agents. On the basis of an indirect comparison of published factorial design studies, olmesartan medoxomil/HCTZ appears to be at least as effective as amlodipine besylate/benazepril and may provide quantitatively greater reductions in diastolic BP at commonly used dosages. A randomized clinical trial comparing the two combinations is needed to confirm these findings.

Comparison of valsartan 160 mg with lisinopril 20 mg, given as monotherapy or in combination with a diuretic, for the treatment of hypertension: the Blood Pressure Reduction and Tolerability of Valsartan in Comparison with Lisinopril (PREVAIL) study

BACKGROUND

The goal of antihypertensive therapy is to provide good blood pressure (BP) control without eliciting adverse effects.

OBJECTIVE

This study compared the risk-benefit profile of the angiotensin II receptor blocker valsartan with that of the angiotensin-converting enzyme inhibitor lisinopril in patients with mild to severe hypertension. The primary objective was to show that the equipotent BP-lowering effect of the valsartan-based treatment is accompanied by a better tolerability profile.

METHODS

This 16-week, randomized, double-blind, parallel-group study was conducted at 88 outpatient centers across Italy. After a 2-week placebo run-in period, patients aged > or = 18 years with mild to severe hypertension (systolic BP [SBP], 160-220 mm Hg; diastolic BP [DBP], 95-110 mm Hg) were eligible. Patients were randomized to receive once-daily, oral, self-administered treatment with valsartan 160-mg capsules or lisinopril 20-mg capsules under double-blind conditions for 4 weeks. Responders continued monotherapy, whereas nonresponders had hydrochlorothiazide 12.5 mg added for the final 12 weeks of the study. The 2 primary variables used to assess the equivalence of therapeutic efficacy of the 2 regimens were sitting SBP and sitting DBP, which were measured at weeks 0 (baseline), 4, 8, and 16. The rate of drug-related adverse events (AEs) was used to assess whether 1 treatment had a better tolerability profile than the other. Tolerability was assessed by collecting information about AEs by means of questioning the patient or physical examination at each visit.

RESULTS

A total of 1213 patients were enrolled (635 men, 578 women; mean [SD] age, 54.5 [10.1] years [range, 28-78 years]). The study was completed by 1100 patients (553 receiving valsartan and 547 receiving lisinopril). Fifty-one patients (8.4%) treated with valsartan and 62 (10.2%) [corrected] treated with lisinopril withdrew, mainly because of AEs (9 [1.5%] and 23 patients [3.8%], respectively). The valsartan- and lisinopril-based treatments were similarly effective in reducing sitting BP, with mean SBP/DBP reductions of 31.2/15.9 mm Hg and 31.4/15.9 mm Hg, respectively. At the end of the study, BP was controlled in 82.6% [corrected] of the patients receiving valsartan and 81.6% of those receiving lisinopril. AEs were experienced by 5.1% of the patients treated with valsartan and 10.7% of those treated with lisinopril (P=.0001), with dry cough observed in 1.0% and 7.2% of patients, respectively (P<0.001).

CONCLUSIONS

Valsartan and lisinopril were both highly effective in controlling BP in these patients with mild to severe hypertension, but valsartan was associated with a significantly reduced risk for AEs, especially cough.

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

Hypertension is a major risk factor for cardiovascular morbidity and mortality. Monotherapy of hypertension is often ineffective, since it controls approximately 50% of the blood pressure of hypertensive patients. For lowering blood pressure to less than 140/90 mmHg (or <130/80 mmHg among people with diabetes or chronic renal disease) according to JNC-7 guidelines, combination therapy of two or more drugs is often necessary. The combination of a diuretic with an angiotensin-converting enzyme inhibitor (ACEI) or an angiotensin receptor blocker (ARB) is effective and provides the additional benefit of blocking the effects of angiotensin II, which is responsible for cardiovascular remodeling and its complications. ARBs may have an advantage over the ACEIs because they block the action of all angiotensin II directly, whereas ACEIs are ineffective in blocking angiotensin II generated by nonclassical ACE pathways. Valsartan (Diovan, Novartis) is one of the seven currently approved ARBs in the USA for the treatment of hypertension, and it has been shown to be very effective in controlling blood pressure given once-daily in doses of 80-160 or 320 mg. Its fixed combination with hydrochlorothiazide (HCT) is even more effective in controlling blood pressure in 70% of the cases. The most commonly used combinations are valsartan/HCT (Diovan/HCT), 80/12.5 and 160/12.5 mg given once-daily.

A randomized, double-blind, active-controlled, parallel-group comparison of valsartan and amlodipine in the treatment of isolated systolic hypertension in elderly patients: the Val-Syst study

BACKGROUND

Some antihypertensive therapies are limited by dose-dependent adverse effects (AEs). The angiotensin II receptor blocker valsartan has been shown to reduce blood pressure (BP) in a dose-related manner with minimal dose-limiting AEs. Amlodipine besylate is a potent dihydropyridine calcium channel blocker also with dose-related antihypertensive efficacy, but with possible dose-limiting AEs, particularly peripheral edema.

OBJECTIVES

This study compared the risk/benefit profiles of valsartan and amlodipine in elderly patients who have isolated systolic hypertension (ISH).

METHODS

This 24-week, randomized, double-blind, active-controlled, titration-to-effect, parallel-group study was conducted at 35 outpatient centers in Italy. Elderly (aged 60-80 years) patients with ISH received oral treatment with valsartan 80-mg capsules or amlodipine 5-mg capsules once daily. After 8 weeks of treatment, the dose of the patients with poorly controlled systolic BP (SBP) was titrated to 160 mg (valsartan) or 10 mg (amlodipine) once daily. At week 16, if trough SBP was still not adequately controlled, a low-dose diuretic (hydrochlorothiazide [HCTZ] 12.5 mg) was added to the treatment regimen for an additional 8 weeks. Tolerability was assessed at all study visits using physical examination and patient interview.

RESULTS

Of 421 randomized patients (231 women, 190 men; mean [SD] age, 69 [6] years), 208 were included in the valsartan group, and 213 in the amlodipine group. The efficacy of valsartan-based treatment. in reducing SBP was similar to that of amlodipine-based treatment. With doubled doses, efficacy (change in SBP) increased significantly from baseline (both P < 0.01). The frequency of AEs doubled with amlodipine 10 mg but was not clinically relevant with valsartan 160 mg. Overall, AEs were observed in 31.9% of those receiving amlodipine versus 20.2% of the patients receiving valsartan (P < 0.003), with peripheral edema rates of 26.8% and 4.8%, respectively (P < 0.001).

CONCLUSIONS

In this study population of elderly patients with ISH, valsartan-given alone or in combination with HCTZ 12.5 mg-showed similar efficacy but better tolerability than amlodipine-based treatment.

Efficacy and Safety of Valsartan 160mg/Hydrochlorothiazide 25mg Combination in Patients with Hypertension not Adequately Controlled by Valsartan 160mg/Hydrochlorothiazide 12.5mg

BACKGROUND AND OBJECTIVE

Hypertension guidelines emphasise the need to treat high blood pressure (BP) early and aggressively, giving fixed-dose combinations special consideration. Hitherto, it has not been assessed in a sequential way whether hypertensive patients with inadequately controlled hypertension with an angiotensin II receptor antagonist/hydrochlorothiazide combination benefit from a dose increase of the diuretic. We investigated the efficacy and safety of valsartan 160mg/hydrochlorothiazide 25mg combination in patients with hypertension that was not adequately controlled by valsartan 160mg/hydrochlorothiazide 12.5mg.

PATIENTS AND METHODS

This was a multicentre, single-group, prospective study of 646 patients with moderate hypertension (diastolic BP [DBP] 100-109mm Hg). Patients were treated for 4 weeks with valsartan 160mg/hydrochlorothiazide 12.5mg (phase 1: weeks 1-4). In case of non-response (DBP >/=90mm Hg; n = 224) patients were treated for a further 4 weeks with valsartan 160mg/hydrochlorothiazide 25mg (phase 2: weeks 5-8). The primary efficacy measure was a change in mean sitting trough DBP at study end compared with the beginning of phase 2 in the intention-to-treat (ITT) population (n = 221).

RESULTS

Mean age of patients at entry was 58.6 years; 53.7% of patients were female. In phase 1, systolic BP (SBP)/DBP decreased from a baseline value of 161.9/103.3mm Hg by -16.1/-12.4mm Hg (normalisation rate 38.3%, response rate 64.5%). In phase 2, in the ITT non-responder population the additional SBP/DBP decrease was -8.4/-8.3mm Hg. Overall, the normalisation rate in all patients was 55.4% and the responder rate was 76.3%.Tolerability of both the valsartan 160mg/hydrochlorothiazide 12.5mg and the valsartan 160mg/hydrochlorothiazide 25mg combinations was very good, and the switch to the higher dose did not result in an increase in adverse events (AEs) or laboratory abnormalities. Only 16.6% of patients in phase 1 and 10.3% of patients in phase 2 experienced one or more AEs.

CONCLUSION

In patients with moderate hypertension, first-line therapy with the fixed-dose valsartan/hydrochlorothiazide combination leads to high normalisation and response rates. Patients with hypertension not controlled by valsartan 160mg/ hydrochlorothiazide 12.5mg clearly benefit from dose titration to valsartan 160mg/hydrochlorothiazide 25mg with a clinically relevant additional BP response and have excellent tolerability.