Combination therapy with ACE inhibitors/angiotensin II receptor antagonists and diuretics in hypertension

Evaluation of Anti-Oxinflammatory and ACE-Inhibitory Properties of Protein Hydrolysates Obtained from Edible Non-Mulberry Silkworm Pupae (Antheraea assama and Philosomia ricinii)

Food-derived bioactive peptides (BAPs) obtained from edible insect-protein hold multiple activities promising the potential to target complex pathological mechanisms responsible for chronic health conditions such as hypertension development. In this study, enzymatic protein hydrolysates from non-mulberry edible silkworm Antheraea assama (Muga) and Philosomia ricini (Eri) pupae, specifically Alcalase (A. assama) and Papain (P. ricini) hydrolysates obtained after 60 and 240 min, exhibited the highest ACE-inhibitory and antioxidant properties. The hydrolysates' fractions (<3, 3-10 and >10 kDa), specifically Alc_M60min_F3 (≤3 kDa) and Pap_E240min_F3 (≤3 kDa), showed the highest antioxidant and ACE-inhibitory activities, respectively. Further RP-HPLC purified sub-fractions F4 and F6 showed the highest ACE inhibition as well as potent anti-oxinflammatory activities in lipopolysaccharide (LPS)-treated endothelial cells. Indeed, F4 and F6 ACE-inhibitory peptide fractions were effective in preventing p65 nuclear translocation after 3 h of LPS stimulation along with the inhibition of p38 MAPK phosphorylation in HUVEC cells. In addition, pretreatment with F4 and F6 ACE-inhibitory peptide fractions significantly prevented the LPS-induced upregulation of COX-2 expression and IL-1β secretion, while the expression of NRF2 (nuclear factor erythroid 2-related factor 2)-regulated enzymes such as HO-1 and NQO1 was induced by both peptide fractions. The derived peptides from edible pupae protein hydrolysates have potentialities to be explored as nutritional approaches against hypertension and related cardiovascular diseases.

Asymmetric organocatalysis: an enabling technology for medicinal chemistry

The efficacy and synthetic versatility of asymmetric organocatalysis have contributed enormously to the field of organic synthesis since the early 2000s. As asymmetric organocatalytic methods mature, they have extended beyond the academia and undergone scale-up for the production of chiral drugs, natural products, and enantiomerically enriched bioactive molecules. This review provides a comprehensive overview of the applications of asymmetric organocatalysis in medicinal chemistry. A general picture of asymmetric organocatalytic strategies in medicinal chemistry is firstly presented, and the specific applications of these strategies in pharmaceutical synthesis are systematically described, with a focus on the preparation of antiviral, anticancer, neuroprotective, cardiovascular, antibacterial, and antiparasitic agents, as well as several miscellaneous bioactive agents. The review concludes with a discussion of the challenges, limitations and future prospects for organocatalytic asymmetric synthesis of medicinally valuable compounds.

Quantitative Estimation of Anti Hypertension Combination by Ratio Subtraction Spectrophotometry Method

BACKGROUND:

Irbesartan and hydrochlorothiazide are a group of anti-hypertensive drugs that are very effective and safe to use to reduce blood pressure and oedema. The combination has a small active ingredient content so that if the treatment didn’t meet the requirements for therapeutic doses, it not achieved to the maximum therapy.

AIM:

The research aims to the simultaneous determination of irbesartan and hydrochlorothiazide in tablets by Ratio subtraction spectrophotometry method.

METHODS:

The absorption spectra and sample measurement in the Ratio subtraction method performed on Irbesartan at a wavelength of 247.6 nm and 273.6 nm for the Hydrochlorothiazide (HCT) using 0.1 N NaOH as a solution. This method is validated with linearity, accuracy, and precision in intraday and interday, LOD and LOQ and applied in the determination of a mixture of irbesartan and hydrochlorothiazide in the dosage tablet.

RESULTS:

The validation test for IRB is 101.03 for accuracy, with a precision of 0.57; with precision testing at intraday 0.34 and interday 1.34, and LOD is 0.70 and LOQ is 2.12. Meanwhile, validation for HCT that the accuracy 100.34%; precision 0.89 and precision on intraday 1.20 and interday 1.18, and LOD 0.78 and LOQ 2.37 with IRB levels are 101.03 ± 0.63% and HCT is 100.59 ± 0.91%.

CONCLUSION:

The ultraviolet spectrophotometric method in subtraction ratio method was validated a method of linearity, accuracy, precision in intraday and interday, LOD, and LOQ and according to ICH guidelines and successfully applied for the determination simultaneous of irbesartan and hydrochlorothiazide in the tablet’s dosage form.

Efficacy of zofenopril in combination with thiazide diuretics in patients with acute myocardial infarction: a pooled individual data analysis of four randomized, double-blind, controlled, prospective studies

Background

In the Survival of Myocardial Infarction Long-Term Evaluation (SMILE) studies, early administration of zofenopril after acute myocardial infarction (AMI) was prognostically beneficial as compared to placebo and other angiotensin-converting enzyme inhibitors (ACEIs), such as lisinopril and ramipril. Here, we investigated whether zofenopril efficacy could be affected by a concomitant use of thiazide diuretics (TDs).

Methods

This was a post hoc analysis of pooled individual patient data from the SMILE studies. Patients treated with other diuretics than TDs were excluded. The primary study endpoint was the 1-year combined occurrence of death or hospitalization for CV causes, with or without TD.

Results

Among 2,995 patients, 263 (8.8%) were treated with a combination including a TD (TD+), whereas 2,732 (91.2%) were not treated with any diuretic (TD−). Proportions of subjects who were treated with TD were equally distributed (p=0.774) within the placebo, zofenopril, and other ACEIs groups. The 1-year risk of major cardiovascular events was similar in TD+ (18.3%) and TD− (16.8%) patients (hazard ratio [HR] 1.04; 95% CI 0.74–1.45; p=0.838). After stratifying per concomitant treatment and TD, the 1-year risk of CV events was significantly lower with zofenopril than with placebo (HR 0.70; 95% CI 0.55–0.88; p=0.002) and other ACEIs (HR 0.58; 95% CI 0.46–0.74; p=0.0001). Treatment with ACEIs and TD as concomitant therapy was associated with a larger blood pressure (BP) reduction (p=0.0001 for systolic BP and p=0.045 for diastolic BP).

Conclusion

In post AMI patients, zofenopril maintained its positive impact on prognosis compared to placebo or other ACEIs, regardless concomitant TD administration. In this setting, TD shows advantages in managing the most difficult hypertensive patients.

The comparative efficacy and safety of the angiotensin receptor blockers in the management of hypertension and other cardiovascular diseases

All national guidelines for the management of hypertension recommend angiotensin receptor blockers (ARBs) as an initial or add-on antihypertensive therapy. The eight available ARBs have variable clinical efficacy when used for control of hypertension. Additive blood pressure-lowering effects have been demonstrated when ARBs are combined with thiazide diuretics or dihydropyridine calcium channel blockers, augmenting hypertension control. Furthermore, therapeutic use of ARBs goes beyond their antihypertensive effects, with evidence-based benefits in heart failure and diabetic renal disease particularly among angiotensin-converting enzyme inhibitor-intolerant patients. On the other hand, combining renin-angiotensin system blocking agents, a formerly common practice among medical subspecialists focusing on the management of hypertension, has ceased, as there is not only no evidence of cardiovascular benefit but also modest evidence of harm, particularly with regard to renal dysfunction. ARBs are very well tolerated as monotherapy, as well as in combination with other antihypertensive medications, which improve adherence to therapy and have become a mainstay in the treatment of stage 1 and stage 2 hypertension.

Blood Pressure Response to Zofenopril or Irbesartan Each Combined with Hydrochlorothiazide in High-Risk Hypertensives Uncontrolled by Monotherapy: A Randomized, Double-Blind, Controlled, Parallel Group, Noninferiority Trial

In this randomized, double-blind, controlled, parallel group study (ZENITH), 434 essential hypertensives with additional cardiovascular risk factors, uncontrolled by a previous monotherapy, were treated for 18 weeks with zofenopril 30 or 60 mg plus hydrochlorothiazide (HCTZ) 12.5 mg or irbesartan 150 or 300 mg plus HCTZ. Rate of office blood pressure (BP) response (zofenopril: 68% versus irbesartan: 70%; p = 0.778) and 24-hour BP response (zofenopril: 85% versus irbesartan: 84%; p = 0.781) was similar between the two treatment groups. Cardiac and renal damage was equally reduced by both treatments, whereas the rate of carotid plaque regression was significantly larger with zofenopril. In conclusion, uncontrolled monotherapy treated hypertensives effectively respond to a combination of zofenopril or irbesartan plus a thiazide diuretic, in terms of either BP response or target organ damage progression.

Modeling of the pharmacokinetic/pharmacodynamic interaction between irbesartan and hydrochlorothiazide in normotensive subjects

PURPOSE

To investigate the pharmacokinetic/pharmacodynamic (PK/PD) interaction between irbesartan (IRB) and hydrochlorothiazide (HCT) in normotensive subjects.

METHODS

A three-way crossover study was used. Serial drug concentrations and drug effects, including systolic and diastolic blood pressure and heart rate were monitored after administration of irbesartan and hydrochlorothiazide alone and in combination. The data were fitted to a PK/PD model and the parameters for irbesartan and hydrochlorothiazide when administered alone and in combination were compared.

RESULTS

The plasma profiles for irbesartan and hydrochlorothiazide followed the two-compartment model after a single dose. The PK parameters of irbesartan were not affected by hydrochlorothiazide; however irbesartan decreased the hydrochlorothiazide AUC by 25% and increased its clearance by 25%. There were no significant changes in heart rate after each drug alone or in combination. Irbesartan plus hydrochlorothiazide had a greater blood pressure lowering effect compared with irbesartan alone, despite the unchanged irbesartan PK. The relationship between irbesartan plasma concentration and its effects plotted in chronological order showed anticlockwise hysteresis. The PD parameter estimates for the effect of irbesartan on systolic blood pressure, when administered with hydrochlorothiazide were significantly different from those when irbesartan was administered alone. This was manifested by a 25% increase in Emax , and a 40% decrease in EC50 , suggesting a synergistic blood pressure lowering effect for the combination. While parameter estimates for the effect of irbesartan on diastolic blood pressure were changed by hydrochlorothiazide, the differences were only significant for EC50 .

CONCLUSION

A limited potential for clinically significant interactions between irbesartan and hydrochlorothiazide at the given doses were observed; therefore, no dosage adjustments were recommended for either drug when used together. (ClinicalTrials.gov Identifier NCT01858610)

Comparative efficacy and safety of triple therapy (ramipril, telmisartan, hydrochlorothiazide) vs dual anti hypertensive therapy (ramipril or telmisartan, hydrochlorothiazide) in stage 2 hypertensive patients

AIM

To evaluate the comparative efficacy and safety of ramipril 5mg plus hydrochlorothiazide 12.5mg (R + HCTZ), telmisartan 40mg plus hydrochlorothiazide12.5mg (T + HCTZ) and ramipril 2.5mg plus telmisartan 20mg plus hydrochlorothiazide12.5mg (R + T + HCTZ) in patients with stage 2 hypertension.

MATERIALS AND METHODS

A prospective, open label, randomized comparative study was conducted to study the comparative efficacy and safety of R+HCTZ (group 1), T+HCTZ (group 2)and R+T+TCTZ (group3) in 88 patients with stage 2 hypertension without co-morbid conditions. Echocardiography was done to assess left ventricular function. Patients were followed up to 24 weeks and any ADR occurring in this period was recorded.

RESULTS

All the three treatment groups showed significant fall in both systolic and diastolic blood pressure compared to the baseline scores (p<0.0001). Intergroup comparison did not reveal any significant difference. Total number of adverse drug events reported were 15. Group III had higher percentage ADRs. Dry cough (8) was most common ADR. The echocardiography parameters did not change from baseline values with all three treatment regimens.

CONCLUSION

All three medications were of equal efficacy in patients with stage 2 hypertension without co morbid conditions, failing to prove superiority over each other.

Effectiveness of hydrochlorothiazide in combination with telmisartan and olmesartan in adults with moderate hypertension not controlled with monotherapy: a prospective, randomized, open-label, blinded end point (PROBE), parallel-arm study

BACKGROUND

The potential combinations of antihypertensive agents are many, and making rational choices depends on the characteristics of each drug and on their complementary mechanisms of action.

OBJECTIVE

The aim of this study was to evaluate the effectiveness of adding hydrochlorothiazide (HCTZ) 12.5 mg to olmesartan 20 mg or telmisartan 80 mg on blood pressure (BP) in patients with moderate hypertension.

METHODS

Consecutive outpatients at the Centro per l'Ipertensione e la Fisiopatologia Cardiovascolare, University of Pavia, Pavia, Italy, of both sexes aged 39 to 75 years were considered eligible for enrollment if they had a sitting diastolic BP (DBP) ->99 mm Hg and <110 mm Hg at the end of an initial 2-week washout period. Patients were random- ized to olmesartan 20 mg QD or telmisartan 80 mg QD according to a prospective, open-label, blinded end point, parallel-arm design. After 8 weeks of monotherapy, patients whose BP was not controlled (DBP ->90 mm Hg) received HCTZ 12.5 mg QD for 8 additional weeks. Clinical and ambulatory BPs were measured at the end of the washout period and at the end of both treatment periods. Adverse events (AEs) were recorded from spontaneous reports and direct inquiry from investigators.

RESULTS

One hundred forty-five patients, all of whom were white, were recruited for the study. After the initial washout period, 13 patients did not meet the inclusion criteria and 6 refused to continue. A total of 126 white patients (69 men, 57 women; mean [SD] age, 60.2 [11.6] years) were randomized to receive monotherapy. Of these, 35 patients (56%) in the olmesartan group and 33 (52%) in the telmisartan group had previously received antihypertensive therapy. At the end of monotherapy, the 52 patients in the olmesartan group and the 49 patients in the telmisartan treatment group who were still in the study and had their BP inadequately controlled by treatment had HCTZ 12.5 mg QD added to their treatment regimen. Both combinations induced a greater ambulatory mean (SD) systolic BP (SBP) and DBP reduction than monothera- py (SBP: 145.3 [6.1] in the olmesartan group and 140.1 [6.4] in the telmisartan group, P < 0.05; DBP: 88.1 [5.1] in the olmesartan group and 84.9 [4.9] in the telmisartan group, P < 0.05). The mean (SD) reduction from baseline in the telmisartan/HCTZ-treated patients (21.5 [10.1]/14.6 [5.2] mm Hg for 24 hours, 21.8 [10.2]/14.9 [5.2] mm Hg for daytime, and 20.4 [10.3]/13.7 [5.9] mm Hg for nighttime; all, P < 0.001 vs baseline) was significantly greater than that observed in the olmesartan/HCTZ-treated patients (18.8 [9.8]/12.3 [4.9] mm Hg for 24 hours, 19.3 [9.8]/12.8 [4.9] mm Hg for daytime, and 17.4 [10.2]/10.6 [5.5] mm Hg for nighttime; all, P < 0.001 vs baseline), with a significant difference between the 2 treatment groups (P < 0.01). Compared with mono- therapy, the add-on effect of HCTZ 12.5 mg QD administration was significantly greater in the telmisartan group than in the olmesartan group (P < 0.05); the differ- ence being more evident for nighttime BP values (SBP, P 0.031; DBP, P 0.025). Reported AEs were similar in the olmesartan/HCTZ and the telmisartan/HCTZ groups (4 patients [7%] vs 3 patients [6%]).

CONCLUSION

The addition of HCTZ 12.5 mg to telmisartan 80 mg monothera- py was associated with greater BP reduction than the addition of the same dose of HCTZ to olmesartan 20 nag monotherapy in these patients previously uncontrolled on monotherapy.

Zofenopril plus hydrochlorothiazide and irbesartan plus hydrochlorothiazide in previously treated and uncontrolled diabetic and non-diabetic essential hypertensive patients

INTRODUCTION

In most treated patients with hypertension, a two or more drug combination is required to achieve adequate blood pressure (BP) control. In our study we assessed whether the combination of zofenopril + hydrochlorothiazide (HCTZ) was at least as effective as irbesartan + HCTZ in essential hypertensives with at least one additional cardiovascular risk factor, uncontrolled by a previous monotherapy.

METHODS

After a 2-week placebo washout, 361 treated hypertensive patients [office sitting diastolic BP (DBP), ≥90 mmHg], aged 18-75 years, were randomized double blind to 18-week treatment with zofenopril 30 mg plus HCTZ 12.5 mg or irbesartan 150 mg plus HCTZ 12.5 mg once daily, in an international, multicenter study. After the first 6 and 12 weeks, zofenopril and irbesartan doses could be doubled in non-normalized subjects. The primary study end point was the office sitting DBP reduction after 18 weeks of treatment. Secondary end points included office systolic BP (SBP), ambulatory BP and high sensitivity C-reactive protein (hs-CRP).

RESULTS

The between-treatment difference for office DBP averaged to +1.0 (95% CI -0.4, +0.8) mmHg (P = 0.150), the upper limit of the 95% confidence interval being inferior to the protocol-defined non-inferiority limit (3 mmHg). In the subset of patients with valid ambulatory BP, no difference in 24-h average DBP [n = 181; 6.7 (8.7, 4.6) zofenopril + HCTZ vs. 6.3 (8.8, 3.7) mmHg irbesartan + HCTZ, P = 0.810] and SBP reductions [11.7 (15.4, 8.0) vs. 12.6 (17.2, 8.0) mmHg, P = 0.758] were observed between the two treatment groups. hs-CRP was reduced by zofenopril + HCTZ [-0.52 (-1.05, 0.01) mg/L], while it was increased by irbesartan plus HCTZ [0.97 (0.29, 1.65) mg/L, P = 0.001 between treatments].

CONCLUSION

In previously monotherapy-treated, uncontrolled patients with hypertension, zofenopril 30-60 mg + HCTZ 12.5 mg is as effective as irbesartan 150-300 mg plus HCTZ 12.5 mg, with the added value of a potential protective effect against vascular inflammation.

Free radicals and antioxidants in cardiovascular diseases

It has been demonstrated that redox homeostasis is important in the pathophysiology of several human diseases, including cardiovascular diseases. In this respect, genetic polymorphism, nutritional and environmental factors, age, lifestyle and physical activity may account for variable antioxidant defenses, which may be more or less effective at counteracting oxidative damage. Since accumulating oxidative damage may be associated with several pathologic conditions, including different cardiovascular diseases, prevention of oxidative stress appears to be a promising approach to improve such diseases. Exercise training, diets rich in antioxidants and a good control of blood glucose and lipid levels help to strengthen the physiologic antioxidant defense system, perhaps coupled to drugs capable of increasing the nitric oxide bioavailability and decreasing superoxide production. Within the next few years other therapeutic approaches will be available, such as gene therapy, which will prove to be even more effective but devoid of several important systemic side effects.

Telmisartan/hydrochlorothiazide: a new fixed dose combination

Many patients with hypertension require two or more antihypertensive drugs with complementary mechanisms of action to lower their blood pressure and attain the therapeutic goals specified in internationally accepted guidelines. Yet, these latter guidelines offer the choice of fixed dose combinations as possible first-step therapies. The angiotensin II type 1-receptor antagonist telmisartan and the diuretic hydrochlorothiazide are two antihypertensive agents that have a well-recognized clinical efficacy. Their combination was shown in randomized, controlled trials to be more effective than each agent alone in lowering blood pressure, due to a dual and synergistic mechanism. Indeed, combining telmisartan with hydrochlorothiazide enhances the antihypertensive efficacy of telmisartan in almost two-thirds of hypertensive patients with mild-to-moderate hypertension. The pharmacokinetics and -dynamics of the combination are similar to monotherapy, and the addition of hydrochlorothiazide to telmisartan does not modify the excellent tolerability profile of the drug.

The fixed-dose combination of losartan/hydrochlorothiazide elicits potent blood pressure lowering during nighttime in obese hypertensive patients

Background

Hypertension is one of the most powerful predictor of the future cardiovascular events, and antihypertensive therapy adopting multiple drug regimen is often needed to obtain the appropriate blood pressure (BP) control. To clarify the blood pressure-lowering effect of the fixed-dose combination (FDC) of an angiotensin receptor blocker (ARB) and diuretic agent in poorly controlled hypertensive patients, we intended a multicenter prospective observational study (Investigation for Normalized Blood pressure control with the Appropriate medication: INBA) by means of the sequential ambulatory blood pressure monitoring (ABPM).

Methods

One hundred and thirteen hypertensive patients who had not achieved the target BP control proposed in the guidelines with medication containing any ARB but without diuretic agents (54 men; mean age, 66 years old; mean office systolic/diastolic BP (SBP/DBP), 158/82 mmHg) were enrolled. Daytime and nighttime blood pressures were assessed with ABPM before and at 12 weeks after switching the ARB to the FDC of 50 mg of losartan, and 12.5 mg of hydrochlorothiazide (HCTZ).

Results

Daytime SBP/DBP (mean ± SD) decreased from 151 ± 14/88 ± 8 mmHg to 140 ± 11/82 ± 8 mmHg (P < 0.001, P < 0.001, respectively), and nocturnal SBP/DBP from 138 ± 18/78 ± 9 mmHg to 125 ± 14/72 ± 9 mmHg (P < 0.001, P < 0.001, respectively) during the 12 weeks treatment. Pulse rate did not change irrespective of the time window. Among various parameters (age, history of hypertension, body mass index (BMI), serum potassium, uric acid, estimated glomerular filtration rate, plasma B-type natriuretic peptide), BMI alone showed significant negative correlation with 12-weeks reduction in nocturnal SBP (r = -0.43, P < 0.05). No parameters correlated with reduction in daytime SBP during this period. Patients with BMI ≥ median (25.8 kg/m²) showed significantly greater reduction in nocturnal SBP for 12 weeks than patients with BMI < median (20.1 ± 15.6 mmHg vs 6.1 ± 10.9 mmHg, P < 0.001) although reduction in daytime SBP was comparable between the two groups (8.9 ± 13.5 mmHg vs 11.9 ± 12.7 mmHg).

Conclusions

The administration of the FDC of losartan/HCTZ lowers BP both in day- and nighttime, and the nocturnal antihypertensive potency is remarkable in obese patients.

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

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

Long-term safety and tolerability of the oral direct renin inhibitor aliskiren with optional add-on hydrochlorothiazide in patients with hypertension: a randomized, open-label, parallel-group, multicentre, dose-escalation study with an extension phase

BACKGROUND

Most patients with hypertension will require combination therapy with at least two agents from different antihypertensive classes to achieve blood pressure (BP) control. Thiazide diuretics, such as hydrochlorothiazide (HCTZ), are widely used in combination therapy. The volume reduction with these agents stimulates the renin-angiotensin system (RAS), making RAS inhibitors such as the direct renin inhibitor aliskiren a logical choice for combination therapy with HCTZ.

OBJECTIVE

The aim of this study was to investigate the long-term safety, tolerability and efficacy of the direct renin inhibitor aliskiren, with or without addition of the diuretic HCTZ.

METHODS

In the 12-month core study, patients with hypertension (mean sitting diastolic BP ≥90 mmHg and <110 mmHg) were randomized in a 3 : 2 ratio to once-daily aliskiren 150 mg or 300 mg. At months 2, 3, 4, 6 and 9, treatment was adjusted in patients not achieving a BP goal of <140/90 mmHg. Patients not at goal on aliskiren 150 mg once daily were up-titrated to aliskiren 300 mg once daily. Patients not at goal with aliskiren 300 mg once daily received add-on HCTZ 12.5 mg once daily, which was up-titrated to 25 mg once daily if BP remained inadequately controlled. At month 12, patients who received aliskiren/HCTZ 300 mg/25 mg once daily for at least 8 months in the core study were eligible to enter a 4-month extension study.

RESULTS

Overall, 1625/1955 patients completed the core study, and 870/1955 patients received add-on HCTZ; 189/198 patients completed the 4-month extension. Aliskiren, with or without add-on HCTZ, was generally well tolerated; the incidence of adverse events (AEs) during the core study was similar among the four final treatment groups. The most frequently reported AEs in the core and extension studies were mild and transient cases of nasopharyngitis, headache and dizziness. Few patients exhibited laboratory abnormalities. Overall, aliskiren, with or without add-on HCTZ, reduced mean BP by 18.0/12.7 mmHg at core study endpoint, and 61.2% of patients achieved BP control. BP reductions with aliskiren/HCTZ 300 mg/25 mg combination therapy at the core study endpoint were maintained during the extension study.

CONCLUSION

In patients with hypertension, long-term treatment with aliskiren, with or without add-on HCTZ, is well tolerated and provides effective BP lowering that is sustained over 12 months.

An overview of candesartan in clinical practice

Hypertension is a major risk factor for coronary heart disease, stroke, heart failure and renal disease. The Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure 7 defined hypertension as a blood pressure of more than 140/90 mmHg and recommended to initiate treatment with a two-drug combination for stage 2 hypertension (blood pressure of 160-179/100-109 mmHg). The need for drug combinations is clear from a patient and physician perspective as they provide more effective blood pressure lowering, reduce pill burden, improve compliance and decrease hypertension-related morbidity and mortality. Angiotensin II receptor blocker therapy has been proven to be well tolerated and effective in the management of hypertension, chronic heart failure with left ventricular dysfunction and the prevention and progression of diabetic renal disease. Blockers of the renin-angiotensin system are an important component of antihypertensive combination therapy. Thiazide-type diuretics are usually added to increase the blood pressure lowering efficacy. Fixed drug-drug combinations of both principles, such as candesartan/hydrochlorothiazide, are highly effective in lowering blood pressure while providing improved compliance, a good tolerability and largely neutral metabolic profile. In this article, we review the literature for the role of candesartan-based therapy for hypertension, stroke, diabetes mellitus and heart failure.

Candesartan cilexetil/hydrochlorothiazide combination treatment versus high-dose candesartan cilexetil monotherapy in patients with mild to moderate cardiovascular risk (CHILI Triple T)

BACKGROUND

Candesartan cilexetil has been shown to effectively reduce blood pressure and cardiovascular risk. Whether it is advantageous to combine candesartan cilexetil with low-dose hydrochlorothiazide (HCTZ) or uptitrate it in cases of insufficient blood pressure control has not been fully investigated under routine clinical conditions.

METHODS

CHILI Triple T is a prospective, noninterventional, observational study. Patients with uncontrolled hypertension and added cardiovascular risk received a fixed-dose combination of candesartan cilexetil 16 mg and HCTZ 12.5 mg (combination therapy group) or high-dose monotherapy with candesartan cilexetil 32 mg (high-dose monotherapy group).

RESULTS

A total of 4600 patients with a mean age of 63.1 ± 11.0 years, of which 44.7% were female, was included. The combination therapy group had 3337 patients, and the high-dose monotherapy group 1263 patients. Patients in both treatment groups were comparable with respect to age and gender, but patients receiving high-dose monotherapy had a slightly higher mean systolic blood pressure, more prior revascularizations, renal insufficiency, diabetic nephropathy, peripheral artery disease, and a lower ankle brachial index. The use of combination therapy resulted in a blood pressure reduction of -28.5 ± 13.8/-14.2 ± 9.4 mm Hg (P < 0.001 vs 160.2 ± 13.3/94.5 ± 8.2 mm Hg at baseline). The use of high-dose monotherapy reduced blood pressure by -29.73 ± 15.3/-14.1 ± 9.6 mm Hg (P < 0.001 vs 162.4 ± 14.7/94.7 ± 8.7 mm Hg at baseline). Differences in subgroups of patients defined by age, gender, body mass index, dyslipidemia, waist circumference, smoking, prior cardiovascular event, glomerular filtration rate, and microalbuminuria were minor, although partially significant. Tolerability was excellent, with only 28 out of 3358 patients (0.8%) in the combination therapy group and 15 out of 1273 patients (1.2%) in the high-dose monotherapy group experiencing any adverse event, of which one in each group was considered to be serious (<0.1%).

CONCLUSIONS

Both the fixed-dose combination of candesartan cilexetil 16 mg and HCTZ 12.5 mg and high-dose monotherapy with candesartan 32 mg were highly effective in lowering blood pressure in patients at increased cardiovascular risk. Tolerability was excellent. The choice of either strategy therefore largely depends on the principal aim: blood pressure reduction with pronounced volume restriction or pronounced additional end-organ protection.

Central Pressure and Biomarker Responses to Renin Inhibition with Hydrochlorothiazide and Ramipril in Obese Hypertensives: The ATTAIN Study

BACKGROUND/AIMS

In obese, hypertensive subjects, the renin-angiotensin system (RAS) is enhanced and natriuresis impaired, suggesting a role for combination RAS blockade with diuretics. Data suggest that renin inhibition may attenuate diuretic-induced RAS activation and oxidative stress.

METHODS

In this 8-week, double-blind study of 386 obese individuals (mean body mass index: 35.3) with stage 2 hypertension (mean age: 54.9 years; mean sitting systolic blood pressure, SBP: ≧160 but <200 mm Hg), we compared the efficacy of aliskiren + hydrochlorothiazide (HCTZ) in reducing blood pressure (BP), plasma renin activity (PRA), and a urinary marker of oxidative stress to ramipril. Subjects were randomized to aliskiren/HCTZ 150/12.5 mg or ramipril 5 mg for 1 week, and after the 1st week force titrated to aliskiren/HCTZ 300/25 mg or ramipril 10 mg for 7 weeks.

RESULTS

After 8 weeks, aliskiren/HCTZ provided greater reductions in office BP than ramipril (-28.1/-10.1 vs. -16.6/-3.6 mm Hg, p < 0.0001) as well as 24-hour ambulatory and central pressure measures. Aliskiren/HCTZ also lowered PRA (-45 vs. +83%) and the urinary F2-isoprostane/creatinine ratio (-18 vs. +7%) to a greater extent than ramipril. Adverse events (AEs) were similar in the two groups (35.8% with aliskiren/HCTZ vs. 37.3% on ramipril reporting at least one AE).

CONCLUSIONS

Our findings suggest that the aliskiren/HCTZ combination reduced BP, PRA, and isoprostanes to a greater extent than did ramipril in obese patients with stage 2 hypertension.

First-line treatment of hypertension: critical appraisal of potential role of aliskiren and hydrochlorothiazide in a fixed combination

Arterial hypertension is one of the major diseases in the Western world. It is an independent cardiovascular risk factor and is associated with increased morbidity and mortality. Several drug classes have been shown to be effective in the treatment of hypertension. Aliskiren is a direct renin inhibitor and belongs to the class of renin-angiotensin-aldosterone system inhibitors. Several large studies have shown that aliskiren is effective in lowering blood pressure, and equivalent in this respect to the angiotensin-converting enzyme (ACE) inhibitors and the angiotensin receptor-1 blockers (ARBs). Furthermore, aliskiren has a safety and tolerability profile comparable with that of the ARBs and slightly better than that of the ACE inhibitors. From a pathophysiologic perspective, it can be combined with hydrochlorothiazide successfully, because it can block the diuretic-induced increase in plasma renin activity. Its combination with hydrochlorothiazide in a single pill has been investigated and shown to be superior to monotherapy with respect to blood pressure control and improvement in patient compliance with therapy. Further studies are needed to show whether aliskiren and its combination with hydrochlorothiazide is effective in preventing cardiovascular events and mortality when end organ damage is present.

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

BACKGROUND

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

METHODS

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

FINDINGS

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

CONCLUSIONS

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

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.

Should diuretics always be included as initial antihypertensive management in early-stage CKD?

PURPOSE OF REVIEW

This review focuses on the need for combined antihypertensive therapy drugs in patients with chronic kidney disease and the relevance of diuretics.

RECENT FINDINGS

Chronic kidney disease is a high-risk situation characterized by the presence of volume overload-related hypertension, micro/macroalbuminuria and other traditional and nontraditional risk factors. To achieve the blood pressure goal in these patients, combined antihypertensive therapy (including diuretics) is usually required.

SUMMARY

Extracellular volume expansion is an important, if not the most important, contributing factor to hypertension seen in chronic kidney disease. Protection against progression of renal dysfunction has two main requirements: strict blood pressure control and lowering proteinuria to values as near to normal as possible. Diuretics have been a useful tool to manage volume overload and to achieve strict blood pressure control in patients with chronic kidney disease. Albeit other blood pressure-lowering agents offer additional favorable effects independently of blood pressure changes, diuretics will continue to be used in these patients.

Renin inhibition with aliskiren in hypertension: focus on aliskiren/hydrochlorothiazide combination therapy

Hypertension is a major risk factor for the development of cardiovascular and renal disease. The incidence of hypertension is increasing globally and the rate of blood pressure control remains inadequate. Renin-angiotensin-aldosterone system (RAAS) plays a crucial role in volume regulation and maintenance of blood pressure. Pathological activation of RAAS results in chronic hypertension and consequent end organ damage. Most patients with hypertension require combination therapy using agents with complimentary mechanisms of action. Hydrochlorothiazide (HCTZ) together with an agent blocking the RAAS such as an angiotensin converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) are widely used effective anti-hypertensive therapy. Aliskiren is an orally effective direct renin inhibitor that blocks the generation of angiotensin I from angiotensinogen, the rate limiting step of RAAS activation. Studies have shown equivalent antihypertensive efficacy of aliskiren when compared to existing medications such as HCTZ, ACE inhibitors and ARBs. Aliskiren has also been tested in combination therapies. The current review aims to look at the efficacy of aliskiren therapy in hypertension and the evidence for using aliskiren in combination with HCTZ.

Antihypertensive efficacy and tolerability of aliskiren/hydrochlorothiazide (HCT) single-pill combinations in patients who are non-responsive to HCT 25 mg alone

OBJECTIVE

Thiazide diuretics such as hydrochlorothiazide (HCT) are a widely used first-line treatment for hypertension, but most patients will not achieve blood pressure (BP) control with HCT alone and so will require combination therapy. In this study the efficacy, safety and tolerability of a single-pill combination (SPC) of the direct renin inhibitor aliskiren with HCT were investigated in patients non-responsive to HCT 25 mg therapy.

METHODS

In this study, 722 patients with hypertension and an inadequate response to 4 weeks of HCT 25 mg (mean sitting diastolic BP > or =90 and <110 mmHg) were randomized to once-daily, double-blind treatment for 8 weeks with an SPC of aliskiren/HCT 300/25 mg or 150/25 mg, or continued HCT 25 mg monotherapy. Least-squares mean changes in mean sitting systolic/diastolic BP (msSBP/DBP) from double-blind baseline were analyzed for the ITT population at week 8 endpoint.

RESULTS

Aliskiren/HCT 300/25 mg and 150/25 mg SPCs lowered msSBP/DBP from baseline by 16.7/10.7 and 12.9/8.5 mmHg, respectively, both significantly greater reductions than HCT 25 mg alone (7.1/4.8 mmHg; both p < 0.001). Rates of BP control (<140/90 mmHg) were also significantly higher with aliskiren/HCT 300/25 mg (58%) and 150/25 mg (49%) than with HCT (26%; both p < 0.001). Aliskiren/HCT 300/25 mg provided significantly greater msSBP/DBP reductions and rates of BP control than the 150/25 mg SPC dose (all p < 0.05). Aliskiren/HCT SPC treatment showed similar tolerability to HCT alone and a numerically lower incidence of hypokalemia (serum potassium <3.5 mmol/L; aliskiren/HCT, 1.3-2.2%: HCT alone, 3.4%).

CONCLUSION

Aliskiren/HCT SPCs provide clinically significant BP reductions and improved BP control rates in patients who are non-responsive to HCT 25 mg monotherapy. Limitations of the study were the mainly Caucasian patient population and the non-responder design.

Initial combination therapy for rapid and effective control of moderate and severe hypertension

Moderate (grade 2) and severe (grade 3) hypertension are important public health problems associated with high cardiovascular risk. Blood pressure (BP) control becomes more difficult to achieve as hypertension progresses. Therefore, early and effective treatment is essential to prevent hypertensive urgencies and emergencies and reduce cardiovascular risk. Currently, less than 50% of patients being treated for moderate or severe hypertension in the United States achieve their BP goal as recommended by treatment guidelines. This review examines the cardiovascular risk and physician inertia associated with moderate and severe hypertension, and concludes that increased use of initial combination therapy can overcome many of the barriers to effective BP control. Furthermore, initial combination therapy with a renin-angiotensin system (RAS) inhibitor and diuretic has the potential to rapidly and effectively reduce BP across a range of baseline BPs, with a comparable adverse event profile to monotherapy.

Role of combination therapy in the treatment of hypertension: focus on valsartan plus amlodipine

Hypertension control is rare in clinical practice, particularly in high-risk patients. A large factor is therapeutic inertia deriving from poorly prescribed lifestyle changes, excess monotherapy use, and scarce on-treatment modifications. The use of drug combinations significantly improves blood pressure (BP) control; in particular, fixed combinations improve therapy without increasing daily pill intake, thereby favouring patient compliance and therapy continuation. The most widely used fixed combination is based on thiazide diuretics added to either angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs). Several large-scale clinical trials have been conducted showing that these combinations are effective in lowering BP. However, thiazide diuretics can reduce the metabolic benefits derived from renin-angiotensin-aldosterone system (RAAS) inhibitors in high metabolic risk patients. In contrast, ACE inhibitors or ARBs combined with dihydropyridine calcium channel antagonists (DHPCAs) exert a marked antihypertensive effect without decreasing metabolic protection by RAAS blockade. In the recent JIKEI heart study, approximately 60% of patients affected by hypertension, heart failure, coronary heart disease or their combination in the valsartan arm were simultaneously treated with DHPCAs. Of note, a 39% reduction in the primary endpoint of combined morbidity and mortality was reported in the valsartan compared with the non-valsartan arm. Furthermore, in a recent multinational study, 83% of 3161 hypertensive patients treated with valsartan and the DHCPA amlodipine reported a concontrolled BP after 8 weeks of treatment. As expected, amlodipine did not negatively influence the metabolic profile of patients, thereby supporting the role of ARB+DHPCA combinations as effective and promising tools in hypertension treatment. In summary, the combination of ARBs with DHPCAs is an effective strategy in hypertension treatment through synergy between their antihypertensive and vascular protective actions, persistent metabolic benefits deriving from RAAS inhibition, and reduced incidence of side effects.

Emerging insights in the first-step use of antihypertensive combination therapy

The blood pressure (BP) goals set by hypertension management guidelines (<140/90 mm Hg in uncomplicated hypertension; <130/80 mm Hg in type 2 diabetes or kidney disease) are not being achieved in a high proportion of patients, partly because monotherapy is insufficient in many patients. In particular, patients with uncontrolled moderate or severe hypertension and/or associated cardiovascular risk factors remain at high risk for cardiovascular events and hypertensive emergency. In recognition of the urgency of treating moderate and severe hypertension, the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) advocates the initial use of 2-drug therapies in patients with systolic BP levels >20 mm Hg above goal or diastolic BP level >10 mm Hg above goal. Regimens should usually include a thiazide diuretic and, for patients with diabetes or kidney disease, an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker. Recently, clinical trial data have shown that first-step antihypertensive treatment of moderate and severe hypertension with carefully chosen fixed-dose combinations provides a high rate of BP goal achievement, a simplified dosing regimen, and superior tolerability compared with monotherapy.

Rationale for Combination Therapy in Hypertension Management: Focus on Angiotensin Receptor Blockers and Thiazide Diuretics

Despite recognition that hypertension is a major risk factor for cardiovascular events and mortality, blood pressure control rates remain low in the US population. Reflecting clinical trial results, hypertension management guidelines assert the clinical benefit of achieving current blood pressure goals and indicate that most patients will require 2 or more drugs to reach goal. Well-designed drug combinations counter hypertension via complementary mechanisms that increase antihypertensive efficacy, potentially with lower rates of adverse events than higher dose monotherapy regimens. Lower adverse event rates, in turn, may contribute to greater adherence with treatment. The combination of a low-dose diuretic with agents that block the effects of the renin-angiotensin system (RAS), such as angiotensin receptor blockers, has been found in numerous clinical trials to be highly effective for lowering blood pressure in patients with uncomplicated as well as high-risk hypertension, with a comparable favorable side effect profile compared with monotherapy. Moreover, agents that block the RAS are associated with a lower risk of new-onset diabetes mellitus than other antihypertensive classes. Complementary combinations of antihypertensive agents provide an efficient and effective approach to hypertension management.

Direct Renin inhibition with aliskiren in obese patients with arterial hypertension

Current guidelines from the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recommend first-line treatment with a thiazide diuretic but do not provide specific guidance for obese patients. The renin system is activated in obesity-associated arterial hypertension. Therefore, we tested the hypothesis that the oral direct renin inhibitor aliskiren could provide additive blood pressure lowering in obese patients with hypertension (body mass index >or=30 kg/m(2); mean sitting diastolic blood pressure: 95 to 109 mm Hg) who had not responded to 4 weeks of treatment with hydrochlorothiazide (HCTZ) 25 mg. After a 2- to 4-week washout, 560 patients received single-blind HCTZ (25 mg) for 4 weeks; 489 nonresponders were randomly assigned to double-blind aliskiren (150 mg), irbesartan (150 mg), amlodipine (5 mg), or placebo for 4 weeks added to HCTZ (25 mg), followed by 8 weeks on double the initial doses of aliskiren, irbesartan, or amlodipine. After 8 weeks of double-blind treatment (4 weeks on the higher dose), aliskiren/HCTZ lowered blood pressure by 15.8/11.9 mm Hg, significantly more (P<0.0001) than placebo/HCTZ (8.6/7.9 mm Hg). Aliskiren/HCTZ provided blood pressure reductions similar to those with irbesartan/HCTZ and amlodipine/HCTZ (15.4/11.3 and 13.6/10.3 mm Hg, respectively), with similar tolerability to placebo/HCTZ. Adverse event rates were highest with amlodipine/HCTZ because of a higher incidence of peripheral edema (11.1% versus 0.8% to 1.6% in other groups). In conclusion, combination treatment with aliskiren is a highly effective and well-tolerated therapeutic option for obese patients with hypertension who fail to achieve blood pressure control with first-line thiazide diuretic treatment.

Renin inhibition with aliskiren provides additive antihypertensive efficacy when used in combination with hydrochlorothiazide

OBJECTIVES

Aliskiren is a novel, orally active renin inhibitor. Its antihypertensive efficacy and safety, alone and in combination with hydrochlorothiazide (HCTZ), were investigated in an 8-week, double-blind, placebo-controlled trial in hypertensive patients. The effects of these treatments on plasma renin activity (PRA) were also assessed.

METHODS

A total of 2776 patients aged >or=18 years with mean sitting diastolic blood pressure (MSDBP) 95-109 mmHg were randomized to receive once-daily treatment with aliskiren (75, 150 or 300 mg), HCTZ (6.25, 12.5 or 25 mg), the combination of aliskiren and HCTZ, or placebo, in a factorial design. The primary endpoint was the change in MSDBP from baseline to week 8. PRA was assessed at these timepoints at selected study centers.

RESULTS

Aliskiren monotherapy was superior to placebo (P < 0.001; overall Dunnett's test) in reducing MSDBP and mean sitting systolic blood pressure (MSSBP). Combination treatment was superior to both component monotherapies in reducing BP (maximum MSSBP/MSDBP reduction of 21.2/14.3 mmHg from baseline with aliskiren/HCTZ 300/25 mg), and resulted in more responders (patients with MSDBP < 90 mmHg and/or >or=10 mmHg reduction) and better control rates (patients achieving MSSBP/MSDBP < 140/90 mmHg) than either monotherapy. Aliskiren monotherapy reduced PRA by up to 65% from baseline. Although HCTZ monotherapy increased PRA by up to 72%, PRA decreased in all of the combination therapy groups. All active treatments were well tolerated.

CONCLUSIONS

Aliskiren monotherapy demonstrated significant BP lowering, and its effect was considerably greater when combined with HCTZ. Renin inhibition with aliskiren neutralized the compensatory rise in PRA induced by HCTZ.

Update of Diuretics in the Treatment of Hypertension

Diuretics, which are primarily used to modify the volume and the composition of body fluids, are widely used to treat hypertension. The diuretics include a) the thiazides and thiazide-like agents, which are the most common drugs used to treat high blood pressure (these drugs inhibit sodium reabsorption in the early distal convoluted tubule); b) loop diuretics, such as furosemide, block chloride and sodium reabsorption by inhibition of the Na/K/2Cl cotransport system in the thick ascending limb of the loop of Henle; and c) potassium-sparing (retaining) diuretics, including aldosterone receptor blockers (such as spironolactone and eplerenone) and epithelial sodium channel blockers (such as amiloride and triamterene, which interfere with the reabsorption of sodium and excretion of potassium and hydrogen that takes place in the late distal tubule, the connecting tubule, and the cortical collecting duct). Hydrochlorothiazide 12.5 mg once daily or equivalent low dosages of other similar agents reduce blood pressure in approximately one-half to two-thirds of patients who are responsive to this class of drugs; higher doses add little to the effect on blood pressure and also increase side effects. Some combinations of very small doses of thiazide diuretics - for example, 6.25 mg hydrochlorothiazide or 0.625 mg indapamide, with a low dose of an antihypertensive drug of a different class - have average antihypertensive efficacy when used once daily. Furosemide is used in patients with renal failure or severe heart failure and is best given by continuous intravenous infusion. The potassium-sparing diuretics are generally used in combination with thiazide diuretics to treat hypertension. Side effects occur at about the same frequency and severity with equipotent doses of all diuretics. The incidence of side effects is dose-dependent and also increases as a function of the duration of the renal excretory and antihypertensive actions. However, longer-acting diuretics provide better 24-hour control of blood pressure and increase compliance and adherence to the treatment regimen.

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.

Fixed-Drug Combinations as First-Line Treatment for Hypertension

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