The long-term antihypertensive activity and tolerability of irbesartan with hydrochlorothiazide

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.

Safety and tolerability of azilsartan medoxomil in subjects with essential hypertension: a one-year, phase 3, open-label study

This 56-week phase 3, open-label, treat-to-target study, involving 2 consecutive, non-randomized cohorts, evaluated the safety and tolerability of azilsartan medoxomil (AZL-M) in essential hypertension (mean baseline blood pressure [BP] 152/100 mmHg). All subjects (n = 669) initiated AZL-M 40 mg QD, force-titrated to 80 mg QD at week 4, if tolerated. From week 8, subjects could receive additional medications, starting with chlorthalidone (CLD) 25 mg QD (Cohort 1) or hydrochlorothiazide (HCTZ) 12.5–25 mg QD (Cohort 2), if required, to reach BP targets. Adverse events (AEs) were reported in 75.9% of subjects overall in the two cohorts (73.8% Cohort 1, 78.5% Cohort 2). The most common AEs were dizziness (14.3%), headache (9.9%) and fatigue (7.2%). Transient serum creatinine elevations were more frequent with add-on CLD. Clinic systolic/diastolic BP (observed cases at week 56) decreased by 25.2/18.4 mmHg (Cohort 1) and 24.2/17.9 mmHg (Cohort 2). These results demonstrate that AZL-M is well tolerated over the long term and provides stable BP improvements when used in a treat-to-target BP approach with thiazide-type diuretics.

AT1receptor antagonism in hypertension: what has been learned with irbesartan?

Irbesartan is a long-acting angiotensin II antagonist acting specifically at the level of the Type 1-receptor subtype (AT1-receptor). This compound lowers blood pressure dose-dependently in hypertensive patients and has a placebo-like tolerability. The antihypertensive efficacy of irbesartan is greatly enhanced by the coadministration of a diuretic, and fixed-dose combinations of irbesartan and hydrochlorothiazide are now available. Irbesartan-based treatment appears especially effective for high-risk patients, such as those with diabetes, renal disease and cardiac hypertrophy. In patients with Type 2 diabetes, irbesartan delays the development of nephropathy as well as the progression of renal failure. Irbesartan may have antiatherosclerotic properties beyond those expected from blood pressure lowering per se: this AT1-blocker decreases the vascular oxidative stress and prevents the procoagulant as well as the pro-inflammatory effects of angiotensin II. Irbesartan given alone or in combination with a diuretic therefore represents a rational approach to treat hypertensive patients.

Comprehensive overview: efficacy, tolerability, and cost-effectiveness of irbesartan

Background

Hypertension represents a major health problem, affecting more than one billion adults worldwide. Irbesartan, an angiotensin II receptor blocker, is considered to be a highly effective treatment in the management of hypertension. The purpose of this review is to evaluate the efficacy, safety and tolerability profile , and cost-effectiveness of treatment with irbesartan in hypertension.

Methods

A review of the literature was conducted using the electronic PubMed and Cochrane Library databases and the Health Economic Evaluations Database of search terms relating to irbesartan efficacy, tolerability, and cost-effectiveness, and the results were utilized.

Results

Findings from the present analysis show that irbesartan either as monotherapy or in combination with other antihypertensive agents can achieve significant reductions in blood pressure, both systolic and diastolic, compared with alternative treatment options. Irbesartan was also found to have a renoprotective effect independent of its blood pressure-lowering in patients with type 2 diabetes and nephropathy. Furthermore, irbesartan demonstrated an excellent safety and tolerability profile , with either lower or equal adverse events compared with placebo and other alternative treatments. In terms of economic analyses, compared with other antihypertensive therapy alternatives, irbesartan was found to be a preferred option, that is less costly and more effective.

Conclusion

The evidence indicates that treating patients with hypertension alone or with type 2 diabetes and nephropathy using irbesartan can control hypertension, prolong life, and reduce costs in relation to existing alternatives.

Long-term use and tolerability of irbesartan for control of hypertension

In this review, we discuss the pharmacological and clinical properties of irbesartan, a noncompetitive angiotensin II receptor type 1 antagonist, successfully used for more than a decade in the treatment of essential hypertension. Irbesartan exerts its antihypertensive effect through an inhibitory effect on the pressure response to angiotensin II. Irbesartan 150-300 mg once daily confers a lasting effect over 24 hours, and its antihypertensive efficacy is further enhanced by the coadministration of hydrochlorothiazide. Additionally and partially beyond its blood pressure-lowering effect, irbesartan reduces left ventricular hypertrophy, favors right atrial remodeling in atrial fibrillation, and increases the likelihood of maintenance of sinus rhythm after cardioversion in atrial fibrillation. In addition, the renoprotective effects of irbesartan are well documented in the early and later stages of renal disease in type 2 diabetics. Furthermore, both the therapeutic effectiveness and the placebo-like side effect profile contribute to a high adherence rate to the drug. Currently, irbesartan in monotherapy or combination therapy with hydrochlorothiazide represent a rationale pharmacologic approach for arterial hypertension and early-stage and late-stage diabetic nephropathy in hypertensive type II diabetics.

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

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

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

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

Fixed combination of irbesartan and hydrochlorothiazide in the management of hypertension

Approximately 25% of the adult population worldwide is hypertensive and thus at risk of cardiovascular morbidity and mortality. Despite the availability of many antihypertensive drugs, at least 50% of patients do not achieve blood pressure (BP) targets and thus remain at increased cardiovascular risk. Fixed-dose (FD) irbesartan/hydrochlorothiazide (HCTZ) is an antihypertensive combination therapy approved for the treatment of patients whose BP is not adequately controlled on monotherapy and for initial treatment of patients likely to need multiple drugs to achieve their BP goal. The efficacy and tolerability of FD irbesartan/HCTZ has been demonstrated in both patient populations in large multicenter studies. In patients failing antihypertensive monotherapy, FD irbesartan/HCTZ (150/12.5 mg) has been shown to be more effective than FD valsartan/HCTZ (80/12.5 mg) and at least comparable to FD losartan/HCTZ (50/12.5 mg). In patients with moderate or severe hypertension receiving FD irbesartan/HCTZ as initial therapy, this combination achieved more rapid BP reductions compared with irbesartan monotherapy and enabled a greater proportion of patients with severe hypertension to achieve their BP target. FD irbesartan/HCTZ is thus a valuable addition to the clinician’s armamentarium for the management of hypertension and should help more patients achieve their BP target.

Comparison of angiotensin II type 1 receptor antagonists in the treatment of essential hypertension

Hypertension is a major health problem worldwide, yet remains under-diagnosed and under-treated. Angiotensin II type 1 receptor antagonists (angiotensin receptor blockers [ARBs]) are highly effective at reducing blood pressure (BP), exhibit renoprotective properties and have placebo-like tolerability. However, it is unclear whether there are clinical differences in efficacy and tolerability between the available ARBs. A review of published, randomized, comparative clinical trials suggests that differences in BP-lowering efficacy and 24-hour BP control may exist between ARBs, although it appears that there is no evidence for important differences in tolerability between ARBs. Few studies have assessed attainment rates for important combined systolic BP (SBP)/diastolic BP (DBP) goals recommended in treatment guidelines. Likewise, few studies have directly compared more than two agents or ARB/hydrochlorothiazide fixed-dose combinations, and most ARBs have not been compared across their full recommended dosage ranges. Overall, there is insufficient weight of evidence to allow definitive conclusions to be drawn regarding the comparative efficacy of the available ARBs. However, newer ARBs (e.g. olmesartan medoxomil and telmisartan) appear to be more effective than older ARBs (e.g. losartan and valsartan) in reducing DBP and/or SBP in some trials. In addition, olmesartan medoxomil treatment regimens resulted in high BP control rates in several trials, but head-to-head trials with other ARBs are required to put these control rates into perspective, especially for SBP control with various agents. The purpose of this review is to present published data from ARB efficacy trials for a comparison of various efficacy parameters among the agents within this drug class.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Efficacy and safety of fixed combinations of irbesartan/hydrochlorothiazide in older vs younger patients with hypertension uncontrolled with monotherapy

Subgroup analysis of the Irbesartan/Hydrochlorothiazide Blood Pressure Reductions in Diverse Patient Populations (INCLUSIVE) trial evaluated the efficacy and safety of irbesartan/hydrochlorothiazide (HCTZ) fixed combinations in patients aged 65 years or older with uncontrolled systolic blood pressure (SBP) after >or= 4 weeks of antihypertensive monotherapy. The INCLUSIVE trial was a prospective, open-label, single-arm trial carried out in 119 sites. Of 844 patients completing placebo treatment, 212 were aged 65 years or older. Participants received treatment with placebo (4-5 weeks), HCTZ 12.5 mg (2 weeks), irbesartan/HCTZ 150/12.5 mg (8 weeks), and then irbesartan/HCTZ 300/25 mg (8 weeks). From baseline to week 18 (n=184, intent-to-treat population), mean change in SBP was -23.0+/-13.3 mm Hg (P<.001) and diastolic BP (DBP) was -10.9+/-7.7 mm Hg (P<.001). Mean SBP/DBP at study end was 134.0+/-14.7/75.1+/-8.4 mm Hg, and SBP, DBP, and SBP/DBP goal was achieved in 73%, 96%, and 72% of patients, respectively. Irbesartan/HCTZ combination therapy allowed SBP goal attainment in 73% of patients aged 65 years or older whose hypertension was previously uncontrolled with antihypertensive monotherapy.

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

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

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.

Initial combination therapy with irbesartan/hydrochlorothiazide for hypertension: an analysis of the relationship between baseline blood pressure and the need for combination therapy

Hypertension treatment guidelines recommend initiating 2-drug therapy whenever blood pressure (BP) is > or =20 mm Hg systolic or > or =10 mm Hg diastolic above goal. This post hoc pooled analysis of 2 multicenter, randomized, double-blind, active-controlled forced-titration studies in 1235 patients with moderate and severe hypertension examined how baseline BP levels relate to the need for combination therapy by comparing the antihypertensive efficacy and tolerability of once-daily fixed-dose irbesartan/hydrochlorothiazide (HCTZ) 300/25 mg compared with irbesartan 300-mg or HCTZ 25-mg monotherapies. In study 1, patients with severe hypertension (seated diastolic BP [SeDBP] > or =110 mm Hg) were treated for 7 weeks with irbesartan or irbesartan/HCTZ combination therapy, with forced-titration after week 1. In study 2, patients with moderate hypertension (seated systolic BP [SeSBP] 160-180 mm Hg or SeDBP 100-110 mm Hg) were treated for 12 weeks with irbesartan/HCTZ, irbesartan monotherapy, or HCTZ monotherapy, with forced-titration after week 2. The relationship between baseline BP and the likelihood of achieving BP goals (SeSBP <140 mm Hg or SeDBP <90 mm Hg; SeSBP <130 mm Hg or SeDBP <80 mm Hg) as well as the antihypertensive response was evaluated at week 7/8. The need for combination therapy increased with increasing baseline BP and lower BP goals across the range of BP levels studied, with a comparable adverse effect profile to monotherapy. These results suggest that the likelihood of achieving an early BP goal for a given BP severity should be considered when choosing initial combination therapy vs monotherapy.

BP goal achievement in patients with uncontrolled hypertension : results of the treat-to-target post-marketing survey with irbesartan

BACKGROUND AND OBJECTIVE

Despite the fact that high BP is a leading risk factor for cardiovascular morbidity and mortality, BP goals are achieved in less than 10-30% of hypertensive patients. Irbesartan alone or in combination with hydrochlorothiazide has been shown to control BP in >70% of hypertensive patients in clinical trials. We set out to investigate the role in clinical practice of irbesartan in improving BP in uncontrolled hypertensive patients with a particular focus on patients with the metabolic syndrome through analysis of data from a post-marketing surveillance study.

METHODS

A multicentre, prospective, post-marketing surveillance study was conducted over 9 months in 14 200 patients aged > or =18 years with previously uncontrolled hypertension (either receiving therapy or newly diagnosed), paying particular attention to a subgroup of patients receiving irbesartan/hydrochlorothiazide as first-line combination therapy. BP was measured by a sphygmomanometer. The main outcome measures were systolic BP (SBP) and diastolic BP (DBP) reduction, response rate (DBP reduction of > or =10mm Hg or to <90 mm Hg), and BP normalisation (SBP <140 and DBP <90 mm Hg) in patients treated with irbesartan alone or in combination with hydrochlorothiazide. Analyses per patient subgroup, previous medication and whether treatment was initiated by the treating physician as first-line combination therapy were conducted. The number and nature of adverse events were documented.

RESULTS

Use of irbesartan 300 mg/day as monotherapy in previously uncontrolled patients resulted in a significant reduction in SBP/DBP (-26.8/-13.3mm Hg, p < 0.0001), which was comparable to the subgroup of patients with the metabolic syndrome (-26.3/-13.0mm Hg, p < 0.0001 vs baseline). Combination therapy (irbesartan 300 mg/hydrochlorothiazide 12.5mg once daily) lowered BP by -27.9/-14.2mm Hg (p < 0.0001) in previously uncontrolled patients; again the subgroup of patients with the metabolic syndrome achieved a comparable BP reduction (-27.5/-14.1mm Hg, p < 0.0001 vs baseline). Overall, no linear dose-response relationship was observed. Use of irbesartan/hydrochlorothiazide as first-line combination therapy was effective (BP normalisation rates between 65.7% and 78.6%) and safe. The mean number of antihypertensive tablets taken was reduced and after a mean period of 9 months, 92% of patients were still taking irbesartan therapy.

CONCLUSION

The study demonstrates that treatment with an irbesartan-based regimen for 9 months results in a strong BP reduction and is feasible as first-line combination therapy. Similar BP reductions were observed in the subgroup of patients with the metabolic syndrome. Compliance with treatment is particularly good, with >90% of patients continuing with treatment after 9 months.

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.

Early and late results of combined mitral-aortic valve surgery

OBJECTIVE

This retrospective study was designed to assess the early morbidity and mortality as well as long-term mortality of combined aortic-mitral valve procedures at a single centre.

METHODS

Patients were identified by analysing the intensive care and perfusion databases, from 1989 to 2003, with 113 receiving aortic-mitral valve procedures. Eighty-four percent of patients received a mechanical bileaflet valve. Survival was assessed using a Kaplan-Meier method, and determinants of survival with the Cox proportional hazards model.

RESULTS

There were 57 men and 56 women, median age 59 (18-84) years. The 30-day mortality was 9% (n=10). This cohort contained a number of high risk patients, 38% were classified as New York Heart Association class IV, 33.5% had at least moderate ventricular impairment, 20% were redo procedures and 17% urgent procedures. Survival estimates at 5 and 10 years were 85% (0.76-0.90) and 65% (0.49-0.77), respectively. Multivariate pre-operative predictors of death included renal dysfunction (creatinine >200 micromol/L) and hypertension. Rheumatic aetiology was associated with improved survival.

CONCLUSION

This study shows acceptable short and long-term survival in patients undergoing combined aortic-mitral valve surgical procedures at a single centre. Renal impairment and hypertension were associated with a poorer long-term prognosis and rheumatic aetiology was associated with improved survival. Age, LVEF and NYHA class were not associated with a worse outcome. This may affect future decision making in light of an aging population.

Optimizing hypertension management in clinical practice

A clear relationship exists between elevated blood pressure (BP) and various manifestations of cardiovascular disease. Despite the availability of numerous treatment guidelines, hypertension remains inadequately controlled, with only a small proportion of patients achieving target BP levels. Many factors, both patient and physician related, contribute to this poor level of hypertension control. Major determinants include the implementation of inappropriate treatment regimens that do not enable patients to achieve goal and poor patient compliance. For example, it is widely acknowledged that most patients require two or more antihypertensive drugs to achieve BP goal; however, physicians may be reluctant to employ such treatment strategies. The aim of this review is to explore factors that contribute to poor hypertension control rates and how to overcome these, including the rationale for selecting combination therapy, with particular reference to angiotensin II receptor blocker combinations.

Managing hypertension in patients with type 2 diabetes mellitus

PURPOSE

Current guideline recommendations for effective strategies to optimize the treatment of patients with concomitant hypertension and type 2 diabetes mellitus are reviewed.

SUMMARY

Current estimates indicate that 20 million people in the United States have diabetes, 90-95% of whom have type 2 diabetes mellitus. Type 2 diabetes mellitus is associated with an increased risk of premature death from cardiovascular disease (CVD), stroke, and end-stage renal disease. Hypertension is an extremely common comorbidity in patients with type 2 diabetes mellitus. The coexistence of hypertension in patients with type 2 diabetes is particularly destructive because of the strong linkage of the two conditions with CVD, stroke, progression of renal disease, and diabetic nephropathy. Current guidelines, including those issued by the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure, the National Kidney Foundation, and the American Diabetes Association, provide evidence-based recommendations for the treatment of hypertension in patients with type 2 diabetes mellitus. However, studies indicate that guidelines are not widely followed. Therefore, the beneficial effects of appropriate hypertension treatment observed in clinical trials are often not recognized in clinical practice. Pharmacists are ideally positioned to help improve guideline implementation and patient outcome.

CONCLUSION

Pharmacists must become more vigilant about following current guidelines for the treatment of patients with concomitant hypertension and type 2 diabetes mellitus. Strategies such as patient education and medication assessment can help to optimize care for these patients and slow the progression to diabetic nephropathy.

Ambulatory blood pressure comparison of the anti-hypertensive efficacy of fixed combinations of irbesartan/hydrochlorothiazide and losartan/hydrochlorothiazide in patients with mild-to-moderate hypertension

This study examined whether the greater anti-hypertensive efficacy of irbesartan monotherapy over losartan monotherapy extends to the respective fixed-dose combinations with hydrochlorothiazide (HCTZ) in patients with mild-to-moderate hypertension. Patients were treated with either irbesartan 150 mg/HCTZ 12.5 mg or losartan 50 mg/HCTZ 12.5 mg over a 4-week period. Twenty-four hour daytime and night-time mean blood pressure (BP), BP load and duration of action were assessed using ambulatory BP monitoring. Both treatment regimens significantly reduced BP from baseline for all efficacy variables assessed. A significant difference was noted in adjusted mean changes from baseline in 24-h ambulatory diastolic BP with irbesartan/HCTZ versus losartan/HCTZ. Reduction in diastolic load was significantly greater with irbesartan/HCTZ than with losartan/HCTZ as was mean ambulatory systolic BP during the last 4 h of the dosing interval. Both regimens were well tolerated, with no significant differences in terms of adverse event profile observed. Irbesartan 150 mg/HCTZ 12.5 mg resulted in greater reductions in ambulatory BP than losartan 50 mg/HCTZ 12.5 mg.

Pharmacokinetic and pharmacodynamic interaction between irbesartan and hydrochlorothiazide in renal hypertensive dogs

Combined irbesartan/hydrochlorothiazide (HCTZ) formulations are often used clinically. Pharmacokinetic-pharmacodynamic (PK/PD) modeling was applied to investigate the pharmacokinetic and pharmacodynamic interaction between irbesartan and HCTZ in renal hypertensive dogs at non-steady-state and steady-state. The renal hypertensive dogs were treated with oral irbesartan alone, or HCTZ alone, or the combination of irbesartan and HCTZ for 8 days. Blood pressure and plasma concentrations were measured and pharmacokinetic-pharmacodynamic parameters were analyzed. Irbesartan showed a two-compartment model pharmacokinetic profile. The concentration-time course of irbesartan was not changed by HCTZ, but irbesartan increased the peak plasma concentration and area under the curve of HCTZ at steady-state. HCTZ had no blood pressure lowering effect at non-steady-state. Irbesartan plus HCTZ had greater blood pressure lowering action than irbesartan alone. HCTZ increased actions of irbesartan. Hysteresis loops were found between effect and plasma concentrations of irbesartan after a single dose. However, hysteresis loops disappeared at steady state with more rapid realization of maximum concentration and effects. The relationship between effects and effect-compartment concentrations of the drugs was represented by a sigmoid Emax model. The results suggest synergistic pharmacodynamic interaction between irbesartan and HCTZ in renal hypertensive dogs and some differences of pharmacokinetic-pharmacodynamic properties between irbesartan and irbesartan/HCTZ combinations at non-steady-state and steady state.

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

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

Effect of three months' treatment with irbesartan on blood and pulse pressure of hypertensive type 2 diabetic patients: open, observational study in 31,793 patients

OBJECTIVES

In hypertensive diabetics the cardiovascular risk is substantially increased. Therefore, an effective reduction of both blood pressure and pulse pressure is of particular importance for these patients. The aim of the prospective observational study in hypertensive type 2 diabetics was to assess the effect of a switch from the previous antihypertensive therapy to the angiotensin-II-receptor antagonist irbesartan (alone or in combination with HCTZ) on the reduction of blood pressure and pulse pressure, the reduction of diabetic nephropathy (microalbuminuria), and tolerability.

METHODS

8714 general practitioners included 31,793 type 2 diabetics aged at least 18 years in an open observational study. After inclusion in to the study the patients received irbesartan 300 mg as monotherapy or in combination with hydrochlorothiazide 12.5 mg (HCTZ). Main outcome measures for efficacy were the reduction of systolic (SBP) and diastolic (DBP) blood pressures, reduction of pulse pressure, and blood pressure responder (reduction in DBP > or = 10 mmHg or diastolic < 90 mmHg), diastolic normalization (DBP < 90 mmHg) and overall normalization rates (SBP < 140 mmHg and DBP < 90 mmHg) after 3 months. Further outcome measures included the reduction of microalbuminuria or proteinuria, and adverse events (AEs) as a measure of tolerability.

RESULTS

Thirty-eight per cent of patients received irbesartan 300 mg and 61% irbesartan in combination with HCTZ. Mean systolic blood pressure was reduced by 22.5 mmHg, diastolic blood pressure by 10.7 mmHg (baseline values: 160.2 and 93.2 mmHg). Pulse pressure fell on average by 11.6 mmHg. 83.4% of the patients were responders, with an overall normalization rate of 42.7% (SBP < 140 mmHg and DBP < 90 mmHg), respectively 73.8% (DBP < 90 mmHg). The antihypertensive benefit was achieved irrespective of the previous medication. Mean albuminuria decreased by about 27.7 mg/L. Only 0.3% of patients experienced adverse events.

CONCLUSIONS

In type 2 diabetics with hypertension and either uncontrolled or no previous antihypertensive therapy a change to treatment with irbesartan or irbesartan/HCTZ for 3 months resulted in a distinct reduction of systolic and diastolic blood pressures, with concomitant effective reductions of pulse pressure and microalbuminuria.

Optimizing therapeutic strategies to achieve renal and cardiovascular risk reduction in diabetic patients with angiotensin receptor blockers

The major challenge for the treatment of hypertensive patients with type 2 diabetes is to achieve the uniformly recommended blood pressure goal of 130/80 mmHg, and 120/75 mmHg in proteinuric patients. Such low target blood pressure levels require the administration of multiple drugs. Angiotensin receptor blockers and the combination of angiotensin receptor blockers with diuretics fulfil the criteria to lower blood pressure effectively with a placebo-like side-effect profile. Beyond pressure control, clinical prospective trials have documented that it does matter what kind of antihypertensive agent is used to control blood pressure. Large-scale follow-up trials have documented blood pressure independent effects of angiotensin receptor blocker on cardiac [left-ventricular hypertrophy (LVH), congestive heart failure] and renal protection (proteinuria, chronic renal failure). Of note, in these trials, angiotensin receptor blockers have been combined with diuretics, and most of the included patients have been on combination therapy comprising two to four antihypertensive agents. In addition to the combination of an angiotensin receptor blocker with a diuretic, the combination of an angiotensin receptor blocker with an angiotensin-converting enzyme inhibitor appeared to be most effective in reducing proteinuria, attenuating chronic renal failure and treating congestive heart failure.

Angiotensin receptor blockade in the challenging era of systolic hypertension

Systolic blood pressure is a major cardiovascular risk factor which is often associated with arterial stiffness. Markers of arterial stiffness, such as pulse pressure and carotid-femoral pulse wave velocity, have been proved independent predictors of cardiovascular risk. Recent evidence suggests that the renin-angiotensin system is involved in the pathogenesis of systolic hypertension and arterial stiffness. Outcome trials have shown impressive cardiovascular protection by reducing systolic blood pressure (BP) with drug treatment. However, in clinical practice systolic hypertension remains largely uncontrolled, first, because systolic BP goal is more difficult to be reached than diastolic and, second, because physicians are often reluctant to intensify treatment in patients with systolic BP close to 150 mmHg. Recent trials have focused on the effects of antihypertensive drugs not only on blood pressure, but also on pulse pressure and pulse-wave velocity. Blockade of the renin-angiotensin-aldosterone system, using angiotensin-converting enzyme inhibitors and more recently angiotensin receptor blockers, has been shown to provide beneficial effects on arterial stiffness that appear to be independent of their antihypertensive effects. Recent outcome trials have shown significant cardiovascular protection with angiotensin receptor blockers. These drugs have an excellent placebolike profile of adverse effects which is maintained when these drugs are combined with low-dose diuretics. Therefore, an angiotensin receptor blocker-based treatment strategy appears to be an attractive and evidence-based approach for the management of systolic hypertension, the reduction of arterial stiffness and the prevention of cardiovascular disease.

Irbesartan: a review of its use in hypertension and in the management of diabetic nephropathy

Irbesartan (Avapro, Aprovel) is a potent and selective angiotensin II subtype 1 receptor antagonist indicated for use in patients with hypertension, including those with type 2 diabetes mellitus and nephropathy. Once-daily administration of irbesartan provided 24-hour control of blood pressure (BP). In patients with mild-to-moderate hypertension irbesartan was as effective as enalapril, atenolol and amlodipine, and more effective than valsartan in terms of absolute reduction in BP and response rates. Irbesartan produced a greater reduction in diastolic BP at trough than once-daily losartan, but had a smaller effect than olmesartan; the reduction in systolic BP achieved with irbesartan was similar or greater than that with losartan and similar to that seen with olmesartan. The combination of irbesartan with hydrochlorothiazide produced additive effects on BP reduction. Irbesartan also induced regression of left ventricular mass in patients with hypertension and left ventricular hypertrophy. In two large studies (IRbesartan MicroAlbuminuria type 2 diabetes mellitus in hypertensive patients [IRMA 2] and the Irbesartan Diabetic Nephropathy Trial [IDNT]) irbesartan exerted a renoprotective effect in hypertensive patients with type 2 diabetes at both the early and later stages of diabetic nephropathy. The renoprotective effect was at least partly independent of the BP-lowering effect. In the IRMA 2 trial, the proportion of patients progressing to overt nephropathy was significantly lower for recipients of irbesartan 300mg once daily than placebo. In patients with overt nephropathy in the IDNT, irbesartan 300mg once daily provided significantly greater renoprotection than amlodipine 10mg once daily or placebo. The relative risk of doubling of serum creatinine was significantly lower with irbesartan than amlodipine or placebo. Irbesartan is well tolerated in hypertensive patients, including those with type 2 diabetes and incipient or overt nephropathy. The overall incidence of adverse events with irbesartan was similar to that with placebo. Irbesartan was associated with a lower incidence of cough than enalapril and was not associated with ankle oedema or with any clinically significant drug interactions. In conclusion, irbesartan is a well tolerated and effective antihypertensive agent. It also slows the progression of renal disease in hypertensive patients with type 2 diabetes at both the early and later stages of diabetic nephropathy. Thus, irbesartan is a valuable agent in the management of patients with these indications.

Once-daily fixed-combination irbesartan 300 mg/ hydrochlorothiazide 25 mg and circadian blood pressure profile in patients with essential hypertension

BACKGROUND

More than 60% of patients with hypertension included in morbidity and mortality trials needed >or=2 drugs to achieve a substantial, sustained reduction in blood pressure. Tolerable combinations using higher doses of antihypertensive drugs are frequently required to control blood pressure.

OBJECTIVE

The goal of this study was to assess the effect of a once-daily fixed combination of irbesartan 300 mg/hydrochlorothiazide (HCTZ) 25 mg on the circadian blood pressure profile in patients with essential hypertension that was not controlled with full-dose single therapy or low-dose combined therapy.

METHODS

Study patients were recruited consecutively from the outpatient hypertension clinics of 3 university hospitals in Spain. After a 1-week washout period, patients with a mean daytime blood pressure >135/85 mm Hg were treated with irbesartan 300 mg/HCTZ 25 mg once daily for 12 weeks. Twenty-four-hour ambulatory blood pressure monitoring was performed at the end of the washout period and during the last week of treatment.

RESULTS

Fifty-seven patients with essential hypertension (28 men, 29 women) were enrolled; their mean (SD) age was 60.4 (7.2) years (range, 45-78 years). After treatment, a significant reduction in both clinic and ambulatory mean (SD) blood pressure values was observed in the whole group of 57 patients (from 146.0 [11.0] mm Hg to 123.3 [13.3] mm Hg, P < 0.001 for 24-hour systolic blood pressure [SBP]; from 89.9 [8.2] mm Hg to 76.5 [9.4] mm Hg, P < 0.001 for 24-hour diastolic blood pressure [DBP]. The mean lowering of ambulatory SBP and DBP at peak was 25.2 (14.5) mm Hg and 14.7 (9.5) mm Hg, respectively, and at trough, 22.3 (18.3) mm Hg and 12.3 (10.9) mm Hg. The trough-to-peak ratio of the group was 0.92 for SBP (0.97 in responders) and 0.84 for DBP (0.89 in responders). The smoothness index, calculated as the mean of all individual values, was 1.7 (1.0) for SBP (1.8 [0.9] in responders) and 1.3 (0.8) for DBP (1.5 [0.6] in responders). Seven side effects in 6 patients were reported. No metabolic changes were observed, and no patient discontinued the study because of treatment-related adverse effects.

CONCLUSIONS

The fixed combination of irbesartan 300 mg/HCTZ 25 administered once daily produced a crude meaningful effect in reducing 24-hour blood pressure and was well tolerated. The circadian profile was preserved, as shown by trough-to-peak ratios and smoothness index values for both SBP and DBP.

Acute pancreatitis associated with angiotensin II receptor antagonists

OBJECTIVE

To report a case of acute pancreatitis in a patient receiving a combination formulation of irbesartan and hydrochlorothiazide (HCTZ).

CASE SUMMARY

A 33-year-old white woman developed acute pancreatitis 10 days after starting irbesartan 300 mg and hydrochlorothiazide 12.5 mg for treatment of hypertension. Her symptoms disappeared and serum concentrations of lipase and amylase returned to normal 2 days after irbesartan/HCTZ was discontinued. A search of MEDLINE (1990-September 2002) and the Australian Adverse Drug Reaction Advisory Committee database revealed 1 additional case of pancreatitis associated with irbesartan/HCTZ and 3 cases of pancreatitis associated with losartan.

DISCUSSION

An objective causality assessment indicates that it is probable that pancreatitis was caused by the angiotensin II receptor antagonist irbesartan (and the same is probably true for losartan). It is less likely that the hydrochlorothiazide in irbesartan/HCTZ caused pancreatitis in our patient since the dose was lower than that usually associated with thiazide-induced pancreatitis. Angiotensin II receptors are thought to be important in regulation of pancreatic secretion and microcirculation, but the mechanism of pancreatitis induced by angiotensin II receptor antagonists remains unclear.

CONCLUSIONS

Clinicians should be aware that irbesartan/HCTZ or losartan may cause acute pancreatitis. If abdominal pain develops, the medication should be discontinued and the patient investigated for acute pancreatitis.

The importance of 24-h blood pressure control

The primary goal of antihypertensive therapy is to restore blood pressure to normal levels and to prevent the complications associated with hypertension. In order to maximize these goals by improving patient compliance, clinical researchers have focused on developing antihypertensive agents that can be given once daily. These agents provide many advantages over multiple-dose daily therapies, but it should not be assumed that they are all equivalent in providing adequate blood pressure control over the full 24-h dosing interval. Ambulatory blood pressure monitoring has uncovered important differences in commonly used once-daily therapies and has provided additional insights into the cardiovascular risks associated with high blood pressure loads and blood pressure variability. In addition to ambulatory blood pressure monitoring data, the calculated trough:peak ratio provides useful information on an agent's ability to provide smooth and consistent blood pressure control. Using such assessments, it has been found that agents with a trough:peak ratio > or = 0.50 are better able to control blood pressure over the full 24h while maintaining natural circadian patterns. Ambulatory blood pressure monitoring studies assessing a recently introduced class of antihypertensive drugs, the angiotensin receptor blockers, have demonstrated 24-h efficacy with once-daily dosing, particularly with the newer agents.