Aliskiren: a review of its use as monotherapy and as combination therapy in the management of hypertension

Aliskiren is an orally administered, nonpeptide direct renin inhibitor indicated for the management of hypertension. Aliskiren was effective in controlling blood pressure (BP) as monotherapy and in combination with other antihypertensives, in large, randomized trials. Aliskiren 150-300?mg/day as monotherapy was effective in lowering BP across short- (≤12 weeks) and longer-term (up to 54 weeks) periods, providing sustained and consistent effects with 24-hour BP control. Compared with other antihypertensives, aliskiren was generally as effective as hydrochlorothiazide (HCTZ), valsartan, losartan, irbesartan and lisinopril in reducing BP. Furthermore, short-term aliskiren was noninferior to ramipril in reducing BP, but with a longer treatment duration, a greater efficacy of aliskiren-based therapy over ramipril-based therapy was demonstrated. Additional BP-lowering effects occurred when aliskiren was coadministered (as a fixed-dose combination or separate tablets) with other antihypertensives, including HCTZ, valsartan and amlodipine, according to large, randomized trials of short- (≤12 weeks) and longer-term (up to 54 weeks) duration. Combination therapy with aliskiren plus HCTZ was effective in hypertensive patients when administered as initial therapy or to patients previously treated with HCTZ or aliskiren monotherapy. Aliskiren-based therapy was also effective in lowering BP in obese patients, patients with type 1 or 2 diabetes mellitus, patients with metabolic syndrome and the elderly. Aliskiren efficacy was observed irrespective of patient age, sex or ethnicity. Aliskiren monotherapy or combination therapy was generally well tolerated over short- and longer-term study durations in large, randomized clinical trials. Clinical trials to evaluate the effects of aliskiren on clinical outcomes, including renoprotective and cardioprotective effects, are currently ongoing. Thus, aliskiren is a useful option for the treatment of patients with stage 1 to stage 2 (mild to moderate) hypertension, alone or in combination with other antihypertensives, including HCTZ, valsartan or amlodipine.     

Efficacy and safety of the direct renin inhibitor aliskiren and ramipril alone or in combination in patients with diabetes and hypertension.

OBJECTIVE: To assess the antihypertensive efficacy and safety of the combination of the direct renin inhibitor aliskiren and ramipril in patients with diabetes and hypertension. METHODS: In this double-blind, multicentre trial, 837 patients with diabetes mellitus and hypertension (mean sitting diastolic blood pressure [BP] > 95 and < 110 mmHg) were randomised to once-daily aliskiren (150 mg titrated to 300 mg after four weeks; n=282), ramipril (5 mg titrated to 10 mg; n=278) or the combination (n=277) for eight weeks. Efficacy variables were cuff mean sitting diastolic BP (msDBP) and mean sitting systolic BP (msSBP); 24-hour ambulatory BP, plasma renin activity (PRA) and plasma renin concentration (PRC) were also assessed. RESULTS: At week 8, aliskiren, ramipril and aliskiren/ramipril lowered msDBP (mean+/-SEM) by 11.3+/-0.5, 10.7+/-0.5 and 12.8+/-0.5 mmHg, and msSBP by 14.7+/-0.9, 12.0+/-0.9 and 16.6+/-0.9 mmHg, respectively. Aliskiren/ramipril provided superior msDBP reductions to ramipril (p=0.004) or aliskiren (p=0.043) monotherapy; adding aliskiren to ramipril provided an additional mean BP reduction of 4.6/2.1 mmHg. Aliskiren monotherapy was non-inferior to ramipril for msDBP reduction (p=0.0002) and superior for msSBP reduction (p=0.021). All treatments significantly lowered mean 24-hour ambulatory BP. Aliskiren significantly reduced PRA from baseline as monotherapy (by 66%, p<0.0001) or in combination with ramipril (by 48%, p<0.0001), despite large increases in PRC in all treatment groups. Aliskiren was well tolerated as monotherapy or in combination with ramipril. CONCLUSIONS: Combining aliskiren with ramipril provided a greater reduction in msDBP than either drug alone in patients with diabetes and hypertension.     

Long-term safety,tolerability and efficacy of aliskiren in combination with valsartan in patients with hypertension: a 6-month interim analysis

ABSTRACT

Background: Renin–angiotensin system (RAS) blockade with ACE inhibitor and/or angiotensin receptor blocker therapy can lead to increased potassium levels, hence the need to assess dual blockade involving a direct renin inhibitor. Here we report the results of a pre-planned 6-month interim analysis of a long-term, open-label study examining the safety, tolerability and efficacy of the aliskiren/valsartan 300/320-mg combination in patients with hyper­tension.

Methods: A total of 601 patients with hyper­tension (msDBP ≥?90 and <?110?mmHg) received a combination of aliskiren/valsartan 150/160?mg for 2 weeks followed by forced titration to aliskiren/valsartan 300/320?mg once daily for a targeted duration of 52 weeks. Optional hydrochlorothiazide (HCTZ) addition was allowed from week 8 for inadequate BP control (≥?140/90?mmHg). The primary objective was to assess the safety of combination therapy; potassium elevations were a pre-defined safety outcome. BP was measured at regular intervals during the study.

Results: At the 6-month cut-off date, 512 patients (85.2%) were still ongoing with study treatment, and 192 patients had received at least one dose of HCTZ add-on during this period. Combination therapy was generally well-tolerated; the most commonly reported adverse events were headache (7.5%), dizziness (7.3%) and nasopharyngitis (7.2%). Ten patients (2.5%) receiving aliskiren/valsartan and two patients (1.0%) receiving aliskiren/valsartan/HCTZ had serum potassium elevations >?5.5?mmol/L. Only one patient (0.2%) exhibited potassium levels ≥?6.0?mmol/L during this period and the patient was treated with aliskiren/valsartan. Mean msSBP/DBP reductions of 22.3/14.4?mmHg were observed at 6-month endpoint (LOCF analysis) and 73.4% of patients achieved BP control (<?140/90?mmHg; LOCF).

Conclusions: Although lack of an active comparator group is a limitation of the study, our findings show that long-term treatment with the aliskiren/valsartan 300/320-mg combin­ation provided clinically significant BP lowering, was well-tolerated and was associated with a very low rate of potassium elevations in patients with hyper­tension.     

Efficacy and tolerability of valsartan in combination with hydrochlorothiazide in essential hypertension

OBJECTIVE: This study compared the efficacy and tolerability of two combination regimens of valsartan and hydrochlorothiazide (HCTZ) with valsartan monotherapy in patients with essential hypertension inadequately controlled with valsartan 80mg once daily. PATIENTS AND METHODS: A total of 708 patients with inadequately controlled blood pressure after 4 weeks' treatment with valsartan 80mg once daily participated in this double-blind comparative trial. Patients were randomly allocated once-daily treatment with valsartan 80mg, valsartan 160mg, valsartan 80mg + HCTZ 12.5mg or valsartan 80mg + HCTZ 25mg for 8 weeks. RESULTS: Statistically significant decreases in mean sitting diastolic blood pressure (SDBP) and mean sitting systolic blood pressure (SSBP) from baseline were seen in all treatment groups (least squares mean change from baseline SDBP: -5.1mm Hg, -6.2mm Hg, -8.2mm Hg, -10.8mm Hg; SSBP: -3.9mm Hg, -6.5mm Hg, -9.8mm Hg, -16.0mm Hg for valsartan 80mg, valsartan 160mg, HCTZ 12.5mg combination, HCTZ 25mg combination, respectively). A significant difference for mean SDBP, SSBP and responder rates in favour of the combination regimens was observed compared with either valsartan monotherapy. All treatments were well tolerated with the percentage of patients reporting treatment-related adverse experiences at any time ranging from 9.9% (valsartan 160mg) to 21.0% (HCTZ 25mg combination). CONCLUSION: The study demonstrated that a combination of valsartan 80mg and HCTZ 12.5mg or 25mg provides an effective and well tolerated treatment in patients who need additional blood pressure control beyond valsartan monotherapy.     

Once vs twice daily administration of a fixed combination of captopril plus hydrochlorothiazide in essential hypertension: a double-blind crossover study in known responders to a standard combination.

The purpose of this randomized, double-blind, crossover trial was to compare the hypotensive effects of a fixed combination of captopril (C) 50 mg and hydrochlorothiazide (HCTZ) 25 mg (C 50/HCTZ 25) once daily with those of a fixed combination of C 25 mg and HCTZ 12.5 mg (C 25/HCTZ 12.5) twice daily. We studied 199 patients (108 M, 91 F) with mild to moderate essential hypertension whose BP was already controlled by the co-administration of C 25 mg and HCTZ 12.5 mg twice daily. They were randomly assigned to either C 25/HCTZ 12.5 twice daily during the first 6 weeks and C 50/HCTZ 25 once daily during the second 6 weeks or C 50/HCTZ 25 once daily followed by C 25/HCTZ 12.5 twice daily. Both regimens showed comparable efficacy on office diastolic BP (91.6 vs 91.3 mm Hg). Systolic BP was slightly but significantly higher (P = 0.02) with the once daily formulation (141.2 vs 139.1 mm Hg). Fixed combinations once daily and twice daily resulted in identical working ambulatory BP (133.7 +/- 13/83.6 +/- 8 mm Hg vs 132.4 +/- 11/83.3 +/- 7 mm Hg) without affecting heart rate. Adverse events were reported by 16% of patients and cough was the most common occurring in 7%. In conclusion, these results indicate that the fixed combination of C 50/HCTZ 25 given once daily controls office and working BP as well as the fixed combination C 25/HCTZ 12.5 given twice daily in patients with mild to moderate hypertension.     

Current concepts: renin inhibition in the treatment of hypertension

The development of aliskiren, the first orally effective renin inhibitor, utilized molecular modeling based upon X-ray crystallographic analysis of renin's active site to design a potent, low molecular weight renin inhibitor with improved bioavailability (approximately 2.6%). In patients with hypertension, dose-dependent BP reduction occurs with aliskiren 75-300 mg once daily; at these doses, the safety and tolerability profile is comparable to placebo. In direct comparison studies, BP reduction with aliskiren is equivalent to commonly used antihypertensive agents including diuretics, ACE inhibitors, and ARBs. Persistent BP reduction and prolonged suppression of plasma renin activity (PRA) is observed after aliskiren withdrawal. Aliskiren suppresses PRA when given either as monotherapy or in combination with other agents. When added to an ARB, aliskiren blocks compensatory RAS activation and produces significant additional BP reduction. In patients with diabetic nephropathy, addition of aliskiren to losartan, 100 mg resulted in a 20% greater reduction in proteinuria. Ongoing studies evaluating the long-term renal protective effects of aliskiren and its effects on ventricular remodeling are currently planned or underway.     

Clinical pharmacokinetics and pharmacodynamics of aliskiren

Aliskiren is the first orally bioavailable direct renin inhibitor approved for the treatment of hypertension. It acts at the point of activation of the renin-angiotensin-aldosterone system, or renin system, inhibiting the conversion of angiotensinogen to angiotensin I by renin and thereby reducing the formation of angiotensin II by angiotensin-converting enzyme (ACE) and ACE-independent pathways. Aliskiren is a highly potent inhibitor of human renin in vitro (concentration of aliskiren that produces 50% inhibition of renin 0.6 nmol/L). Aliskiren is rapidly absorbed following oral administration, with maximum plasma concentrations reached within 1-3 hours. The absolute bioavailability of aliskiren is 2.6%. The binding of aliskiren to plasma proteins is moderate (47-51%) and is independent of the concentration. Once absorbed, aliskiren is eliminated through the hepatobiliary route as unchanged drug and, to a lesser extent, through oxidative metabolism by cytochrome P450 (CYP) 3A4. Unchanged aliskiren accounts for approximately 80% of the drug in the plasma following oral administration, indicating low exposure to metabolites. The two major oxidized metabolites of aliskiren account for less than 5% of the drug in the plasma at the time of the maximum concentration. Aliskiren excretion is almost completely via the biliary/faecal route; 0.6% of the dose is recovered in the urine. Steady-state plasma concentrations of aliskiren are reached after 7-8 days of once-daily dosing, and the accumulation factor for aliskiren is approximately 2. After reaching the peak, the aliskiren plasma concentration declines in a multiphasic fashion. No clinically relevant effects of gender or race on the pharmacokinetics of aliskiren are observed, and no adjustment of the initial aliskiren dose is required for elderly patients or for patients with renal or hepatic impairment. Aliskiren showed no clinically significant increases in exposure during coadministration with a wide range of potential concomitant medications, although increases in exposure were observed with P-glycoprotein inhibitors. Aliskiren does not inhibit or induce CYP isoenzyme or P-glycoprotein activity, although aliskiren is a substrate for P-glycoprotein, which contributes to its relatively low bioavailability. Aliskiren is approved for the treatment of hypertension at once-daily doses of 150 mg and 300 mg. Phase II and III clinical studies involving over 12,000 patients with hypertension have demonstrated that aliskiren provides effective long-term blood pressure (BP) lowering with a good safety and tolerability profile at these doses. Aliskiren inhibits plasma renin activity (PRA) by up to 80% following both single and multiple oral-dose administration. Similar reductions in PRA are observed when aliskiren is administered in combination with agents that alone increase PRA, including diuretics (hydrochlorothiazide, furosemide [frusemide]), ACE inhibitors (ramipril) and angiotensin receptor blockers (valsartan), despite greater increases in the plasma renin concentration. Moreover, PRA inhibition and BP reductions persist for 2-4 weeks after stopping treatment, which is likely to be of benefit in patients with hypertension who occasionally miss a dose of medication. Preliminary data on the antiproteinuric effects of aliskiren in type 2 diabetes mellitus suggest that renoprotective effects beyond BP lowering may be possible. Further studies to evaluate the effects of aliskiren on cardiovascular outcomes and target organ protection are ongoing and will provide important new data on the role of direct renin inhibition in the management of hypertension and other cardiovascular disease.     

Aliskiren as Add-On Therapy in the Treatment of Hypertensive Diabetic Patients Inadequately Controlled with Valsartan/HCT Combination

Background

Hypertension frequently coexists with diabetes mellitus, resulting in increased cardiovascular risk. Thus, BP control is crucial in decreasing morbidity and mortality in this difficult-to-treat patient population.

Objective

The objective of this study was to evaluate the efficacy and safety of aliskiren in hypertensive patients with diabetes not adequately responsive to the combination of valsartan and hydrochlorothiazide (HCT).

Methods

After a 1-to 4-week washout period, patients with a mean sitting diastolic BP (msDBP) ≥95mmHg were treated with valsartan 160mg for 2 weeks followed by valsartan/HCT 160mg/25mg for an additional 4 weeks (single-blind active run-in period). Patients whose msDBP remained ≥85mmHg after the active run-in period were randomized (1 : 1) to receive aliskiren 150mg (n = 184) or placebo (n = 179) as add-on therapy for 6 weeks. Aliskiren was then force-titrated to 300mg once daily for another 6 weeks. Efficacy variables were: the change in msDBP and mean sitting systolic BP (msSBP) from baseline to week 12 endpoint, diastolic response (msDBP < 80mmHg or reduction of at least 10mmHg), and BP control rate (<130/80mmHg).

Results

Of the 363 patients randomized, 328 (90.4%) completed the study (aliskiren and placebo groups: 89.7% and 91.1%, respectively). At week 12 endpoint, the least squares mean (LSM) changes in msDBP (aliskiren vs placebo: ?5.8 vs ?4.8mmHg; p = 0.2767) and msSBP (aliskiren vs placebo: ?7.3 vs ?4.8 mmHg; p = 0.0725) were numerically greater in patients treated with aliskiren compared with those treated with placebo; however, this difference was not statistically significant. The proportion of diastolic responders (aliskiren and placebo: 68.5% and 72.9%, respectively; p = 0.8482) and patients achieving BP control (aliskiren and placebo: 16.0% and 16.4%, respectively; p = 0.7511) were similar for both groups. Overall, 63 (34%) and 59 (33%) patients in the aliskiren and placebo groups, respectively, experienced adverse events (AEs). The most commonly reported AEs were headache (placebo group: 6.1%) and dizziness (aliskiren group: 4.4%). Aliskiren was well tolerated.

Conclusion

The reductions in BP with aliskiren added to valsartan/HCT in this study were numerically greater compared with placebo added to valsartan/HCT, although not statistically significant. Trial Registration: ClinicalTrials.gov identifier NCT00219102.     

Efficacy and tolerability of combination therapy with valsartan/hydrochlorothiazide in the initial treatment of severe hypertension

ABSTRACT

Objective: Most patients with severe hypertension are at high risk for cardiovascular events and require prompt blood pressure (BP)-lowering and combination therapy to achieve BP goals. This study evaluated the therapeutic efficacy and tolerability of initial treatment with the combination of valsartan and hydrochlorothiazide (HCTZ) compared with valsartan monotherapy in patients with severe hypertension.

Research design and methods: This was a 6-week, randomized, double-blind, multicenter, forced titration study that compared initial therapy with the combination of valsartan/HCTZ 160/12.5?mg (force titrated to 160/25?mg after 2 weeks and to 320/25?mg after 4 weeks) to monotherapy with valsartan 160?mg (force titrated to 320?mg after 2 weeks and sham-titrated to 320?mg after 4 weeks). Eligible patients were 18–80 years old with severe essential hypertension (mean sitting diastolic BP?≥?110?mmHg and <120?mmHg and mean sitting systolic BP?≥?140?mmHg and <200?mmHg). The Clinical Trial Registry number was NCT00273299.

Main outcome measures: The primary efficacy variable was the rate of BP control (mean sitting BP?<?140/90?mmHg) at Week 4. Tolerability was evaluated by monitoring all adverse events, vital signs, and laboratory tests including hematology and biochemistry.

Results: A total of 608 patients were randomized to either valsartan/HCTZ (n?=?307) or valsartan monotherapy (n?=?301). Significantly more patients achieved overall BP control (<140/90?mmHg) with valsartan/HCTZ compared to monotherapy at Week 4 (primary efficacy variable and timepoint) (39.6% vs. 21.8%; p?<?0.0001) and Week 6 (48.2% vs. 27.2%; p?<?0.0001). Mean reductions in BP at Week 4 were significantly greater for valsartan/HCTZ (30.8/22.7?mmHg vs. 21.7/17.5?mmHg; p?<?0.0001), with further reductions at Week 6. BP control rates were greater with combination therapy as early as Week 2. The overall incidence of adverse events was comparable between the combination therapy (34.9%) and monotherapy (36.7%) treatment groups. A potential limitation of the forced-titration design is that some patients were titrated to higher doses despite having achieved goal BP. This may impact the interpretation of the incidence of dose-dependent adverse events.

Conclusions: Initial therapy with valsartan/HCTZ is effective and well tolerated in patients with severe hypertension.     

Antihypertensive effect of low-dose hydrochlorothiazide alone or in combination with quinapril in black patients with mild to moderate hypertension

In this study, using 24-hour ambulatory blood pressure (BP) monitoring, the authors assessed the potential for BP control using hydrochlorothiazide (HCTZ, 12.5 mg daily), given as a monotherapy over 12 months to 49 black South African patients with mild to moderate hypertension (mean day diastolic blood pressure [DBP] > or = 90 and < 115 mmHg). Uncontrolled patients received fixed combination of quinapril/HCTZ 10/12.5, 20/12.5, and 20/25 mg, with dose titration at 3 monthly intervals if BP control was not achieved (day DBP < 90 mmHg). Overall, profound and sustained BP reduction was observed at the end of the study. The 24-hour BP decreased from 151 +/- 14/98 +/- 7 to 136 +/- 15/87 +/- 9 mmHg (p < 0.0001 at end of study vs. baseline); the mean day BP decreased from 155 +/- 14/104 +/- 7 to 140 +/- 15/91 +/- 10 mmHg (p < 0.0001 at end of study vs. baseline). The overall control (mean day DBP < 90 mmHg) and response (decrease in day DBP > or = 10 mmHg) rates were 49% and 61%, respectively. At the end of the study, only 2 patients (4%) remained on treatment with HCTZ. Out of the initial 12 patients controlled on HCTZ at 3 months (12/49, 24%), 5 patients remained controlled at 6 months and only 1 patient at 12 months. In contrast, quinapril/HCTZ combinations maintained their antihypertensive effect up to 9 months, with a significant number of patients (22/49, 45%) requiring the highest dose of the combination (20/25 mg daily). In conclusion, low-dose HCTZ should not be recommended as monotherapy in black patients with mild to moderate hypertension due to the fact that the BP-lowering effect is attenuated already at 6 months of treatment, with most patients requiring the addition of the ACE inhibitor.     

Safety and efficacy of aliskiren in the treatment of hypertension and associated clinical conditions

Aliskiren is the first known representative of a new class of non-peptide orally active renin inhibitors that blocks the renin-angiotensin-aldosterone-system (RAAS) at its rate-limiting step. It induces a net reduction in plasma renin activity (PRA), angiotensin II and aldosterone levels. Aliskiren is effective in reducing blood pressure (BP) and is well tolerated. The incidence of adverse events and the number of study discontinuations as a result of adverse events during aliskiren treatment were relatively low and generally not dissimilar from placebo. In placebo-controlled studies, aliskiren showed a dose-related systolic/diastolic BP lowering effect at doses between 75 and 300 mg/day. When compared to active treatments, aliskiren was generally as effective as hydrochlorothiazide, angiotensin-converting-enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs) and beta-blockers, in reducing BP. Aliskiren exhibits synergistic effects when combined with drugs that lead to a reactive increase in the PRA, such as diuretics, ACE inhibitors or ARBs. Although in clinical studies aliskiren proved to reduce proteinuria, the early termination of the Aliskiren Trial in Type 2 Diabetes Using Cardiovascular and Renal Disease Endpoints (ALTITUDE) confirms previous concerns about the full suppression of the RAAS, in this case with aliskiren combined with ACE-inhibitors or ARBs, in patients with diabetes and concomitant renal impairment. This review summarizes the available data on its safety profile and its clinical development for treatment of arterial hypertension, diabetes and nephropathy.     

Effects of valsartan or ramipril addition to amlodipine/hydrochlorothiazide combination on left ventricular mass in diabetic hypertensive patients with left ventricular hypertrophy

Objective: The objective of this study was to compare valsartan or ramipril addition to amlodipine + hydrochlorothiazide (HCTZ) on blood pressure (BP) and left ventricular hypertrophy (LVH) in hypertensive diabetic patients with LVH.

Research design and methods: 293 patients were treated with amlodipine 10 mg + HCTZ 12.5 combination and then randomized to receive valsartan 160 mg or ramipril 5 mg, in addition to the previous therapy, for 1 year.

Main outcome measures: Clinic BP was measured every month; echocardiographic assessments were performed at the end of the placebo period, both before the randomization and after 1-year of triple combination therapy.

Results: Both triple regimens similarly reduced SBP/DBP values (-13.5/10.9 mm Hg in the valsartan group and -13.4/10.4 mm Hg in the ramipril group). Triple combination including valsartan better reduced LVMI (-20.1%, p < 0.001), interventricular septal thickness (IVST) (-20.3%, p < 0.001) and left ventricular posterior wall thickness (PWT) (-16.3%, p < 0.001), compared with triple combination including ramipril (-14%, p < 0.01; -16.2%, p < 0.001 and -9%, p < 0.01, respectively); the difference between treatments being statistically significant (p < 0.05). Triple combination with valsartan gave a greater increase of E/A ratio (p < 0.05 between groups).

Conclusions: Valsartan addition to dual therapy with amlodipine + HCTZ was more effective than ramipril addition in reducing LVH.     

Renin inhibition with aliskiren

1. Initial attempts to inhibit renin in humans have faced numerous difficulties. Molecular modelling and X-ray crystallography of the active site of renin have led to the development of new orally active renin inhibitors, such as aliskiren. 2. Aliskiren has a low bioavailability (between 2.6 and 5.0%) compensated by its high potency to inhibit renin (IC50: 0.6 nmol/L) and a long plasma half-life (23-36 h), which makes it suitable for once-daily dosing. 3. The once-daily administration of aliskiren to hypertensive patients lowers BP as strongly as standard doses of established angiotensin II type 1 (AT1) receptor blockers (losartan, valsartan, irbesartan), hydrochlorothiazide, angiotensin converting enzyme inhibitors (ramipril and lisinopril) or long acting calcium channel blockers (amlodipine). In combination therapy, aliskiren further decreases blood pressure when combined with either hydrochlorothiazide, amlodipine, irbesartan or ramipril. 4. The biochemical consequences of renin inhibition differ from those of angiotensin I-converting enzyme (ACE) inhibition and Ang II antagonism, particularly in terms of angiotensin profiles and interactions with the bradykinin-nitric oxide-cyclic guanosine monophosphate pathway and possibly the (pro)renin receptor. 5. Blockade of the renin angiotensin system (RAS) with ACE inhibitors, AT1 receptor blockers or a combination of these drugs has become one of the most successful therapeutic approaches in medicine. However, it remains unclear how to optimize RAS blockade to maximize cardiovascular and renal benefits. In this context, renin inhibition to render the RAS fully quiescent is a new possibility requiring further study.     

Azilsartan medoxomil: a review of its use in hypertension

Azilsartan medoxomil (Edarbi?; Ipreziv?) is an orally administered angiotensin II receptor type 1 antagonist (blocker) used in the treatment of adults with essential hypertension. This article reviews data on the clinical efficacy and tolerability of azilsartan medoxomil in adults with essential hypertension and provides a summary of its pharmacological properties. Azilsartan medoxomil is a prodrug that undergoes rapid hydrolysis in the gastrointestinal tract after oral administration to the bioactive moiety azilsartan, before systemic absorption. Azilsartan medoxomil produces antihypertensive effects by selectively blocking the binding of angiotensin II to the angiotensin type 1 (AT(1)) receptor, thereby antagonizing the pressor response activity of angiotensin II. In vitro, azilsartan produced greater and more sustained AT(1) receptor binding/blockade activity than several comparator angiotensin II receptor antagonists. Azilsartan medoxomil reduces blood pressure (BP) in hypertensive adults. In addition, the drug has been shown to have pleiotropic effects (i.e. effects beyond AT(1) receptor blockade). In adults with essential hypertension, azilsartan medoxomil 20, 40 or 80?mg effectively reduced BP over a 24-hour period with once-daily administration in three major, randomized, controlled trials in which the primary endpoints were changes from baseline in 24-hour mean systolic BP (SBP) at week 6 (two trials) or week 24, assessed by ambulatory BP monitoring (ABPM). In the two 6-week trials, azilsartan medoxomil showed dose-dependent efficacy over all evaluated dosages and was more effective than placebo in lowering SBP. At the maximum approved dosage of 80?mg once daily, azilsartan medoxomil was significantly more effective than maximum dosages of olmesartan medoxomil (40?mg once daily) or valsartan (320?mg once daily), based on primary endpoint assessments. Mean reductions in clinic measurements of SBP and diastolic BP (DBP) measurements were also generally greater with azilsartan medoxomil 80?mg once daily than with the comparator drugs in these 6-week studies. Over a longer treatment period of 24 weeks, azilsartan medoxomil showed sustained BP-lowering efficacy, with the reduction in 24-hour mean SBP at week 24 significantly greater with azilsartan medoxomil 40 or 80?mg once daily than with valsartan 320?mg once daily. Mean reductions from baseline in mean clinic SBP and DBP as well as DBP by ABPM were also significantly greater with azilsartan medoxomil 40 or 80?mg once daily than with valsartan. Azilsartan medoxomil was generally well tolerated, with a tolerability profile similar to that of placebo in the 6-week trials. Across the three major trials, headache and dizziness were among the most common adverse events. Overall, rates of treatment discontinuation as a result of adverse events were low in the 6-week and 24-week trials. In conclusion, once-daily azilsartan medoxomil effectively lowers BP in adults with essential hypertension and has shown better antihypertensive efficacy than maximum therapeutic dosages of olmesartan medoxomil or valsartan in major trials of up to 24 weeks' duration. Azilsartan medoxomil is generally well tolerated and the low rates of discontinuation due to adverse events suggest that patients are likely to persist with long-term treatment. Azilsartan medoxomil is therefore a useful and attractive new option for lowering BP in patients with essential hypertension, particularly for those not able to tolerate other antihypertensive drugs. Further studies are required to evaluate the effects of azilsartan medoxomil on cardiovascular morbidity and mortality.     

新型口服抗高血压药阿利克伦的临床药理学研究进展

肾素直接抑制剂阿利克伦是一种新型、安全、有效的口服抗高血压药物,并且具有肾脏保护、减少左心窒肥厚等作用,可以单用或者与ACE抑制剂(如雷米普利)、Aug Ⅱ受体阻滞剂(如缬沙坦)和噻嗪类利尿剂等降压药物联合使用,降压作用具有剂量依赖性,病人耐受性良好.     

Comparative effect of canrenone or hydrochlorothiazide addition to valsartan/amlodipine combination on urinary albumin excretion in well-controlled type 2 diabetic hypertensive patients with microalbuminuria

Objective: To compare the effect of adding canrenone or hydrochlorothiazide (HCTZ) to valsartan/amlodipine combination on urinary albumin excretion (UAE) in microalbuminuric type 2 diabetic hypertensives.

Research design and methods: After a 2-week placebo period and after 4 weeks of valsartan 160 mg plus amlodipine 5 mg combination, 120 patients whose blood pressure (BP) was not controlled (> 130/80 mmHg) were randomized to canrenone 25 mg or HCTZ 12.5 mg in addition to the previous therapy for 24 weeks. After the first 6 weeks of triple therapy, canrenone or HCTZ doses were doubled in the patients whose BP was yet uncontrolled. At the end of each period (placebo, dual combination and triple combination therapy), clinic and ambulatory BP measurements were recorded and 24 h UAE was evaluated.

Results: Both triple combinations produced greater clinical and ambulatory BP reduction than dual therapy, with no difference between the two groups. UAE was reduced by both regimens, but the decrease associated with canrenone add-on therapy was more pronounced. At week 24, UAE decreased by 45.3% in the canrenone group and by 20.3% in the HCTZ group (p < 0.01).

Conclusions: These findings indicate that, despite similar BP-lowering effect, the addition of canrenone to valsartan/amlodipine combination was more effective in reducing UAE than HCTZ addition.     

厄贝沙坦氢氯噻嗪初始治疗2级高血压80例临床观察

目的 评价厄贝沙坦氢氯噻嗪片初始治疗2级高血压的疗效及安全性.方法 采用自身对照,开放单一治疗试验设计方法,对80例新发2级高血压病人口服厄贝沙坦氢氯噻嗪片1片,4周时血压不达标则剂量加倍,观察8周,记录治疗前后诊所血压及24h动态血压的变化,观察不良反应,以评价疗效与安全 性.结果 厄贝沙坦氢氯噻嗪片治疗1周后血压即...     

Telmisartan/hydrochlorothiazide: in the treatment of essential hypertension

Oral telmisartan/hydrochlorothiazide (HCTZ) combines two antihypertensive agents, a selective angiotensin II receptor antagonist with a long half-life and once-daily administration, and a thiazide diuretic. In two large, 8-week, double-blind trials, patients with hypertension unresponsive to monotherapy who received combined telmisartan/HCTZ 80/12.5 or 40/12.5 mg/day, achieved significantly larger reductions in diastolic and systolic blood pressure (BP), than recipients of continued telmisartan monotherapy (p < 0.05 for all). Compliance with telmisartan/HCTZ 80/12.5 mg/day was 98.9%. In patients with hypertension, telmisartan/HCTZ resulted in similar BP reductions to oral enalapril/HCTZ and atenolol/HCTZ in 26-week double-blind trials and greater reductions than oral losartan/HCTZ 50/12.5 mg/day in a 6-week randomised open-label trial (p < 0.001). Up to one-third of patients with hypertension initially responsive to telmisartan 40 or 80 mg/day in a 4-year study required the eventual addition of HCTZ 12.5 or 25 mg/day and/or another agent to maintain BP control. BP was controlled in about 75% of these by adding only HCTZ. In clinical trials of up to 4 years, including elderly patients, telmisartan/HCTZ had similar tolerability to placebo, with few reports of hypokalaemia. Most adverse events were mild to moderate.     

Time course of antiproteinuric effect of aliskiren in arterial hypertension associated with type 2 diabetes and microalbuminuria

Objective: The aim was to compare the antiproteinuric effect of aliskiren and ramipril in hypertensive patients with type 2 diabetes and microalbuminuria.

Research design and methods: A total of 138 patients were treated with aliskiren 300 mg/day or ramipril 10 mg/day for 12 weeks and checked after 1, 2, 4, 8 and 12 weeks and 2 and 4 weeks after treatment withdrawal.

Main outcome measures: Clinic and ambulatory BP, urinary albumin excretion rate (UAER) and plasma aldosterone were measured.

Results: Both aliskiren and ramipril induced a similar lowering in clinic and ambulatory BP (p < 0.001 vs baseline). However, such a lowering persisted longer after stopping aliskiren than after stopping ramipril regimen. Both treatments reduced UAER, but the decrease in UAER associated with aliskiren was more pronounced, the difference vs ramipril being maximal at week 12 (?42 vs ?15%, p < 0.01). Two weeks after stopping therapy, UAER remained below baseline values with aliskiren, but not in the ramipril group. Plasma aldosterone decreased in the aliskiren group, whereas in the ramipril group it decreased until week 8 and thereafter increased toward baseline values.

Conclusions: Aliskiren has a greater and more prolonged antiproteinuric effect than R; it might partly be related to a higher degree of intrarenal renin–angiotensin–aldosterone system blockade.     

Effects of valsartan versus olmesartan addition to amlodipine/hydrochlorothiazide combination in treating stage 2 hypertensive patients

Objective: The objective of this study was to assess the effects of valsartan or olmesartan addition to dual therapy with amlodipine + hydrochlorothiazide (HCTZ) in the treatment of stage 2 hypertension.

Research design and methods: 180 patients with diastolic blood pressure (DBP) ≥ 99 and < 110 mm Hg were treated with amlodipine 5 mg + HCTZ 12.5 mg combination. After 4 weeks, 149 patients whose blood pressure (BP) was not controlled, were randomized to the combination of valsartan 160 mg + amlodipine 5 mg + HCTZ 12.5 mg or olmesartan 20 mg + amlodipine 5 mg + HCTZ 12.5 mg for 4 weeks.

Main outcome measures: At the end of each period, clinical and ambulatory BP measurements were recorded.

Results: Both triple combinations produced greater ambulatory and clinical SBP/DBP reduction than dual therapy. However, mean reduction from baseline in the valsartan + amlodipine + HCTZ-treated patients was significantly greater than in the olmesartan + amlodipine + HCTZ-treated patients. Compared with dual therapy, the add-on effect of valsartan was significantly greater than that of olmesartan, the difference being more evident for nighttime SBP/DBP values (-3.3 (95% CI 0.44 – 3.51)/3.0 (95% CI 0.59 – 3.34) mm Hg, p < 0.01).

Conclusions: The addition of valsartan to amlodipine + HCTZ produced greater BP reduction than the addition of olmesartan.