Antihypertensive, insulin-sensitising and renoprotective effects of a novel, potent and long-acting angiotensin II type 1 receptor blocker, azilsartan medoxomil, in rat and dog models

The pharmacological profile of a novel angiotensin II type 1 receptor blocker, azilsartan medoxomil, was compared with that of the potent angiotensin II receptor blocker olmesartan medoxomil. Azilsartan, the active metabolite of azilsartan medoxomil, inhibited the binding of [(125)I]-Sar(1)-I1e(8)-angiotensin II to angiotensin II type 1 receptors. Azilsartan medoxomil inhibited angiotensin II-induced pressor responses in rats, and its inhibitory effects lasted 24h after oral administration. The inhibitory effects of olmesartan medoxomil disappeared within 24h. ID(50) values were 0.12 and 0.55 mg/kg for azilsartan medoxomil and olmesartan medoxomil, respectively. In conscious spontaneously hypertensive rats (SHRs), oral administration of 0.1-1mg/kg azilsartan medoxomil significantly reduced blood pressure at all doses even 24h after dosing. Oral administration of 0.1-3mg/kg olmesartan medoxomil also reduced blood pressure; however, only the two highest doses significantly reduced blood pressure 24h after dosing. ED(25) values were 0.41 and 1.3mg/kg for azilsartan medoxomil and olmesartan medoxomil, respectively. In renal hypertensive dogs, oral administration of 0.1-1mg/kg azilsartan medoxomil reduced blood pressure more potently and persistently than that of 0.3-3mg/kg olmesartan medoxomil. In a 2-week study in SHRs, azilsartan medoxomil showed more stable antihypertensive effects than olmesartan medoxomil and improved the glucose infusion rate, an indicator of insulin sensitivity, more potently (≥ 10 times) than olmesartan medoxomil. Azilsartan medoxomil also exerted more potent antiproteinuric effects than olmesartan medoxomil in Wistar fatty rats. These results suggest that azilsartan medoxomil is a potent angiotensin II receptor blocker that has an attractive pharmacological profile as an antihypertensive agent.     

Azilsartan medoxomil for the treatment of hypertension

The use of angiotensin receptor blockers (ARBs) represents a favorable approach for the control of blood pressure in patients with hypertension. Azilsartan medoxomil, a prodrug that undergoes rapid hydrolysis to its active moiety azilsartan, is an angiotensin AT(1) receptor antagonist with promising antihypertensive activity and a good safety profile. The agent has been evaluated as monotherapy and in combination with amlodipine or chlorthalidone in phase III trials in patients with essential hypertension. In 2011, azilsartan medoxomil was approved in the U.S. for the treatment of hypertension.     

Clinical and experimental aspects of olmesartan medoxomil, a new angiotensin II receptor antagonist

Olmesartan medoxomil is a new orally active angiotensin II (Ang II) type 1 receptor antagonist. It is a prodrug and is rapidly de-esterified during absorption to form olmesartan, the active metabolite. Olmesartan is a potent, competitive and selective Ang II type 1 receptor antagonist. Olmesartan is not metabolized by the cytochrome P-450 and has a dual route of elimination, by kidneys and liver. In patients with essential hypertension olmesartan medoxomil administered once daily at doses of 10-80 mg dose-dependently reduced diastolic blood pressure (DBP). Troughto-peak ratios for both DBP and systolic blood pressure (SBP) were above 50%. At the recommended once-daily starting doses, olmesartan medoxomil (20 mg) was more effective than losartan (50 mg), valsartan (80 mg) or irbesartan (150 mg) in reducing cuff DBP in patients with essential hypertension. The results of cuff SBP and mean 24-h DBP and SBP were similar to those of cuff DBP measurement. In mild-to-moderate hypertensive patients the recommended starting dose of olmesartan medoxomil was as effective as that of amlodipine besylate (5 mg/day) in reducing both cuff and 24-h blood pressure. In lowering DBP olmesartan medoxomil, at 10-20 mg/day, was as effective as atenolol at 50-100 mg/day. In mild-to-moderate hypertensive patients, olmesartan medoxomil, at 5-20 mg once daily, was more effective than captopril at 12.5-50 mg twice daily. At 20-40 mg once daily olmesartan medoxomil was as effective as felodipine, at 5-10 mg once daily. Olmesartan medoxomil has minimal adverse effects with no clinically important drug interactions. Animal studies have shown that olmesartan medoxomil provides a wide range of organ protection. Olmesartan medoxomil ameliorated atherosclerosis in hyperlipidemic animals and ameliorated cardiac remodeling and improved survival in rats with myocardial infarction. Olmesartan medoxomil has renoprotective effects in a remnant kidney model and type 2 diabetes models. Future investigation should reveal whether these beneficial effects of olmesartan medoxomil are applicable to human diseases.     

Olmesartan medoxomil: a review of its use in the management of hypertension

Olmesartan medoxomil (Olmetec, Benicar) is an angiotensin II type 1 (AT(1)) receptor antagonist (angiotensin receptor blocker [ARB]) that inhibits the actions of angiotensin II on the renin-angiotensin-aldosterone system, which plays a key role in the pathogenesis of hypertension. Oral olmesartan medoxomil 10-40 mg once daily is recommended for the treatment of adult patients with hypertension. In those with inadequate BP control using monotherapy, fixed-dose olmesartan medoxomil/hydrochlorothiazide (HCTZ) [Olmetec plus, Benicar-HCT] combination therapy may be initiated. Extensive clinical evidence from several large well designed trials and the clinical practice setting has confirmed the antihypertensive efficacy and good tolerability profile of oral olmesartan medoxomil, as monotherapy or in combination with HCTZ, in patients with hypertension, including elderly patients with isolated systolic hypertension (ISH). Notably, BP control is sustained throughout the 24-hour dosage interval, including during the last 4 hours of this period. In clinical trials, olmesartan medoxomil monotherapy provided better antihypertensive efficacy than losartan, candesartan cilexetil or irbesartan monotherapy, and was at least as effective as valsartan treatment, with a faster onset of action than other ARBs in terms of reductions from baseline in diastolic BP (DBP) and, in most instances, systolic BP (SBP). Combination therapy with olmesartan medoxomil plus HCTZ was superior to that with benazepril plus amlodipine, as effective as that with losartan plus HCTZ, noninferior to that with atenolol plus HCTZ, but less effective than that with telmisartan plus HCTZ, in individual trials. Data from ongoing clinical outcome trials are required to more fully determine the relative position of olmesartan medoxomil therapy in the management of hypertension. In the meantime, the consistent antihypertensive efficacy during the entire 24-hour dosage interval and good tolerability profile of olmesartan medoxomil, with or without HCTZ, make it a valuable option for the treatment of adult patients with hypertension, including the elderly.     

Use of 24-Hour Ambulatory Blood Pressure Monitoring to Assess Antihypertensive Efficacy

INTRODUCTION: Goal rates, the percentage of patients with hypertension achieving recommended SBP/DBP, are a clinically important assessment of an antihypertensive agent's efficacy. Twenty-four-hour ambulatory blood pressure monitoring (ABPM) allows accurate assessment of a patient's hypertension and risk for cardiovascular events, and provides the most accurate measure of an antihypertensive agent's efficacy throughout a 24-hour dosing interval. METHODS: A 12-week (4-week single-blind placebo run-in phase followed by an 8-week double-blind active treatment phase) randomized, parallel-group study reported that the recommended starting dose of the angiotensin II receptor antagonist (angiotensin receptor blocker; ARB) olmesartan medoxomil (Benicar(trade mark)) 20 mg/day was more effective than starting doses of losartan potassium (Cozaar) 50 mg/day, valsartan (Diovan) 80 mg/day, or irbesartan (Avapro) 150 mg/day in reducing cuff DBP in patients with essential hypertension. The present report includes analyses of secondary efficacy variables from this 12-week trial. RESULTS: The mean reduction in blood pressure from baseline to week 8 (end of treatment) was significantly greater with olmesartan medoxomil than with valsartan for all ABPM times analyzed (24 hours, daytime, night-time, and last 2 and 4 hours of monitoring). Statistical significance was reached for comparisons of olmesartan medoxomil with losartan potassium for a majority of times analyzed and with irbesartan for SBP in the last 4 hours of monitoring. Goal rates for accepted critical ambulatory blood pressure (ABP) values of <130/80 mm Hg for mean 24-hour ABP, <135/85 mm Hg for mean daytime ABP, and <120/75 mm Hg for mean night-time ABP were significantly greater for patients receiving olmesartan medoxomil than for those receiving losartan potassium or valsartan. Goal rates were numerically superior, but not statistically significant, to those achieved with irbesartan. Compared with losartan potassium or valsartan recipients, a significantly higher percentage of patients treated with olmesartan medoxomil achieved the 24-hour ABP goal of <130/85 mm Hg. The last 2 and 4 hours of ABPM indicated that olmesartan medoxomil maintained larger mean decreases in blood pressure through the morning surge. DISCUSSION/CONCLUSION: ABP goal rates are a meaningful measure of antihypertensive efficacy. The effects on mean change from baseline in ABP and ABP goal rates after 8 weeks of treatment were numerically better, but not statistically significant, for olmesartan medoxomil than for irbesartan. However, olmesartan medoxomil was significantly more effective than losartan potassium or valsartan.     

Olmesartan medoxomil: in children and adolescents with hypertension

Olmesartan medoxomil is an orally administered angiotensin II receptor antagonist, selective for the angiotensin II type 1 receptor, which has established antihypertensive efficacy in adults. In children and adolescents with hypertension (n?=?302), oral olmesartan medoxomil significantly and dose-dependently reduced seated systolic blood pressure (BP) and seated dystolic BP from baseline (the primary endpoint) in a 3-week, dose-response period in a well designed phase II/III clinical trial. Patients received olmesartan medoxomil high dose (20 or 40?mg once daily depending on bodyweight) or low dose (2.5 or 5.0?mg once daily depending on bodyweight). The response was significant for both cohorts, which were stratified by race (cohort A was mixed race [62% White] and cohort B was 100% Black). In addition, BP control was maintained in olmesartan recipients relative to placebo recipients in cohort A and the combined cohort A?+?B, but not for patients in cohort B, during a placebo-controlled withdrawal period of this trial. Oral olmesartan medoxomil was generally well tolerated in children and adolescents with hypertension. The majority of adverse events were of mild to moderate intensity.     

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

The combination of valsartan [an angiotensin II type 1 (AT(1)) receptor blocker] and hydrochlorothiazide (a thiazide diuretic), administered once daily, has been evaluated in the treatment of patients with hypertension in clinical trials ranging in duration from 8 weeks to 3 years. These studies showed that combination treatment with valsartan 80 or 160mg and hydrochlorothiazide 12.5 or 25mg induced significant reductions from baseline in systolic blood pressure (SBP) and diastolic BP (DBP) in patients with mild to severe hypertension. Clinical trials have demonstrated that the combination of valsartan 80 or 160mg with hydrochlorothiazide 12.5 or 25mg is significantly more effective than either drug alone. Furthermore, valsartan plus hydrochlorothiazide was effective at reducing BP in patients unresponsive to monotherapy with either agent alone. Effective BP control with valsartan plus hydrochlorothiazide was maintained in long-term studies, with reductions observed after 3 months of treatment being similar to those seen after 1, 2 or 3 years. Fixed-dose valsartan/hydrochlorothiazide showed similar BP reductions to amlodipine and to valsartan plus benazepril. Valsartan/hydrochlorothiazide also provided effective 24-hour ambulatory SBP/DBP control. Headache, dizziness and fatigue were the most common adverse events occurring in clinical trials; the incidence of these events in valsartan plus hydrochlorothiazide recipients was not significantly different to that in placebo recipients. Hypokalaemia occurred in 4.5% of valsartan plus hydrochlorothiazide recipients; valsartan attenuated the hydrochlorothiazide-associated decrease in serum potassium concentrations. CONCLUSIONS: the combination of valsartan and hydrochlorothiazide is an effective treatment for patients with hypertension. Clinical trials have demonstrated that the combination is more effective than either drug alone, and is effective in patients not responding to monotherapy with either agent. Furthermore, the adverse event profile of valsartan/hydrochlorothiazide is similar to that of placebo. Unless there are compelling or specific indications for other drugs, current data support the use of valsartan/hydrochlorothiazide when patients are unresponsive to monotherapy with either agent. Results from clinical trials evaluating the effects of valsartan/hydrochlorothiazide on cardiovascular morbidity and mortality will help to further define the role of the combination in the management of hypertension.     

Azilsartan medoxomil in the treatment of hypertension: the definitive angiotensin receptor blocker?

Introduction: Azilsartan medoxomil is the newest angiotensin receptor blocker marketed for the treatment of arterial hypertension. The aim of this article was to review the available evidence about this drug alone or combined with other antihypertensive agents in the treatment of hypertensive population.

Areas covered: For this purpose, a search on MEDLINE and EMBASE databases was performed. The MEDLINE and EMBASE search included both medical subject headings (MeSHs) and keywords including azilsartan or azilsartan medoxomil or angiotensin receptor blockers or renin angiotensin system or chlorthalidone and hypertension. References of the retrieved articles were also screened for additional studies. There were no language restrictions.

Expert opinion: Azilsartan medoxomil has a potent and persistent ability to inhibit binding of angiotensin II to AT1 receptors, which may play a role in its superior blood pressure (BP) -lowering efficacy compared with other drugs, including ramipril, candesartan, valsartan or olmesartan, without an increase of side effects. Chlortalidone is a diuretic which significantly differs from other classic thiazides and has largely demonstrated clinical benefits in outcome trials. The fixed-dose combination of azilsartan and chlorthalidone has been shown to be more effective than other potent combinations of angiotensin receptor blockers plus hydrochlorothiazide, with a good tolerability profile.     

Olmesartan medoxomil

Olmesartan medoxomil is a nonpeptide angiotensin II receptor antagonist which selectively and competitively inhibits the type 1 angiotensin II receptor without affecting other receptors regulating the cardiovascular system. In well designed randomised trials, olmesartan medoxomil was significantly more effective than placebo, and at dosages of 10 to 20 mg/day was at least as effective as atenolol 50 to 100 mg/day in reducing diastolic blood pressure (DBP). At dosages of 5 to 20 mg/day, olmesartan medoxomil was more effective than captopril 12.5 to 50mg twice daily at lowering seated DBP in patients with mild to moderate hypertension in a dose titration study. Reductions in seated DBP were greater with olmesartan medoxomil 10 to 20 mg/day than losartan 50 to 100 mg/day. Olmesartan medoxomil at 20 mg/day was more effective in lowering seated DBP than losartan 50 mg/day, valsartan 80 mg/day or irbesartan 150 mg/day, and was more efficacious than losartan 50 mg/day or valsartan 80 mg/day at reducing 24-hour ambulatory systolic blood pressure. Olmesartan medoxomil has shown no clinically important pharmacokinetic interactions with digoxin, warfarin or antacid (aluminium magnesium hydroxide). Adverse events were infrequent in clinical studies of olmesartan medoxomil and were similar to those attributed to placebo. With olmesartan medoxomil, the frequency of dizziness was higher than with placebo but similar to that occurring with losartan, valsartan and irbesartan.     

奥美沙坦酯与缬沙坦治疗中度原发性高血压临床研究

目的比较奥美沙坦酯和缬沙坦治疗中度原发性高血压的疗效和安全性。方法入选482例中度原发性高血压患者,按照1∶1随机分组,分别接受奥美沙坦酯20～40 mg/d或缬沙坦80～160 mg/d治疗,共8周。观察并比较其降压效果。结果治疗4周后,奥美沙坦酯组SeDBP平均下降了(10.58±6.82)mmHg,缬沙坦组下降了(9.38±7.16)mmHg;两组比较,P=0.004。奥美沙坦组与缬沙坦组分别有60%、61.74%的患者剂量加倍,加量有效率分别为52.22%、51.85%;治疗8周后,两组SeDBP平均下降(15.72±6.03)mmHg及(14.12±6.79)mmHg;治疗4周后,两组的药物不良反应发生率分别为3.33%、7.5%(P>0.05)。结论口服奥美沙坦酯胶囊20～40 mg/d,1次/d,能保持24 h平稳降压,8周总有效率为79.65%;与缬沙坦80～160 mg/d的降压疗效相近。而两组药物不良反应发生率差异无统计学意义。     

国产缬沙坦治疗原发性高血压病的疗效和安全性评价

目的评价国产缬沙坦治疗原发性高血压病的临床疗效和安全性。方法124例原发性高血压患者坐位舒张压（SeDBP）12.63～15.29kPa，坐位收缩压（SeSBP）<23.94kPa，进行随机、盲法的8周平行对照观察。经1周药物洗脱期及2周安慰剂期后，随机双盲口服缬沙坦(n=64)80mg     

缬沙坦与苯磺酸左旋氨氯地平治疗原发性高血压的疗效及对血尿酸影响的比较研究

目的：比较缬沙坦与苯磺酸左旋氨氯地平治疗原发性高血压的疗效及对血尿酸的影响。方法将84例原发性高血压患者随机分为治疗组和对照组各42例。对照组予以缬沙坦片80mg,每日1次。治疗组予以苯磺酸左旋氨氯地平片5mg,每日1次。两组疗程均为8周。结果两组患者治疗后收缩压、舒张压与同组治疗前比较,差异均有统计学意义（P＜0.01）。治疗组治疗后收缩压、舒张压与对照组比较,差异均无统计学意义（P＞0.05）。治疗组治疗后血压达标有26例,达标率为61.90%,对照组治疗后血压达标有17例,达标率为54.76%。两组血压达标率比较,差异无统计学意义（P＞0.05）。治疗后,治疗组血尿酸与对照组比较,差异具有统计学意义（P＜0.01）。结论缬沙坦与苯磺酸左旋氨氯地平均能改善原发性高血压患者的血压水平,且缬沙坦能显著降低原发性高血压患者血尿酸水平。     

抗高血压新药选择性AT1亚型血管紧张素II受体拮抗剂——阿齐沙坦酯

阿齐沙坦酯为新一代选择性AT1血管紧张素II亚型1受体拮抗剂,临床前和临床研究证实其具有平稳持久的抗高血压作用。2011年2月25日,FDA批准阿齐沙坦酯(商品名为Edarbi)用于治疗成人高血压。本综述主要介绍其药物作用机制,药物代谢动力学、疗效、安全性及临床研究进展。     

阿齐沙坦与奥美沙坦酯治疗轻中度原发性高血压的疗效比较

目的 比较阿齐沙坦与奥美沙坦酯治疗轻中度原发性高血压的临床疗效。方法 2015年9月—2017年2月从全国多家研究中心筛选轻、中度原发性高血压304例,随机分为奥美沙坦酯组和阿齐沙坦组。受试者从起始剂量开始,阿齐沙坦片20 mg/次和奥美沙坦酯片模拟剂,1次/d,或奥美沙坦酯片20 mg/次和阿齐沙坦片模拟剂,1次/d,开始治疗。用药后第8周末对受试者进行血压评价,如果服药前（药物浓度谷值时）坐位收缩压≥140 mmHg（1 mmHg=133 Pa）和/或舒张压≥90 mmHg则试验药物剂量加倍（阿齐沙坦片40 mg/次口服或奥美沙坦酯片40 mg/次,1次/d）继续治疗8周,如果服药前（药物浓度谷值时）坐位收缩压<140 mmHg且舒张压<90 mmHg则维持原剂量继续治疗8周。治疗总周期16周。观察两组的有效率和达标率。比较两组治疗前,治疗8、12、16周收缩压、舒张压,血压与治疗前差值的变化情况。结果 用药8、16周,奥美沙坦酯组有效率分别是66.89%、69.59%;阿齐沙坦组有效率分别是59.60%、58.94%,两组有效率比较差异没有统计学意义。用药8、16周,奥美沙坦酯组达标率分别是62.16%、61.49%;阿齐沙坦组达标率分别是56.95%、56.29%,两组达标率比较差异均没有统计学意义。治疗8、12、16周,两组受试者的坐位收缩压、舒张压逐渐降低,与同组治疗前比较差异均有统计学意义（P<0.05）;治疗后,两组血压比较差异无统计学意义。用药后两组受试者的坐位收缩压和舒张压均逐渐降低,至16周末时,两组间坐位舒张压下降值比较差异具有统计学意义（P<0.05）;16周末时两组收缩压下降值差异均没有统计学意义。结论 有效性方面,阿齐沙坦组疗效未达非劣效于奥美沙坦酯组,但阿齐沙坦自身的降压效果显著并具临床意义;安全性方面,阿齐沙坦组与奥美沙坦酯组不良事件、严重不良事件、不良反应发生率相当,安全性良好。     

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.     

心血管疾病新药阿齐沙坦酯的药理与临床评价

阿齐沙坦酯(azilsartan medoxomil)是一种血管紧张素II受体拮抗剂,用于治疗高血压,可与其他抗高血压药物联用。本文参照美国FDA有关该药的申报资料,对其药理作用、药代动力学、临床评价、安全性评价及药物相互作用等进行综述。     

Telmisartan/Amlodipine

Telmisartan/amlodipine is a single-pill combination of telmisartan, an angiotensin II receptor antagonist, and amlodipine, a dihydropyridine calcium channel antagonist, which is taken orally once daily for the treatment of hypertension. In the US and the EU, single-pill telmisartan/amlodipine can be used as a replacement for separate telmisartan and amlodipine tablets, and by patients not achieving BP goals with amlodipine monotherapy. In addition, the US indication includes patients not achieving BP goals with telmisartan (or another angiotensin II receptor antagonist or calcium channel antagonist other than amlodipine) alone, and as initial therapy in patients considered likely to require multiple drugs to achieve their BP goals. In an 8-week, randomized, double-blind, factorial-design, placebo-controlled, multicenter study in adult patients with hypertension (n =1461), mean DBP was reduced from baseline to a significantly greater extent in recipients of telmisartan 40 or 80mg/day plus amlodipine 5 or 10mg/day than in those receiving equivalent dosages of telmisartan or amlodipine monotherapy. Single-pill telmisartan/amlodipine recipients had significantly greater reductions in BP than telmisartan or amlodipine monotherapy recipients in an 8-week, randomized, double-blind, multicenter study in adult patients with severe hypertension (n = 858), and in four 8-week, randomized, double-blind, multicenter trials in patients who had not responded to amlodipine (n = 1097, 947, and 531) or telmisartan (n = 314) monotherapy. Telmisartan/amlodipine was generally well tolerated in clinical trials, including two 36-week follow-up studies.     

Updated meta-analytical approach to the efficacy of antihypertensive drugs in reducing blood pressure

BACKGROUND AND OBJECTIVE: Despite advances in the treatment of hypertension, control rates continue to be suboptimal in both Europe and the US. Strategies that improve hypertension control are therefore urgently needed. This study aimed to assess the relative efficacies of various antihypertensive drugs commonly used in France in reducing systolic and diastolic blood pressure (SBP and DBP) by using a meta-analytical approach. This update of a previously published meta-analytical approach extends the number of drugs evaluated from 13 to 19. METHODS: A total of 80 randomised, controlled trials published between 1973 and 2007 involving 10 818 patients were selected for inclusion in the meta-analytical approach. Data were examined for 19 drugs, and 16 drugs were included in the analysis: hydrochlorothiazide, indapamide sustained-release (SR), atenolol, amlodipine, lercanidipine, manidipine, enalapril, ramipril, trandolapril, candesartan cilexetil, irbesartan, losartan, olmesartan medoxomil, telmisartan, valsartan and aliskiren. Weighted average reductions in SBP and DBP over a period of 8-12 weeks were calculated for each drug from information on both the mean and the variability in BP reduction. No trials evaluating furosemide, spironolactone or cicletanine satisfied the inclusion criteria for this analysis. RESULTS: The average weighted reductions in SBP over 8-12 weeks were most marked with diuretics, and in particular indapamide SR 1.5 mg/day (mean change from baseline -22.2mm Hg), which reduced SBP to a greater extent than any of the other drugs evaluated (at any dosage considered). Average weighted reductions in DBP were generally similar with all classes of antihypertensives and ranged from -11.4mm Hg with the beta-adrenoceptor blocker atenolol and calcium channel antagonists to -10.3mm Hg with the angiotensin II type 1 receptor antagonists. CONCLUSION: This new analysis supports the results of the earlier investigation, in that indapamide SR 1.5 mg/day appeared to be the most effective drug for producing significant reductions in SBP within 8-12 weeks, which is an essential element in optimising cardiovascular prevention among hypertensive patients. The clinical application of these results should take into consideration all the limitations discussed in this analysis.     

Antihypertensive efficacy of olmesartan medoxomil or valsartan in combination with amlodipine: A review of factorial-design studies

ABSTRACT

Background: Most patients with hypertension require more than one drug to attain recommended blood pressure (BP) targets. Initiating therapy with two agents is recommended for patients at high risk of a cardiovascular event or with a BP?>?20/10?mmHg above goal. Combination therapy is effective when comprised of agents with complementary mechanisms of action, such as calcium channel blockers (CCBs) and angiotensin II-receptor blockers (ARBs). Two fixed-dose CCB/ARB combinations are approved in the US: amlodipine/valsartan (AML/VAL) and amlodipine/olmesartan medoxomil (AML/OM).

Objectives: To review and describe the efficacy of AML/VAL and AML/OM combinations by discussing similarly designed clinical trials.

Methods: Three 8-week, randomized, double-blind, placebo-controlled, parallel-group factorial-design studies were examined (two AML/VAL; one AML/OM). The study endpoints presented in this review were: change from baseline in least-squares mean seated diastolic BP (SeDBP) and least-squares mean seated systolic BP (SeSBP). In addition to the efficacies of AML/VAL and AML/OM combinations, the efficacies of AML, VAL and OM administered as monotherapy are presented. Placebo-subtracted BP reductions were calculated for this review.

Results: Patient demographics were similar but mean baseline SeBP was higher in the OM study (163.8/101.6?mmHg) than in the VAL studies (152.8/99.3 and 156.7/99.1?mmHg), possibly suggesting that the OM study included a more difficult-to-treat patient population. AML/ARB combinations consistently produced greater mean SeBP reductions than monotherapy. Least squares (LS) mean SeDBP reductions were 19.4?mmHg (AML/OM 10/40?mg; placebo-corrected: 15.9?mmHg) and 18.6?mmHg (AML/VAL 10/320?mg; placebo-corrected: 9.8?mmHg). LS mean SeSBP reductions were 28.5?mmHg (AML/OM 10/40?mg; placebo-corrected: 25.7?mmHg) and 28.4?mmHg (AML/VAL 10/320?mg; placebo-corrected: 15.5?mmHg).

Conclusions: This review of published factorial-design studies showed that the maximal marketed doses of an amlodipine/olmesartan medoxomil combination (10/40?mg) and an amlodipine/valsartan combination (10/320?mg) produced large reductions in BP from baseline. Limitations of this review include the small number of studies analyzed and the inherent heterogeneity between patient populations. Further research is warranted to directly compare the efficacy of these combinations in a randomized, controlled trial, or additional published clinical trials are required to provide larger data sets for robust meta-analyses and to overcome heterogeneity observed within these studies.     

Azilsartan Medoxomil,an Angiotensin II Receptor Antagonist for the Treatment of Hypertension

Azilsartan (AZL) medoxomil was approved by the United States Food and Drug Administration in 2011 for the treatment of hypertension and has shown promising results both in blood pressure (BP) reduction and in tolerability, but has not yet been taken into practice to the same extent as other angiotensin II receptor blockers (ARBs) that have been on the market for a longer period. AZL antagonizes the AT₁ receptor for angiotensin II (ANG II), whereas angiotensin‐converting enzyme inhibitors block the conversion of angiotensin I to ANG II, but not alternative routes of formation of ANG II. The bioavailability of AZL is about 60% and it has a t_max of 1.5–3 hr and a half‐life of approximately 11 hr. With its IC₅₀ of 7.4 nM after 5 hr of drug washout in radioligand assays, AZL has a tighter and longer‐lasting binding to the AT₁ receptor by several orders of magnitude than other ARBs, which might lead to a more effective reduction in BP. Clinical studies have revealed that AZL doses of 40 and 80 mg/day reduce BP significantly better than maximal clinical doses of valsartan or olmesartan, while being well tolerated and exhibiting a spectrum of adverse effects comparable to those of other ARBs. These properties of AZL might lower the risk of cardiovascular disease and thereby reduce mortality rates. However, the existing mortality studies have not found this correlation, which should be further investigated.