Pharmacological profiles and clinical effects of olmesartan medoxomil, a novel angiotensin II receptor blocker

Olmesartan medoxomil is a new angiotensin II receptor blocker (ARB) indicated for the treatment of hypertension. Olmesartan medoxomil is a pro-drug that is converted to the active metabolite olmesartan. Olmesartan does not undergo further metabolism and does not interact with cytochrome P450 enzymes. Olmesartan is a potent ARB with high selectivity for the type 1 (AT(1)) receptor subtype and shows insurmountable antagonism against the AT(1) receptor in vascular tissues. This antagonistic mode, which could be attributed to tight binding of this drug to the receptor, would underlie the potent and persistent action of olmesartan medoxomil in vivo. In fact, oral administration of olmesartan medoxomil produces a potent and long-lasting antihypertensive action without inducing tachycardia. The preventive effects of olmesartan medoxomil on end-organ damage in the kidney, heart, and blood vessels have been demonstrated in various animal models. In clinical studies, olmesartan medoxomil is shown to be well tolerated and have an excellent safety profile that is comparable to that of placebo. Head-to-head comparisons with other ARBs (losartan, valsartan, irbesartan, and candesartan cilexetil) conducted in the United States and Europe have revealed that olmesartan medoxomil is superior to these other ARBs in lowering blood pressure. These facts suggest that olmesartan medoxomil would be beneficial for the treatment of hypertension and other end-organ 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.     

Olmesartan medoxomil-based therapy for the management of hypertension

Contemporary practice guidelines for hypertension recommend a goal systolic/diastolic blood pressure (BP) of less than 140/90 mmHg for patients with hypertension and less than 130/80 mmHg for patients with diabetes mellitus or chronic kidney disease. Current guidelines recognize that most patients will require combination therapy to achieve these BP goals and recommend that the agents used in such therapy should have complementary mechanisms of action. Olmesartan medoxomil is an angiotensin receptor blocker approved for the treatment of hypertension as monotherapy or in combination with antihypertensive agents. It is also approved in a fixed-dose combination with hydrochlorothiazide or amlodipine. Olmesartan medoxomil-based therapy can manage hypertension across a range of patient types and has demonstrated good BP-lowering efficacy and goal attainment in individuals with stage 1 or stage 2 hypertension. The comparative antihypertensive efficacy and safety of olmesartan medoxomil, as monotherapy and as part of combination therapy, has been established in several large, randomized clinical trials. This review evaluates the chemistry, efficacy and safety of olmesartan medoxomil-based therapy and its expanding role in hypertension management.     

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.     

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.     

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.     

The role of angiotensin II type 1 receptor antagonists in elderly patients with hypertension

Hypertension is a major risk factor for stroke and coronary events in elderly people and clinical trials have shown that treatment of hypertension with various drugs can result in a substantial reduction in cerebrovascular and cardiovascular events. The angiotensin II type 1 (AT1) receptor antagonists are the newest class of antihypertensive agents to be used widely in clinical practice. AT1 receptor antagonists can generally be given once-daily. They are also extremely well tolerated with minimal first-dose hypotension and an incidence of adverse effects similar to that seen with placebo. Adverse event rates are significantly lower than with other classes of antihypertensive drugs including ACE inhibitors. These factors result in improved compliance and increased rates of continuance on therapy. AT1 receptor antagonists show similar efficacy in lowering blood pressure to other classes of antihypertensive agents and their antihypertensive effect is potentiated when they are given concomitantly with low-dose thiazide diuretics. AT1 receptor antagonists are eliminated predominantly by the hepatic route but most are not subject to extensive metabolism and interactions with other drugs are uncommon. This is an advantage in the elderly, who are often receiving multiple medications which increases the risk for adverse drug interactions. Dose adjustments are not usually required in the elderly unless there is plasma volume depletion. Although plasma AT1 receptor antagonist concentrations are generally higher in the elderly than in younger subjects, this pharmacokinetic difference may be balanced by decreased activation of the circulating renin-angiotensin-aldosterone system in the elderly. Recent clinical studies in high-risk hypertensive patients with left ventricular hypertrophy or in patients with diabetic nephropathy or heart failure have demonstrated that AT1 receptor antagonists can improve clinical outcomes to a similar or sometimes greater extent than other antihypertensive agents. Many of these studies have included large numbers of older patients and have confirmed the excellent tolerability profile of these drugs. Thus, AT1 receptor antagonists should be considered as a possible first-line treatment or as a component of combination therapy in patients with type 2 diabetes mellitus and microalbuminuria or nephropathy and as an alternative or additional treatment to ACE inhibitors in patients with heart failure or left ventricular dysfunction. AT1 receptor antagonists also appear to reduce the onset of new diabetes compared with some other antihypertensive drugs. The benefits in terms of organ protection have mainly been seen in studies using higher doses of particular AT1 receptor antagonists and it is not certain at present whether these results can be extrapolated to other members of the class. As the elderly are more likely to have developed organ damage related to hypertension or to have heart failure or diabetes as concomitant conditions, AT1 receptor antagonists represent an appropriate option for many elderly patients. The main disadvantage of these drugs is the cost of the medication but this may be offset by their improved tolerability with fewer adverse reactions and thus increased compliance, resulting in better blood pressure control and fewer clinical events. Overall, AT1 receptor antagonists are well tolerated and efficacious for blood pressure-lowering when given as a single daily dose in elderly patients and have many potential benefits in high-risk hypertensive subjects.     

奥美沙坦:一种新的血管紧张肽Ⅱ受体拮抗剂

奥美沙坦 (olmesartan)是最新的血管紧张肽Ⅱ受体 (AT1)拮抗剂 ,对不同程度的高血压均有很好的降压作用 ,病人对其亦有很好的耐受性。本文对该药的药效学、药动学和临床应用等研究作一综述     

奥美沙坦酯治疗轻中度原发性高血压的疗效和安全性

目的评价奥美沙坦酯治疗轻中度原发性高血压的疗效和安全性。方法随机、双盲、双模拟、阳性药物(氯沙坦钾)平行对照。40例轻中度原发性高血压患者随机分为奥美沙坦酯或氯沙坦钾组,均治疗8周,观察两组治疗前后的血压、心率、心电图和血、尿常规等实验室检查结果的变化。结果奥美沙坦酯组与氯沙坦钾组比较,患者平均坐位收缩压和舒张压的降低程度均有显著性差异,分别为(18.9±8.7)mmHg和(12.6±7.6)mmHg(P<0.01);(13.8±3.5)mmHg和(11.7±3.3)mmHg(P<0.05)。治疗前后两组血压降低幅度均有显著差异,心率无明显变化。奥美沙坦酯和氯沙坦钾组降压显效率分别为63.2%和57.9%,总有效率分别为84.2%和68.4%,组间无显著差异。两组共出现3例头晕,实验室检查无异常改变。结论奥美沙坦酯治疗轻中度原发性高血压的疗效良好,不良反应发生率低。     

Olmesartan: Induced maculopapular rash

Olmesartan medoxomil is an angiotensin receptor blocker (ARB) which is shown to be effective and well tolerated in hypertensive patients. It is a frequently prescribed antihypertensive as it is considered safe. Here, we report the case of a patient who developed maculopapular rash during the course of the treatment with olmesartan medoxomil.KEY WORDS: Angiotensin receptor blockers, maculopapular rash, olmesartan     

Olmesartan medoxomil/amlodipine/hydrochlorothiazide: fixed-dose combination in hypertension

The antihypertensive agents olmesartan medoxomil, amlodipine and hydrochlorothiazide (HCTZ) are now available as a fixed-dose combination tablet (olmesartan medoxomil/amlodipine/HCTZ). In a 12-week, randomized, double-blind, multicentre trial (TRINITY) in adults with moderate to severe hypertension, olmesartan medoxomil?+?amlodipine?+?HCTZ triple combination therapy produced significantly greater least squares mean reductions from baseline in seated diastolic blood pressure (BP) [primary endpoint] and seated systolic BP than olmesartan medoxomil/amlodipine, olmesartan medoxomil/HCTZ or amlodipine?+?HCTZ. Furthermore, significantly more patients achieved BP goals and targets with the triple combination regimen than with any of the dual combination regimens at week 12, with olmesartan medoxomil?+?amlodipine?+?HCTZ also demonstrating benefit over the dual regimens in terms of ambulatory BP control. According to subgroup analyses of the TRINITY trial, olmesartan medoxomil?+?amlodipine?+?HCTZ was more effective in reducing BP and achieving BP goals than each of the dual therapies, irrespective of hypertension severity, age, sex, race or diabetes mellitus status. Data from a number of smaller clinical studies indicated that olmesartan medoxomil?+?amlodipine?+?HCTZ triple combination therapy provides antihypertensive efficacy in patients whose BP is not adequately controlled with olmesartan medoxomil?+?amlodipine. Olmesartan medoxomil?+?amlodipine?+?HCTZ was generally well tolerated in the TRINITY study, with adverse events usually being mild or moderate in severity.     

奥美沙坦酯片治疗轻、中度原发性高血压的疗效和安全性

目的观察奥美沙坦酯片治疗轻、中度原发性高血压的疗效和安全性。方法61例轻、中度原发性高血压患者随机分为奥美沙坦酯组(n=30)和氯沙坦组(n=31),治疗8wk,观察2组治疗前后的血压、心率、心电图和血、尿实验室检查的变化。结果奥美沙坦酯组与氯沙坦组比较,坐位收缩压和舒张压降低程度都有显著差异,分别为(132±13 vs 139±13)mmHg(P<0.01)和(85±9 vs 87±9)mmHg(P<0.05)。奥美沙坦酯组降压有效率为83%;每日1次服用奥美沙坦酯作用可持续24h,药物降低收缩压和舒张压的谷峰比值均>50%。2组药物不良反应发生分别为1例和3例,2组比较无显著差别。结论奥美沙坦酯治疗轻、中度原发性高血压患者,能24h平稳降压,谷峰比满意,且耐受性较好。     

Blood pressure reduction with olmesartan in mild-to-moderate essential hypertension: a planned interim analysis of an open label sub-study in German patients

OBJECTIVE: To present the baseline characteristics and open-label treatment phase results for German patients in OLMEBEST, a European, multinational, partially randomized, partially double-blind study in patients with mild-to-moderate essential hypertension. RESEARCH DESIGN AND METHODS: After a 2-week placebo run-in, patients received olmesartan 20 mg for 8 weeks. Controlled patients (mean sitting diastolic blood pressure [sDBP] < 90 mmHg) continued on olmesartan 20 mg/day for a further 4 weeks. Non-controlled patients (sDBP > 90 mmHg) were randomized to olmesartan 40 mg/day or olmesartan 20 mg/day plus 12.5 mg hydrochlorothiazide for 4 weeks. Of 823 patients included, 558 continued olmesartan 20 mg treatment and 228 patients were randomized to olmesartan 40 mg/day or combination therapy. Efficacy variables included the change from baseline in mean sitting DBP and systolic blood pressure [sSBP] at Week 8 (and Week 12 for controlled patients), and the proportion of controlled patients and responders (mean sDBP < 90 mmHg or improvement of > 10 mmHg from baseline at Week 8). RESULTS: After 8 weeks of olmesartan medoxomil 20 mg, mean reduction from baseline in sDBP was 11.8 mmHg and in sSBP was 17.1 mmHg. In controlled patients continuing open-label olmesartan medoxomil 20 mg, mean reduction from baseline at 12 weeks in sDBP was 14.9 mmHg and in sSBP was 20.1 mmHg. At Week 8, the response rate was 76% and the control rate was 70%. Olmesartan medoxomil 20 mg/day was well tolerated; 30.9% of patients experienced an adverse event, and the majority of these events were judged by the investigators to be mild. CONCLUSION: Olmesartan medoxomil monotherapy at the recommended dosage of 20 mg once daily is effective and well tolerated in patients with mild-to-moderate 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.     

奥美沙坦酯对老年高血压患者肌酐清除率的影响

目的：评价奥美沙坦酯对老年高血压患者肌酐清除率的影响。方法：42例老年高血压患者随机接受奥美沙坦酯20mg或氯沙坦50mg,qd治疗,总疗程8周。结果：奥美沙坦酯组和氯沙坦组治疗前后肌酐清除率均有不同程度上升,但与治疗前相比无统计学差异,两组间差异无统计学意义（P〉0．05）。奥美沙坦酯组和氯沙坦组均未出现不良反应。结论：老年高血压患者应用奥美沙坦酯后肌酐清除率有轻度上升,提升对肾脏有保护作用。     

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.     

Olmesartan, an AT1-selective antihypertensive agent

Olmesartan is an angiotensin II receptor antagonist indicated for the treatment of essential hypertension. Angiotensin II is an important hormonal effector and end-product of the renin-angiotensin system. When it binds to its endogenous receptor sites, it causes widespread vasoconstriction and a subsequent increase in blood pressure. Olmesartan works by selectively binding to AT(1) against the pathophysiologic events leading to diabetic nephropathy and cardiovascular morbidity/mortality. This end-organ protection is independent of olmesartan's blood pressure lowering properties and is therefore thought to be mediated by different mechanisms. In summary, olmesartan has an efficacy profile superior to other available antihypertensive agents, with a tolerability profile comparable to that of placebo. In addition, the convenience of its once-daily dosing means that olmesartan should be considered not only as an alternative, but also as a first-line treatment for patients with mild to severe essential hypertension. Thus, olmesartan appears to be a very promising new therapy for the treatment of hypertension.     

Antihypertensive Drugs

For most patients with systemic hypertension, long-term drug treatment is indicated and is beneficial. There is overwhelming evidence to suggest that antihypertensive drugs offer protection against complications of hypertension. Whereas nondrug therapeutic options should be implemented in all patients, a vast majority will require pharmacological treatment to achieve goal blood pressure levels. Fortunately, a number of drugs are available to accomplish successful treatment of hypertensive disorders. While it is conventional to initiate treatment with a single drug, a suitable combination of drugs is often required to control the blood pressure effectively. Although diuretics and β-blockers are effective and well tolerated, other classes of drugs are being increasingly used as the initial choice of therapy for hypertension. Every class of antihypertensive drugs offer advantages and some disadvantage; the physician should weigh the benefits and risks in selecting one drug over another. While the clinical parameters are followed in the management of patients with hypertension, it is also necessary to monitor the patients’ biochemical profile periodically in order to modify and adjust the therapy accordingly. A careful selection of drug therapy along with close follow-up offers the best prospect to reduce the burden of morbidity and mortality in hypertension. This article provides an overview of drugs in the management of patients with hypertension.