Eprosartan: a review of its use in the management of hypertension

Angiotensin II type 1 receptor antagonists in the treatment of hypertension in elderly patients: focus on patient outcomes

Hypertension in the elderly is one of the main risk factors of cardiovascular and cerebrovascular diseases. Knowledge regarding the mechanisms of hypertension and specific considerations in managing hypertensive elderly through pharmacological intervention(s) is fundamental to improving clinical outcomes. Recent clinical studies in the elderly have provided evidence that angiotensin II type 1 (AT(1)) receptor antagonists can improve clinical outcomes to a similar or, in certain populations, an even greater extent than other classical arterial blood pressure-lowering agents. This newer class of antihypertensive agents presents several benefits, including potential for improved adherence, excellent tolerability profile with minimal first-dose hypotension, and a low incidence of adverse effects. Thus, AT(1) receptor antagonists represent an appropriate option for many elderly patients with hypertension, type 2 diabetes, heart failure, and/or left ventricular dysfunction.

Simultaneous analysis of eprosartan and hydrochlorothiazide in tablets by high-performance liquid chromatography

OBJECTIVE

A simple, precise and accurate isocratic reversed phase (RP) column high-performance liquid chromatographic (HPLC) method has been developed for simultaneous analysis of eprosartan (EPR) and hydrochlorothiazide (HCT) in tablet formulations.

MATERIALS AND METHODS

Isocratic RP-HPLC separation was achieved on phenomenex C18 column (250 × 4.6 mm i.d., 5 μm particle size) using mobile phase composed of 0.5% formic acid-methanol-acetonitrile [(80 : 25 : 20 v/v/v) pH, 2.80 ± 0.04] at a flow rate of 1.0 ml/min. The retention time for EPR and HCT was 7.69 ± 0.10 and 4.24 ± 0.09 minutes, respectively. The detection was performed at 272 nm.

RESULTS

The method was linear in the concentration range of 60-600 μg/ml for EPR and 2.5-25 μg/ml for HCT with a correlation coefficient of 0.9992 and 0.9997, respectively. The repeatability for six samples was 0.53 and 0.61 % RSD for EPR and HCT, respectively. The accuracy (recovery) was found to be in the range of 99.46 to 100.61% for EPR and 99.06 to 100.93% for HCT, respectively.

CONCLUSIONS

The method was validated and successfully used for determination of the drugs in tablets.

Eprosartan: a review of its use in hypertension

Eprosartan is an angiotensin II receptor antagonist (angiotensin II receptor blocker [ARB]) used in the treatment of hypertension. In large, randomized trials, eprosartan (with or without hydrochlorothiazide [HCTZ]) demonstrated superior antihypertensive efficacy to that of placebo and, when administered at comparable dosage regimens, had similar blood pressure-lowering effects to enalapril. Eprosartan was generally well tolerated in clinical trials and had a lower incidence of persistent dry cough than enalapril. Eprosartan has a neutral effect on metabolic parameters, such as serum lipid levels and glucose homeostasis, and a low propensity for pharmacokinetic drug interactions. The use of eprosartan or other ARBs in combination with HCTZ tends to reverse the potassium loss associated with thiazide diuretics. Independent of its antihypertensive effects, eprosartan was associated with improved clinical outcomes (primary composite endpoint of all causes of mortality and all cardiovascular and cerebrovascular events, including all recurrent events) compared with nitrendipine in a randomized, secondary prevention trial in hypertensive patients with previous cerebrovascular events (MOSES trial). Eprosartan also reduced blood pressure and was associated with a modest improvement in cognitive function in a large observational study in patients > or =50 years of age with newly diagnosed hypertension (OSCAR study). In both of these trials, additional antihypertensive therapy, such as HCTZ, was permitted. Therefore, eprosartan is a useful treatment option in the management of a broad range of patients with hypertension, and its use with HCTZ provides a rational combination regimen.

Validated quantitation of angiotensin II receptor antagonists (ARA-II) in human plasma by liquid-chromatography-tandem mass spectrometry using minimum sample clean-up and investigation of ion suppression

For the quantitation of angiotensin II receptor antagonists (ARA-II) in human plasma, a method using liquid-chromatography (LC)-electrospray ionization tandem mass spectrometry (MS/MS) has been developed with respect to simple sample clean-up and investigation of ion suppression effects. For sample preparation, protein precipitation using zinc sulphate and methanol showed advantages in speed, recovery, and reproducibility over solid-phase extraction. A triple quadrupole mass spectrometer (Sciex API 365) with turbo ionspray source was used for detection of compounds with multireaction monitoring (MRM) of two transitions per compound. Suppression effects caused by endogenous matrix compounds were investigated by post-column infusion of analytes and LC analysis of precipitates of blank plasma samples and could be excluded. A validation was performed for the ARA-II drugs (valsartan, irbesartan, losartan and its active metabolite EXP 3174, eprosartan, candesartan, and telmisartan). The developed method showed good intra- and interday precision (<12% relative standard deviation) and accuracy (<11.5% bias) at different concentrations for all the studied compounds. The calculated lower limits of quantitation were between 7 and 13 ng/mL, and the compounds were stable during the analytical process. These rather expensive drugs against hypertension are prescribed with increasing numbers in Europe and the industrialized nations. Complications might arise from overdosage or metabolic disorders. However, drug monitoring is not usually performed. Because the therapeutic concentrations range from a few nanograms to hundreds of nanograms per milliliter for the different drugs, and they are not amenable to gas chromatography/MS analysis because of their high molecular weight and polarity, the LC-MS/MS method is the golden standard for therapeutic drug monitoring and for clinical and forensic toxicology of ARA-II drugs.

Effects of eprosartan on target organ protection

Hypertension is the most important cardiovascular risk factor for stroke. Blood pressure reduction by antihypertensive treatment is clearly efficacious in the prevention of stroke (both primary and secondary), although no clear differences have yet been observed between antihypertensive drug classes. However, a recent study reported the clear superiority of the angiotensin-receptor blocker eprosartan over the calcium channel blocker nitrendipine in cardiovascular protection of hypertensive patients with a previous stroke. Comparative studies using angiotensin-receptor blockers have also suggested the superiority of this class of drugs on primary stroke prevention. This effect may be linked to their beneficial actions on left ventricular hypertrophy, atrial enlargement, and supraventricular arrhythmias, endothelial dysfunction, inflammation, and remodelling, as well as a direct neuroprotective effect mediated through the stimulation of the angiotensin II type-2 receptor. In addition, a sympathoinhibition observed with the renin–angiotensin system blockers and particularly demonstrated with eprosartan, may help to explain the better cardiovascular and cerebrovascular protection in comparison with the calcium antagonist nitrendipine.

Angiotensin type 1 receptor antagonists induce human in-vitro adipogenesis through peroxisome proliferator-activated receptor-γ activation

OBJECTIVE

In clonal animal cells, certain angiotensin receptor blockers (ARB) activate the peroxisome proliferator-activated receptor-gamma (PPARgamma). The aim of this work was to validate that observation in human cells and humans.

METHODS

We investigated the induction of in-vitro adipogenesis and the activation of PPARgamma-target genes, adiponectin and lipoprotein lipase, by ARB in human preadipocytes. We also studied PPARgamma response-element-driven luciferase reporter gene activation in human adipocytes. Finally, we treated 14 obese men for 10 days with placebo crossed over with 150 mg/day irbesartan. Subcutaneous fat was analyzed for mRNA expression of adiponectin and lipoprotein lipase.

RESULTS

Telmisartan and irbesartan, and to a lesser degree losartan, induced adipogenesis and activated PPARgamma-target genes. This stimulation of PPARgamma-target genes was prevented by the PPARgamma antagonist GW9662. Eprosartan had no effect. Paradoxically, all ARB activated the luciferase reporter gene. PPARgamma activity increased approximately two-fold with pioglitazone and 1.5-fold with the ARB in all assays. In the cross-over clinical study, irbesartan lowered blood pressure but had no effect on adiponectin or lipoprotein lipase mRNA expression.

CONCLUSIONS

Our data are the first to show that ARB induce adipogenesis and PPARgamma-target gene expression in human adipocytes. Pharmacokinetic differences may contribute to the heterogeneous effects on metabolism and preadipocyte differentiation. In humans, larger doses of ARB, longer treatments, or both may be required to activate PPARgamma in adipose cells.

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.

Haemodynamic effects of eprosartan and valsartan in hypertensive patients during isometric and mental stress

OBJECTIVE

To assess the effects of eprosartan and valsartan on the haemodynamics of forearm circulation in hypertensives undergoing isometric and mental stress.

DESIGN AND METHODS

Thirty-six patients with essential stable hypertension underwent haemodynamic evaluations on the left arm: humeral flux and calibre by means of colour Doppler ultrasound, microcirculatory flux on the third finger of left hand by means of laser Doppler flowmetry, blood pressure and heart rate monitor. District resistance was calculated as the ratio between mean arterial pressure and blood flow, and microcirculatory conductance was calculated as the ratio between flux and the mean pressure. The evaluations were performed at rest, during handgrip and during mental stress. Patients were randomized to receive eprosartan (600 mg) or valsartan (160 mg); tests were repeated after 15 days of therapy.

RESULTS

Both treatments reduced blood pressure (P<0.05) and peripheral resistance during tests. Eprosartan obtained a greater reduction in resistance during handgrip than valsartan. Laser Doppler flowmetry showed a significant decrease of flux only with mental stress. Laser Doppler flowmetry showed a reduction in conductance during both tests--this reduction was smaller with eprosartan during handgrip. None of the molecules affected the conductance during mental stress. While both were able to reduce microcirculatory decrease in conductance; in particular, eprosartan controlled this drop during handgrip better than valsartan.

CONCLUSIONS

Angiotensin II receptor type 1 inhibition exerts protective effects during adrenergic and noradrenergic stress in hypertensives. Eprosartan is more efficacious than valsartan in controlling noradrenergic effects.

Effects of telmisartan compared with eprosartan on blood pressure control, glucose metabolism and lipid profile in hypertensive, type 2 diabetic patients: a randomized, double-blind, placebo-controlled 12-month study

We evaluated the antihypertensive activity, glucose homeostasis and plasma lipid profile in patients with mild hypertension and type 2 diabetes mellitus treated by diet and exercise, and not in receipt of oral hyperglycemics, following 12-month treatment with either telmisartan or eprosartan. In this double-blind, placebo-controlled trial, 119 patients with mild essential hypertension (diastolic blood pressure [DBP] 91-104 mmHg) and type 2 diabetes were divided into three groups and randomized to receive once-daily telmisartan 40 mg, eprosartan 600 mg, or placebo for 12 months. At enrollment, patients were advised on diet (1,400-1,600 kcal/day) and exercise (physical aerobics on a bicycle for at least 30 min on 4 days each week). Compared with baseline, a significant reduction (p<0.01) in seated trough systolic blood pressure (SBP) was detected after 12-month treatment with either telmisartan or eprosartan. Seated trough DBP was also reduced by telmisartan (p<0.01) and eprosartan (p<0.05); the antihypertensive effect of telmisartan was significantly superior (p<0.05). No change in body mass index or glucose metabolism was observed with either active treatment, or with placebo. Telmisartan, but not eprosartan, significantly improved plasma total cholesterol (p<0.01), low-density lipoprotein cholesterol (p<0.01) and triglycerides (p<0.05) compared with eprosartan. In conclusion, 12-month telmisartan treatment produced a significantly greater reduction in DBP than eprosartan and significantly improved plasma lipids. The improvement could be due to varying pharmacokinetic/pharmacodynamic properties of telmisartan compared with eprosartan, even if it is not clear about the relationship between angiotensin-II receptor blockade and 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibition.

Angiotensin II receptor antagonists alone and combined with hydrochlorothiazide: potential benefits beyond the antihypertensive effect

Angiotensin II receptor antagonists (angiotensin receptor blockers; ARBs) and thiazide diuretics have an accepted place in the management of hypertension. Most patients require combination therapy with two or more drugs to adequately control blood pressure to targets recommended by European and international guidelines. ARBs and the thiazide diuretic hydrochlorothiazide have complementary modes of action. Fixed-dose combinations of an ARB and low-dose hydrochlorothiazide provide a convenient and effective treatment option for patients who do not achieve blood pressure targets on monotherapy, without compromising the placebo-like tolerability of ARBs. In Europe, fixed-dose combinations with hydrochlorothiazide currently are available for the ARBs candesartan, eprosartan, irbesartan, losartan, telmisartan, and valsartan. Recently, a number of studies have focused on the use of ARBs in monotherapy and in combination therapy, in conditions including congestive heart failure, post-myocardial infarction management, hypertension with cardiovascular risk factors, and diabetic and non-diabetic nephropathy. Evidence from these studies suggests a beneficial role beyond the antihypertensive effect of these therapies in providing protection against cardiovascular, renovascular, and cerebrovascular events.

Eprosartan

The angiotensin II receptor antagonist eprosartan is approved for the treatment of essential hypertension and may be administered using a convenient once-daily regimen. The drug is a well tolerated and effective antihypertensive agent with benefit in the secondary prevention of cerebrovascular events, independent of blood pressure (BP)-lowering effects. Eprosartan has a low potential for serious adverse events and has not been associated with clinically significant drug interactions, establishing it as a promising agent for combination antihypertensive strategies. Unlike ACE inhibitors such as enalapril, eprosartan does not have a tendency to cause persistent nonproductive cough. Accordingly, eprosartan represents a useful therapeutic option in the management of patients with hypertension, including those who have had a stroke and those with co-morbid type 2 diabetes mellitus.

Antihypertensive therapy: special focus on drug interactions

Today, the lifetime risk of patients aged 55-65 years to receive antihypertensive drugs approaches 60%. Yet, recent trials suggest that hypertension is not adequately controlled in the majority of patients. The prevalence of hypertension increases with advancing age, as does the prevalence of comorbid conditions and the total number of medications taken. Multi-drug therapy, advancing age and comorbid conditions are also key risk factors for adverse drug reactions and drug interactions. In this review, the authors evaluate the most frequently used antihypertensive drugs (diuretics, beta-adrenergic blockers, angiotensin-converting enzyme inhibitors, calcium channel blockers, angiotensin II receptor Type 1 blockers and alpha-adrenergic blockers) with special reference to pharmacodynamic and pharmacokinetic drug interactions. As the spectrum of drugs prescribed is constantly changing, safety yesterday does not imply safety today and safety today does not imply safety tomorrow. Furthermore, therapeutic efficacy should not be neglected over concerns regarding drug interactions. Many patients are at risk of clinically relevant drug interactions involving antihypertensive drugs but, presently, even more patients may be at risk of suffering from the consequences of their inadequately treated hypertension. In this respect, the authors discuss controversial viewpoints on the overall clinical relevance of drug interactions occurring at the level of cytochrome P450 metabolism.

Eprosartan: an angiotensin-II receptor antagonist for the management of hypertension

Eprosartan is a competitive angiotensin-II receptor antagonist with a high affinity for the angiotensin-II subtype 1 receptor. The drug has an elimination half-life of approximately 5 to 9 hours and duration of antihypertensive effect of up to 24 hours. The antihypertensive efficacy of eprosartan has been examined in a number of placebo-controlled, dose-finding, and comparative trials. Results of these clinical trials have consistently shown statistically significant differences in antihypertensive efficacy favoring eprosartan doses of 400 mg or greater per day over placebo. Eprosartan was also shown to be at least as effective as enalapril at lowering blood pressure in patients with mild to severe hypertension. The frequency of adverse events observed with eprosartan has been similar to that seen with placebo. In addition, there are no clinically significant drug interactions associated with eprosartan. Given the excellent tolerability and drug-interaction profiles of eprosartan, the use of this agent may help to improve patient compliance to a drug regimen. In addition, eprosartan may be particularly advantageous when used as a part of combination therapy for the management of hypertension.

Angiotensin II receptor blockers for the treatment of hypertension

The rising incidence of stroke, congestive heart failure (CHF) and end stage renal disease (ESRD) has signalled a need to increase awareness, treatment and control of hypertension. There continues to be a need for effective antihypertensive medications since hypertension is a major precursor to various forms of cardiovascular disease. The renin-angiotensin (AT) aldosterone system (RAAS) is a key component to the development of hypertension and can be one target of drug therapy. Angotensin II (ATII) receptor blockers (ARBs) are the most recent class of agents available to treat hypertension, which work by by inhibiting ATII at the receptor level. Currently, national consensus guidelines recommend that ARBs should be reserved for hypertensive patients who cannot tolerate angiotensin converting enzyme (ACE) inhibitors (ACEIs). ARBs, however, are moving to the forefront of therapy with a promising role in the area of renoprotection and CHF. Recent trials such as the The Renoprotective Effect of the Angiotensin-Receptor Antagonist Irbesartan in Patients with Nephropathy Due to Type 2 Diabetes Trial (IDNT), the Effect of Irbesartan on the Development of Diabetic Nephropathy in Patients with Type 2 Diabetes (IRMA2), and The Effects of Losartan on Renal and Cardiovascular Outcomes in Patients with Type 2 Diabetes and Nephropathy (RENAAL) study have demonstrated the renoprotective effects of ARBs in patients with Type 2 diabetes. The Valsartan Heart Failure Trial (Val-HeFT) adds to the growing body of evidence that ARBs may improve morbidity and mortality in CHF patients. As a class, ARBs are well tolerated and have a lower incidence of cough and angioedema compared to ACEIs. This article reviews the differences among the ARBs, existing efficacy data in hypertension, and explores the role of ARBs in CHF and renal disease.