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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated the short-term and sustained hormonal and renal effects of angiotensin II (Ang II) receptor blockade in normotensive healthy volunteers. Twenty-four subjects maintained on a fixed sodium diet were randomized to receive for 8 days a placebo or 10 or 50 mg doses of the Ang II antagonist irbesartan (SR 47436, BMS 186295) according to a double-blind, parallel group design. Plasma renin activity, plasma immunoreactive Ang II and aldosterone levels, blood pressure, renal hemodynamics, and urinary electrolyte excretion were measured for 8 hours after the first and eighth administration of each dose of irbesartan or placebo. Ang II receptor blockade with irbesartan induced a dose-dependent compensatory increase in plasma renin activity and plasma angiotensin levels and a significant decrease in plasma aldosterone levels. The compensatory rise in plasma renin activity and Ang II levels was more pronounced on day 8, reflecting a long duration of the blocking effect of irbesartan. Irbesartan induced small changes in blood pressure and did not significantly modify renal blood flow and glomerular filtration rate. However, a significant decrease in filtration fraction was observed during receptor blockade on days 1 and 8. The tubular effects of irbesartan were characterized by a dose-dependent increase in sodium and chloride excretions. Interestingly, the cumulative natriuretic response to Ang II receptor blockade was similar on days 1 and 8, suggesting that in these subjects, renal Ang II receptors are not blocked over 24 hours during repeated administration even though this antagonist has a long duration of action (t1/2 of 15 to 17 hours).(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension 1995 Apr
PMID:Short-term and sustained renal effects of angiotensin II receptor blockade in healthy subjects. 772 4

Irbesartan inhibits the activity of angiotensin II (AII) via specific, selective noncompetitive antagonism of the AII receptor subtype 1 (AT1) which mediates most of the known physiological activities of AII. In patients with mild to moderate hypertension, once daily administration of irbesartan 150 or 300 mg, with or without adjunctive antihypertensive agents, provides effective 24-hour BP control. Irbesartan reduced BP to a similar extent to enalapril and atenolol and to a significantly greater extent than losartan. The combination of irbesartan and hydrochlorothiazide resulted in additive antihypertensive effects. The drug is effective in the elderly and dosage adjustment is not required in these patients or in those with renal or hepatic failure. Preliminary studies evaluating the efficacy of irbesartan in patients with heart failure have produced encouraging results. Irbesartan is very well tolerated and neither the frequency nor the pattern of adverse events differed from those seen in placebo recipients, although headache was significantly more frequent with the latter. Similarly, the incidence of adverse events did not differ significantly between irbesartan and enalapril in patients who received either drug as monotherapy. Headache, upper-respiratory tract infection and musculoskeletal pain were the most common complaints. Thus, irbesartan is an effective therapy for patients with mild to moderate hypertension and had an adverse event profile similar to that of placebo in clinical trials. On this basis it would appear to be an effective therapeutic option in this indication.
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PMID:Irbesartan. A review of its pharmacodynamic and pharmacokinetic properties and therapeutic use in the management of hypertension. 942 95

Irbesartan is an angiotensin II receptor (AT1 subtype) antagonist that has been extensively studied in the Bristol-Myers Squibb/Sanofi clinical development program. As shown in seven placebo controlled clinical trials, irbesartan provides clinically significant dose related reductions in blood pressure in patients with mild-to-moderate hypertension. Once daily dosing provides full 24 h blood pressure control with blood pressure reductions equivalent to those of twice daily dosing, and long-term control with monotherapy in a high percentage of patients. The antihypertensive effect of irbesartan is comparable to or exceeds that of leading antihypertensive agents. Whereas irbesartan demonstrates a relationship between dose and antihypertensive effect, there is no such relationship between dose and rates of adverse events or discontinuations due to adverse events, the incidence of which are comparable to those with placebo. Thus, irbesartan provides significant dose related antihypertensive effects with placebo-like tolerability.
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PMID:Clinical overview of irbesartan: a new angiotensin II receptor antagonist. 943 76

Two multicenter, double-blind, placebo-controlled, parallel group studies were conducted to evaluate the efficacy, safety, pharmacokinetics, and pharmacodynamics of the angiotensin II receptor (AT1 subtype) antagonist irbesartan. The effect of irbesartan withdrawal and the effect of adding hydrochlorothiazide (HCTZ) to irbesartan were also assessed. After a placebo lead-in phase, all patients were randomized to 8 weeks of double-blind therapy with either placebo (n = 158) or irbesartan at doses of 1, 5, 10, 25, 50, 100, 200, or 300 mg (n = 731 total) orally once daily. Irbesartan reduced blood pressure in a dose-related manner. Reductions from baseline in trough seated diastolic blood pressure ranged from 7.5 mm Hg for 50 mg irbesartan to 11.6 mm Hg for 300 mg irbesartan. At week 8, statistically significant reductions over placebo were observed in trough seated blood pressure with all irbesartan doses > or = 50 mg. These reductions reached statistical significance versus placebo within 2 weeks with 100, 200, and 300 mg irbesartan. Plasma irbesartan concentrations correlated with dose. Angiotensin II and aldosterone levels generally showed dose-related changes, consistent with AT1 receptor blockade. In patients not controlled at 8 weeks, the addition of 12.5 mg HCTZ resulted in further dose-related reductions in blood pressure. Irbesartan demonstrated a placebo-like safety profile and no dose-related toxicity. Irbesartan, administered alone or in combination with HCTZ, was well tolerated. Withdrawal of irbesartan did not result in rebound hypertension or adverse events. Thus, once-daily irbesartan is both an effective and safe antihypertensive agent for the treatment of mild-to-moderate hypertension.
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PMID:Dose-related antihypertensive effects of irbesartan in patients with mild-to-moderate hypertension. 960 85

Results of eight multicenter, randomized, placebo-controlled, double-blind, parallel-group studies were pooled to assess the efficacy of the angiotensin II-receptor blocker irbesartan over the dose range of 1 to 900 mg. A total of 2955 adults with a seated diastolic blood pressure of 95 to 110 mm Hg were randomized to treatment with oral irbesartan once daily or placebo for 6 to 8 weeks. Office blood pressure was measured at trough (24+/-3 hours after the last dose) and peak (3+/-1 hours after the last dose) by mercury sphygmomanometry. Demographic characteristics (mean blood pressure; 151/101 mm Hg; mean age, 54 years; 63% male; and 82% white) were similar across all dose groups. After the groups were pooled, antihypertensive efficacy was assessed by therapeutic response (trough seated diastolic blood pressure <90 mm Hg or a reduction from baseline of > or = 10 mm Hg) and by modeling of the maximum reductions in trough and peak seated diastolic and systolic blood pressure. Antihypertensive effects increased with increasing doses and reached a plateau at > or = 300 mg. Irbesartan 150 mg provided placebo-subtracted reductions in trough seated systolic and diastolic blood pressure of approximately 8 and approximately 5 mm Hg, respectively, with 56% of patients displaying a favorable response. In conclusion, irbesartan provides clinically significant blood pressure lowering, with a clear relationship between (log) dose and antihypertensive effect.
Hypertension 1998 Jun
PMID:Dose-related efficacy of irbesartan for hypertension: an integrated analysis. 962 47

The SILVER (Study of Irbesartan in Left VEntricular hypertrophy Regression) trial is designed to test the hypothesis that the newly developed angiontensin-II receptor antagonist, irbesartan, will produce a greater reduction in left ventricular (LV) mass than felodipine ER, in a population of hypertensive patients defined by seated diastolic blood pressure (SeDBP) in the range 95-115 mmHg or seated systolic blood pressure (SeSBP) in the range 160-200 mm Hg. A population of 360 men and women of non-childbearing potential, >18 years of age, with hypertension, newly diagnosed or after a 3-week washout from previous anti-hypertensive or vasodilator therapies, will be randomised at approximately 80-90 European sites. Add-on therapy with hydrochlorothiazide and atenolol will be allowed for blood pressure control. Patients will be studied by two-dimensional and M-mode echocardiography at baseline (central validation of LV hypertrophy), on randomisation day, and after 6 and 12 months randomised therapy. Blinded analysis of echocardiograms will be performed at a central laboratory, which will provide measurements of the LV mass index (LVMI), determined by M-mode readings according to Devereux formula and using the Penn convention. The primary end-point of the study will be the change in LVMI from baseline to 12 months. The study power is 90% to detect differences between groups from baseline of approximately 8 g/m2.
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PMID:Comparison of irbesartan vs felodipine in the regression after 1 year of left ventricular hypertrophy in hypertensive patients (the SILVER trial). Study of Irbesartan in Left VEntricular hypertrophy Regression. 970 35

Although an impressive array of efficacious antihypertensive agents are available to treat hypertension, the optimal use of these agents is limited by dose-related side-effect profiles. This is particularly the case for widely used first-line antihypertensive agents such as diuretics, beta-blockers, calcium antagonists, and alpha1-blockers; this represents a major therapeutic dilemma in treating hypertension. With the development of the angiotensin II receptor antagonists (AIIRAs), this dilemma might have been solved. Irbesartan is a long-acting AIIRA that provides dose-related efficacy with placebo-like tolerability at all clinical doses. The results of placebo and active-control trials of irbesartan have demonstrated that the agent is as effective as the leading members of major antihypertensive classes with respect to blood pressure control, while having superior tolerability. Pooled data from nine multicenter, randomized, placebo-controlled trials with irbesartan have documented no adverse events caused by dose-response. This feature could widen the traditionally narrow therapeutic window in the treatment of hypertension and point to the use of AIIRAs such as irbesartan as first-line therapy in the management of hypertension.
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PMID:A look through the new therapeutic window: irbesartan. 985 26

The number of cases of diabetic nephropathy is increasing, especially among patients with non-insulin-dependent diabetes mellitus (NIDDM). It is difficult to prevent the occurrence or progression of NIDDM, and current levels of treatment are below standard. According to one study, actuarial 5-year survival rates are only about 38% for patients with insulin-dependent diabetes mellitus and 9% for those with NIDDM receiving renal replacement therapy. Because cardiovascular diseases are responsible for more than half of these deaths, hypertension, as a major contributing factor to cardiac death, is a crucial component in the therapy for such patients. It is well established that lowering blood pressure is an important preventive measure to be taken in patients with diabetic nephropathy; blockade of the renin-angiotensin system offers benefits beyond lowering blood pressure in type I diabetic nephropathy. Two major trials are currently underway to determine the effects of angiotensin II receptor antagonists on nephropathy in patients with NIDDM. The Irbesartan Diabetic Nephropathy Trial (IDNT) has already enrolled approximately 85% of the proposed 1650 NIDDM patients to be randomly assigned to placebo, irbesartan or amlodipine. Baseline characteristics of the initial cohort are presented. In light of the well-documented case for blockade of the renin-angiotensin system in diabetes, the potentially superior blockade afforded by angiotensin II receptor antagonists, and the superior tolerability of these agents, trials such as the IDNT take on special importance for the treatment of diabetic patients. From these data may come the justification for the belief that angiotensin II receptor antagonists impart greater benefits in the treatment of diabetes than merely their well-documented role in lowering blood pressure.
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PMID:Optimizing antihypertensive therapy in patients with diabetic nephropathy. 985 27

Angiotensin-converting enzyme (ACE) inhibitors have proven an effective means to control hypertension and manage cardiac hypertrophy. It is presently unknown if newer specific angiotensin II subtype 1 receptor (AT1R) antagonists are as effective or more effective in treating these conditions compared with ACE inhibitors. There is evidence that these classes of drugs may affect cardiac hypertrophy by different mechanisms. This study compared the effect of irbesartan, an AT1R antagonist, with that of captopril, an ACE inhibitor, on expression of early genetic markers of cardiac hypertrophy in lean male SHHF/Mcc-fa(cp) rats. SHHF/Mcc-fa(cp) rats (n = 10/group) were given captopril (100 mg/kg/day), irbesartan (50 mg/kg/day), or placebo for 16 weeks. Irbesartan and captopril significantly reduced systolic pressure and produced similar rightward shifts in the angiotensin I dose-response curve. Renal renin gene expression was increased 8.6-fold by irbesartan and 17.7-fold by captopril. The only effect on echocardiographic findings was a similar decrease in aortic peak velocity, an index of systolic function, by both treatments. Early markers of cardiac hypertrophy were significantly attenuated by both drugs. Both drugs produced marked and equivalent reductions in left ventricular atrial natriuretic peptide (ANP) messenger RNA (mRNA) levels compared with controls. This decrease in ANP gene expression was accompanied by a decrease in plasma ANP concentration in the treatment groups. The shift from V1 to V3 myosin isozymes was similarly decreased in both treatment groups, compared with controls. These data suggest that captopril and irbesartan are similarly effective in controlling expression of genes associated with ventricular hypertrophy in heart failure-prone SHHF/Mcc-fa(cp) rat.
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PMID:Comparison of irbesartan with captopril effects on cardiac hypertrophy and gene expression in heart failure-prone male SHHF/Mcc-fa(cp) rats. 1006 82

Irbesartan is a novel AT1 subtype angiotensin II receptor antagonist. Blockade of AT1 receptors by irbesartan is not competitive, but "insurmountable". The drug inhibits in a significant dose-dependent manner the maximal contractile response that can be induced by angiotensin II in isolated strips of rabbit aorta. Even high doses of angiotensin II are unable to overcome the AT1 specific receptor blockade. The drug is directly active and requires no prior biotransformation. Its bioavaility after oral administration is excellent (60-80%) and is not altered by meals. The maximal hypotensive effect is measured 3-6 h after intake. The long half life (11-15 h) allows administration in one single daily dose. Irbesartan is registered in Belgium fot the treatment of essential arterial hypertension only. The hypotensive clinical effects, present from the start, become obvious after 1-2 weeks and maximal after 4-6 weeks. The usual daily dose is 150 mg. If needed, it can be increased up to 300 mg/day or, else, be decreased to 75 mg daily in the dialysed or aged patient. Side effects are negligible.
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PMID:[Drug clinics. Drug of the month. Irbesartan (Aprovel)]. 1022 Oct 67


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