Losartan

? Losartan binds selectively to the angiotensin II subtype 1 receptor, blocking the activity of angiotensin II. ? Losartan 50–100 mg/day was compared with atenolol 50–100 mg/ day in patients with essential hypertension and left ventricular hypertrophy (LVH) [n = 9193] in the randomized, double-blind Losartan Intervention For Endpoint reduction in hypertension (LIFE) study. Two substudies compared these drugs in patients with diabetes mellitus (n = 1195) or isolated systolic hypertension (ISH) [n = 1326]. ? The target BP (‘140/90mm Hg) was achieved in ≈45% of losartan and atenolol recipients in the LIFE study. Significant regression of LVH occurred with losartan versus atenolol in the LIFE study, as well as in the diabetes mellitus and ISH substudies. ? In the LIFE study, although BP reduction was similar for the two treatments, the risk of a cardiovascular event (the composite of cardiovascular death, stroke, and myocardial infarction; primary endpoint), stroke, or new-onset diabetes mellitus was significantly lower with losartan than with atenolol. ? Losartan was generally well tolerated in patients with hypertension and LVH in the LIFE study. Significantly fewer losartan than atenolol recipients discontinued treatment because of adverse events, drug-related adverse events, or serious, drug-related adverse events.     

联合用药治疗高龄单纯收缩期高血压的疗效观察

目的探讨非洛地平缓释片联合小剂量美托洛尔加小剂量氢氯噻嗪治疗高龄（≥80岁）老年单纯收缩期高血压（ISH）的降压疗效和安全性。方法选择100例中、高危高龄（≥80岁）老年单纯收缩期高血压（ISH）患者,随机分为试验组和对照组,试验组：给予非洛地平缓释片（5mg,1次/d）;美托洛尔（12.5mg,2次/d）;氢氯噻嗪（12.5mg,2次/d）。对照组：给予硝苯地平缓释片（10mg,2次/d）;美托洛尔（12.5mg,2次/d）,氢氯噻嗪（12.5mg,2次/d）。比较两组治疗前后（2周末）的降压疗效及生化指标变化。结果试验组能显著降低收缩压与脉压,降压疗效试验组为94.0%、对照组为84.0%,两组比较差异有显著（P〈0.05）。两组心率及生化指标与基线值比较差异不显著（P〉0.05）。结论非洛地平缓释片联合小剂量美托洛尔加小剂量氢氯噻嗪能有效降低中、高危高龄（≥80岁）老年ISH患者的血压;以非洛地平缓释片为基础的降压治疗,在高龄（≥80岁）老年单纯收缩期高血压（ISH）的降压治疗中其疗效、安全性、依从性均较高。     

Losartan: a review of its use in stroke risk reduction in patients with hypertension and left ventricular hypertrophy

Losartan (Cozaar) is an angiotensin AT1 receptor antagonist. It is approved in numerous countries for the treatment of hypertension and has been approved in the UK, the US and several European countries for stroke risk reduction in patients with hypertension and left ventricular hypertrophy (LVH). Losartan is recommended for use alone or with hydrochlorothiazide, but it can also be administered with other antihypertensive medications. In patients with hypertension, losartan effectively lowers blood pressure and also leads to regression of LVH. In the large, well designed LIFE (Losartan Intervention For Endpoint reduction in hypertension) study in patients with hypertension and LVH, losartan was more effective than atenolol in reducing the composite primary endpoint of cardiovascular (CV) mortality, stroke or myocardial infarction (MI). This was mainly due to a significant 25% reduction in the risk of stroke in the losartan group. Losartan recipients also had a significantly lower incidence of new-onset diabetes mellitus compared with atenolol recipients. Similar benefits were observed in several patient subgroups from the LIFE study, but not in the subgroup of Black patients. Losartan is well tolerated and is a cost effective alternative to atenolol in the setting of stroke reduction. Comparative data on clinical outcomes in hypertensive patients for losartan versus other antihypertensive agents would be of interest. Nonetheless, in addition to its established antihypertensive and end organ effects, the LIFE study indicates that, with the possible exception of Black patients, losartan can reduce the risk of stroke in patients with hypertension and LVH.     

Losartan: a selective angiotensin II type 1 (AT1) receptor antagonist for the treatment of heart failure

Losartan (COZAAR) is the prototype of a new class of potent and selective angiotensin II (AII) type 1 (AT(1)) receptor antagonists with the largest published preclinical and clinical data base. Since all of the AII antagonists are selective for the AT(1) receptor, these drugs should exhibit similar cardiovascular effects. However, since the pharmacokinetic/pharmacodynamic profiles of these agents and their degree of affinity for the AT(1) receptor differ, it is likely that differences in clinical profiles between these drugs exist and will require investigation. Losartan (parent compound), has moderate affinity for the AT(1) receptor (competitive inhibition). Losartan is well-absorbed orally as an active drug and is rapidly converted via oxidation in the human liver to a more potent metabolite (designated E3174) with an affinity 20- to 30-times greater for the AT(1) receptor (non-competitive inhibition). E3174 has a half-life of 6 - 9 h; elimination is via renal and hepatic routes. Antihypertensive and, in heart failure patients, haemodynamic activity is observed over a 24 h period with once daily dosing. Over 6 million patients have been treated for hypertension with continued excellent tolerability. Clinical experience in heart failure is growing, and recent data suggest an improved survival with losartan versus captopril, a drug from the angiotensin-converting-enzyme inhibitor class with proven benefit in this population. The current comprehensive losartan clinical end-point programme (4 large scale morbidity/mortality trials) should provide evidence regarding the efficacy of direct blockade of the AT(1) receptor with losartan compared to standard therapy: 1) The Losartan Heart Failure Survival Study - ELITE II, 2) The Losartan Post-Myocardial Infarction Survival Study - OPTIMAAL, 3) The Losartan Hypertension Survival Study - LIFE and 4) The Losartan Renal Protection Study - RENAAL.     

Losartan: a selective angiotensin II type 1 (AT1) receptor antagonist for the treatment of heart failure

Losartan (COZAARΟχιρχ^?) is the prototype of a new class of potent and selective angiotensin II (AII) type 1 (AT₁) receptor antagonists with the largest published preclinical and clinical data base. Since all of the AII antagonists are selective for the AT₁ receptor, these drugs should exhibit similar cardiovascular effects. However, since the pharmacokinetic/pharmacodynamic profiles of these agents and their degree of affinity for the AT₁ receptor differ, it is likely that differences in clinical profiles between these drugs exist and will require investigation. Losartan (parent compound), has moderate affinity for the AT₁ receptor (competitive inhibition). Losartan is well-absorbed orally as an active drug and is rapidly converted via oxidation in the human liver to a more potent metabolite (designated E3174) with an affinity 20- to 30-times greater for the AT₁ receptor (non-competitive inhibition). E3174 has a half-life of 6 - 9 h; elimination is via renal and hepatic routes. Antihypertensive and, in heart failure patients, haemodynamic activity is observed over a 24 h period with once daily dosing. Over 6 million patients have been treated for hypertension with continued excellent tolerability. Clinical experience in heart failure is growing, and recent data suggest an improved survival with losartan versus captopril, a drug from the angiotensin-converting-enzyme inhibitor class with proven benefit in this population. The current comprehensive losartan clinical end-point programme (4 large scale morbidity/mortality trials) should provide evidence regarding the efficacy of direct blockade of the AT₁ receptor with losartan compared to standard therapy: 1) The Losartan Heart Failure Survival Study - ELITE II, 2) The Losartan Post-Myocardial Infarction Survival Study - OPTIMAAL, 3) The Losartan Hypertension Survival Study - LIFE and 4) The Losartan Renal Protection Study - RENAAL.     

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.     

海捷亚对24h血压控制效果观察

目的　观察海捷亚 (氯沙坦 /氢氯噻嗪 )对高血压患者 2 4h血压的控制作用。方法　从心内科门诊及病房高血压患者中通过用 2 4h动态血压监测 ,观察 2 5例以血压超负荷为特征的原发性高血压患者。治疗开始前行 2 4h动态血压监测 ,服药之前当日记录门诊偶测血压。海捷亚每日晨服用 1片 ,服药第 1,2 ,4周分别记录门诊偶测血压 ,第 4周结束时再次行 2 4h动态血压监测。结果　所有患者服用海捷亚 1周后白天门诊偶测血压已开始降低 (P <0 0 5 ) ,第 2周后血压水平继续降低 ,第 4周结束时白天偶测血压值降低有非常显著性 (P <0 0 1)。第 4周动态血压监测与治疗前相比 ,白昼收缩压 (SBP) >14 0mmHg和舒张压 (DBP) >90mmHg读数的百分数 ,夜间SBP >12 0mmHg和DBP >80mmHg的读数百分数均明显下降 (P <0 0 5 )。第 4周的夜间血压下降百分率较治疗前升高(P <0 0 5 )。结论　海捷亚有快速、稳定的降压疗效 ,能明显减轻白昼及夜间血压超负荷 ,并对血压昼夜节律的恢复有调节作用     

Enalapril. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic use in hypertension and congestive heart failure

Enalapril maleate is an orally active angiotensin-converting enzyme inhibitor. It lowers peripheral vascular resistance without causing an increase in heart rate. Enalapril 10 to 40 mg/day administered either once or twice daily is effective in lowering blood pressure in all grades of essential and renovascular hypertension, and shows similar efficacy to usual therapeutic dosages of hydrochlorothiazide, beta-blockers (propranolol, atenolol and metoprolol) and captopril. Most patients achieve adequate blood pressure control on enalapril alone or with hydrochlorothiazide. In patients with severe congestive heart failure resistant to conventional therapy, enalapril improves cardiac performance by a reduction in both preload and afterload, and improves clinical status long term. Enalapril appears to be well tolerated, with few serious adverse effects being reported. It does not induce the bradycardia associated with beta-blockers or the adverse effects of diuretics on some laboratory values. In fact, the hypokalaemic effect of hydrochlorothiazide is attenuated by the addition of enalapril. The incidence of the main (but rare) side effects of hypotension in hypovolaemic patients and reduced renal function in certain patients with renovascular hypertension, which are also seen with captopril, might be reduced by careful dosage titration, discontinuation of diuretics, and monitoring of at-risk patients. Thus, enalapril is a particularly worthwhile addition to the antihypertensive armamentarium, as an alternative for treatment of all grades of essential and renovascular hypertension. It also shows promise in the treatment of congestive heart failure.     

Felodipine/metoprolol: a review of the fixed dose controlled release formulation in the management of essential hypertension

The main objective of fixed dose combination therapy for hypertension is to improve blood pressure (BP) control with lower, better tolerated dosages of 2 antihypertensives rather than higher dosages of a single agent. Felodipine and metoprolol lower BP via different, but complementary, mechanisms and controlled release formulations of these 2 drugs are available as a fixed dose combination, felodipine/metoprolol. In clinical trials in patients with hypertension, felodipine/metoprolol was significantly more effective than placebo and the respective monotherapies administered at the same dosages. Mean BP was reduced to < 155/90 mm Hg in patients treated with combination therapy and controlled in approximately 70% of patients. In one study that titrated dosages to effect, fewer felodipine/metoprolol than felodipine or metoprolol monotherapy recipients required dosage increases to achieve BP control (45 vs 60 and 67%, respectively). Data from double blind comparative studies show that the antihypertensive efficacy of felodipine/metoprolol 5 to 10/50 to 100 mg/day is significantly greater than that of enalapril monotherapy or captopril plus hydrochlorothiazide and equivalent to nifedipine/atenolol and amlodipine. In comparisons with enalapril, fewer felodipine/metoprolol than enalapril recipients required dosage titration to achieve BP control. Compared with amlodipine, felodipine/metoprolol significantly reduced mean 24-hour average BP (8.9/5.5 vs 14.4/9.5 mm Hg after 6 weeks; p < 0.001). Both treatments preserved diurnal rhythm. Long term follow-up studies show that the antihypertensive effect of felodipine/metoprolol occurs mostly during the first month of treatment with small additional decreases in BP being observed in the second and third months, and a relatively constant effect thereafter. According to a validated questionnaire, quality of life was relatively similar during 12 weeks treatment with felodipine/metoprolol, enalapril or placebo. In a retrospective pharmacoeconomic analysis conducted in Sweden, felodipine/metoprolol was more cost effective than enalapril as initial treatment for hypertension. Peripheral oedema, headache and flushing were the most commonly reported adverse events with felodipine/metoprolol and felodipine monotherapy, whereas dizziness, fatigue, headache and respiratory infection were more frequent with metoprolol monotherapy. Dose-dependent adverse events such as oedema may occur less often in patients taking lower dosages in combination than in those taking higher dosages of felodipine monotherapy. Thus, patients with hypertension treated with felodipine/metoprolol experience greater control of BP, with less need for dosage titration, than those treated with felodipine, metoprolol or enalapril monotherapy. Importantly this greater efficacy does not appear to be associated with a higher incidence of adverse events relative to monotherapy. Additionally, in short term studies felodipine/metoprolol had a similar (minimal) effect on QOL to enalapril monotherapy but was more cost effective.     

The role of angiotensin antagonism in stroke prevention in patients with hypertension: focus on losartan

Optimal management of hypertension has been shown to reduce the risk of stroke. In recent years, newer classes of antihypertensive such as the angiotensin II (Ang II) antagonists have become available. Results from the Losartan Intervention for Endpoint reduction in hypertension (LIFE) study suggest the utility of this particular Ang II antagonist in stroke prevention. Treatment with a losartan-based regimen or an atenolol-based regimen produced similar reductions in blood pressure during almost 5 years of follow up. Losartan, however, reduced the risk of stroke by 25% compared with atenolol (p = 0.001). For a subgroup of patients with isolated systolic hypertension, losartan reduced the risk of stroke by 40% (p = 0.02). As well as blocking the Ang II type 1 receptor, losartan also acts as an antagonist at the thromboxane A2 receptor and has uricosuric effects, which may provide additional mechanisms by which losartan provides protective benefits beyond its antihypertensive action. The relevance of these molecular properties of losartan over other Ang II antagonists is further supported by comparison of the outcomes obtained in clinical trials employing two other Ang II antagonists, valsartan and candesartan.     

Atenolol. A reappraisal of its pharmacological properties and therapeutic use in cardiovascular disorders.

Atenolol is a selective beta 1-adrenoceptor antagonist with a duration of activity of at least 24 hours. The scope of therapeutic use of the drug has been expanded and become better defined since it was first reviewed in the Journal in 1979. Atenolol is effective and generally well tolerated in patients with all grades of hypertension. Data from comparative studies show that when administered orally, atenolol reduces blood pressure to a similar extent, and in a similar proportion of patients, as usual therapeutic doses of other beta-adrenoceptor antagonists (such as acebutolol, celiprolol, betaxolol, indenolol, metoprolol, nadolol, pindolol, propranolol, tertatolol), angiotensin converting enzyme (ACE) inhibitors (e.g. captopril, enalapril and lisinopril), calcium antagonists (e.g. amlodipine, diltiazem, felodipine, isradipine, nitrendipine, nifedipine, verapamil), doxazosin, ketanserin and alpha-methyldopa. Atenolol effectively lowers blood pressure in elderly patients with hypertension and in women with hypertension associated with pregnancy, and improves objective and subjective indices in patients with stable angina pectoris. Oral atenolol is used for preventing recurrence of supraventricular arrhythmias once control is achieved by intravenous administration of atenolol. Early intervention with intravenous atenolol followed by oral maintenance therapy reduces infarct recurrence and cardiovascular mortality in patients with known or suspected myocardial infarction. There is also encouraging evidence of reduced mortality from cardiovascular disease during long term therapy with atenolol in patients with hypertension. Atenolol is well tolerated in most patients. Increases in plasma levels of both total triglycerides and very low density lipoprotein (VLDL) triglycerides have accompanied atenolol therapy although the clinical relevance, if any, of longer term metabolic effects has yet to be determined. Its low lipid solubility and limited brain penetration results in a lower incidence of central nervous system effects than that associated with propranolol. After many years of clinical usage atenolol is a well established treatment option in several areas of cardiovascular medicine such as mild to moderate hypertension and stable angina pectoris. Furthermore, it has also shown potential in the treatment of some cardiac arrhythmias and has been associated with reduced cardiovascular mortality in patients with hypertension and in patients with myocardial infarction.     

The role of angiotensin antagonism in stroke prevention in patients with hypertension: focus on losartan

Summary

Optimal management of hypertension has been shown to reduce the risk of stroke. In recent years, newer classes of antihypertensive such as the angiotensin II (Ang II) antagonists have become available. Results from the Losartan Intervention for Endpoint reduction in hypertension (LIFE) study suggest the utility of this particular Ang II antagonist in stroke prevention. Treatment with a losartan-based regimen or an atenolol-based regimen produced similar reductions in blood pressure during almost 5 years of follow up. Losartan, however, reduced the risk of stroke by 25% compared with atenolol (p = 0.001). For a subgroup of patients with isolated systolic hypertension, losartan reduced the risk of stroke by 40% (p = 0.02). As well as blocking the Ang II type 1 receptor, losartan also acts as an antagonist at the thromboxane A₂ receptor and has uricosuric effects, which may provide additional mechanisms by which losartan provides protective benefits beyond its antihypertensive action. The relevance of these molecular properties of losartan over other Ang II antagonists is further supported by comparison of the outcomes obtained in clinical trials employing two other Ang II antagonists, valsartan and candesartan.     

ACE inhibitors or AT-1 antagonists - which is OPTIMAAL after acute myocardial infarction?

OPTIMAAL (Optimal Trial in Myocardial Infarction with the Angiotensin II Antagonist Losartan) is the first major study to compare an angiotensin II Type 1 antagonist losartan (Cozaar trade mark, Merck) with an ACE inhibitor captonpril (Capoten trade mark, Elan) after myocardial infarction in patients with left ventricular dysfunction. Patients were assigned to a target dose of losartan 50 mg/day and captopril 50 mg t.i.d., as tolerated. The primary end point was all-cause mortality and there were 499 (18%) and 447 (16%) deaths in the losartan and captopril group, respectively (p = 0.07). However, there were significantly more cardiovascular deaths with losartan (420, 15%) than with captopril (363, 13%; p = 0.03). Losartan was better tolerated than captopril with fewer patients discontinuing medication (17 versus 23% for losartan and captopril, respectively). In conclusion, if tolerated, captopril should remain the preferred treatment for patients after complicated acute myocardial infarction.     

Sorafenib for the treatment of renal cancer

OPTIMAAL (Optimal Trial in Myocardial Infarction with the Angiotensin II Antagonist Losartan) is the first major study to compare an angiotensin II Type 1 antagonist losartan (Cozaar?, Merck) with an ACE inhibitor captonpril (Capoten?, Elan) after myocardial infarction in patients with left ventricular dysfunction. Patients were assigned to a target dose of losartan 50 mg/day and captopril 50 mg t.i.d., as tolerated. The primary end point was all-cause mortality and there were 499 (18%) and 447 (16%) deaths in the losartan and captopril group, respectively (p = 0.07). However, there were significantly more cardiovascular deaths with losartan (420, 15%) than with captopril (363, 13%; p = 0.03). Losartan was better tolerated than captopril with fewer patients discontinuing medication (17 versus 23% for losartan and captopril, respectively). In conclusion, if tolerated, captopril should remain the preferred treatment for patients after complicated acute myocardial infarction.     

Ramipril. A review of its pharmacological properties and therapeutic efficacy in cardiovascular disorders

Ramipril is a long acting angiotensin converting enzyme (ACE) inhibitor, which exhibits similar pharmacodynamic properties to captopril and enalapril. Like enalapril it is a prodrug, which is hydrolysed after absorption to form the active metabolite ramiprilat which has a long elimination half-life, permitting once daily administration. In hypertensive patients daily doses in the range 2.5 to 20 mg are usually effective in reducing high blood pressure and maintaining satisfactory control during long term treatment. Patients who do not respond adequately to monotherapy with ramipril usually respond with the addition of a diuretic such as hydrochlorothiazide or piretanide. Ramipril 5 to 10 mg once daily shows comparable antihypertensive efficacy to usual therapeutic dosages of captopril, enalapril and atenolol in patients with mild to moderate essential hypertension. Preliminary data indicate that ramipril may be effective in indications such as severe essential hypertension and renal hypertension. It has also displayed beneficial effects in patients with moderate to severe congestive heart failure. Ramipril has been well tolerated and exhibits an adverse effect profile typical of ACE inhibitors as a class. In conclusion, ramipril will likely represent a useful alternative ACE inhibitor for use in patients with hypertension or congestive heart failure.     

Do losartan and atenolol have differential effects on BNP and central haemodynamic parameters?

INTRODUCTION: It has been suggested that angiotensin-converting enzyme inhibitors (ACE-Is) and angiotensin II receptor blockers (ARBs) have a differential effect on brachial and aortic haemodynamics. This is why they seem to have beneficial effects that are beyond brachial blood pressure (BP) lowering. We aimed to investigate if this was the case with losartan when compared to atenolol. We also investigated the differential effect of losartan and atenolol on the prognostic marker, brain type natriuretic peptide (BNP). METHODS: We studied 17 patients who were similar to those in the Losartan Intervention For Endpoint reduction in hypertension (LIFE) study. Patients were randomised to receive four months of losartan and atenolol in a crossover fashion. Main outcome measures were BNP and Augmentation index (AIx), which gives an indication of central haemodynamics. Brachial pulse wave velocity (PWV) and time to reflected wave (Tr) were measured as an indication of vascular stiffness. RESULTS: BNP was significantly lower on losartan than atenolol (p=0.007). AIx was lower on losartan than atenolol (p=0.03), however, this result was not significant when heart rate was considered as a covariate (p=0.09). Heart rate was significantly lower on atenolol than losartan (p=0.03). There was no difference between treatments for both brachial PWV and Tr (p=0.2 and p=0.99, respectively). CONCLUSION: The benefits seen when losartan was compared to atenolol in the LIFE trial may be due to a reduction in BNP. We failed to detect a differential effect in central compared to peripheral haemodynamics when losartan was compared to atenolol.     

Losartan for LIFE in hypertension with left ventricular hypertrophy?

When ACE inhibitors are used to lower blood pressure to the same degree as beta-adrenoceptor antagonists or calcium channel blockers, ACE inhibitors do not seem to have additional benefits to these agents. In the Losartan Intervention for End Point Reduction in Hypertension study (LIFE), losartan was compared to atenolol in hypertensives with the additional risk factor of left ventricular hypertrophy (LVH). For similar effects on blood pressure, losartan had a greater benefit on the primary composite end point (cardiovascular mortality, stroke and myocardial infarction) than atenolol in the hypertensives with LVH, including a prespecified subgroup of patients with additional diabetes mellitus. Losartan also had a greater ability to reverse LVH than atenolol. Thus, losartan should become the standard treatment for hypertension when LVH is present.     

Stability study of losartan/hydrochlorothiazide tablets

The purpose of stability testing is to investigate how the quality of a drug product changes with time under the influence of environmental factors, to establish a shelf life for the product and to recommend storage conditions. Stability study of losartan/hydrochlorothiazide tablets is presented in this paper. Losartan (angiotensin II receptor antagonist) and hydrochlorothiazide (diuretic) are successfully used in association in the treatment of hypertension. Stability study of losartan/hydrochlorothiazide tablets consisted of three steps: stress test (forced degradation study), preliminary testing (selection of packaging) and formal stability testing. The results of stress test suggested that losartan/hydrochlorothiazide tablets are sensitive to moisture. It was demonstrated that the developed analytical methods are stability indicating. Additional preliminary testing was performed in order to select appropriate packaging for losartan/hydrochlorothiazide tablets. OPA/Al/PVC//Al blisters were found to provide adequate protection for the product. Based on the first 12 months of the formal stability study, a shelf life of 24 months was proposed. Losartan/hydrochlorothiazide tablets in OPA/Al/PVC//Al blisters are demonstrated to be chemically, physically and microbiologically stable.     

Irbesartan: an updated review of its use in cardiovascular disorders

Irbesartan interrupts the renin-angiotensin system via selective blockade of the angiotensin II subtype 1 receptor; the latter being responsible for the pressor related effects of angiotensin II. As treatment for mild to moderate hypertension, irbesartan 150 mg/day controlled diastolic BP in 56% of patients according to pooled data from several phase III studies and 77% of patients in a large phase IV study. in comparative trials, irbesartan was significantly more effective than losartan and valsartan as treatment for mild to moderate essential hypertension and as effective as enalapril or atenolol. Results from many studies show an additive antihypertensive effect when hydrochlorothiazide is added to irbesartan monotherapy. The drug also induces statistically significant regression of left ventricular mass in patients with hypertension and left ventricular hypertrophy, and preliminary evidence suggests it has beneficial haemodynamic effects in patients with heart failure. Irbesartan is very well tolerated, exhibiting an adverse event profile similar to that seen with placebo in comparative trials. In conclusion, although the role of irbesartan as a treatment for heart failure is little clearer than it was 2 years ago, the place of the drug in the management of hypertension is now better established. There is evidence to suggest the drug may have a role as initial therapy for hypertension, although formal recommendation in management guidelines will almost certainly not occur until long term morbidity and mortality benefits are established.     

A cost-utility analysis of losartan versus atenolol in the treatment of hypertension with left ventricular hypertrophy

INTRODUCTION: The LIFE (Losartan Intervention For Endpoint reduction in hypertension) study demonstrated a 13% relative risk reduction in the primary composite endpoint (myocardial infarction, stroke or death) for patients with hypertension and electrocardiographically diagnosed left ventricular hypertrophy (LVH) treated with losartan compared with atenolol. Losartan recipients also had a 25% relative risk reduction for stroke compared with atenolol recipients. Incorporating the results found in the LIFE study into an economic model, an incremental cost-effectiveness analysis was performed comparing losartan with atenolol in the treatment of 67-year old patients with hypertension and LVH. METHODS: A Markov state transition model, based on published results of the LIFE trial (mean follow-up of 4.8 years), was utilised to extrapolate the outcomes observed in this trial to the patients' lifetime. Utility estimates for the associated health states were obtained from various published sources. Lifetime treatment costs were calculated adopting a societal perspective. Both costs and benefits were discounted and incremental cost-effectiveness ratios (ICERs) were estimated. One-way and probabilistic sensitivity analyses were performed. RESULTS: The estimated ICER for losartan versus atenolol was 1337 Canadian dollars per QALY gained (1 Canadian dollar =0.75 US dollars, 2002 values). This ICER was robust to extensive sensitivity analysis, demonstrating a 95% probability that the ICER would be <20,000 Canadian dollars per QALY gained. CONCLUSION: From a Canadian societal perspective, losartan appears to be a cost-effective alternative to atenolol in patients with hypertension and LVH. The estimated ICERs, including the sensitivity analyses, were within the range of cost-effectiveness ratios for various currently funded interventions and drugs in developed countries.