The efficacy and tolerability of losartan versus atenolol in patients with isolated systolic hypertension. Losartan ISH Investigators Group

Candesartan and hydrochlorothiazide in isolated systolic hypertension

AIM

We investigated the efficacy and safety of daily candesartan 8/16mg and hydrochlorothiazide 12.5 mg as monotherapy and in combination in older patients with systolic hypertension.

METHODS

The study used a double-blind randomized placebo-controlled crossover design. Treatment phases were of 6 weeks duration. For inclusion, patients were aged 55-84 years with sitting systolic blood pressure (SBP) 160-210 mmHg and diastolic blood pressure (DBP) < 95 mmHg. Nineteen patients (11 male, eight female, median age 68 years) completed the study.

MAJOR FINDINGS

Compared with the placebo phase, clinic and ambulatory SBP was significantly reduced with both dose-adjusted candesartan and fixed-dose hydrochlorothiazide as monotherapy, the effect of candesartan being greater than that of hydrochlorothiazide. In combination, the effects of the two drugs were additive. Both drugs were well tolerated either as monotherapy or in combination.

CONCLUSION

Both candesartan and a low dose of hydrochlorothiazide are effective and well-tolerated antihypertensive agents in isolated systolic hypertension with additive effects in combination. Candesartan was more effective than hydrochlorothiazide, although it is possible that dose adjustment only of candesartan could have enhanced its relative effectiveness.

Treatment of systolic hypertension: spotlight on recent studies with angiotensin II antagonists

Systolic blood pressure has a continuous, graded, strong, independent, and aetiologically significant relationship to mortality from coronary heart disease, stroke, and all cardiovascular diseases, as well as to all-cause mortality and life expectancy. Angiotensin II (AII) may be intimately involved in the pathogenesis of systolic hypertension through multiple mechanisms, including decreasing the elastin content and increasing the collagen content of the arterial wall, thickening and fibrotic remodelling of the vascular intima, and proliferating smooth muscle cells in the arterial wall, resulting in increased thickness, stiffening, and partial loss of contractility. AII antagonists may therefore offer hitherto unrecognized benefits (independent of blood pressure) on age-related vascular damage and provide particular benefits in patients with systolic hypertension. Recent evidence has demonstrated that losartan offers cardiovascular outcomes benefits in isolated systolic hypertension (ISH) associated with an excellent tolerability profile. This, in patients with ISH, AII antagonists more facilitate systolic BP control, providing cardiovascular protection and offering an excellent risk-benefit profile.

Chronobiologically explored effects of Telmisartan

Effects of Micardis (Telmisartan), alone or with low-dose aspirin, on blood pressure and other cardiovascular endpoints are examined in 20 patients with MESOR-hypertension in a crossover, double-blind, randomized study consisting of three stages, each lasting 7 days: I-placebo, II-Micardis, and III-Micardis with low-dose aspirin. Treatment was administered each day at a different circadian stage, upon awakening, and 3, 6, 9, 12, 15 and 18 hr after awakening. During each stage, the following variables were measured at 3-hr intervals during waking: systolic and diastolic blood pressure, heart rate, ejection fraction, intrarenal resistive index, acceleration time, and serum creatinine. Each data series was analyzed by single cosinor. Results were summarized by population-mean least squares spectra. At matched treatment times, the MESOR and circadian amplitude of each variable were compared among the three treatments by paired t-tests. A prominent circadian rhythm characterizes all variables. Micardis was associated not only with a lowering of blood pressure, but also with a reduction of the circadian blood pressure amplitude. The ejection fraction was increased, and the resistive index and acceleration time were decreased, the effect being more pronounced when low-dose aspirin was added to Micardis. Any circadian-stage dependent effect of Micardis, with or without low-dose aspirin, will require monitoring over spans longer than a single day for a given treatment administration time.

Angiotensin II receptor antagonist telmisartan in isolated systolic hypertension (ARAMIS) study: efficacy and safety of telmisartan 20, 40 or 80 mg versus hydrochlorothiazide 12.5 mg or placebo

OBJECTIVE

To identify telmisartan doses that are more effective than placebo and non-inferior to hydrochlorothiazide (HCTZ) 12.5 mg, and are well tolerated, in lowering systolic blood pressure (SBP) in patients with isolated systolic hypertension (ISH).

PATIENTS AND METHODS

A 2-4-week single-blind placebo run-in was followed by randomization of 1039 patients (age 36-84 years) with ISH [seated SBP 150-179 mmHg and seated diastolic blood pressure (DBP) < 90 mmHg] to once-daily double-blind treatment with telmisartan 20, 40 or 80 mg, HCTZ 12.5 mg, or placebo. The change in seated trough SBP after 6 weeks compared with baseline was the primary end point. Secondary end points were the percentage achieving the target fall in SBP and the change from baseline in seated trough DBP. Incidence and severity of adverse events and physical examination and laboratory parameters were monitored for the safety evaluation.

RESULTS

Baseline demographics in telmisartan 20 mg (n = 206), 40 mg (n = 210), 80 mg (n = 207), HCTZ 12.5 mg (n = 205) and placebo (n = 211) treatment groups were comparable: (mean +/- SD) age, 63.0 +/- 10.9 years; SBP, 162.9 +/- 8.1 mmHg; and DBP 83.4 +/- 5.0 mmHg. No previous antihypertensive therapy had been received by 66% of the patients. Mean reductions in seated trough SBP (adjusted for baseline and country) were: telmisartan 20 mg, 15.6 mmHg (n = 204); 40 mg, 17.9 mmHg (n = 209); and 80 mg, 16.9 mmHg (n = 205), compared with placebo, 11.4 mmHg (n = 208), and HCTZ 12.5 mg, 15.7 mmHg (n = 204). The target fall in seated trough SBP (< or =140 mmHg or reduction by > or =20 mmHg) was achieved in 46.6% (telmisartan 20 mg), 51.7% (telmisartan 40 mg), 53.9% (telmisartan 80 mg), 27.4% (placebo) and 42.7% (HCTZ 12.5 mg); the response rate was significantly higher for telmisartan 80 mg than for HCTZ 12.5 mg (P = 0.03). All-causality adverse events occurred in 19.9, 17.6 and 20.3% receiving telmisartan 20, 40 and 80 mg, respectively; 20.9% receiving placebo and 22.0% receiving HCTZ 12.5 mg. No drug-related serious adverse events occurred.

CONCLUSIONS

All doses of telmisartan (20-80 mg) were significantly superior to placebo in reducing SBP in patients with ISH and clinically comparable to HCTZ 12.5 mg. Tolerability of telmisartan was similar to that of placebo.

Comparison of the blood pressure-lowering effects and tolerability of Losartan- and Amlodipine-based regimens in patients with isolated systolic hypertension

BACKGROUND

Elevated systolic blood pressure is a more important risk factor for cardiovascular and renal disease than elevated diastolic blood pressure. Isolated systolic hypertension (ISH) is the predominant form of hypertension in the elderly. Effects of angiotensin II on the vascular wall and endothelium may contribute to development of ISH.

OBJECTIVE

The primary objective of this study was to compare the effects on trough sitting systolic blood pressure (SiSBP) of a regimen of losartan, a selective angiotensin II-receptor antagonist, and an amlodipine-based regimen in patients with ISH.

METHODS

This multicenter, prospective, randomized, double-blind, parallel-group study consisted of a 4-week placebo phase and an 18-week active-treatment phase. The losartan-based regimen consisted of losartan 50 mg, increased as needed to losartan 50 mg/hydrochlorothiazide (HCTZ) 12.5 mg at week 6 and to losartan 100 mg/HCTZ 25 mg at week 12 to achieve a target SiSBP <140 mm Hg. the amlodipine-based regimen consisted of amlodipine 5 mg, increased as needed to amlodipine 10 mg at week 6 and to amlodipine 10 mg/HCTZ 25 mg at week 12. The primary efficacy measure was change in trough SiSBP from baseline to week 18. Information on the tolerability of study treatments was collected at each visit, including the investigator's and patient's observations of clinical adverse experiences (CAEs), laboratory adverse experiences, and responses to a symptom questionnaire.

RESULTS

Eight hundred fifty-seven patients (65.6% female) were randomized to treatment, 432 in the losartan group and 425 in the amlodipine group. Their mean age was 67.6 years, and they had a mean duration of hypertension of 6.7 years at baseline. The losartan and amlodipine groups (intent-to-treat population) had baseline mean SiSBP values of 171.2 and 171.9 mm Hg, respectively. At week 18 (the primary end point), the mean change from baseline in SiSBP was -27.4 mm Hg for 426 patients who received losartan and -28.1 mm Hg for 419 patients who received amlodipine (estimated least-square mean difference, 0.3 mm Hg; 95% CI, -1.4 to 2.0), indicating that losartan's effect on systolic blood pressure was noninferior to that of amlodipine. The proportion of patients who responded (SiSBP <140 mm Hg or a > or =20-mm Hg decrease in SiSBP from baseline) was comparable between groups (73.9% losartan, 75.4% amlodipine). The incidence of CAEs and drug-related CAEs was significantly greater in the amlodipine group (amlodipine, 79.8% and 43.8%, respectively; losartan, 67.8% and 25.5%; P < or = 0.001). In addition, more patients in the amlodipine group discontinued therapy due to a drug-related CAE compared with patients in the losartan group (12.9% vs 4.4%, respectively; P < or = 0.001). Lower-extremity edema was the most common drug-related CAE in the amlodipine group (24.0% amlodipine, 2.5% losartan; P < or = 0.001); dizziness was the most common drug-related CAE in the losartan group (6.0% losartan, 4.0% amlodipine).

CONCLUSIONS

In these patients with ISH, losartan and amlodipine produced comparable clinically relevant reductions in SiSBP; however, losartan was better tolerated, as evidenced by fewer CAEs and discontinuations compared with amlodipine. Losartan may be considered for the initial treatment of ISH.

Hypertension in the elderly

Both systolic and diastolic blood pressure increase with advanced age and more than 50% of hypertensive patients are aged above 65 years. Age-related vascular and neuro-humoral changes are important factors leading to the development of hypertension in the elderly and the increase in systolic and diastolic blood pressure with age in any individual is a consequence of the relative change in arterial resistance and stiffness. Therefore, hypertension is predominantly or purely systolic in the elderly both in women and men. The risks of hypertensive patients over the age of 65 years are significant and several trials have provided compelling evidence that treatment of hypertension in the elderly is beneficial in terms of reduced morbidity and mortality. Goal blood pressure should be similar in older and younger patients. Lifestyle modifications are of proven benefit and may be the only therapy needed for stage 1 hypertension. The Sixth report of the JNC recommends diuretics, specifically thiazide diuretics as the initial choice for the treatment of elderly patients without any comorbid conditions. Beta-blockers are less effective than thiazides as first line treatment and may only reduce stroke events. Recently, dihydropiridine calcium antagonists have been advocated as first choice agents for the treatment of hypertension in the elderly and are suitable alternatives when diuretics are ineffective, contraindicated or not tolerated. Newer drugs such as AT1 antagonists are also effective in lowering blood pressure in the elderly but large scale data concerning their protective effects are still lacking.

Should beta blockers be used in the treatment of hypertension in the elderly?

The lack of benefit and the potential negative side effects of beta blockers are overstated, especially in the elderly. This emphasis has led to recommendations by some investigators that these agents not be used in the management of hypertension in this age group. There are numerous reasons why these recommendations should not be followed. The use of beta blockers in the elderly hypertensive has resulted in a reduction in strokes and congestive heart failure. In addition, it should be emphasized that elderly patients are more likely to have silent coronary artery disease or sustain myocardial infarctions. There is abundant evidence that beta blockers are effective therapy in reducing mortality once a myocardial infarction has occurred. In fact, there is a clear reduction in sudden cardiac death. Furthermore, national statistics document that elderly patients have a prevalence of congestive heart failure that varies from 6%-10%. Multiple studies have now documented that beta blockers are additive to angiotensin-converting enzyme inhibitors in reducing mortality for congestive heart failure. Thus, elderly hypertensive patients may benefit from the use of beta blockers, especially if there is evidence of ischemic heart disease, cardiac arrhythmias, or congestive heart failure.

A multicenter, randomized, double-blind, placebo-controlled, 8-week trial of the efficacy and tolerability of once-daily losartan 100 mg/hydrochlorothiazide 25 mg and losartan 50 mg/hydrochlorothiazide 12.5 mg in the treatment of moderate-to-severe essential hypertension

BACKGROUND

Many patients with moderate-to-severe hypertension require multiple drug therapy to achieve blood-pressure goals. Fixed-dose combination therapy with losartan and hydrochlorothiazide may be useful in this population.

OBJECTIVE

This study was conducted to obtain additional data on the antihypertensive efficacy and tolerability of once-daily, fixed-dose combinations of losartan and hydrochlorothiazide.

METHODS

This was a multicenter, randomized, double-blind, parallel-group, placebo-controlled trial. Patients > or = 21 years of age with moderate-to-severe essential hypertension, defined as a mean trough sitting diastolic blood pressure (SiDBP) of 105 to 115 mm Hg, were randomly assigned in a 2:2:1 ratio to receive losartan 100 mg/hydrochlorothiazide 25 mg (L100/25), losartan 50 mg/hydrochlorothiazide 12.5 mg (L50/12.5), or placebo (PBO) once daily for 8 weeks. The primary efficacy measurement was the mean change from baseline in trough SiDBP in the L100/25 versus L50/12.5 treatment groups. Responders were defined as patients with mean trough SiDBP <90 mm Hg or a > or = 10-mm Hg decrease in mean trough SiDBP.

RESULTS

A total of 446 patients were randomly assigned to receive L100/25 (n = 173), L50/12.5 (n = 184), or PBO (n = 89). At week 8, mean trough SiDBP was significantly lower than at baseline in the L100/25 (-17.5 mm Hg), L50/12.5 (-15.2 mm Hg), and PBO groups (-8.5 mm Hg) (all P < 0.001). The difference between the active-treatment groups was statistically significant (-2.2 mm Hg; 95% Cl, range -3.8 to -0.6) (P = 0.006), as was the difference between the L100/25 and PBO groups (-9.0 mm Hg; 95% CI, range -I1.0 to -7.0) (P < 0.001) and the L50/12.5 and PBO groups (-6.7 mm Hg; 95% CI, range -8.7 to -4.8) (P < 0.001). At week 8, the percentages of responders were 86.7% (144 of 166), 78.9% (142 of 180), and 50.0% (42 of 84) in the L100/25, L50/12.5, and PBO groups, respectively. The incidence of adverse experiences (AEs) was 34.7% (60 of 173) in the L100/25 group, 23.9% (44 of 184) in the L50/12.5 group, and 32.6% (29 of 89) in the PBO group. The incidence of drug-related AEs was similar among the treatment groups (L100/25, 7.5% [13 of 173]; L50/12.5, 7.1% [13 of 184]; and PBO, 11.2% [10 of 89]).

CONCLUSIONS

This study demonstrates the antihypertensive efficacy and tolerability of the once-daily, fixed-dose combination L50/12.5 in patients with moderate-to-severe essential hypertension. In this study, L100/25 provided additional anti-hypertensive efficacy beyond that of L50/12.5 (and both were more efficacious than PBO). Approximately 4 of 5 patients (78.9%) treated with L50/12.5 responded to therapy, as did nearly 9 of 10 patients (86.7%) treated with L100/25. The tolerability profiles of L50/12.5 and L100/25 were similar to that of PBO.

Effects of long-term enalapril and losartan therapy of hypertension on cardiovascular aldosterone

BACKGROUND

Plasma aldosterone escape is found during long-term angiotensin-converting enzyme inhibitor therapy. Evidence for aldosterone production in cardiovascular tissues raised the question of whether or not aldosterone escape occurs in these tissues.

METHOD

Spontaneously hypertensive rats were treated with enalapril (20 mg/kg/day) and losartan (50 mg/kg/day) for 20 weeks; untreated spontaneously hypertensive and Wistar rats were used as positive and normal controls, respectively. Ex vivo mesenteric artery and heart perfusion, high-performance liquid chromatography, and radioimmunoassay for aldosterone were performed.

RESULTS

The results showed that enalapril failed to significantly inhibit aldosterone production in mesenteric artery, myocardium and plasma. Losartan significantly inhibited aldosterone production to that of Wistar rats in the mesenteric artery, myocardium and plasma.

CONCLUSION

This study provides the first evidence that long-term angiotensin-converting enzyme inhibition therapy induces aldosterone escape in hypertensive cardiovascular tissues, and angiotensin II subtype 1 receptor antagonist does not induce aldosterone escape in mesenteric artery, myocardium and plasma of spontaneously hypertensive rats.

The effect of a losartan-based treatment regimen on isolated systolic hypertension

This study was conducted to compare the antihypertensive efficacy and tolerability, over 12 weeks, of a losartan-based treatment regimen and placebo in patients with isolated systolic hypertension. Three hundred eight patients > or =35 years of age with isolated systolic hypertension, defined as trough sitting blood pressure between 140 and 200 mm Hg systolic and between 70 and 89 mm Hg diastolic, were randomized to losartan 50 mg (n=157) or placebo (n=151) once daily, with titration as necessary to achieve a goal trough sitting systolic blood pressure (SBP) <140 mm Hg. At baseline, mean trough sitting SBP was 140-159 mm Hg in 20.5% of patients, 160-179 mm Hg in 62.7%, and 180-200 mm Hg in 16.9%, and was similar in the two groups (losartan, 165.3 mm Hg; placebo, 166.1 mm Hg). At 12 weeks, mean trough sitting SBP decreased significantly (p<0.001) in both the losartan-based treatment group (by 19.2 mm Hg) and in the placebo group (by 7.6 mm Hg). The reduction in sitting SBP was significantly greater for losartan than placebo (-11.6 mm Hg; 95% confidence interval, -14.8 to -8.4). In patients with isolated systolic hypertension, a once-daily losartan-based treatment regimen significantly lowered SBP. The losartan-based regimen exhibited antihypertensive efficacy that was superior to that of placebo, with a similar tolerability profile.