Antihypertensive efficacy and safety of fixed-dose combination therapy with losartan plus hydrochlorothiazide in Japanese patients with essential hypertension

The comparative efficacy and safety of the angiotensin receptor blockers in the management of hypertension and other cardiovascular diseases

All national guidelines for the management of hypertension recommend angiotensin receptor blockers (ARBs) as an initial or add-on antihypertensive therapy. The eight available ARBs have variable clinical efficacy when used for control of hypertension. Additive blood pressure-lowering effects have been demonstrated when ARBs are combined with thiazide diuretics or dihydropyridine calcium channel blockers, augmenting hypertension control. Furthermore, therapeutic use of ARBs goes beyond their antihypertensive effects, with evidence-based benefits in heart failure and diabetic renal disease particularly among angiotensin-converting enzyme inhibitor-intolerant patients. On the other hand, combining renin-angiotensin system blocking agents, a formerly common practice among medical subspecialists focusing on the management of hypertension, has ceased, as there is not only no evidence of cardiovascular benefit but also modest evidence of harm, particularly with regard to renal dysfunction. ARBs are very well tolerated as monotherapy, as well as in combination with other antihypertensive medications, which improve adherence to therapy and have become a mainstay in the treatment of stage 1 and stage 2 hypertension.

Comparison of olmesartan combined with a calcium channel blocker or a diuretic in elderly hypertensive patients (COLM Study): safety and tolerability

The cardiovascular effects of combined therapy with the angiotensin receptor blocker (olmesartan) and a dihydropyridine calcium channel blocker (CCB) or a diuretic were compared in high-risk elderly Japanese hypertensive patients by performing a randomized, open label, blinded-endpoint study of morbidity and mortality (the COLM study). Here we report the results obtained with respect to safety and tolerability. High-risk hypertensive patients aged 65–84 years were enrolled and were randomized to receive olmesartan combined with either a CCB (amlodipine or azelnidipine) or a low-dose diuretic for at least 3 years. The primary endpoint was a composite of fatal and non fatal cardiovascular events, whereas adverse events (AEs) and the percentage of patients who discontinued the allocated treatment were evaluated as secondary endpoints. A total of 5141 patients were randomized. Both combination regimens achieved a similar reduction of cardiovascular morbidity and mortality. The incidences of AEs, serious AEs, drug-related serious AEs and discontinuation due to serious AEs were lower in the olmesartan plus CCB group than in the olmesartan plus diuretic group. Serum levels of uric acid and creatinine were significantly higher in the olmesartan plus diuretic group than in the olmesartan plus CCB group. Olmesartan combined with a CCB was significantly superior to olmesartan plus a diuretic with regard to the frequency of AEs and discontinuation of treatment.

Blood pressure-lowering efficacy of monotherapy with thiazide diuretics for primary hypertension

BACKGROUND

Hypertension is a modifiable cardiovascular risk factor. Although it is established that low-dose thiazides reduce mortality as well as cardiovascular morbidity, the dose-related effect of thiazides in decreasing blood pressure has not been subject to a rigorous systematic review. It is not known whether individual drugs within the thiazide diuretic class differ in their blood pressure-lowering effects and adverse effects.

OBJECTIVES

To determine the dose-related decrease in systolic and/or diastolic blood pressure due to thiazide diuretics compared with placebo control in the treatment of patients with primary hypertension. Secondary outcomes included the dose-related adverse events leading to patient withdrawal and adverse biochemical effects on serum potassium, uric acid, creatinine, glucose and lipids.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2014, Issue 1), Ovid MEDLINE (1946 to February 2014), Ovid EMBASE (1974 to February 2014) and ClinicalTrials.gov.

SELECTION CRITERIA

We included double-blind, randomized controlled trials (RCTs) comparing fixed-dose thiazide diuretic monotherapy with placebo for a duration of 3 to 12 weeks in the treatment of adult patients with primary hypertension.

DATA COLLECTION AND ANALYSIS

Two authors independently screened articles, assessed trial eligibility, extracted data and determined risk of bias. We combined data for continuous variables using a mean difference (MD) and for dichotomous outcomes we calculated the relative risk ratio (RR) with 95% confidence interval (CI).

MAIN RESULTS

We included 60 randomized, double-blind trials that evaluated the dose-related trough blood pressure-lowering efficacy of six different thiazide diuretics in 11,282 participants treated for a mean duration of eight weeks. The mean age of the participants was 55 years and baseline blood pressure was 158/99 mmHg. Adequate blood pressure-lowering efficacy data were available for hydrochlorothiazide, chlorthalidone and indapamide. We judged 54 (90%) included trials to have unclear or high risk of bias, which impacted on our confidence in the results for some of our outcomes.In 33 trials with a baseline blood pressure of 155/100 mmHg, hydrochlorothiazide lowered blood pressure based on dose, with doses of 6.25 mg, 12.5 mg, 25 mg and 50 mg/day lowering blood pressure compared to placebo by 4 mmHg (95% CI 2 to 6, moderate-quality evidence)/2 mmHg (95% CI 1 to 4, moderate-quality evidence), 6 mmHg (95% CI 5 to 7, high-quality evidence)/3 mmHg (95% CI 3 to 4, high-quality evidence), 8 mmHg (95% CI 7 to 9, high-quality evidence)/3 mmHg (95% CI 3 to 4, high-quality evidence) and 11 mmHg (95% CI 6 to 15, low-quality evidence)/5 mmHg (95% CI 3 to 7, low-quality evidence), respectively.Direct comparison of doses did not show evidence of dose dependence for blood pressure-lowering for any of the other thiazides for which RCT data were available: bendrofluazide, chlorthalidone, cyclopenthiazide, metolazone or indapamide.In seven trials with a baseline blood pressure of 163/88 mmHg, chlorthalidone at doses of 12.5 mg to 75 mg/day reduced average blood pressure compared to placebo by 12.0 mmHg (95% CI 10 to 14, low-quality evidence)/4 mmHg (95% CI 3 to 5, low-quality evidence).In 10 trials with a baseline blood pressure of 161/98 mmHg, indapamide at doses of 1.0 mg to 5.0 mg/day reduced blood pressure compared to placebo by 9 mmHg (95% CI 7 to 10, low-quality evidence)/4 (95% CI 3 to 5, low-quality evidence).We judged the maximal blood pressure-lowering effect of the different thiazides to be similar. Overall, thiazides reduced average blood pressure compared to placebo by 9 mmHg (95% CI 9 to 10, high-quality evidence)/4 mmHg (95% CI 3 to 4, high-quality evidence).Thiazides as a class have a greater effect on systolic than on diastolic blood pressure, therefore thiazides lower pulse pressure by 4 mmHg to 6 mmHg, an amount that is greater than the 3 mmHg seen with angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs) and renin inhibitors, and the 2 mmHg seen with non-selective beta-blockers. This is based on an informal indirect comparison of results observed in other Cochrane reviews on ACE inhibitors, ARBs and renin inhibitors compared with placebo, which used similar inclusion/exclusion criteria to the present review.Thiazides reduced potassium, increased uric acid and increased total cholesterol and triglycerides. These effects were dose-related and were least for hydrochlorothiazide. Chlorthalidone increased serum glucose but the evidence was unclear for other thiazides. There is a high risk of bias in the metabolic data. This review does not provide a good assessment of the adverse effects of these drugs because there was a high risk of bias in the reporting of withdrawals due to adverse effects.

AUTHORS' CONCLUSIONS

This systematic review shows that hydrochlorothiazide has a dose-related blood pressure-lowering effect. The mean blood pressure-lowering effect over the dose range 6.25 mg, 12.5 mg, 25 mg and 50 mg/day is 4/2 mmHg, 6/3 mmHg, 8/3 mmHg and 11/5 mmHg, respectively. For other thiazide drugs, the lowest doses studied lowered blood pressure maximally and higher doses did not lower it more. Due to the greater effect on systolic than on diastolic blood pressure, thiazides lower pulse pressure by 4 mmHg to 6 mmHg. This exceeds the mean 3 mmHg pulse pressure reduction achieved by ACE inhibitors, ARBs and renin inhibitors, and the 2 mmHg pulse pressure reduction with non-selective beta-blockers as shown in other Cochrane reviews, which compared these antihypertensive drug classes with placebo and used similar inclusion/exclusion criteria.Thiazides did not increase withdrawals due to adverse effects in these short-term trials but there is a high risk of bias for that outcome. Thiazides reduced potassium, increased uric acid and increased total cholesterol and triglycerides.

Combination of antihypertensive therapy in the elderly, multicenter investigation (CAMUI) trial

Angiotensin receptor blockers (ARBs) with calcium channel blockers (CCBs) or diuretics are a widely used combination therapy for hypertensive patients. The present study aimed to determine which combination was better for elderly hypertension patients aged ≧ 65 years.We designed a multicentre, randomized, open-label, parallel comparison study. Hypertensive outpatients aged ≧ 65 years who did not achieve the target blood pressure (BP < 140/90 mmHg) with usual dosages of ARBs were randomly assigned to switch treatment to losartan 50 mg/hydrochlorothiazide 12.5 mg or amlodipine 5 mg in addition to ARBs. The primary endpoint was a change in the systolic blood pressure (SBP) and diastolic blood pressure (DBP) after the 3-month treatment period, while secondary endpoints were changes in the BP, albuminuria, laboratory values, and cognitive function with the mini-mental state examination (MMSE) at baseline and after one year. The results from the CAMUI trial should provide new evidence for selecting optimal combination therapies for elderly hypertensive patients.

Long-term antihypertensive efficacy of losartan/hydrochlorothiazide combination therapy on home blood pressure control

Angiotensin receptor blocker (ARB)/hydrochlorothiazide (HCTZ) combination therapy has been shown to produce a prompt reduction in clinic blood pressure (BP) without serious adverse effects; however, long-term antihypertensive efficacy on home BP has not been fully investigated. In this open-label multicenter observational study, a total of 151 hypertensive patients uncontrolled with antihypertensive regimens including standard dose of ARBs were switched to the fixed-dose combination of losartan (50 mg)/HCTZ (12.5 mg) (mean age 66.9 ± 9.5 years, 51% male, 19% with diabetes mellitus, and 57% with dyslipidemia). After 3 months, losartan/HCTZ treatment significantly reduced mean home systolic BP/diastolic BP from a baseline level of 153 ± 11/85 ± 9 mm Hg to 136 ± 12/77 ± 10 mm Hg (P < .001) and mean clinic BP from 158 ± 9/87 ± 9 to 136 ± 12/77 ± 10 (P < .001), which were maintained through the study period of 12 months (132 ± 11/75 ± 9 and 136 ± 12/77 ± 10; home and clinic BP at 12 months, respectively, P < .001). Furthermore, younger patients (< 65 years) receiving ARB monotherapy at the start of the study showed a significantly greater reduction in home BP, but not in clinic BP, compared with elderly patients (≥ 65 years). In conclusion, losartan/HCTZ combination therapy exerted a 1-year long-term efficacy on home BP as well as clinic BP. In patients uncontrolled with ARB monotherapy, the antihypertensive efficacy on home BP is more pronounced in younger patients compared with that in elderly patients.

Losartan/hydrochlorothiazide combination vs. high-dose losartan in patients with morning hypertension--a prospective, randomized, open-labeled, parallel-group, multicenter trial

The treatment of morning hypertension has not been established. We compared the efficacy and safety of a losartan/hydrochlorothiazide (HCTZ) combination and high-dose losartan in patients with morning hypertension. A prospective, randomized, open-labeled, parallel-group, multicenter trial enrolled 216 treated outpatients with morning hypertension evaluated by home blood pressure (BP) self-measurement. Patients were randomly assigned to receive a combination therapy of 50 mg losartan and 12.5 mg HCTZ (n=109) or a high-dose therapy with 100 mg losartan (n=107), each of which were administered once every morning. Primary efficacy end points were morning systolic BP (SBP) level and target BP achievement rate after 3 months of treatment. At baseline, BP levels were similar between the two therapy groups. Morning SBP was reduced from 150.3±10.1 to 131.5±11.5 mm Hg by combination therapy (P<0.001) and from 151.0±9.3 to 142.5±13.6 mm Hg by high-dose therapy (P<0.001). The morning SBP reduction was greater in the combination therapy group than in the high-dose therapy group (P<0.001). Combination therapy decreased evening SBP from 141.6±13.3 to 125.3±13.1 mm Hg (P<0.001), and high-dose therapy decreased evening SBP from 138.9±9.9 to 131.4±13.2 mm Hg (P<0.01). Although both therapies improved target BP achievement rates in the morning and evening (P<0.001 for both), combination therapy increased the achievement rates more than high-dose therapy (P<0.001 and P<0.05, respectively). In clinic measurements, combination therapy was superior to high-dose therapy in reducing SBP and improving the achievement rate (P<0.001 and P<0.01, respectively). Combination therapy decreased urine albumin excretion (P<0.05) whereas high-dose therapy reduced serum uric acid. Both therapies indicated strong adherence and few adverse effects (P<0.001). In conclusion, losartan/HCTZ combination therapy was more effective for controlling morning hypertension and reducing urine albumin than high-dose losartan.

Differential effects of strict blood pressure lowering by losartan/hydrochlorothiazide combination therapy and high-dose amlodipine monotherapy on microalbuminuria: the ALPHABET study

We investigated the effects of losartan/hydrochlorothiazide (HCTZ) fixed combination therapy and high-dose amlodipine monotherapy on BP measurements and target organ protection. In this open-label multicenter trial, hypertensive patients were randomly allocated to receive losartan 50 mg or amlodipine 5 mg for 4 weeks, and the treatments were changed to combination of losartan 50 mg/HCTZ 12.5 mg or amlodipine 10 mg for a further 4 weeks. A total of 91 hypertensive patients (age 63.6 years), 47 in the losartan/HCTZ group and 44 in amlodipine group, were enrolled. After 8 weeks, the clinic BP, home BP, and 24-hour ambulatory BP were successfully controlled to the same level in both treatment groups (P < .001). Furthermore, both groups showed the same degree of BP reduction in the 24-hour, daytime, and nighttime (P < .001). B-type natriuretic peptide (BNP) also significantly decreased to the same level in both groups, whereas the reduction of urinary albumin/creatinine ratio (UACR) was greater in the losartan/HCTZ group than in the high-dose amlodipine group (-47.6% vs 2.4%, P < .001). Losartan/HCTZ combination and high-dose amlodipine have similar effects on clinic, home, and ambulatory BP control and BNP reduction, whereas losartan/HCTZ has superior effect on UACR reduction when compared with high-dose amlodipine.

Mechanism underlying the efficacy of combination therapy with losartan and hydrochlorothiazide in rats with salt-sensitive hypertension

Although thiazide diuretics are commonly used to supplement angiotensin receptor blockers for treatment of hypertension, the mechanism underlying the therapeutic effects of this drug combination remains unclear. We investigated the antihypertensive and cardioprotective effects of combination therapy with losartan (LOS) and hydrochlorothiazide (HCTZ), in comparison with those of either drug alone, in Dahl salt-sensitive hypertensive rats. Rats fed a high-salt diet from 6 weeks of age were treated with LOS, HCTZ, both drugs (COMB) and vehicle from 6 to 11 weeks. The salt-induced increase in systolic blood pressure was attenuated moderately by LOS and to a greater extent by HCTZ and COMB. Left ventricular (LV) hypertrophy and fibrosis, diastolic dysfunction, as well as angiotensin-converting enzyme and angiotensin II type 1A (AT(1A)) receptor gene expression were attenuated similarly by LOS and HCTZ and more so by COMB. LOS downregulated expression of the AT(1A) receptor gene, without affecting that of the AT(2) receptor gene, in the aorta. In contrast, neither HCTZ nor COMB affected aortic expression of the AT(1A) receptor gene, but both markedly upregulated that of the AT(2) receptor gene. The salt-induced decrease in the plasma concentration of nitric oxide metabolites was attenuated substantially by LOS and abolished by both HCTZ and COMB. In conclusion, the combination of LOS and HCTZ attenuated hypertension, as well as LV remodeling and diastolic dysfunction, more effectively than did LOS or HCTZ alone in rats with salt-sensitive hypertension. Modulation of the cardiac and vascular renin-angiotensin system may have contributed to these beneficial effects of the drug combination.

Relationship between blood pressure control status and lifestyle in hypertensive outpatients

OBJECTIVE

Lifestyle modification as well as combination antihypertensive therapy is necessary to achieve strict blood pressure (BP) control as advocated by the guidelines for the treatment of hypertension. The aim of this study was to investigate the status of adherence to lifestyle modifications and BP control status in hypertensive outpatients.

METHODS AND PATIENTS

Subjects are 661 hypertensive outpatients who had been followed at National Kyushu Medical Center. We assessed BP control status based on the average clinic BP on two occasions. In addition, we investigated the adherence to the individual items of lifestyle modification by a questionnaire.

RESULTS

Average BP was 129 ± 10/71 ± 11 mmHg and overall rate of achieving goal BP was 60.1%. Achieving rate of each target BP category was 83.3% in the elderly patients (<140/90 mmHg), 56.7% in the young/middle patients (<130/85 mmHg) and 45.5% in the patients with diabetes mellitus/chronic kidney disease/myocardial infarction (<130/80 mmHg). Adherance to each item of lifestyle modification was as follows: Patients who answered to be conscious about salt restriction was 80.9%, those with increased intake of fruits/vegetables was 79.0%, reduced intake of cholesterol/saturated fatty acids was 67.9%, presence of obesity was 37.7%, daily exercise for ≥30 min was 31.9%, habitual alcohol intake was 38.0%, habitual smoking was 9.8%. Only 22.5% of the patients had no lifestyle items to be modified. On the other hand, 19.6% of patients had more than 3 items to be modified. Subjects with more than 3 lifestyle items to be modified are more frequently found in young, male, and obese groups.

CONCLUSION

We conclude that about 60% of the patients achieved goal BP by the intensive combination therapy. The lifestyle modification seems to be important especially for the young, male and obese patients.

Combination therapy with angiotensin-converting enzyme inhibitors and indapamide impairs glucose tolerance in Chinese hypertensive patients

BACKGROUND

Elevated blood glucose (BG) induced by antihypertensive agents increases the risk of cardiovascular events. This study was designed to investigate whether fosinopril+indapamide combination therapy has any effect on glucose tolerance (GT), and if it did, whether conversion to fosinopril alone could reverse the impaired GT.

METHODS

Included in the present study were 124 hypertensive patients, of whom 62 patients were treated with fosinopril plus indapamide (F/I group) and the remaining 62 patients were treated with fosinopril alone (F group). Of them, 89 patients completed a mean of 14-month follow-up. In the F/I group, 29 patients were converted to the use of fosinopril for 4-12 months after they completed the follow-up.

RESULTS

In the F group, fasting BG decreased significantly from 5.1+/-0.5 to 4.8+/-0.7 mmol/l (p<0.01), and 2-h postprandial BG decreased significantly from 7.2+/-1.6 to 6.4+/-1.4 mmol/l (p<0.01), while in the F/I group, fasting BG increased significantly from 5.1 +/-0.6 to 5.3+/-0.9 mmol/l (p<0.05), and 2-h postprandial BG increased significantly from 7.2+/-1.7 to 7.7+/-1.8 mmol/l (p<0.05). In 29 patients of the F/I group who completed the follow-up and were converted to fosinopril, fasting BG decreased significantly from 5.5+/-1.0 to 5.3+/-1.0 mmol/l (p<0.05), and 2-h postprandial BG decreased significantly from 7.5+/-2.0 to 7.0+/-2.7 mmol/l (p<0.05).

CONCLUSION

Fosinopril+indapamide combination therapy impaired GT in Chinese hypertensive patients, and fosinopril alone was able to reverse fosinopril+indapamide-induced GT impairment in part of these patients.

Effects of Additional Administration of Low-Dose Indapamide on Patients With Hypertension Treated With Angiotensin II Receptor Blocker

Background: Low-dose thiazide or thiazide-like diuretics have proven useful for the management of blood pressure in patients older than 65 years (elderly group). However, there are few reports about the antihypertensive effects of antihypertensive diuretic agents in patients younger than 65 years (middle-aged group). So, we evaluated the efficacy of low-dose indapamide on blood pressure. Methods: Indapamide(1 mg) was given daily for 3 months and was then given every other day for 3 months to patients whose hypertension was poorly controlled with angiotensin II receptor blocker (ARB)-based treatment. Results: After daily administration of indapamide, blood pressure was significantly decreased in both the middle-aged and elderly groups. Blood pressure was not significantly changed by every-other-day administration compared with that observed after daily administration in either group. The rate of attainment of the target blood pressure was 90.3% and 85.7% in the middle-aged and elderly groups, respectively. The serum uric acid levels were reduced after every-other-day administration compared to daily administration but tended to be higher than the levels at the baseline in both groups. Conclusions: The addition of low-dose indapamide is a useful strategy for the management of hypertension, as it reduced blood pressure without marked side effects.

Efficacy and tolerability of a fixed-dose combination of metoprolol extended release/amlodipine in patients with mild-to-moderate hypertension: a randomized, parallel-group, multicentre comparison with losartan plus amlodipine

BACKGROUND

Epidemiological studies and clinical trials have shown that prevention of cardiovascular disease, the ultimate goal of hypertension treatment, requires a sufficient reduction in blood pressure.

OBJECTIVE

The primary objective of this study was to compare the mean decrease in systolic (SBP) and diastolic (DBP) blood pressure between metoprolol extended release (XL)/amlodipine fixed-dose combination and losartan plus amlodipine combination in patients with mild-to-moderate essential hypertension. The secondary objectives of this study were to compare the proportion of responders in the two treatment groups and to evaluate the tolerability of the study medications.

METHODS

This was a randomized, parallel-group, multicentre comparative study conducted at the outpatient departments of three teaching hospitals in India. Patients with mild-to-moderate hypertension (defined as DBP 90-109 mmHg) aged between 18 and 75 years were enrolled in this study and followed up for 12 weeks. Response to study treatments was evaluated in terms of mean decrease in SBP and DBP and the response rate (reduction to SBP <140 mmHg and DBP <90 mmHg).

RESULTS

Out of 152 patients who underwent a 1-week placebo washout, 148 eligible patients were randomized to receive either metoprolol XL 25 mg/amlodipine 2.5 mg fixed-dose combination (76 patients) or losartan 25 mg plus amlodipine 2.5 mg (72 patients). The two treatment groups were similar with respect to demographic and baseline characteristics. Non-responders after 4 weeks of therapy were escalated to metoprolol XL 50 mg/amlodipine 5 mg fixed-dose combination or losartan 50 mg plus amlodipine 5 mg, respectively. The study was completed by 66 patients in each group, of whom 43 patients in each group responded to the starting doses. After 4 weeks' therapy, both treatments were associated with significant decreases in SBP and DBP from baseline (p < 0.001) and were comparable with respect to mean decrease in SBP (p = 0.304), mean decrease in DBP (p = 0.630) and response rate (p = 1.0). Also, both the step-up therapies were comparable with respect to mean decrease in SBP (p = 0.484), mean decrease in DBP (p = 0.650) and response rate (p = 0.134) at week 12. Both treatments were well tolerated in the studied population.

CONCLUSION

Metoprolol XL/amlodipine fixed-dose combination was found to be as effective and well tolerated as losartan plus amlodipine in the treatment of essential hypertension.

Clinical experience in treating hypertension with fixed-dose combination therapy: angiotensin II receptor blocker losartan plus hydrochlorothiazide

The goal of antihypertensive treatment is to reduce cardiovascular and cerebrovascular events associated with high blood pressure. A combination therapy with different antihypertensive agents is more successful than monotherapy in most hypertensive patients, with the added advantage of a better safety profile. Therefore, treatment of hypertensive patients with fixed-dose combination therapy consisting of the angiotensin II receptor blocker losartan along with hydrochlorothiazide (HCTZ) has several potential benefits over monotherapy with each individual component. It provides more effective blood pressure control, a reduction in the likelihood of adverse effects and facilitation of patient compliance due to a simple once-daily regimen. One of the advantages of the combination of losartan with HCTZ is the potential reduction in HCTZ-induced metabolic disorders; in particular, this combination can have attractive benefits for patients of hyperuricemia. Losartan plus HCTZ fixed-dose combination therapy is frequently recommended for the treatment of hypertension and lowers blood pressure in mild-to-moderate and even severe hypertensive patients to a level comparable with other classes of antihypertensive agents in combination with HCTZ. Fixed-dose combination therapy with losartan plus HCTZ is a logical choice as antihypertensive therapy for patients in whom combination therapy is necessary to achieve additional blood pressure reduction.

Blood pressure lowering efficacy of diuretics as second-line therapy for primary hypertension

BACKGROUND

Diuretics are widely prescribed for hypertension not only as a first-line drug but also as a second-line drug. Therefore, it is essential to determine the effects of diuretics on blood pressure (BP), heart rate and withdrawals due to adverse effects (WDAEs) when given as a second-line drug.

OBJECTIVES

To quantify the additional reduction in systolic blood pressure (SBP) and diastolic blood pressure (DBP) of diuretic therapy as a second-line drug in patients with primary hypertension

SEARCH STRATEGY

CENTRAL (The Cochrane Library 2008, Issue 2), MEDLINE (1966-July 2008), EMBASE (1988-July 2008) and bibliographic citations of articles and reviews were searched.

SELECTION CRITERIA

Double-blind, randomized, controlled trials evaluating the BP lowering efficacy of a diuretic in combination therapy with another class of anti-hypertensive drugs compared with the respective monotherapy (without a diuretic) for a duration of 3 to 12 weeks in patients with primary hypertension.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted the data and assessed trial quality.

MAIN RESULTS

Fifty-three double-blind RCTs evaluating a thiazide in 15129 hypertensive patients (baseline BP of 156/101 mmHg) were included. Hydrochlorothiazide was the thiazide used in 49/53 (92%) of the included studies. The additional BP reduction caused by the thiazide as a second drug was estimated by comparing the difference in BP reduction between the combination and monotherapy groups. Thiazides as a second-line drug reduced BP by 6/3 and 8/4 mmHg at doses of 1 and 2 times the manufacturer's recommended starting dose respectively. The BP lowering effect was dose related. The effect was similar to that obtained when thiazides are used as a single agent. Only 3 double-blind RCTs evaluating loop diuretics were identified. These RCTs showed a BP lowering effect of a starting dose of about 6/3 mmHg.

AUTHORS' CONCLUSIONS

Thiazides when given as a second-line drug have a dose related effect to lower blood pressure that is similar to when they are added as a first-line drug. This means that the BP lowering effect of thiazides is additive. Loop diuretics appear to have a similar blood pressure lowering effect as thiazides at 1 times the recommended starting dose. Because of the short duration of the trials and lack of reporting of adverse events, this review does not provide a good estimate of the incidence of adverse effects of diuretics given as a second-line drug.

Effect of switching from amlodipine to combination therapy with telmisartan and low-dose hydrochlorothiazide

One of the most effective pairs in combination therapy is that of an inhibitor of the renin-angiotensin system (RAS) and a low-dose thiazide diuretic. Possible candidates for this combination therapy are hypertensive patients with blood pressure (BP) that is not controlled by a calcium channel blocker (CCB). Thus, we characterized the antihypertensive effect of the combination of telmisartan and low-dose hydrochlorothiazide in patients with hypertension that was not controlled by amlodipine, which is the most common CCB. A total of 75 patients with BP levels higher than 140/90 mm Hg, treated with 5 mg per day of amlodipine for at least 3 months, were divided into groups that were switched to treatment with 40-80 mg per day of telmisartan plus 12.5 mg per day of hydrochlorothiazide (TH, n=37) or that were continuously treated with 5-7.5 mg per day of amlodipine (Am, n=38). After 12 weeks of treatment, the mean BP level was significantly lower in the TH group than in the Am group (decrease in BP: -9.9+/-11.4 vs. -3.7+/-8.9 mm Hg, P<0.02; normalization rate: 67.6 vs. 30.3%, P<0.01). Serum uric acid was slightly higher in the TH group, but other laboratory data were not different between groups. Therefore, it is suggested that the combination of a RAS inhibitor and a low-dose thiazide is useful if treatment with a CCB cannot control BP in patients with hypertension.

Issues in blood pressure control and the potential role of single-pill combination therapies

Hypertension (HTN) is a major risk factor for cardiovascular mortality, yet only a small proportion of hypertensive individuals receive appropriate therapy and achieve target blood pressure (BP) values. Factors influencing the success of antihypertensive therapy include physicians' acceptance of guideline BP targets, the efficacy and tolerability of the drug regimen, and patient compliance and persistence with therapy. It is now well recognised that most hypertensive patients require at least two antihypertensive agents to achieve their target BP. However, complicated treatment regimens are a major contributory factor to poor patient compliance. The use of combination therapy for HTN offers a number of advantages over the use of monotherapy, including improved efficacy, as drug combinations with a synergistic mechanism of action can be used. This additive effect means that lower doses of the individual components can be used, which may translate into a decreased likelihood of adverse events. The use of single-pill combination therapy, in which two or more agents are combined in a single dosage form, offers all the benefits of free combination therapy (improved efficacy and tolerability over monotherapy) together with the added benefit of improved patient compliance because of the simplified treatment regimen. The use of single-pill combination therapy may also be associated with cost savings compared with the use of free combinations for reasons of cheaper drug costs, fewer physician visits and fewer hospitalisations for uncontrolled HTN and cardiovascular events. Thus, the use of single-pill combination therapy for HTN should help improve BP goal attainment through improved patient compliance, leading to reduced costs for cardiovascular-related care.

Randomized, double-blinded trial evaluation of valsartan/hydrochlorothiazide combination therapy in mild to moderate essential hypertension in north-east China

In this randomized, double-blind study, 126 mild to moderate essential hypertensive patients from northern China were studied to determine the efficacy and safety of a combination therapy of valsartan and hydrochlorothiazide. Patients were randomized to the V80/H12.5 (80 mg valsartan/12.5 mg hydrochlorothiazide) group or the V80 (80 mg valsartan) group. Six weeks after treatment, the mean decrease from baseline in mean sitting systolic blood pressure (MSSBP) was significantly higher in the V80/H12.5 group than the V80 group, but there was no difference in the change of mean sitting diastolic blood pressure (MSDBP) in the two groups. Overall, 80.33% and 70.97% had a controlled response (normalized MSDBP), and 85.25% and 77.42% had a diastolic response (normalized MSDBP or > 10 mmHg reduction in MSDBP) in the V80/H12.5 and V80 groups, respectively (not significantly different). The incidence of adverse events was also similar between the two groups. The combination of 80 mg valsartan/12.5 mg hydrochlorothiazide was efficacious and well tolerated in mild and moderate essential hypertensive patients.

Current awareness: Pharmacoepidemiology and drug safety

In order to keep subscribers up‐to‐date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of pharmacoepidemiology and drug safety. Each bibliography is divided into 20 sections: 1 Reviews; 2 General; 3 Anti‐infective Agents; 4 Cardiovascular System Agents; 5 CNS Depressive Agents; 6 Non‐steroidal Anti‐inflammatory Agents; 7 CNS Agents; 8 Anti‐neoplastic Agents; 9 Haematological Agents; 10 Neuroregulator‐Blocking Agents; 11 Dermatological Agents; 12 Immunosuppressive Agents; 13 Autonomic Agents; 14 Respiratory System Agents; 15 Neuromuscular Agents; 16 Reproductive System Agents; 17 Gastrointestinal System Agents; 18 Anti‐inflammatory Agents ‐ Steroidal; 19 Teratogens/fetal exposure; 20 Others. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted.