Candesartan cilexetil in combination with low-dose hydrochlorothiazide is effective in severe hypertension

Candesartan cilexetil 32 mg/hydrochlorothiazide 25 mg in unselected patients with high or very high cardiovascular risk: efficacy, safety, and metabolic impact

BACKGROUND AND OBJECTIVES

Safety and efficacy of the fixed-dose combination candesartan cilexetil 32 mg/hydrochlorothiazide 25 mg has been demonstrated in a number of randomized clinical trials. Because stringent inclusion and exclusion criteria prohibit many high-risk patients from being investigated in clinical trials we aimed to assess the effectiveness, tolerability, and safety in a large unselected cohort of high-risk patients in primary care. The primary objective was the efficacy of candesartan cilexetil 32 mg/hydrochlorothiazide 25 mg in lowering the office-based blood pressure (BP). Secondary objectives were changes of metabolic parameters and safety.

METHODS

A multicenter, non-interventional study of patients with a BP ≥ 140 mmHg systolic and/or 90 mmHg diastolic and additional cardiovascular risk factors. Patients received the fixed-dose combination of candesartan cilexetil 32 mg and hydrochlorothiazide 25 mg for 24 weeks.

RESULTS

A total of 3,390 patients with a mean age of 61.7 ± 10.6 years, 57.8 % being male, and a mean body mass index of 29.7 kg/m(2) were documented. Of these, 70.9 % had at least one additional cardiovascular risk factor such as coronary artery disease (45.5 %) or diabetes mellitus (44.5 %). Baseline BP was 159.6 ± 15.3 over 93.5 ± 9.5 mmHg. BP at 24 weeks was reduced by 32.3 ± 15.8 systolic and 16.1 ± 10.2 mmHg diastolic compared with baseline (p < 0.001 each). Systolic BP (SBP) and diastolic BP (DBP) was normalized (<140/<90 mmHg) in 57.4 % of non-diabetic patients. An SBP <140 mmHg or SBP reduction of ≥ 20 mmHg was achieved by 77.9 % non-diabetic patients. Fasting plasma glucose (-5.9 mg/dL), glycosylated hemoglobin (-0.18 %), low-density lipoprotein cholesterol (-8.5 mg/dL) and triglycerides (-20.3 mg/dL) were reduced significantly, high-density lipoprotein was increased by 0.18 %, while potassium and creatinine levels remained stable. The proportion of patients with adverse drug reactions (ADRs) was 1.3 % (n = 61 events in 45 patients). There were ten serious ADRs in eight patients; four patients died without causal relationship to study drug.

CONCLUSIONS

The results confirm previous randomized clinical trial data supporting the effectiveness, tolerability, and safety of this fixed-dose combination in an unselected patient population with high cardiovascular risk.

An overview of candesartan in clinical practice

Hypertension is a major risk factor for coronary heart disease, stroke, heart failure and renal disease. The Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure 7 defined hypertension as a blood pressure of more than 140/90 mmHg and recommended to initiate treatment with a two-drug combination for stage 2 hypertension (blood pressure of 160-179/100-109 mmHg). The need for drug combinations is clear from a patient and physician perspective as they provide more effective blood pressure lowering, reduce pill burden, improve compliance and decrease hypertension-related morbidity and mortality. Angiotensin II receptor blocker therapy has been proven to be well tolerated and effective in the management of hypertension, chronic heart failure with left ventricular dysfunction and the prevention and progression of diabetic renal disease. Blockers of the renin-angiotensin system are an important component of antihypertensive combination therapy. Thiazide-type diuretics are usually added to increase the blood pressure lowering efficacy. Fixed drug-drug combinations of both principles, such as candesartan/hydrochlorothiazide, are highly effective in lowering blood pressure while providing improved compliance, a good tolerability and largely neutral metabolic profile. In this article, we review the literature for the role of candesartan-based therapy for hypertension, stroke, diabetes mellitus and heart failure.

Candesartan: widening indications for this angiotensin II receptor blocker?

Candesartan cilexetil is one of a number of drugs of the angiotensin II receptor blocker (ARB) class. Their principal mode of action involves competitive blockade of the angiotensin II type 1 receptor, thereby modulating the activity of the rennin-angiotensin-aldosterone system. Angiotensin II receptor blocker therapy has been proven to be well tolerated and effective in the management of hypertension, chronic heart failure with left ventricular dysfunction and the prevention and progression of diabetic renal disease. Candesartan is a highly potent, long-acting and selective angiotensin II type 1 receptor blocker. It was launched in 1998 for the treatment of hypertension. Its use has increased dramatically, with recently published data suggesting benefit in the treatment of stroke, heart failure, diabetic renal disease and most recently in preventing the development of or delaying the progression of diabetic retinopathy. In this article we review the literature on the use of ARB drugs in general before focusing on candesartan.

Fixed combination of candesartan with hydrochlorothiazide in patients with severe primary hypertension

OBJECTIVE

The new guidelines for treatment of hypertension by the JNC VII in 2003 permit the initial use of a combination therapy, if blood pressure has to be lowered more than 20/10 mmHg. The aim of this investigation was to document the efficacy and safety of a combination therapy with candesartan cilexetil and hydrochlorothiazide in severe hypertension.

METHODS

116 patients freshly diagnosed as having severe primary hypertension (Grade III) and untreated for this condition were enrolled. The study was performed without a placebo control group for ethical reasons. Thus, all patients were treated for 6 weeks with 16 mg candesartan cilexetil plus 12.5mg hydrochlorothiazide daily after forced titration with 8 and 16 mg candesartan cilexetil each for <or= 2 weeks. Sitting trough BP was measured always with the same device in the morning after 15 min at rest, and the median of three measurements was used for analysis. Safety parameters included alanyl aminotransferase (ALAT), aspartyl aminotransferase (ASAT), creatinine, urea, BUN and electrolytes.

RESULTS

The mean reduction in systolic/diastolic BP at the end was 38.1/29.4 mmHg. 90.1% of patients were considered to be responders, while 39.6% of patients treated became normotensive (< 140/< 90 mmHg). No drug-related adverse events or changes in laboratory parameters were reported.

CONCLUSION

Although this was an open-label, single-group study, on the basis of efficacy and safety, the combination therapy appears to offer a promising treatment for patients with severe primary hypertension.

Evaluation of angiotensin II receptor blockers for 24-hour blood pressure control: meta-analysis of a clinical database

Angiotensin II receptor blockers are well tolerated and improve compliance in hypertensive patients. The need for 24-hour blood pressure control has focused attention on whether all agents in this class maintain smooth antihypertensive effects over a 24-hour period. Insight into this issue emerged from a meta-analysis of five large, multicenter trials in which ambulatory blood pressure monitoring was used to compare the antihypertensive effects of three angiotensin II receptor blockers: telmisartan, losartan, and valsartan. These trials used either a double-blind, placebo-controlled or a prospective, randomized, open-label, blinded-end point design. Initial analysis established the validity of combining ambulatory blood pressure monitoring data from the double-blind, placebo-controlled and prospective, randomized, open-label, blinded-end point designs. Subsequent analyses revealed that telmisartan 80 mg was significantly more effective than losartan 50 mg and valsartan 80 mg for reducing 24-hour mean blood pressure. Furthermore, telmisartan 80 mg was comparable to amlodipine 5 mg for controlling the early morning surge in blood pressure.

Efficacy and tolerability of a fixed-dose combination of telmisartan plus hydrochlorothiazide in patients uncontrolled with telmisartan monotherapy

The antihypertensive effects of a telmisartan 80 mg/hydrochlorothiazide (HCTZ) 12.5 mg fixed-dose combination and telmisartan 80 mg monotherapy were compared in patients with a history of mild-to-moderate essential hypertension and inadequate BP control (DBP > or = 90 mm Hg) following 8 weeks of telmisartan monotherapy. At the end of this period, 491 patients (62.9% men; mean age 55.3 years) whose DBP was > or = 90 mm Hg were double-blind randomised to once-daily telmisartan 80 mg/HCTZ 12.5 mg (n = 246) or telmisartan 80 mg (n = 245). Trough (24 h post-dose) clinic BP was measured after 4 and 8 weeks of double-blind therapy. At the end of double-blind treatment, patients receiving telmisartan 80 mg/HCTZ 12.5 mg had significant additional decrements in clinic SBP/DBP over telmisartan 80 mg of -5.7/-3.1 mm Hg (P < 0.01). Most of the additional effect occurred during the first 4 weeks of treatment. The proportion of patients with normalised BP (SBP < 140 mm Hg and DBP < 90 mm Hg) was significantly greater in the telmisartan 80 mg/HCTZ 12.5 mg group than the telmisartan 80 mg group (41.5%vs 26.1%;P < 0.05). Both treatments were well tolerated. The incidence of adverse events was similar except for diarrhoea, which occurred more frequently in the telmisartan 80 mg/HCTZ 12.5 mg group, and oedema, which occurred more frequently in the telmisartan group. Our results indicate that a telmisartan 80 mg/HCTZ 12.5 mg fixed-dose combination confers significant additional BP reductions compared with continuation of telmisartan monotherapy in non-responders.

Effects of telmisartan, hydrochlorothiazide and their combination on blood pressure and renal excretory parameters in spontaneously hypertensive rats

The effects of telmisartan and hydrochlorothiazide (HCTZ) alone and in combination on blood pressure (BP) and renal excretory function were investigated in male spontaneously hypertensive rats (SHR) after oral administration for five consecutive days. Four treatments were studied: vehicle (0.5% Natrosol), telmisartan 3 mg/kg, HCTZ 10 mg/kg, and telmisartan 3 mg/kg+HCTZ 10 mg/kg. The effects on BP and heart rate were studied in 40 SHRs (10 animals per group) using an implanted telemetry device. Renal excretory function was assessed in 76 SHRs (18 animals per group, of which nine were used for urine sampling and nine for blood sampling). The telmisartan/HCTZ combination produced the greatest reductions in trough DBP (-44+/-1.5 mmHg), SBP (-60+/-1.9 mmHg) and mean BP (mBP; -53+/-1.7 mmHg) after five days of therapy (p<0.05 vs. vehicle and vs. telmisartan). Telmisartan monotherapy also decreased DBP, SBP and mBP significantly (p<0.05), but only minor BP fluctuations occurred in SHRs receiving HCTZ or vehicle. Telmisartan/HCTZ elevated heart rate by approximately 12 beats per minute (p<0.05 vs.control). Significant increases in urine volume and Na+, Cl, K+, creatinine and glucose excretion were observed with HCTZ treatment (p<0.01). Telmisartan/HCTZ also promoted renal water and electrolyte excretion (p<0.01); the diuretic effect appeared to be greater with the combination than with HCTZ alone, and there was some attenuation of urinary K+ loss. Elevated blood urea nitrogen levels were observed only in HCTZ-treated SHRs. These results indicate that the antihypertensive efficacy of telmisartan in SHRs is augmented by co-administration with HCTZ. The combination did not affect renal excretory function, with the exception of an increase in blood urea nitrogen and a possible amelioration of HCTZ-related K+ depletion.

Telmisartan plus hydrochlorothiazide versus telmisartan or hydrochlorothiazide monotherapy in patients with mild to moderate hypertension: a multicenter, randomized, double-blind, placebo-controlled, parallel-group trial

BACKGROUND

Recent surveys reveal continuing deficiencies in the awareness, treatment, and control of hypertension. In many cases, failure to achieve blood pressure targets may be attributable to the use of antihypertensive monotherapy.

OBJECTIVES

This study was undertaken to identify combinations of telmisartan, a new oral angiotensin II type 1-receptor antagonist, and hydrochlorothiazide (HCTZ) that might provide greater antihypertensive efficacy than monotherapy with either agent in the treatment of mild to moderate hypertension. It also examined the dose-response surface for the 2 drugs alone and in combination.

METHODS

This was a multicenter, randomized, double-blind, placebo-controlled, parallel-group study that employed all cells of a 4 x 5 factorial design. After a 4-week, single-blind, placebo run-in period, men and women between 18 and 80 years of age with mild to moderate hypertension (defined as mean supine diastolic blood pressure [DBP] between 95 and 114 mm Hg during the last 2 weeks of the placebo run-in period and systolic blood pressure [SBP] between 114 and 200 mm Hg immediately before randomization) were eligible to enter the 8-week, double-blind, double-dummy treatment period. Study comparisons were between once-daily telmisartan monotherapy (20, 40, 80, or 160 mg), HCTZ monotherapy (6.25, 12.5, or 25 mg), 12 combinations of these telmisartan/HCTZ doses, and placebo. The focus was on 2 combinations: telmisartan 40 mg/HCTZ 12.5 mg and telmisartan 80 mg/HCTZ 12.5 mg. The primary efficacy variable was change in supine trough DBP from baseline to the last evaluable measurement during double-blind treatment. Plasma renin activity and safety parameters, including treatment-emergent adverse events, physical findings, electrocardiograms, and serum electrolyte levels (which are known to increase with HCTZ treatment), were also assessed.

RESULTS

Of 1293 patients screened, 818 (63.3%) were enrolled at 47 centers. Of these 818, 749 (91.6%) completed the study. The intent-to-treat population (randomized with > or = 1 postrandomization blood pressure measurement) consisted of 807 patients (98.7%). Telmisartan 80 mg/HCTZ 12.5 mg significantly decreased mean supine trough SBP/DBP by 23.9/14.9 mm Hg, a benefit of 8.5/3.4 mm Hg compared with telmisartan 80 mg and of 17.0/7.6 mm Hg compared with HCTZ 12.5 mg (both comparisons, P < 0.01). Telmisartan 40 mg/HCTZ 12.5 mg significantly reduced mean supine SBP by 18.8 mm Hg, a benefit of 6.6 mm Hg compared with telmisartan 40 mg and 11.9 mm Hg compared with HCTZ 12.5 mg (both, P < 0.01). This same combination significantly reduced mean supine DBP by 12.6 mm Hg, a benefit of 5.3 mm Hg compared with HCTZ 12.5 mg (P < 0.01), but was not significantly different from telmisartan 40 mg. Telmisartan 80 mg/HCTZ 12.5 mg was significantly more effective than telmisartan 40 mg/HCTZ 12.5 mg in reducing mean supine DBP and SBP (both, P < 0.05). The response surface and responder analyses confirmed the additive antihypertensive efficacy of the combination of telmisartan and HCTZ. All regimens were well tolerated.

CONCLUSIONS

Once-daily telmisartan 80 mg/HCTZ 12.5 mg was effective and well tolerated when used to reduce SBP and DBP in patients with mild to moderate hypertension. In addition to enhancing efficacy, this combination protected against potassium depletion, a common side effect of thiazide monotherapy.

Efficacy and safety of losartan/hydrochlorothiazide in patients with severe hypertension

This 12-week, open-label, multicenter study assessed the efficacy and safety of losartan/hydrochlorothiazide (HCTZ), alone or in combination with other antihypertensive agents, in the treatment of patients with severe systemic hypertension. Treatment began with once-daily losartan/HCTZ 50/12.5 mg. The dose was increased to 100/25 mg, if required, to achieve blood pressure (BP) control (sitting diastolic BP <95 mm Hg); felodipine (extended release) and/or atenolol could be added if target sitting diastolic BP was not achieved with losartan/HCTZ alone. Mean sitting systolic BP of the 131 patients enrolled was 165.3 mm Hg at baseline and 139.8 mm Hg at final visit (reduction -25.4 mm Hg; p < or =0.01). Mean sitting diastolic BP was 111.9 mm Hg at baseline and 93.6 mm Hg at final visit (reduction -18.4 mm Hg; p < or =0.01). After 2 weeks of treatment, 63.8% of patients (83 of 130) were taking losartan/HCTZ 50/12.5 mg alone. By the final visit, one third of patients (35.1%; 46/131) were still only taking losartan/HCTZ. Most patients (48.1%; 63 of 131) were taking losartan/HCTZ 100/25 mg plus felodipine (extended release) at the final visit. Losartan/HCTZ was well tolerated. Drug-related adverse experiences occurred in 30 patients (22.9%). Only 2 patients (1.5%) had a serious adverse experience; 6 patients (4.6%) discontinued the drug because of an adverse experience. In conclusion, losartan/ HCTZ, alone or as part of a regimen with other standard antihypertensive agents, is effective and well tolerated in the treatment of patients with severe hypertension.