Candesartan cilexetil: comparison of once-daily versus twice-daily administration for systemic hypertension. Candesartan Cilexetil Study Investigators

Twice-daily versus once-daily lisinopril and losartan for hypertension: Real-world effectiveness and safety

BACKGROUND

Lisinopril and losartan manufacturer labels recommend twice-daily dosing (BID) if once-daily (QDay) is insufficient to lower blood pressure (BP).

METHODS AND RESULTS

Retrospective cohort study of patients taking QDay lisinopril and losartan who experienced a dose-doubling (index date). A text-processing tool categorized BID and QDay groups at the index date based on administration instructions. We excluded: pregnant/hospice, regimens other than BID/QDay, and without BP measurements -6 months/+12 months of the index date. The most proximal BP measurements -6 months and +2 weeks to 12 months of the index date were used to evaluate BP differences. Propensity scores were generated, and differences in BP and adverse events (angioedema, acute kidney injury, hyperkalemia) between BID/QDay groups were analyzed within dosing cohorts using inverse propensity of treatment-weighted regression models. Of 11,210 and 6,051 patients who met all criteria for lisinopril and losartan, 784 (7.0%) and 453 (7.5%) were taking BID, respectively. BID patients were older and had higher comorbidity and medication burdens. There were no differences in systolic/diastolic BP between BID and QDay, with absolute differences in mean systolic BP ranging from -1.8 to 0.7 mmHg and diastolic BP ranging from -1.1 to 0.1 mmHg (all 95% confidence intervals [CI] cross 0). Lisinopril 10mg BID was associated with an increased odds of angioedema compared to lisinopril 20mg QDay (odds ratio 2.27, 95%CI 1.13-4.58).

CONCLUSIONS

Adjusted models do not support improved effectiveness or safety of BID lisinopril and losartan.

Valsartan vs. other angiotensin II receptor blockers in the treatment of hypertension: a meta-analytical approach

OBJECTIVE

To compare the efficacy of valsartan in systolic (SBP) and diastolic blood pressure (DBP) reduction with other angiotensin II receptor blockers (ARBs) in essential hypertension.

METHODS

Systematic literature search of databases between October 1997 and May 2008. Meta-analysis of short-term, double-blind, parallel group, randomised controlled trials (RCTs) for treatment of adult hypertension (DBP: 90-115 mmHg). Random-effects meta-regression adjusting for baseline blood pressure (BP) was used to analyse the data. Mean change in SBP and DBP was estimated for each individual drug and dose combination.

RESULTS

In all, 31 RCTs (n = 13,110 patients) were included in the analysis. Six studies include trial arms with candesartan, six irbesartan, 13 losartan, two olmesartan, five telmisartan and 12 valsartan. The weighted average reduction in mean SBP and DBP for valsartan 160 mg was -15.32 mmHg (95% CI: -17.09, -13.63) and -11.3 mmHg (95% CI: -12.15, -10.52) and for 320 mg was -15.85 mmHg (95% CI: -17.60, -14.12) and -11.97 mmHg (95% CI: -12.81, -11.16); these are statistically significantly greater reductions compared with losartan 100 mg, which was -12.01 mmHg (95% CI: -13.78, -10.25) and -9.37 mmHg (95% CI: -10.18, -8.54) for SBP and DBP respectively. There is evidence that valsartan 160 mg reduces SBP and DBP more than irbesartan 150 mg and reduced DBP more than candesartan 16 mg. No other statistically significant difference in efficacy is demonstrated.

CONCLUSION

Valsartan administered at 160 or 320 mg is more effective at lowering BP than losartan 100 mg and shows comparable efficacy to other ARBs in patients with essential hypertension.

Blood pressure lowering efficacy of angiotensin receptor blockers for primary hypertension

BACKGROUND

Angiotensin receptor blockers (ARBs) are widely prescribed for hypertension so it is essential to determine and compare their effects on blood pressure (BP), heart rate and withdrawals due to adverse effects (WDAE).

OBJECTIVES

To quantify the dose-related systolic and/or diastolic BP lowering efficacy of ARBs versus placebo in the treatment of primary hypertension.

SEARCH STRATEGY

We searched CENTRAL (The Cochrane Library 2007, Issue 1), MEDLINE (1966 to February 2007), EMBASE (1988 to February 2007) and reference lists of articles.

SELECTION CRITERIA

Double-blind, randomized, controlled trials evaluating the BP lowering efficacy of fixed-dose monotherapy with an ARB compared with placebo for a duration of 3 to 12 weeks in patients with primary hypertension.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted study authors for additional information. WDAE information was collected from the trials.

MAIN RESULTS

Forty six RCTs evaluated the dose-related trough BP lowering efficacy of 9 ARBs in 13 451 participants with a baseline BP of 156/101 mm Hg. The data do not suggest that any one ARB is better or worse at lowering BP. A dose of 1/8 or 1/4 of the manufacturers' maximum recommended daily dose (Max) achieved a BP lowering effect that was 60 to 70% of the BP lowering effect of Max. A dose of 1/2 Max achieved a BP lowering effect that was 80% of Max. ARB doses above Max did not significantly lower BP more than Max. Due to evidence of publication bias, the largest trials provide the best estimate of the trough BP lowering efficacy for ARBs as a class of drugs: -8 mm Hg for SBP and -5 mm Hg for DBP. ARBs reduced BP measured 1 to 12 hours after the dose by about 12/7 mm Hg.

AUTHORS' CONCLUSIONS

The evidence from this review suggests that there are no clinically meaningful BP lowering differences between available ARBs. The BP lowering effect of ARBs is modest and similar to ACE inhibitors as a class; the magnitude of average trough BP lowering for ARBs at maximum recommended doses and above is -8/-5 mmHg. Furthermore, 60 to 70% of this trough BP lowering effect occurs with recommended starting doses. The review did not provide a good estimate of the incidence of harms associated with ARBs because of the short duration of the trials and the lack of reporting of adverse effects in many of the trials.

Updated meta-analytical approach to the efficacy of antihypertensive drugs in reducing blood pressure

BACKGROUND AND OBJECTIVE

Despite advances in the treatment of hypertension, control rates continue to be suboptimal in both Europe and the US. Strategies that improve hypertension control are therefore urgently needed. This study aimed to assess the relative efficacies of various antihypertensive drugs commonly used in France in reducing systolic and diastolic blood pressure (SBP and DBP) by using a meta-analytical approach. This update of a previously published meta-analytical approach extends the number of drugs evaluated from 13 to 19.

METHODS

A total of 80 randomised, controlled trials published between 1973 and 2007 involving 10 818 patients were selected for inclusion in the meta-analytical approach. Data were examined for 19 drugs, and 16 drugs were included in the analysis: hydrochlorothiazide, indapamide sustained-release (SR), atenolol, amlodipine, lercanidipine, manidipine, enalapril, ramipril, trandolapril, candesartan cilexetil, irbesartan, losartan, olmesartan medoxomil, telmisartan, valsartan and aliskiren. Weighted average reductions in SBP and DBP over a period of 8-12 weeks were calculated for each drug from information on both the mean and the variability in BP reduction. No trials evaluating furosemide, spironolactone or cicletanine satisfied the inclusion criteria for this analysis.

RESULTS

The average weighted reductions in SBP over 8-12 weeks were most marked with diuretics, and in particular indapamide SR 1.5 mg/day (mean change from baseline -22.2mm Hg), which reduced SBP to a greater extent than any of the other drugs evaluated (at any dosage considered). Average weighted reductions in DBP were generally similar with all classes of antihypertensives and ranged from -11.4mm Hg with the beta-adrenoceptor blocker atenolol and calcium channel antagonists to -10.3mm Hg with the angiotensin II type 1 receptor antagonists.

CONCLUSION

This new analysis supports the results of the earlier investigation, in that indapamide SR 1.5 mg/day appeared to be the most effective drug for producing significant reductions in SBP within 8-12 weeks, which is an essential element in optimising cardiovascular prevention among hypertensive patients. The clinical application of these results should take into consideration all the limitations discussed in this analysis.

A meta-analytical approach to the efficacy of antihypertensive drugs in reducing blood pressure

INTRODUCTION

Hypertension constitutes a veritable public health issue. Several classes of drugs are available for the treatment of hypertension. The objective of this meta-analytical approach was to assess the efficacy of antihypertensive drugs most commonly used in France in reducing clinical SBP and DBP.

METHODS

The antihypertensive drugs selected were hydrochlorothiazide, indapamide sustained release (SR), furosemide and spironolactone for diuretics; amlodipine and lercanidipine for calcium channel antagonists; atenolol for beta-adrenoceptor antagonists (beta-blockers); enalapril and ramipril for ACE inhibitors; and candesartan cilexetil, irbesartan, losartan, and valsartan for angiotensin II receptor antagonists. The trials selected were published between 1973 and 2004, evaluated monotherapy with trial drugs as fixed-dosage or with dosage increase, and assessed blood pressure reduction between 2 and 3 months. The analysis method used was based on the calculation of the sum weighted for the trial size.

RESULTS

A total of 72 trials (comprising 9094 patients) were selected and analyzed. No trial evaluating furosemide or spironolactone satisfied the inclusion criteria for this analysis. For SBP, the reduction was more marked with diuretics, calcium channel antagonists, and ACE inhibitors. Of all the drugs studied, indapamide SR gave the greatest SBP reduction (-22.2 mm Hg). Evaluated therapeutic classes had a similar magnitude of effect on DBP, i.e. reduction between -11.4 mm Hg with beta-adrenoceptor antagonists and -10.3 mm Hg with angiotensin II type 1 receptor antagonists.

CONCLUSION

Indapamide SR 1.5 mg appeared to be the most effective drug for a significant reduction in SBP within 2-3 months, which is an essential element in optimizing cardiovascular prevention among hypertensive patients. The clinical application of these results should take into consideration all the limitations discussed in this analysis.

Serum concentration of potassium in chronic heart failure patients administered spironolactone plus furosemide and either enalapril maleate, losartan potassium or candesartan cilexetil

OBJECTIVE

To retrospectively investigate elevation of serum potassium when spironolactone (25 or 50 mg/day) and furosemide were administered concomitantly with an angiotensin II converting enzyme inhibitor (ACE-I) or angiotensin II receptor blocker (ARB) to patients with chronic heart failure for 12 months and occurrence of hyperkalemia and hypokalemia because of concomitant administration of spironolactone plus an ACE-I or ARB and furosemide.

METHODS

Patients with chronic heart failure, who visited departments of cardiovascular internal medicine and cardiovascular surgery at the National Hospital Organization Osaka Medical Center, were enrolled for this study. Serum potassium, blood urea nitrogen (BUN), serum creatinine, uric acid, and serum sodium were determined in every patient at the time of start of treatment and at 3 and 12 months of treatment. Data from patients in Groups A (25 mg/day spironolactone + 40 mg/day furosemide + an ACE-I or ARB) and B (50 mg/day spironolactone + 40 mg/day furosemide + an ACE-I or ARB) were analysed for differences with respect to the ACE-I and ARB used.

RESULTS

When 50 mg/day spironolactone plus 5 mg/day enalapril maleate (enalapril) or 50 mg/day losartan potassium (losartan) or 8 mg/day candesartan cilexetil (candesartan) plus 40 mg/day furosemide were concomitantly used, the mean value of serum potassium was significantly elevated only in the group treated with 50 mg/day spironolactone regardless of the concomitant drug. The number of patients with hyperkalemia (>5.5 mEq/L) at 12 months of treatment was 12 (8.8%), while the number of patients with hypokalemia (<or=3.5 mEq/L) was 7 (5.1%). However, the occurrence of hyperkalemia was almost the same regardless of the dose of spironolactone or the ACE-I or ARB concomitantly administered. Therefore, if enalapril, losartan, or candesartan is concomitantly used, it is necessary to monitor the serum concentration of potassium, even if spironolactone is administered at a dose of 25 mg/day.

CONCLUSION

The occurrence of hyperkalemia in patients administered spironolactone is influenced by the dose, but when it is used concomitantly with enalapril, losartan or candesartan, the occurrence of hyperkalemia exceeding 5.5 mEq/L may increase even if the dose of spironolactone is as low as 25 mg. Thus it is essential to always monitor serum potassium.

Efficacy of angiotensin II receptor antagonists in preventing headache: a systematic overview and meta-analysis

PURPOSE

To determine whether angiotensin II receptor antagonists prevent headaches.

METHODS

We systematically searched MEDLINE, EMBASE, the Cochrane Library, and International Pharmaceutical Abstracts for studies in which participants were randomly assigned to an angiotensin II receptor antagonist or placebo. We also contacted experts and manually reviewed all references to identify additional articles. Two reviewers independently extracted data from the studies. Discrepancies were resolved by discussion. We estimated the pooled relative risk (RR) for headache using the random-effects model and examined dose response using random-effects Bayesian logistic regression.

RESULTS

Data from 27 studies involving 12,110 patients were included in the meta-analysis. The risk of headache was about one third lower in patients taking an angiotensin II receptor antagonist than in those taking placebo (RR = 0.69; 95% confidence interval [CI]: 0.62 to 0.76; the test of heterogeneity was negative, P = 0.2). The odds ratio for having a headache per unit dose of the reference drug losartan was 0.81 (95% CI: 0.68 to 0.93).

CONCLUSION

Angiotensin II receptor antagonists appear to be effective in preventing headaches, but the mechanism of this benefit and the types of headaches that are prevented are not known. Randomized trials are warranted.

Clinical pharmacokinetics of candesartan

Candesartan cilexetil is the prodrug of candesartan, an angiotensin II type 1 (AT1) receptor antagonist. Absorbed candesartan cilexetil is completely metabolised to candesartan. Oral bioavailability is low (about 40%) because of incomplete absorption. Plasma protein binding in humans is more than 99%. The volume of distribution in healthy individuals is 0.13 L/kg. CV-15959 is the inactive metabolite of candesartan. Candesartan that reaches the systemic circulation is mainly cleared by the kidneys, and to a smaller extent by the biliary or intestinal route. The apparent oral clearance of candesartan is 0.25 L/h/kg after a single dose in healthy individuals. Oral clearance (3.4 to 28.4 L/h) is highly variable among patients. No relevant pharmacokinetic drug-food or drug-drug interactions are known. The terminal elimination half-life remains unclear, but appears to be longer than the currently used range of 4 to 9 hours. Non-compartmental models do not appear to be appropriate for the analysis of candesartan pharmacokinetic data. A 2-compartment analysis revealed a much longer half-life of 29 hours using data from patients with hypertension. However, a further indepth analysis has never been performed. The concentration-effect relationship is unaffected by age. No gender or race differences have been shown in the effect or pharmacokinetics of candesartan. Renal function affects the pharmacokinetic profile of candesartan. For patients with creatinine clearances of >60 ml/min x 1.73m(2), 30 to 60 ml/min x 1.73m(2) and 15 to 30 ml/min x 1.73m(2), the elimination half-life is 7.1, 10.0 and 15.7 hours, respectively, at a dose of 8 mg/day. However, at 12 mg/day an accumulation factor of 1.71 was found. Thus, a maximum daily dose of up to 8mg appears suitable in patients with severe renal dysfunction. No significant elimination of candesartan occurs with haemodialysis. In patients with mild to moderate hepatic impairment, no relevant pharmacokinetic alterations have been observed. Dosages of up to 12 mg/day do not require precautions in patients with mild to moderate liver disease. Clinically effective dosages range between 8 and 32 mg/day. The response rate of monotherapy with candesartan in patients with hypertension increases with dosage, but never exceeds 60% at a daily dosage of 16mg of candesartan. Dosages up to 32 mg/day do not increase this response rate.

The effects of candesartan on vascular responses to angiotensin II and norepinephrine in normal volunteers

The effects of chronic administration of candesartan, 16 mg once-daily, to normal volunteers on cardiovascular responses to angiotensin II (Ang II) and norepinephrine (NE) were examined. Fifteen healthy, non-smoking volunteers participated in a randomised, double-blind crossover study of two weeks of candesartan therapy, compared with two weeks of placebo. Blood pressure (BP) responses were measured to increasing infusion rates of intravenous Ang II and NE, along with forearm blood flow (FBF) responses into intra-brachial arterial Ang II, 2 and 24 hours after the last dose of candesartan or placebo. FBF responses to intra-brachial arterial NE were recorded approximately 2 hours following the final dose. Systolic and diastolic BP responses to intravenous infusions of Ang II during candesartan treatment were completely suppressed and significantly lower than during placebo treatment, 2 hours (candesartan 96+/-10/55+/-8 mmHg; placebo 105+/-5/64+/-8 mmHg) and 24 hours (candesartan 94+/-8/54+/-8 mmHg; placebo 103+/-7/64+/-7 mmHg) following the last dose. In contrast, FBF responses to intra-brachial arterial Ang II were significantly suppressed by candesartan compared with placebo in a subgroup of subjects 2 hours following the last dose (n=9), but not 24 hours after the last dose (n=8). FBF responses to NE were also suppressed by candesartan treatment 2 hours following the last dose, while BP responses to intravenous NE were unaltered. Chronic candesartan therapy, 16 mg once-daily effectively suppresses pressor responses to Ang II over the duration of the dosing interval.