High-dose Monotherapy Research Articles

Synergistic Protection in Lung Ischemia-Reperfusion Injury With Calcineurin and Thrombin Inhibition

Ischemia-reperfusion injury impairs lung transplant outcomes. The transcription factors, activator protein-1, and nuclear factor kappa B, are activated early in reperfusion and drive the development of injury. Thrombin inhibition with hirudin, and calcineurin inhibition with tacrolimus have independently been shown to ameliorate lung ischemia-reperfusion injury by reducing activator protein-1 and nuclear factor kappa B activation, respectively. However, high doses were required to achieve protection using individual agents, raising concerns about potential toxicities. We sought to determine if low-dose combination therapy reduced injury through synergistic inhibition of pretranscriptional signaling events. Rats were pretreated with either intravenous hirudin or tacrolimus at low doses or high doses, or both at low doses, prior to undergoing left lung ischemia and reperfusion. Lungs were assessed for markers of lung injury, including bronchoalveolar lavage cytokine-chemokine content and transcription factor transactivation of activator protein-1 and nuclear factor kappa B. High-dose monotherapy with hirudin or tacrolimus reduced lung injury and transactivation of activator protein-1 and nuclear factor kappa B activation, respectively, whereas low-dose monotherapy with either agent did not alter transcription factor activation or lung injury compared with positive controls. Low-dose combination therapy was more protective than high-dose monotherapy with either drug, and correlated with a reduction in activation of both transcription factors and their associated cytokines. The significant decrease in lung injury severity and transcription factor activation with combined pathway inhibition suggests pretranscriptional signaling redundancy between the calcineurin and thrombin dependent pathways in lung reperfusion injury.

Outcomes in paediatric metastatic rhabdomyosarcoma: Results of The International Society of Paediatric Oncology (SIOP) study MMT-98

Purpose Results are presented of the SIOP study MMT-98 for paediatric metastatic rhabdomyosarcoma (RMS), which evaluated intensive chemotherapy followed by low intensity ‘maintenance’ chemotherapy in standard risk patients (SRG). For poor risk patients (PRG), the value of a therapeutic window study, sequential high dose monotherapy to achieve a complete response (CR) followed by low dose maintenance chemotherapy was examined. Patients and methods From November 1998 to 2005, 146 patients aged 6 months to 18 years with metastatic RMS were entered. Forty-five were SRG, i.e. age < 10 years and no bone marrow or bone involvement. Treatment was a 6-drug regimen with local therapy of surgery and/or radiotherapy followed by maintenance of 9 courses of vincristine, actinomycin D and cyclophosphamide (VAC). One hundred and one patients were PRG, i.e. >10 years, or with bone marrow or bone metastases. An upfront window study, high dose monotherapy, local treatment and then VAC maintenance therapy were given. Results With a median follow-up of 1.52 years, the 3-year event-free survival (EFS) and overall survival (OS) for SRG were 54.92% and 62.14%, respectively, whilst for the PRG 16.17% and 23.17%. The corresponding adverse hazard ratio (HR) for the PRG was HR = 2.65 (95% CI 1.63–4.31, p-value < 0.001) for EFS and HR = 2.51 (CI 1.53–4.11, p-value < 0.001) for OS. Conclusion SRG patients’ EFS and OS were comparable to those of previous studies. For PRG patients there was no improvement in survival.

Enhanced antiproliferative and apoptotic response to combined treatment of γ-tocotrienol with erlotinib or gefitinib in mammary tumor cells

BackgroundAberrant ErbB receptor signaling is associated with various types of malignancies. γ-Tocotrienol is a member of the vitamin E family of compounds that displays potent anticancer activity that is associated with suppression in ErbB receptor phosphorylation and mitogenic signaling. Erlotinib and gefitinib are tyrosine kinase inhibitors that block ErbB1 receptor activation, whereas trastuzumab is a monoclonal antibody that has been designed to specifically inhibit ErbB2 receptor activation. However, the clinical effectiveness of these agents have been disappointing because of cooperation between different ErbB family members that can rescue cancer cells from agents directed against a single ErbB receptor subtype. It was hypothesized that targeting multiple ErbB receptor subtypes with combined treatment of γ-tocotrienol and ErbB receptor inhibitors would provide greater anticancer effects than monotherapy targeting only a single ErbB receptor subtype.MethodsHighly malignant mouse +SA mammary epithelial cells were maintained in culture on serum-free defined media containing 10 ng/ml EGF as a mitogen. Cell viability wase determined by MTT assay, whereas Western blot and immunofluorescent staining was used to determine treatment effects on ErbB receptor subtype level and activation. Treatment-induced apoptosis was determined using annexin V staining and Western blot analysis of cleaved caspase-3 and PARP levels.ResultsTreatment with 3.5 μM γ-tocotrienol, 0.5 μM erlotinib or 1.0 μM gefitinib alone, significantly inhibited +SA tumor cell growth. Combined treatment with subeffective doses of erlotinib (0.25 μM) or gefitinib (0.5 μM) with subeffective doses of γ-tocotrienol (0.5-3.0 μM) significantly inhibited the growth and induced apoptosis in a dose-responsive manner. Trastuzumab treatment alone or in combination had no effect on +SA cell growth and viability. Combined treatment of γ-tocotrienol with erlotinib or gefitinib also cause a large decrease in ErbB3, ErbB4, and to a lesser extent ErbB2 receptor levels, and EGF-dependent ErbB2-4 tyrosine phosphorylation (activation), but had no effect on ErbB1 receptor levels or activation.ConclusionCombination treatment of γ-tocotrienol with specific ErbB receptor inhibitors is more effective in reducing mammary tumor cell growth and viability than high dose monotherapy, suggesting that targeting multiple ErbB receptors with combination therapy may significantly improve the therapeutic response in breast cancer patients.

New Strategies and Drugs in the Treatment of Hypertension: Monotherapy or Combination?

Hypertension is one of the major risk factors associated with cardiovascular diseases. A range of blood pressure-lowering agents is available including diuretics, alpha- and beta-blockers, aldosterone antagonists, calcium-channel blockers (CCB), angiotensin-converting enzyme inhibitors (ACEI), angiotensin II receptor blockers (ARB) and direct renin inhibitors (DRI). Most patients require two or more medications to control their blood pressures within normal ranges. When high blood pressure cannot be controlled by low-dose monotherapy, physicians employ either high-dose monotherapy or combination therapy. High-dose ARB monotherapy is more effective for reducing proteinuria against low-dose ARB monotherapy or CCBs. Combination therapy is recommended for hypertension patients to facilitate prompt maintenance of blood pressure. Single-pill combination therapy simplifies treatment and optimizes long-term compliance. Thiazide diuretics such as hydrochlorothiazide (HCTZ), alone or in combination are still widely used as first-line hypertension treatment. Recent studies have shown that double (CCB+ARBs) or triple (CCB+ARBs+HCTZ) combination therapies have a greater lowering efficacy and are better tolerated. Moreover, the use of DRIs has been patented and proven effective in selected categories of hypertensive patients with or without concomitant target organ damage (TOD).

A Randomized, Comparative, Multicentric Evaluation of Atenolol/Amlodipine Combination with Atenolol Alone in Essential Hypertensive Patients

As there is a strong, positive, and continuous correlation between blood pressure and risk of cardiovascular diseases; improved control of blood pressure is necessary to produce maximum reduction in clinical cardiovascular endpoints. The primary objective was to demonstrate that atenolol/amlodipine combination therapy is superior to atenolol monotherapy with respect to mean fall in systolic blood pressure and diastolic blood pressure. The secondary objective was to compare the response rate and to evaluate the tolerability of study medications. This randomized, comparative, multicentric, 12-week study consisted of screening visit followed by baseline visit 48-hours postscreening. All enrolled patients received 7-day placebo washout. Eligible patients were randomized to receive either atenolol 25 mg/amlodipine 2.5 mg or atenolol 25 mg alone. Nonresponders after 4 weeks of therapy were escalated to atenolol 50 mg/amlodipine 5 mg or atenolol 50 mg, respectively. Out of 190 enrolled patients (94: combination group; 96: monotherapy group), 174 patients (84: combination therapy, 90: monotherapy) completed the study. After 4 weeks of therapy, low-dose combination group was superior to low-dose monotherapy with respect to mean fall in SBP (P = 0.008) and DBP (P = 0.021) and response rate (P = 0.012). Also high-dose combination therapy was superior to high-dose monotherapy with respect to mean SBP (P = 0.001), DBP (P = 0.011), and response rate (P = 0.035) at the end of 12 weeks of therapy. At the end of therapy, significantly more number of patients from combination group achieved normalization of BP (SBP < 120 mmHg and DBP < 80 mmHg) (P = 0.009). Thus, once daily treatment with atenolol/amlodipine fixed-dose combination offers superior antihypertensive efficacy over atenolol monotherapy in patients with mild-to-moderate essential hypertension.

Synergistic decrease in blood pressure by captopril combined with losartan in spontaneous hypertensive rats

This study was designed to examine the anti-hypertensive effect of the combination therapy of captopril with losartan by oral administration using both independent and cross-over experimental protocols. In independent experimental protocols, four different groups of spontaneous hypertensive rats (SHR) were treated for 1 or 2 weeks: control, captopril (20 mg/kg/day), losartan (20 mg/kg/day), and combination captopril (10 mg/kg/day) with losartan (10 mg/kg/day). In cross-over protocols, each SHR received all four treatments for 1 or 3 days with an interval of several days between each injection for washing-out and return to high blood pressure (BP) levels. BP and heart rate (HR) were measured in conscious telemetered SHR. According to the results from the independent protocol, regardless of a 1- or 2-week administration period, combination therapy with low doses of captopril and losartan had a greater anti-hypertensive effect than individual high-dose monotherapy. Similarly, results from the cross-over protocol showed that regardless of 1-day or 3-day administration, the decrease in BP in the 11(th) and 12(th) hour after administration was greatest with the combination of low-dose captopril and losartan. Therefore, combination therapy with low doses of captopril with losartan lowered BP to a greater extent than a high dose of either individual monotherapy.

Cerebellar atrophy does not increase susceptibility to carbamazepine toxicity.

Cerebellar atrophy (CA) is a frequent finding in patients with chronic epilepsy. To find out whether the existence of CA has an influence on the tolerance of high-dose monotherapy with carbamazepine, we compared the lowest individual toxic serum levels in patients with complex focal seizures, with CA (n = 27) and without CA (n = 20) in computerized tomography (CT). There was no statistical difference between the groups, even after separating patients with mild CA (n = 20) from those with more severe damage (n = 7). In addition, other clinical, EEG and CT data also seemed to have no influence on the individual toxic threshold serum levels of carbamazepine.

Abstract 1927: High-dose Simvastatin Alone Inhibits Rho Kinase and Improves Flow-mediated Vasodilatation to a Greater Extent than Combination of Low-dose Simvastatin and Ezetimibe, Despite Comparable Lipid-Lowering

Background: By inhibiting HMG-CoA reductase, statins not only inhibit cholesterol biosynthesis, but also decrease the formation of isoprenoids, which are important for mediating signaling through the Rho/Rho kinase (ROCK) pathway. In animal studies, inhibition of ROCK by statins improves endothelial function, decreases inflammation, and prevents atherosclerosis. These so-called cholesterol-independent effects of statins are dose-related and may contribute to some of their clinical benefits. We hypothesize that ezetimibe, which inhibits cholesterol absorption, does not exert these cholesterol-independent effects in humans. Methods and Results: We studied 60 dyslipidemia subjects (n=20 in each arm) in a prospective, randomized, observer-blinded study comparing treatment with simvastatin 40 mg/d or simvastatin/ezetimibe 10/10 mg/d to corresponding placebo tablets for 28 days. Prior statin usage was comparable between the groups and a washout period of 2 weeks was instituted before enrollment. Blood samples for fasting lipids, leukocyte ROCK activity and C-reactive protein (CRP) were collected at days 0 and 28. Baseline demographics, lipid levels, ROCK activity and CRP were not different between the 3 groups. Compared to placebo group, both treatment regimens decreased low-density lipoprotein cholesterol (LDL-C) by 38% and CRP by 32– 42% after 28 days (p&lt;0.001 for both compared to placebo). Although LDL-C and CRP were reduced to comparable levels by either lipid-lowering regimen (p&gt;0.05 between the groups), only simvastatin 40 mg reduced ROCK activity and improved forearm flow-mediated vasodilatation (FMD) (p&lt;0.01 for both compared to baseline). The reduction of ROCK activity with simvastatin 40 mg remained significant even after controlling for changes in LDL-C (p=0.01) and correlated with improvement in FMD (R 2 =0.78, p&lt;0.01). However, there was no correlation between changes in FMD with changes in LDL-C or CRP. Conclusions: These findings suggest that despite comparable decrease in LDL-C and CRP, high-dose statin monotherapy has greater effects on both ROCK activity and endothelial function than low-dose statin and ezetimibe. These findings provide additional evidence of potential statin benefits beyond cholesterol lowering.

Valsartan in combination with lisinopril versus the respective high dose monotherapies in hypertensive patients with microalbuminuria: the VALERIA trial

Microalbuminuria is known as an independent predictor for stroke, myocardial infarction, and death. The purpose of the VALERIA trial was a comparison of the efficacy and safety of combination therapy of valsartan and lisinopril with valsartan and lisinopril high-dose monotherapy in patients with hypertension and microalbuminuria. This was a randomized, double-blind, interventional, parallel-group study. After a washout/placebo-run-in phase of 3 weeks, 133 patients were randomized to treatment (1: 1:1) with either lisinopril 40 mg, valsartan 320 mg, or a combination of valsartan/lisinopril 320/20 mg for 30 weeks. At baseline, the urine albumin creatinine ratio was similar for the three treatment groups (geometric means, lisinopril 9.6 mg/mmol, valsartan 9.1 mg/mmol, and valsartan/lisinopril 9.5 mg/mmol). After 30 weeks of treatment, the geometric mean urine albumin creatinine ratio had decreased in all three groups by 41, 51, and 62% to 5.7 mg/mmol (lisinopril), 4.5 mg/mmol (valsartan), and 3.6 mg/mmol (valsartan/lisinopril). The decrease for valsartan/lisinopril was statistically significantly greater compared with lisinopril [adjusted ratio 60%, confidence interval (38-94%), P = 0.029]. Normalization of microalbuminuria was greatest with valsartan and valsartan/lisinopril (lisinopril 17%, valsartan 31%, and valsartan/lisinopril 38% of patients) and was statistically significant for lisinopril in contrast with valsartan/lisinopril (P = 0.034). Differences in blood pressure reduction between the groups were not statistically significant. All treatments were safe and well tolerated. The combination of valsartan and lisinopril provided a significantly better reduction of urine albumin creatinine ratio and more than doubled the rate of patients with normalized urine albumin creatinine ratio compared with lisinopril alone. All treatments were safe and well tolerated.

Statin plus ezetimibe treatment in clinical practice: the SI-SPECT (Slovenia (SI) Statin Plus Ezetimibe in Cholesterol Treatment) monitoring of clinical practice study

ABSTRACTBackground: Poor results from lipid-lowering therapy are mainly due to inadequate dosing and increased adverse effects with high-dose statin monotherapy or drug combinations.Objectives: The SI-SPECT (Slovenia (SI) Statin Plus Ezetimibe in Cholesterol Treatment) study evaluated the effectiveness of either ezetimibe (EZE) 10 mg as monotherapy or co-administered with on-going statin treatment (S + EZE) in clinical practice.Design and methods: A total of 1053 dyslipidaemic patients (52% men, age 60.3 years, 42.9% with CHD, 32.0% with diabetes mellitus and 69.6% with hypertension) were enrolled. The majority (n = 986; 93.6%) were treated with EZE as ‘add-on’ to their already prescribed statin, the rest only received EZE (n = 67).Main outcome measures: Baseline lipid levels were compared with those obtained 16 weeks after initiating treatment.Results: Total (TC) and low density lipoprotein cholesterol (LDL-C), as well as triglycerides (TG) decreased significantly with S + EZE (by 25.3%, 31.4% and 28.9%, respectively; p < 0.0001 for all comparisons), while monotherapy with EZE resulted in a decrease of 20.8% for TC ( p < 0.0001), 28.0% for LDL-C ( p < 0.0001) and 28.8% for TG ( p = 0.016). At the end of the study 43.9% of patients achieved target TC (< 5.0 mmol/L for primary prevention and < 4.5 mmol/L for secondary prevention), 50.5% target LDL-C (< 3.0 mmol/L for primary prevention and < 2.5 mmol/L for secondary prevention) and 61.6% target TG (< 2.0 mmol/L). The overall incidence of adverse effects during the treatment period, and probably related to EZE use, was low (n = 6, 0.6% of patients).Conclusions: (1) S + EZE combination therapy was effective and safe irrespective of the statin used, (2) the S + EZE combination resulted in significantly more patients reaching their recommended target lipid levels and (3) the lipid-lowering efficacy of EZE in monotherapy as well as of the S + EZE combination was related to initial lipid values. The much greater decrease of TG than expected could be, at least in part, due to better control/compliance regarding diet and drug treatment during the study and adherence to the need for an overnight fast before sampling.

High-Dose Ziprasidone Monotherapy in Bipolar I Disorder Patients With Depressed or Mixed Episodes

High-Dose Ziprasidone Monotherapy in Bipolar I Disorder Patients With Depressed or Mixed Episodes

Which Strategy Is More Effective for the Treatment of Cardiovascular Disease

Angiotensin II type 1 (AT(1)) receptor antagonists (blockers) [ARBs] are highly selective for the AT(1) receptor and block the diverse effects of angiotensin II. When high BP is not controlled by low-dose ARB monotherapy, physicians need to employ another strategy, either high-dose ARB monotherapy or combination therapy with calcium channel antagonists (blockers) [CCBs], diuretics, or other agents. High-dose ARB monotherapy is more effective for decreasing proteinuria than low-dose ARB monotherapy or CCBs. Although the ARB valsartan has been shown to prevent coronary restenosis in a clinical study (Val-PREST [Valsartan for prevention of restenosis after stenting of type B2/C lesions]), it is still unclear whether ARBs help to prevent restenosis. The results reported by Peters in this issue highlight the relative efficacies of low- (80 mg/day) and high-dose valsartan (160-320 mg/day) for the prevention of in-stent restenosis after the implantation of bare-metal stents, and suggest that high-dose valsartan can reduce the in-stent restenosis rate, target lesion revascularization and target vessel revascularization rates, late lumen loss, and major adverse cardiac events rate more effectively than low-dose valsartan. A better understanding of the differences in the efficacies of high- and low-dose ARBs could be useful in the treatment of patients with cardiovascular disease and may resolve the issue of whether ARBs prevent coronary restenosis. Clinical benefits may be induced by complete blockade of the renin-angiotensin system using high-dose ARB monotherapy. Therefore, physicians need to select a strategy carefully; i.e. either high-dose ARB monotherapy or combination therapy.

Pulse Pressure Lowering Effect of Dual Blockade With Candesartan and Lisinopril vs. High-dose ACE Inhibition in Hypertensive Type 2 Diabetic Subjects: A CALM II Study Post-hoc Analysis

Elevated pulse pressure (PP) is strongly associated with micro- and macrovascular complications in type 2 diabetic patients. We examined the effect of 12 months of dual blockade with candesartan and lisinopril vs. high-dose lisinopril monotherapy on ambulatory PP in hypertensive type 2 diabetic patients from the CALM (Candesartan and Lisinopril Microalbuminuria Trial) II study. The CALM II study was a 12-month prospective, randomized, parallel-group, double-masked study that included 75 type 1 and type 2 diabetic subjects with hypertension. Participants were randomized for treatment with either high-dose lisinopril (40 mg once daily (o.d.)) or for dual blockade treatment with candesartan (16 mg o.d.) and lisinopril (20 mg o.d.). In this article, we present data from the post-hoc subgroup of 51 type 2 diabetic subjects who completed the full 12-month study period with successful ambulatory blood pressure (BP) measurements at both baseline and follow-up visits. Baseline 24-h BP values were similar in the two groups (24-h systolic BP (SBP) 130 +/- 12 vs. 127 +/- 9, 24-h diastolic BP (DBP) 77 +/- 8 vs. 74 +/- 7, and 24-h PP 53 +/- 8 vs. 53 +/- 7 mm Hg, for the lisinopril and dual blockade groups, respectively, P > 0.2 for all). Compared with lisinopril monotherapy, dual blockade treatment caused a highly significant reduction in 24-h PP levels (-5 +/- 5 mm Hg, P = 0.003), albeit the difference in the BP lowering effect between the treatment groups did not differ significantly for 24-h systolic (P = 0.21) or diastolic (P = 0.49) BP. Dual blockade treatment significantly lowered 24-h SBP (-5 +/- 11 mm Hg, P = 0.03), but not 24-h DBP (-2 +/- 7 mm Hg, P = 0.29), whereas in the lisinopril group, the opposite effect was observed (24-h SBP -1 +/- 9 mm Hg, P = 0.45, 24-h SBP -3 +/- 7 mm Hg, P = 0.03). Twelve months of dual blockade with candesartan and lisinopril significantly reduced PP when compared with high-dose monotherapy with lisinopril. Larger studies are needed to confirm this observation, and to evaluate whether this effect translates into a greater degree of end-organ protection from dual blockade treatment than from conventional angiotensin-converting enzyme (ACE) inhibition.

Combination therapy of tyrosine kinase receptor inhibitor TSU-68 (SU6668) and paclitaxel inhibits subcutaneous xenografts of endometrial cancer

TSU-68 is a small-molecular-weight synthetic inhibitor of the tyrosine kinase receptors Flk-1/KDR, PDGFRβ and FGFR1, which are involved in angiogenesis. Using a mouse model in which endometrial cancer was subcutaneously implanted, we investigated the effects of TSU-68 alone or in combination with paclitaxel. We subcutaneously implanted a cell strain of endometrial cancer, HEC1A, into BALB/c nude mice. TSU-68 was orally administered every day, while paclitaxel was intraperitoneally injected once a week, and the rates of subcutaneous tumor proliferation were compared. In a group treated with high-dose (200 mg/kg/day) TSU-68 alone, subcutaneous tumor proliferation was significantly inhibited in comparison with a vehicle-treated control group (p<0.05). In groups treated with low-dose TSU-68 or paclitaxel alone (100 and 10 mg/kg/day, respectively), tumor proliferation was not significantly inhibited. In a low-dose combination therapy group (100 mg/kg/day of TSU-68 + 10 mg/kg/day of paclitaxel), tumor proliferation was significantly inhibited in comparison with the control and low-dose TSU-68 or paclitaxel therapy groups (p<0.01). High-dose monotherapy with TSU-68 inhibited the proliferation of the subcutaneously implanted tumor. Furthermore, a combination of TSU-68 and paclitaxel at a low dose, one at which respective monotherapy was not effective, inhibited tumor proliferation. Combination therapy with the two agents may therefore be useful for treating endometrial cancer.

Liposomal amphotericin B in combination with caspofungin for invasive aspergillosis in patients with hematologic malignancies

Invasive aspergillosis (IA) has a poor prognosis in immunocompromised patients. Combinations of drugs that act on different targets are expected to improve the clinical efficacy of separate compounds. Patients with proven or probable IA were randomized in a prospective, open pilot study to receive either a combination of liposomal amphotericin B (AmB) at the standard dose (3 mg/kg daily) and caspofungin at the standard dose or monotherapy with a high-dose AmB regimen (10 mg/kg daily). Thirty patients (21 men and 9 women) with hematologic malignancies were analyzed, and there were 15 patients in each arm. The median duration of treatment was 18 days for the combination group and 17 days for the high-dose monotherapy group. At the end of treatment, there were significantly more favorable overall responses (partial or complete responses; P = .028) in the combination group (10 of 15 patients; 67%) compared with the high-dose monotherapy group (4 of 15 patients; 27%). Survival rates at 12 weeks after inclusion were 100% and 80%, respectively. Infusion-related reactions occurred in 3 patients in the high-dose monotherapy group. A 2-fold increase in serum creatinine occurred in 4 of 17 patients (23%) who received high-dose monotherapy and 1 of 15 patient (7%) who received combination therapy; hypokalemia <3 mmol/L occurred in 3 patients and 2 patients, respectively. The combination of liposomal AmB and caspofungin was promising as therapy for IA compared with monotherapy. A trial that includes more patients will be required next to confirm the results of this pilot study.

Clinical Efficacy of High Dose Monotherapy of Oral Dihydroartemisinin in Uncomplicated Falciparum Malaria in Viet Nam

Clinical Efficacy of High Dose Monotherapy of Oral Dihydroartemisinin in Uncomplicated Falciparum Malaria in Viet Nam

Amlodipine and valsartan combined and as monotherapy in stage 2, elderly, and black hypertensive patients: subgroup analyses of 2 randomized, placebo-controlled studies.

Patients with difficult to control hypertension typically require 2 or more agents to achieve goal blood pressure (BP) levels. Fixed-dose combination therapies with lower doses generally are well tolerated and more effective than higher-dose monotherapy. The authors performed prespecified and post hoc subgroup analyses of 2 double-blind, randomized, placebo-controlled trials that assessed the efficacy and safety of amlodipine and valsartan, alone and in combination, in patients with mild to moderate hypertension. Patients were randomized to amlodipine (study 1: 2.5 or 5 mg/d; study 2: 10 mg/d), valsartan (study 1: 40, 80, 160, or 320 mg/d; study 2: 160 or 320 mg/d), combination therapy across the same dose ranges, or placebo. Analyses were performed on changes from baseline in mean sitting systolic and diastolic BP and the occurrence of adverse events in specific subgroups of patients (ie, those with stage 2 hypertension [post hoc], the elderly [65 years or older], and blacks [both prespecified]). Amlodipine + valsartan combination therapy was associated with greater BP-lowering effects in the subgroups compared with each respective monotherapy and placebo. These findings were consistent with the primary efficacy analysis results from the overall study populations. Combination regimens were generally well tolerated by all patient subgroups.

Fixed-Dose Combination Antihypertensives and Reduction in Target Organ Damage

Hypertension is a multifactorial disorder leading to pathophysiologic changes in target organs over time through diverse mechanisms. In addition, hypertension frequently resists control with monotherapy, necessitating combination therapy with two or more antihypertensive agents. Many currently available fixed-dose antihypertensive combinations combine drugs with different, but complementary, mechanisms of action to improve overall efficacy and tolerability. In addition, it is possible to select drug combinations whereby one drug offsets the negative effects of the other drug. Fixed-dose antihypertensive combinations may provide significant advantages over high-dose monotherapy, such as improved BP-lowering efficacy, reduced adverse event frequency, improved patient compliance, potentially lower treatment costs, and shorter time to BP control. Combination therapy has been recommended as potential first-line therapy in recent consensus guideline statements, especially for higher-risk patients, such as those with stage 2 hypertension. The combination of a renin-angiotensin-aldosterone system-targeting agent, such as an ACE inhibitor or angiotensin II receptor antagonist (ARB), and a diuretic or calcium channel antagonist appears to provide synergy with regard to BP lowering. In addition, ACE inhibitors and ARBs have demonstrated beneficial effects beyond BP reduction, reducing cardiovascular morbidity and mortality, inhibiting development and progression of type 2 diabetes mellitus and the progression of renal disease. Preliminary studies of fixed-dose combinations have shown reductions in left ventricular hypertrophy and improvements in markers of renal function. Additional studies currently underway will compare the effects of available fixed-dose combinations on cardiovascular morbidity and mortality, and markers of renal dysfunction.

ACE Inhibitor-Angiotensin Receptor Blocker Combinations: A Clinicians Perspective

ACE Inhibitors (ACEI) and angiotensin receptor blockers (ARB) inhibit the renin-angiotensin system, but ACEI may do so incompletely when administered as monotherapy at conventional doses. In theory, combining an ACEI and ARB might be beneficial, whereas clinical evidence for this approach in hypertension is lacking. An ACEI-ARB combination is likely to be useful in proteinuric renal disease, but recent experimental evidence suggests that very high dose monotherapy with an ARB may be the best approach. However, the results of large outcome studies for combinations vs. ACEI or ARB monotherapy are still awaited.

A Factorial Study of Combination Hypertension Treatment With Metoprolol Succinate Extended Release and Felodipine Extended Release: Results of the Metoprolol Succinate-Felodipine Antihypertension Combination Trial (M-FACT)

Many hypertensive patients require combination therapy to achieve target blood pressure (BP). beta-Blockers and dihydropyridine calcium channel blockers are effective as monotherapy in hypertensive patients and have complementary mechanisms for lowering BP. This multicenter, randomized, placebo-controlled, unbalanced factorial study included a 4- to 5-week single-blind placebo, 9-week, double-blind treatment as well as a 2-week double-blind, down-titration period. Patients (N = 1092) were randomized to one of 16 treatment groups: extended-release (ER) metoprolol succinate (25, 100, or 400 mg), ER felodipine (2.5, 10, or 20 mg), ER felodipine/ER metoprolol succinate (2.5/25, 2.5/100, 2.5/400, 10/25, 10/100, 10/400, 20/25, 20/100, or 20/400 mg), or placebo. At baseline, treatment groups were well balanced; mean sitting BP was 152.6/99.9 mm Hg. Monotherapy with ER metoprolol succinate induced dose-related reductions in sitting systolic/diastolic BP (DBP) (mean 8.1/7.7 to 9.7/11.1 mm Hg) as did ER felodipine (mean 7.7/7.7 to 14.0/11.8) and the combinations reflected additive effects (mean 13.8/11.0 to 19.8/15.2). The decline in the placebo group was 2.1/4.0 mm Hg. All combinations were more effective than their components (P < .05 for all but ER metoprolol succinate 25/ER felodipine 20). When compared with the highest doses of the individual agents (ER metoprolol succinate 400 mg; ER felodipine 20 mg), the low-dose combination ER metoprolol succinate 25/ER felodipine 2.5 was approximately as effective (differences in DBP <1 mm Hg). The most common adverse events leading to discontinuation were peripheral edema (4%), headache (2%), and fatigue (1%). Higher rates of peripheral edema and flushing were associated with high-dose ER felodipine, either alone or in combination. The antihypertensive effects of ER metoprolol succinate and ER felodipine are dose-related, and when given in combination, their BP-lowering effects are additive over a wide dose range. Low-dose combination therapy is comparable in effectiveness to high-dose monotherapy but is better tolerated.