Patterns of antihypertensive therapy in new users of angiotensin II-receptor blockers

Comparison of the efficacy and safety profiles of two fixed-dose combinations of antihypertensive agents, amlodipine/benazepril versus valsartan/hydrochlorothiazide, in patients with type 2 diabetes mellitus and hypertension: a 16-week, multicenter, randomized, double-blind, noninferiority study

BACKGROUND

Hypertension is a prevalent condition that is closely associated with chronic complications in patients with diabetes. Fixed-dose combination therapy is currently recommended for the treatment of hypertension due to the advantage of reducing the pill burden. However, the effects of combination therapy may be diverse because of the different components.

OBJECTIVES

We examined blood pressure reduction and metabolic alterations after amlodipine/benazepril and valsartan/hydrochlorothiazide treatment in patients with type 2 diabetes mellitus and hypertension and microalbuminuria.

METHODS

This randomized, double-blind, parallel comparison, noninferiority clinical trial included patients with type 2 diabetes mellitus and hypertension and microalbuminuria detected within the past year. After a 2-week, placebo run-in period, patients were assigned to treatment with amlodipine/benazepril or valsartan/hydrochlorothiazide for 16 weeks. The primary end point was mean change in diastolic blood pressure. The prespecified boundary for noninferiority was 3.5 mm Hg of the mean change in diastolic blood pressure between treatments (amlodipine/benazepril minus valsartan/hydrochlorothiazide). If the upper limit of the 95% CI fell within 3.5 mm Hg, amlodipine/benazepril would be considered noninferior to valsartan/hydrochlorothiazide.

RESULTS

Of the 226 patients assessed for eligibility, 169 satisfied the inclusion/exclusion criteria and were assigned to a treatment group; 83 patients (54.2% male, mean age of 60.5 [10.0] years) in the amlodipine/benazepril group and 84 patients (64.3% male, mean age of 59.0 [10.6] years) in the valsartan/hydrochlorothiazide group received at least 1 dose of study medication and were included in the intention-to-treat population. In the per-protocol population, amlodipine/benazepril (n = 74) was noninferior to valsartan/hydrochlorothiazide (n = 78) with regard to the mean change in diastolic blood pressure (difference, -0.9 mm Hg; 95% CI, -3.5 to 1.6). The mean change in systolic blood pressure was not significantly different (2.4 mm Hg; 95% CI, -1.2 to 6.0) between study groups (P = 0.195) in the per-protocol population. However, data from the intention-to-treat population suggest that patients in the amlodipine/benazepril group may have better metabolic outcomes than those in the valsartan/hydrochlorothiazide group; specifically, a preservation of the estimated glomerular filtration rate (5.7 mL/min/1.73 m(2) [95% CI, 1.9 to 9.6]; P = 0.004) and improvements in glycosylated hemoglobin (-0.5% [95% CI, -0.7 to -0.2]; P < 0.001), fasting triglycerides (-0.4 mmol/L [95% CI, -0.7 to -0.2]; P = 0.002), HDL-C (0.07 mmol/L [95% CI, 0.01 to 0.12]; P = 0.022), and uric acid (-57.5 μmol/L [95% CI, -74.8 to -40.3]; P < 0.001). There were no significant differences in adverse effects between groups, with the exception of more respiratory disorders in the amlodipine/benazepril group than in the valsartan/hydrochlorothiazide group (17 vs 5; P = 0 .006).

CONCLUSIONS

The study results suggest that amlodipine/benazepril is noninferior to valsartan/hydrochlorothiazide with regard to blood pressure reduction and that this combination exerts beneficial effects on renal function, glucose control, HDL-C, and triglyceride levels compared with valsartan/hydrochlorothiazide. However, respiratory adverse events (particularly coughing) were more frequently reported in the amlodipine/benazepril group. ClinicalTrials.gov identifier: NCT01375322.

Clinical utility of valsartan in the treatment of hypertension in children and adolescents

Valsartan is a potent antagonist of the type 1 angiotensin receptor (AT(1)). By blocking the actions of angiotensin II on the AT(1), it inhibits vasoconstriction and synthesis of aldosterone thus lowering systemic blood pressure. Valsartan has been approved by the FDA for the treatment of hypertension in children aged 6 years and older. Valsartan can be dosed once a day with a sustained 24-hour effect on blood pressure reduction. The starting dose recommended in children is 1.3 mg/kg once daily (maximum 40 mg) which needs adjustment according to blood pressure response (dose range 1.3-2.7 mg/kg daily; up to 160 mg). A suspension form (4 mg/mL) is available for children who cannot swallow tablets. In patients aged 6 to 16 years, valsartan treatment (from a low dose of 10-20 mg to a high dose of 80-160 mg) resulted in dose-dependent reductions of 7.9-11.5 mmHg in systolic blood pressure and 4.6-7.4 mmHg in diastolic blood pressure. In 1- to 5-year-olds, valsartan (from a low dose of 5-10 mg to a high dose of 40-80 mg) reduced the systolic blood pressure by 8.4-8.6 mmHg and the diastolic blood pressure by 5.5 mmHg. Similar to adults and other antihypertensive medications, the most frequent side effect in children subsequent to valsartan use is headache. Current studies have not shown adverse effects on linear growth, weight gain, head growth, or development in children aged 1 to 5 years subsequent to valsartan use. Based on limited pediatric data, valsartan appears to be well tolerated and efficacious in reducing elevated blood pressure.

Optimizationvia experimental design of an SPE-HPLC-UV-fluorescence method for the determination of valsartan and its metabolite in human plasma samples

A chemometric approach was applied for the optimization of the extraction and separation of the antihypertensive drug valsartan and its metabolite valeryl-4-hydroxy-valsartan from human plasma samples. Due to the high number of experimental and response variables to be studied, fractional factorial design (FFD) and central composite design (CCD) were used to optimize the HPLC-UV-fluorescence method. First, the significant variables were chosen with the help of FFD; then, a CCD was run to obtain the optimal values for the significant variables. The measured responses were the corrected areas of the two analytes and the resolution between the chromatographic peaks. Separation of valsartan, its metabolite valeryl-4-hydroxy-valsartan and candesartan M1, used as internal standard, was made using an Atlantis dC18 100 mm x 3.9 mm id, 100 angstroms, 3 microm chromatographic column. The mobile phase was run in gradient elution mode and consisted of ACN with 0.025% TFA and a 5 mM phosphate buffer with 0.025% TFA at pH 2.5. The initial percentage of ACN was 32% with a stepness of 4.5%/min to reach the 50%. A flow rate of 1.30 mL/min was applied throughout the chromatographic run, and the column temperature was kept to 40+/-0.2 degrees C. In the SPE procedure, experimental design was also used in order at achieve a maximum recovery percentage and extracts free from plasma interferences. The extraction procedure for spiked human plasma samples was carried out using C8 cartridges, phosphate buffer (pH 2, 60 mM) as conditioning agent, a washing step with methanol-phosphate buffer (40:60 v/v), a drying step of 8 min, and diethyl ether as eluent. The SPE-HPLC-UV-fluorescence method developed allowed the separation and quantitation of valsartan and its metabolite from human plasma samples with an adequate resolution and a total analysis time of 1 h.