Clinical advantage of valsartan

Transdermal delivery of angiotensin II receptor blockers (ARBs), angiotensin-converting enzyme inhibitors (ACEIs) and others for management of hypertension

CONTEXT

Angiotensin II receptor blockers (ARBs), angiotensin-converting enzyme inhibitors (ACEIs) are some of the most commonly prescribed medications for hypertension.

OBJECTIVE

Most of all conventional dosage forms of ARBs and ACEIs undergo extensive first-pass metabolism, which significantly reduces bioavailability. Majority of ARBs and ACEIs are inherently short acting due to a rapid elimination half-life. In addition, oral dosage forms of ARBs and ACEIs have many high incidences of adverse effects due to variable absorption profiles, higher frequency of administration and poor patient compliance.

METHODS

Many attempts have been made globally at the laboratory level to investigate the skin permeation and to develop transdermal therapeutic systems of various ARBs, ACEIs and other anti-hypertensives, to circumvent the drawbacks associated with their conventional dosage form.

RESULTS

This manuscript presents an outline of the transdermal research specifically in the area of ARBs, ACEIs and other anti-hypertensives reported in various pharmaceutical journals.

CONCLUSION

The transdermal delivery has gained a significant importance for systemic treatment as it is able to avoid first-pass metabolism and major fluctuations of plasma levels typical of repeated oral administration. As we can experience from this review article that transdermal delivery of different ARBs and ACEIs improves bioavailability as well as patient compliance by many folds. In fact, the rationale development of some newer ARBs, ACEIs and other anti-hypertensives transdermal systems will provide new ways of treatment, circumventing current limitations for conventional dosage forms.

Efficacy and safety of valsartan in hypertensive Taiwanese patients: post-marketing surveillance study

OBJECTIVE

To evaluate the efficacy and safety of valsartan in Taiwanese patients with essential hypertension.

METHODS

This 12-week multi-center, open-label, observational, post-marketing surveillance study enrolled 2046 hypertensive patients who were prescribed valsartan 80 or 160 mg as monotherapy or in combination with other antihypertensives based on clinical judgment. The primary endpoint was the incidence rate of dizziness with valsartan 160 mg monotherapy or combination therapy at Week 4. Secondary endpoints included the blood-pressure-lowering efficacy and the overall safety and tolerability of valsartan at Weeks 4 and 12.

RESULTS

The monotherapy and combination groups had comparable baseline characteristics. At Week 4, monotherapy was found non-inferior to combination for incidence rate of dizziness (monotherapy, 9.25%; combination, 10%; difference in incidence of dizziness, 0.75%; 95% CI - 0.61% to 2.12%; non-inferiority margin, -1.33%;WaldTest approach). Greater blood pressure (BP) reduction was noted atWeek 12 than atWeek 4.The antihypertensive effect was greater with combination therapy and the 160-mg dose. BP control (systolic <140 mmHg or diastolic <90 mmHg) was achieved in 80-90% patients.Valsartan was well tolerated; most commonly reported adverse events included dizziness, headache, constipation and cough.

CONCLUSION

Valsartan is an effective treatment option for essential hypertension in Taiwanese patients.

Evolutionary cost analysis of valsartan initiation among patients with hypertension: a time series approach

OBJECTIVES

This study examines the evolutionary impact of valsartan initiation on medical costs.

METHODS

A retrospective time series study design was used with a large, US national commercial claims database for the period of 2004-2008. Hypertensive patients who initiated valsartan between the ages of 18 and 63, and had continuous enrollment for 24-month pre-initiation period and 24-month post-initiation period were selected. Patients' monthly medical costs were calculated based on individual claims. A novel time series model was devised with monthly medical costs as its dependent variables, autoregressive integrated moving average (ARIMA) as its stochastic components, and four indicative variables as its decomposed interventional components. The number of post-initiation months before a cost-offset point was also assessed.

RESULTS

Patients (n = 18,269) had mean age of 53 at the initiation date, and 53% of them were female. The most common co-morbid conditions were dyslipidemia (52%), diabetes (24%), and hypertensive complications (17%). The time series model suggests that medical costs were increasing by approximately $10 per month (p < 0.01) before the initiation, and decreasing by approximately $6 per month (p < 0.01) after the initiation. After the 4th post-initiation month, medical costs for patients with the initiation were statistically significantly lower (p < 0.01) than forecasted medical costs for the same patients without the initiation.

LIMITATIONS

The study has its limitations in data representativeness, ability to collect unrecorded clinical conditions, treatments, and costs, as well as its generalizability to patients with different characteristics.

CONCLUSIONS

Commercially insured hypertensive patients experienced monthly medical cost increase before valsartan initiation. Based on our model, the evolutionary impact of the initiation on medical costs included a temporary cost surge, a gradual, consistent, and statistically significant cost decrease, and a cost-offset point around the 4th post-initiation month.

Captopril and losartan for mitigation of renal injury caused by single-dose total-body irradiation

It is known that angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II type-1 receptor blockers (ARBs) can be used to mitigate radiation-induced renal injury. However, for a variety of reasons, these previous results are not directly applicable to the development of agents for the mitigation of injuries caused by terrorism-related radiation exposure. As part of an effort to develop an animal model that would fit the requirements of the U.S. Food and Drug Administration (FDA) "Animal Efficacy Rule", we designed new studies which used an FDA-approved ACEI (captopril) or an FDA-approved ARB (losartan, Cozaar®) started 10 days after a single total-body irradiation (TBI) at drug doses that are equivalent (on a g/m(2)/day basis) to the doses prescribed to humans. Captopril and losartan were equally effective as mitigators, with DMFs of 1.23 and 1.21, respectively, for delaying renal failure. These studies show that radiation nephropathy in a realistic rodent model can be mitigated with relevant doses of FDA-approved agents. This lays the necessary groundwork for pivotal rodent studies under the FDA Animal Efficacy Rule and provides an outline of how the FDA-required large-animal studies could be designed.

Valsartan ingestions among adults reported to Texas poison control centers, 2000 to 2005

INTRODUCTION

Little data exist on potentially adverse valsartan ingestions reported to poison control centers.

METHODS

Using adult ingestions of valsartan reported to Texas poison control centers during 2000-2005, I determined the proportion of cases involving serious outcomes for selected variables and evaluated for statistical significance by calculating the rate ratio (RR) and 95% confidence interval (CI).

RESULTS

Thirteen (7%) of 185 total cases involved serious outcomes. Serious outcomes were significantly more likely to occur with a maximum dose 320 mg (RR 9.06, CI 1.30-100.14) or 4 tablets (RR 9.00, CI 2.07-39.11) or where the circumstances of the exposures involved self-harm or malicious intent (RR 17.28, CI 4.98-67.13).

CONCLUSIONS

The severity of the medical outcome associated with adult valsartan ingestions depended on the dose and the circumstances of the ingestion. Such information is useful for creating triage guidelines for the management of adult valsartan ingestions.

Alterations of load-induced p38 MAP kinase activation in failing rat hearts

Hemodynamic load-induced cardiac p38 mitogen-activated protein kinase (MAPK) activation was studied in normotensive control Dahl rats (n = 10) and hypertensive Dahl rats with heart failure (n = 16). The isolated heart from each animal was stretched on a Langendorff apparatus at an equivalent diastolic wall stress, and the p38-MAPK activity of the left ventricular (LV) myocardium was analyzed by immunoprecipitation-kinase assay. Compared to the control hearts, the stretch-induced p38-MAPK activities were significantly decreased, and inversely correlated with the LV diameter (r = -0.73, P < 0.01). Chronic treatment with an angiotensin II AT1-receptor antagonist, valsartan (10 mg/kg/day), ameliorated cardiac function and remodeling process in the failing hearts, which was associated with an improvement of the p38-MAPK activities. Thus, the mechano-signal transduction of p38-MAPK pathway is downregulated in the failing hearts, along with progressive ventricular remodeling. The data also suggest that the beneficial effects of the AT1-receptor antagonists are potentially mediated by the restoration of cardiac growth-related signal transduction.