A multicenter, randomized double-blind study of valsartan/hydrochlorothiazide combination versus amlodipine in patients with mild to moderate hypertension

A validated RP-HPLC method for simultaneous determination of propranolol and valsartan in bulk drug and gel formulation

Objective:

A simple, precise, and stability indicating high performance liquid chromatography (HPLC) method was developed and validated for the simultaneous determination of propranolol hydrochloride and valsartan in pharmaceutical dosage form.

Materials and Methods:

The method involves the use of easily available inexpensive laboratory reagents. The separation was achieved on Hypersil ODS C-18 column (250*4.6 mm, i.d., 5 μm particle size) with isocratic flow with UV detector. The mobile phase at a flow rate of 1.0 mL/min consisted of acetonitrile, methanol, and 0.01 M disodium hydrogen phosphate (pH 3.5) in the ratio of 50:35:15 v/v.

Results:

A linear response was observed over the concentration range 5-50 μg/mL of propranolol and the concentration range 4-32 μg/mL of valsartan. Limit of detection and limit of quantitation for propranolol were 0.27 μg/mL and 0.85 μg/mL, and for valsartan were 0.45 μg/mL and 1.39 μg/mL, respectively. The method was successfully validated in accordance to ICH guidelines acceptance criteria for linearity, accuracy, precision, specificity, robustness.

Conclusion:

The analysis concluded that the method was selective for simultaneous estimation of propranolol and valsartan can be potentially used for the estimation of these drugs in combined dosage form.

Peripheral edema associated with calcium channel blockers: incidence and withdrawal rate--a meta-analysis of randomized trials

OBJECTIVE

Peripheral edema is considered to be a common and annoying adverse effect of calcium channel blockers (CCBs). It has been thought to occur secondary to arteriolar dilatation causing intracapillary hypertension and fluid extravasation. We aimed to evaluate the incidence and withdrawal rate of peripheral edema with CCBs.

METHODS

A systematic search was made in PubMed, EMBASE and CENTRAL from 1980 to January 2011 for randomized clinical trials reporting peripheral edema with CCBs in patients with hypertension. Trials enrolling at least 100 patients in the CCB arm and lasting at least 4 weeks were included in the analysis. Both the incidence and withdrawal rate due to edema were pooled by weighing each trial by the inverse of the variance. Head-to-head comparison was done to evaluate the risk of edema between newer lipophilic dihydropyridine (DHP) CCBs and older DHPs.

RESULTS

One hundred and six studies with 99 469 participants, mean age 56 ± 6 years, satisfied our inclusion criteria and were included in this analysis. The weighted incidence of peripheral edema was significantly higher in the CCBs group when compared with controls/placebo (10.7 vs. 3.2%, P < 0.0001). Similarly, the withdrawal rate due to edema was higher in patients on CCBs compared with control/placebo (2.1 vs. 0.5%, P < 0.0001). Both the incidence of edema and patient withdrawal rate due to edema increased with the duration of therapy with CCBs reaching 24 and 5%, respectively, after 6 months. The risk of peripheral edema with lipophilic DHPs was 57% lower than with traditional DHPs (relative risk 0.43; 95% confidence interval 0.34-0.53; P < 0.0001). Incidence of peripheral edema in patients on DHPs was 12.3% compared with 3.1% with non-DHPs (P < 0.0001). Edema with high-dose CCBs (defined as more than half the usual maximal dose) was 2.8 times higher than that with low-dose CCBs (16.1 vs. 5.7%, P < 0.0001).

CONCLUSION

The incidence of peripheral edema progressively increased with duration of CCB therapy up to 6 months. Over the long term, more than 5% of patients discontinued CCBs because of this adverse effect. Edema rates were lower with both non-DHPs and lipophilic DHPs.

Efficacy and Safety of Valsartan/Hydrochlorothiazide Fixed-dose Combination Compared with Amlodipine Monotherapy as First-line Therapy for Mild to Moderate Hypertension

This double-blind, active- and randomized-controlled study compared the efficacy and safety of a fixed-dose combination of valsartan/hydrochlorothiazide 80 mg/12.5 mg once daily ( n = 32) with amlodipine monotherapy 5 mg once daily ( n = 33) for 8 weeks in patients with mild to moderate hypertension. Non-inferiority of valsartan/hydrochlorothiazide to amlodipine was demonstrated by comparable reductions in sitting systolic blood pressure (SBP), sitting diastolic blood pressure (DBP), and daytime, night-time and 24-h SBP and DBP on ambulatory blood pressure monitoring. Between-group comparisons of adverse events and changes in laboratory parameters did not reach statistical significance, except for uric acid which showed a significant increase in the valsartan/hydrochlorothiazide group compared with the amlodipine group, but was still below the laboratory's upper limit of normal. In conclusion, the use of the fixed-dose combination of valsartan/hydrochlorothiazide 80 mg/12.5 mg once daily as a starting regimen in patients with mild to moderate hypertension was shown to have non-inferior efficacy and comparable safety for daily practice compared with amlodipine 5 mg once daily monotherapy.

Valsartan/Hydrochlorothiazide

Valsartan/hydrochlorothiazide is a fixed-dose (valsartan 80, 160 or 320mg plus hydrochlorothiazide 12.5 or 25mg) angiotensin II receptor blocker/diuretic drug combination indicated for the treatment of patients with essential hypertension not adequately controlled by monotherapy.There is ample evidence that valsartan/hydrochlorothiazide is an effective fixed-dose combination antihypertensive agent. However, efficacy and tolerability data pertaining to the 320mg dose of valsartan in the combination are currently relatively few. There is also some evidence of potential benefits associated with the relatively favourable tolerability profile of the combination, the low occurrence of new-onset diabetes mellitus versus amlodipine and the valsartan-associated improvements in cardiac and endothelial function.

Valsartan improves mitochondrial function in hearts submitted to acute ischemia

The effect of valsartan, an angiotensin II-type I receptor blocker, on the mitochondrial function, was studied using an ex vivo animal model (hearts from Wistar rats), perfused in a Langendorff system and then submitted to global acute ischemia. Parameters evaluated were: membrane electrical potential (DeltaPsi, using a tetraphenylphosphonium-TPP+-electrode), oxygen consumption by the respiratory chain (Clark-type O2 electrode), phosphorylation lag phase (time necessary to phosphorylate a fixed amount of ADP) and ATP/ADP ratio (adenine nucleotides quantified by high-pressure liquid chromatography-HPLC). Valsartan acts preferentially in the phosphorylation, increasing ATP/ADP ratios (succinate: 1.6+/-0.4 versus 0.5+/-0.1--P<0.05; ascorbate/N,N,N',N'-tetramethyl-P-phenylenodiamine-TMPD: 1.1+/-0.2 versus 0.4+/-0.1--p<0.05 versus ischemia in the absence of valsartan) and decreasing lag phase (glutamate/malate: 50.0+/-9.6 s versus 127.2+/-19.03 s-84.6+/-16.2% versus 215.3+/-32.2%; P=0.01; succinate: 111.8+/-33.1 s versus 275.73+/-45.99 s-168.2+/-49.8% versus 414.9+/-69.2%; P=0.02 or ascorbate/TMPD: 11.0+/-3.9 s versus 62.4+/-11.63 s-34.9+/-12.4% versus 198.1+/-36.9%; P=0.001 versus ischemia in the absence of valsartan). This enables a higher energy production in hearts submitted to acute ischemia, for which having energy becomes critical to preserve mitochondrial function. These mechanisms allow us to better understand valsartan cytoprotection in ischemic cardiomyopathy.

Valsartan: the past, present and future

Valsartan (Diovan) is a widely use angiotensin receptor blocker that prevents angiotensin II from binding to the subtype 1 receptor. Stimulation of the subtype 1 receptor is believed to mediate many of the deleterious effects accompanied by increased angiotensin II levels. Valsartan is effective in the treatment of hypertension, alone and in combination with hydrochlorothiazide. Valsartan is similarly as effective as angiotensin-converting enzyme (ACE) blockers following myocardial infarction accompanied with left ventricular dysfunction, and/or heart failure. For the treatment of congestive heart failure with left ventricular dysfunction, valsartan offers a reduction in mortality in patients not able to tolerate an ACE inhibitor and in combination with an ACE inhibitor, valsartan reduces morbidity (hospitalization for heart failure).

Clinic blood pressure responses to two amlodipine salt formulations, adipate and besylate, in adult Korean patients with mild to moderate hypertension: A multicenter, randomized, double-blind, parallel-group, 8-week comparison

BACKGROUND

The commercially available formulation of amlodipine is conjugated with besylate salt to increase water solubility. Recently, a new amlodipine salt formulation has been developed in which the free base of amlodipine is conjugated with a chemically different salt, adipate.

OBJECTIVE

The goal of this study was to compare the antihypertensive effect and tolerability of amlodipine adipate with those of amlodipine besylate in patients with mild to moderate hypertension.

METHODS

This was a multicenter, randomized, doubleblind, parallel-group study in which patients received 8 weeks of treatment with either amlodipine adipate or amlodipine besylate. The primary efficacy variable was noninferiority of the difference in mean changes from baseline in trough diastolic blood pressure (DBP) after 8 weeks of treatment. Secondary efficacy variables included mean changes in DBP, systolic blood pressure (SBP), and response rate (defined as the proportion of patients whose DBP was <90 mm Hg or whose DBP had decreased from baseline by > or =10 mm Hg). The incidence of adverse events (AEs) was also assessed.

RESULTS

Two hundred eleven patients were randomly assigned to receive amlodipine adipate (n = 106) or amlodipine besylate (n = 105). Study patients were primarily female (54.5%), with a mean (SD) age of 52.2 (9.6) years and a mean body weight of 67.1 (10.2) kg; there were no between-group differences in demographic profiles. After 4 weeks of randomized treatment, 58 (27.5%) patients (29 [27.4%] amlodipine adipate, 29 [27.6%] amlodipine besylate) had not achieved a mean DBP <90 mm Hg, and their dose was doubled. Mean DBP changes at 8 weeks were -15.2 (7.3) mm Hg in the amlodipine adipate group and -14.2 (7.4) mm Hg in the amlodipine besylate group (P = NS). Because the 95% CI for the difference in mean DBP changes between groups (-0.53 to 2.55) was within the prespecified lower limit (-4 mm Hg), amlodipine adipate was considered noninferior to amlodipine besylate. Mean SBP changes were -24.9 (12.1) mm Hg in the amlodipine adipate group and -22.0 (14.7) mm Hg in the amlodipine besylate group (P = NS). The response rates were 92.0% for amlodipine adipate and 95.4% for amlodipine besylate (P = NS). The overall incidence of clinical AEs was 20.8% in the amlodipine adipate group and 25.7% in the amlodipine besylate group (P = NS). Drug-related clinical AEs occurred in 5.7% and 12.4% of patients in the respective treatment groups (P = NS). Serum uric acid levels decreased significantly from base-line in both groups (P < 0.001).

CONCLUSIONS

Eight weeks of treatment with amlodipine adipate produced significant reductions from baseline in blood pressure in these patients with mild to moderate hypertension. The efficacy of amlodipine adipate was not inferior to that of amlodipine besylate. Tolerability was comparable between the 2 treatment groups.

Differential time effect profiles of amlodipine, as compared to valsartan, revealed by ambulatory blood pressure monitoring, self blood pressure measurements and dose omission protocol

Amlodipine and valsartan are once-daily antihypertensive agents. To date, no comparison between these agents given as monotherapies was reported. This study was aimed to evaluate the therapeutic coverage and safety of amlodipine and valsartan in mild-to-moderate hypertensive patients. Multicenter, double-blind, randomized, comparative study. After a 4-week placebo wash-out period, 246 outpatients with office diastolic blood pressure 95 < or = DBP < or =110 mmHg and systolic blood pressure (SBP) < 180 mmHg, in addition to a mean daytime SBP and/or DBP > 135/85 mmHg on 24-h ambulatory blood pressure monitoring (ABPM), were randomly allocated to once-daily amlodipine 5-10 mg or valsartan 40-80 mg, for 12 weeks. In a subgroup of patients, 48-h ABPM were performed at the end of the treatment period. Dose omission was simulated by a single-blind placebo dosing. The primary efficacy end-point was the 24-h trough office BP after 12 weeks of active therapy. The reductions in 24-h trough BP were more pronounced in amlodipine compared with valsartan group as well in office [SBP: -17.8 +/- 10.9 vs. -14.6 +/- 11.2, P = 0.025, DBP: -12.7 +/- 7.2 vs. -10.9 +/- 7.8 mmHg, P = 0.06) as in ambulatory BP (SBP/DBP: -13.0 +/- 13.7/-10.8 +/- 9.1 vs. -7.2 +/- 19.4/-4.9 +/- 13.4 mmHg, P < 0.05). Forty-eight hours after the last active dose, the slope of the morning BP surge (4-9 h) was less steep with amlodipine vs. valsartan [DBP (P < 0.04), SBP (n.s.)]. Ankle edema were more often reported in amlodipine group. These results suggest a superior BP lowering and a longer duration of action with amlodipine compared with valsartan.

Clinical Experience With Angiotensin Receptor Blockers With Particular Reference to Valsartan

The angiotensin II receptor blockers (ARBs), are highly selective for the AT1 subtype and will block the effects of angiotensin II on peripheral vessels. Several short- and long-term studies have shown these agents to be safe and effective antihypertensive drugs. Since monotherapy of hypertension may be ineffective in lowering the blood pressure to goal, the use of an ARB, especially in combination with a diuretic or another medication, is frequently necessary to bring the blood pressure <140/90 mm Hg (<130/80 mm Hg among people with diabetes mellitus or chronic renal failure), according to JNC 7 guidelines. Besides hypertension, the ARBs have been shown to reduce left ventricular hypertrophy in hypertensive patients. Other benefits of these medications, as well as the angiotensin I converting enzyme inhibitors (ACEIs), include a decrease in cardiovascular morbidity and mortality in patients with heart failure, or hypertensive diabetic nephropathy with proteinuria. Some of the beneficial effects noted with the ACEIs and ARBs (congestive heart failure, left ventricular hypertrophy), have also been demonstrated with the use of b blockers alone and in combination with a diuretic. These drugs, i.e., b blockers, ARBs, and ACEIs, seem to exert their beneficial action through the blockade of the renin-angiotensin-aldosterone system. The role of this system in cardiovascular remodeling and its blockade will be discussed in this review, which will specifically summarize data with the ARB, valsartan.

Development of a parametric simulation model for forecasting goal-oriented treatment outcomes

BACKGROUND

Treatment-to-goal (TTG) analyses are frequently used to predict guideline-directed population control rates for drug therapies based on mean efficacy data. Nevertheless, estimates are commonly inaccurate because variability in efficacy is not considered. A new methodology was developed to improve TTG forecasting.

METHODS

Patient-level blood pressure (BP) lowering data sets, designed to simulate clinical trial results, were generated for testing from three underlying distributions: normal, lognormal, and beta. To emulate real-world conditions where patient-level data are unavailable, two approaches were considered: parametric--simulated BP lowering data were generated using the mean and standard deviation of the test data sets; and point-estimate--BP lowering was uniformly assigned as the mean lowering. BP control (systolic BP < 140 and diastolic BP < 90 mmHg) was forecasted by subtracting values generated by these two methods from baseline BP values in untreated hypertensive patients (n = 2483) from the Third National Health and Nutrition Examination Survey. Estimated control rates were compared to analyses where the patient-level data sets were bootstrapped.

RESULTS

We assumed mean (+/- SD) BP lowering of 20 (12) mmHg systolic and 14 (7) mmHg diastolic. Parametric method predicted a BP control rate of 66.9% [95% confidence interval (CI) 65.7-67.9], similar to the bootstrapping approach (67.3%, 95% CI 65.9-68.8). The control rate projected based on the point-estimate method was 75.5%. The point-estimate method frequently led to substantially different results under a wide range of model assumptions.

CONCLUSIONS

A new parametric-based forecasting method, which addresses underlying variability, improves on estimates based on mean efficacy only. In the absence of patient-level data, this method is generalizable to different therapeutic areas.

Combination therapy with ACE inhibitors/angiotensin II receptor antagonists and diuretics in hypertension

Essential hypertension is a very heterogeneous disease and different pressor mechanisms might interact to increase blood pressure. It is therefore not surprising that antihypertensive drugs, given as monotherapy, normalize blood pressure in only a fraction of hypertensive patients. This is, for instance, the case for diuretics, angiotensin converting enzyme (ACE) inhibitors and angiotensin II (AT1) receptor antagonists administered as single agents. The rationale for combining antihypertensive agents relates in part to the concept that the blood pressure-lowering effect may be enhanced when two classes are coadministered. Also, combination therapy serves to counteract counter-regulatory mechanisms that are triggered whenever pharmacologic intervention is initiated and that act to limit the efficacy of the antihypertensive medication. For example, the compensatory rise in renin secretion induced by sodium depletion may become the predominant factor sustaining high blood pressure. Simultaneous blockade of the renin-angiotensin system, with either an ACE inhibitor or an AT1-receptor blocker, makes this compensatory hyper-reninemia ineffective and allows maximum benefit from sodium depletion. The combination of a blocker of the renin-angiotensin system and a low dose of a diuretic increases the effectiveness, but not at the expense of tolerability compared with the individual components administered alone. Fixed-dose combinations containing an ACE inhibitor or an AT1-receptor blocker and a diuretic are therefore likely to become increasingly used not only as second-line therapy but also as first-line treatment.

Fixed combination therapy of hypertension: focus on valsartan/hydrochlorothiazide combination (Diovan/HCT)

Hypertension is a major risk factor for cardiovascular morbidity and mortality. Monotherapy of hypertension is often ineffective, since it controls approximately 50% of the blood pressure of hypertensive patients. For lowering blood pressure to less than 140/90 mmHg (or <130/80 mmHg among people with diabetes or chronic renal disease) according to JNC-7 guidelines, combination therapy of two or more drugs is often necessary. The combination of a diuretic with an angiotensin-converting enzyme inhibitor (ACEI) or an angiotensin receptor blocker (ARB) is effective and provides the additional benefit of blocking the effects of angiotensin II, which is responsible for cardiovascular remodeling and its complications. ARBs may have an advantage over the ACEIs because they block the action of all angiotensin II directly, whereas ACEIs are ineffective in blocking angiotensin II generated by nonclassical ACE pathways. Valsartan (Diovan, Novartis) is one of the seven currently approved ARBs in the USA for the treatment of hypertension, and it has been shown to be very effective in controlling blood pressure given once-daily in doses of 80-160 or 320 mg. Its fixed combination with hydrochlorothiazide (HCT) is even more effective in controlling blood pressure in 70% of the cases. The most commonly used combinations are valsartan/HCT (Diovan/HCT), 80/12.5 and 160/12.5 mg given once-daily.

A randomized, double-blind, active-controlled, parallel-group comparison of valsartan and amlodipine in the treatment of isolated systolic hypertension in elderly patients: the Val-Syst study

BACKGROUND

Some antihypertensive therapies are limited by dose-dependent adverse effects (AEs). The angiotensin II receptor blocker valsartan has been shown to reduce blood pressure (BP) in a dose-related manner with minimal dose-limiting AEs. Amlodipine besylate is a potent dihydropyridine calcium channel blocker also with dose-related antihypertensive efficacy, but with possible dose-limiting AEs, particularly peripheral edema.

OBJECTIVES

This study compared the risk/benefit profiles of valsartan and amlodipine in elderly patients who have isolated systolic hypertension (ISH).

METHODS

This 24-week, randomized, double-blind, active-controlled, titration-to-effect, parallel-group study was conducted at 35 outpatient centers in Italy. Elderly (aged 60-80 years) patients with ISH received oral treatment with valsartan 80-mg capsules or amlodipine 5-mg capsules once daily. After 8 weeks of treatment, the dose of the patients with poorly controlled systolic BP (SBP) was titrated to 160 mg (valsartan) or 10 mg (amlodipine) once daily. At week 16, if trough SBP was still not adequately controlled, a low-dose diuretic (hydrochlorothiazide [HCTZ] 12.5 mg) was added to the treatment regimen for an additional 8 weeks. Tolerability was assessed at all study visits using physical examination and patient interview.

RESULTS

Of 421 randomized patients (231 women, 190 men; mean [SD] age, 69 [6] years), 208 were included in the valsartan group, and 213 in the amlodipine group. The efficacy of valsartan-based treatment. in reducing SBP was similar to that of amlodipine-based treatment. With doubled doses, efficacy (change in SBP) increased significantly from baseline (both P < 0.01). The frequency of AEs doubled with amlodipine 10 mg but was not clinically relevant with valsartan 160 mg. Overall, AEs were observed in 31.9% of those receiving amlodipine versus 20.2% of the patients receiving valsartan (P < 0.003), with peripheral edema rates of 26.8% and 4.8%, respectively (P < 0.001).

CONCLUSIONS

In this study population of elderly patients with ISH, valsartan-given alone or in combination with HCTZ 12.5 mg-showed similar efficacy but better tolerability than amlodipine-based treatment.

Efficacy and Safety of Valsartan 160mg/Hydrochlorothiazide 25mg Combination in Patients with Hypertension not Adequately Controlled by Valsartan 160mg/Hydrochlorothiazide 12.5mg

BACKGROUND AND OBJECTIVE

Hypertension guidelines emphasise the need to treat high blood pressure (BP) early and aggressively, giving fixed-dose combinations special consideration. Hitherto, it has not been assessed in a sequential way whether hypertensive patients with inadequately controlled hypertension with an angiotensin II receptor antagonist/hydrochlorothiazide combination benefit from a dose increase of the diuretic. We investigated the efficacy and safety of valsartan 160mg/hydrochlorothiazide 25mg combination in patients with hypertension that was not adequately controlled by valsartan 160mg/hydrochlorothiazide 12.5mg.

PATIENTS AND METHODS

This was a multicentre, single-group, prospective study of 646 patients with moderate hypertension (diastolic BP [DBP] 100-109mm Hg). Patients were treated for 4 weeks with valsartan 160mg/hydrochlorothiazide 12.5mg (phase 1: weeks 1-4). In case of non-response (DBP >/=90mm Hg; n = 224) patients were treated for a further 4 weeks with valsartan 160mg/hydrochlorothiazide 25mg (phase 2: weeks 5-8). The primary efficacy measure was a change in mean sitting trough DBP at study end compared with the beginning of phase 2 in the intention-to-treat (ITT) population (n = 221).

RESULTS

Mean age of patients at entry was 58.6 years; 53.7% of patients were female. In phase 1, systolic BP (SBP)/DBP decreased from a baseline value of 161.9/103.3mm Hg by -16.1/-12.4mm Hg (normalisation rate 38.3%, response rate 64.5%). In phase 2, in the ITT non-responder population the additional SBP/DBP decrease was -8.4/-8.3mm Hg. Overall, the normalisation rate in all patients was 55.4% and the responder rate was 76.3%.Tolerability of both the valsartan 160mg/hydrochlorothiazide 12.5mg and the valsartan 160mg/hydrochlorothiazide 25mg combinations was very good, and the switch to the higher dose did not result in an increase in adverse events (AEs) or laboratory abnormalities. Only 16.6% of patients in phase 1 and 10.3% of patients in phase 2 experienced one or more AEs.

CONCLUSION

In patients with moderate hypertension, first-line therapy with the fixed-dose valsartan/hydrochlorothiazide combination leads to high normalisation and response rates. Patients with hypertension not controlled by valsartan 160mg/ hydrochlorothiazide 12.5mg clearly benefit from dose titration to valsartan 160mg/hydrochlorothiazide 25mg with a clinically relevant additional BP response and have excellent tolerability.

Long-acting Ca2+ blockers prevent myocardial remodeling induced by chronic NO inhibition in rats

Chronic inhibition of nitric oxide (NO) synthesis induces cardiac remodeling independent of systemic hemodynamic changes in rats. We examined whether long-acting dihydropyridine calcium channel blockers block myocardial remodeling and whether the activation of 70-kDa S6 kinase (p70S6K) and extracellular signal-regulated kinase (ERK) are involved. Ten groups of Wistar-Kyoto rats underwent 8 weeks of drug treatment consisting of a combination of NO synthase inhibitor NG-nitro-l-arginine methyl ester (L-NAME), an inactive isomer (D-NAME), amlodipine (1 or 3 mg/kg per day), or benidipine (3 or 10 mg/kg per day). In other groups, L-NAME was also used in combination with a p70S6K inhibitor (rapamycin), a MEK inhibitor (PD98059), and hydralazine. Systolic blood pressure (SBP), heart rate, and left ventricular weight (LVW) were measured, together with histological examinations and kinase assay. L-NAME increased SBP and LVW (1048+/-22 versus 780+/-18 mg, P<0.01) compared with the control, showing a significant increase in cross-sectional area of cardiomyocytes after 8 weeks. Amlodipine, benidipine, or hydralazine equally attenuated the increase in SBP induced by L-NAME. However, both amlodipine and benidipine but not hydralazine attenuated the increase in LVW by L-NAME (789+/-27, 825+/-20 mg, P<0.01, and 1118+/-29 mg, NS, respectively), also confirmed by histological analysis. L-NAME caused a 2.2-fold/1.8-fold increase in p70S6K/ERK activity in myocardium compared with the control, both of which were attenuated by both amlodipine and benidipine but not hydralazine. Both rapamycin and PD98059 attenuated cardiac hypertrophy in this model. Thus, long-acting dihydropyridine calcium channel blockers inhibited cardiac hypertrophy induced by chronic inhibition of NO synthesis by inhibiting both p70S6K and ERK in vivo.

Vascular and cardiac benefits of angiotensin receptor blockers

Angiotensin II not only is a vasoconstrictor, but it also affects cell growth and apoptosis, inflammation, fibrosis, and coagulation. Blockade of the renin-angiotensin system, either with inhibitors of the generation of angiotensin (angiotensin-converting enzyme [ACE] inhibitors) or with blockers of angiotensin receptors, reduces blood pressure and inhibits other pathophysiological actions. These other effects provide benefits in coronary heart disease, heart failure, diabetic nephropathy, and stroke beyond blood pressure reduction. These benefits were first demonstrated with ACE inhibitors. However, the mechanism of action of angiotensin receptor blockers, which block angiotensin II stimulation at the angiotensin type 1 receptor but not at the type 2 receptor, may have advantages, particularly for endothelial dysfunction and vascular remodeling, as well as cardiac and renal protection. Recent multicenter trials suggest that ACE inhibitors and angiotensin receptor blockers may reduce morbidity and mortality associated with cardiovascular and renal disease beyond blood pressure reduction. Several studies with different angiotensin receptor blockers, including comparisons with ACE inhibitors, are under way, and should provide further guidance for their clinical use.