Manidipine: a review of its use in hypertension

Bioenergetics impairment of Trypanosoma cruzi by the antihypertensive manidipine: A drug repurposing strategy

Considering the lack of effective and safe therapy for the treatment of Chagas disease, the antihypertensive drug manidipine (MDP) was in vitro evaluated against Trypanosoma cruzi. The bioenergetics of trypomastigotes was studied in the presence of the drug using fluorimetric and luminescent assays. Manidipine showed a potent antiparasitic activity, with IC₅₀ values of 0.1 μM (intracellular amastigotes) and 3 μM (trypomastigotes), resulting in a promising selectivity index against the amastigotes (>1459). Using fluorimetric analysis, the drug showed depolarisation of the electric potential of the plasma membrane with no alteration of the permeability. A decrease in ATP levels suggested a bioenergetic alteration of the mitochondria, which was confirmed by the depolarisation of the mitochondrial membrane potential and a slight increase of the ROS levels. This is the first study to show the promising in vitro effectiveness of the antihypertensive MDP against T. cruzi, which may represent a candidate for future investigations in animal models.

1,4-Dihydropyridine: A Dependable Heterocyclic Ring with the Promising and the Most Anticipable Therapeutic Effects

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Nowadays, heterocyclic compounds act as a scaffold and are the backbone of medicinal chemistry. Among all of the heterocyclic scaffolds, 1,4-Dihydropyridine (1,4-DHP) is one of the most important heterocyclic rings that possess prominent therapeutic effects in a very versatile manner and plays an important role in synthetic, medicinal, and bioorganic chemistry. The main aim of the study is to review and encompass relevant studies related to 1,4-DHP and excellent therapeutic benefits of its derivatives. An extensive review of Pubmed-Medline, Embase and Lancet’s published articles was done to find all relevant studies on the activity of 1,4-DHP and its derivatives. 1,4-DHP is a potent Voltage-Gated Calcium Channel (VGCC) antagonist derivative which acts as an anti-hypertensive, anti- anginal, anti-tumor, anti-inflammatory, anti-tubercular, anti-cancer, anti-hyperplasia, anti-mutagenic, anti-dyslipidemic, and anti-ulcer agent. From the inferences of the study, it can be concluded that the basic nucleus, 1,4-DHP which is a voltage-gated calcium ion channel blocker, acts as a base for its derivatives that possess different important therapeutic effects. There is a need of further research of this basic nucleus as it is a multifunctional moiety, on which addition of different groups can yield a better drug for its other activities such as anti-convulsant, anti-oxidant, anti-mutagenic, and anti-microbial. This review would be significant for further researches in the development of several kinds of drugs by representing successful matrix for the medicinal agents.

A Randomized, Open-Label, Crossover Phase 1 Study to Evaluate the Effects of Food on the Pharmacokinetics of a Single Oral Dose of a 15-mg Tylerdipine Tablet in Healthy Chinese Male Volunteers

Tylerdipine hydrochloride is a novel L-type and T-type dual calcium channel antagonist that has the potential effects of expanding blood vessels and lowering blood pressure. It is expected to reduce the side effect of ankle edema observed with other drugs in the same class. A randomized, open-label, crossover phase 1 study was performed to evaluate the effect of food on the bioavailability of tylerdipine. Fourteen healthy male volunteers were enrolled. The administration of tylerdipine after a high-fat meal increased the bioavailability of tylerdipine. In the fed state there was a 130% increase in the mean total systemic exposure (AUC_inf ) and a 73% increase in the mean peak plasma concentration (C_max ) compared with that in the fasting state. The geometric mean ratios (90% confidence interval) of C_max and AUC_inf were 2.54 (1.94, 3.33) and 1.75 (1.50, 2.04) for tylerdipine. The exposures of the 2 main metabolites M2 and M4 were increased by approximately 10% after a high-fat meal. The median time to peak plasma concentration of tylerdipine showed no difference between fasting and fed states.

How to Improve Effectiveness and Adherence to Antihypertensive Drug Therapy: Central Role of Dihydropyridinic Calcium Channel Blockers in Hypertension

Essential hypertension is a complex clinical condition, characterized by multiple and concomitant abnormal activation of different regulatory and contra-regulatory pathophysiological mechanisms, leading to sustained increase of blood pressure (BP) levels. Asymptomatic rise of BP may, indeed, promote development and progression of hypertension-related organ damage, which in turn, increases the risk of major cardiovascular and cerebrovascular events. A progressive and independent relationship has been demonstrated between high BP levels and increased cardiovascular risk, even in the high-to-normal range. Conversely, evidence from randomized controlled clinical trials have independently shown that lowering BP to the recommended targets reduces individual cardiovascular risk, thus improving event-free survival and reducing the incidence of hypertension-related cardiovascular events. Despite these benefits, overall rates of BP control remain poor, worldwide. Currently available guidelines support a substantial equivalence amongst various antihypertensive drug classes. However, several studies have also reported clinically relevant differences among antihypertensive drugs, in terms of both BP lowering efficacy and tolerability/safety profile. These differences should be taken into account not only when adopting first-line antihypertensive therapy, but also when titrating or modulating combination therapies, with the aim of achieving effective and sustained BP control. This review will briefly describe evidence supporting the use of dihydropyridinic calcium channel blockers for the clinical management of hypertension, with a particular focus on barnidipine. Indeed, this drug has been demonstrated to be effective, safe and well tolerated in lowering BP levels and in reducing hypertension-related organ damage, thus showing a potential key role for improving the clinical management of hypertension.

Screening of FDA-Approved Drugs for Inhibitors of Japanese Encephalitis Virus Infection

Japanese encephalitis virus (JEV), an arthropod-borne flavivirus, is a major cause of acute viral encephalitis in humans. No approved drug is available for the specific treatment of JEV infections, and the available vaccines are not effective against all clinical JEV isolates. In the study described here, a high-throughput screening of an FDA-approved drug library for inhibitors of JEV was performed. Five hit drugs that inhibited JEV infection with a selective index of >10 were identified. The antiviral activities of these five hit drugs against other flavivirus, including Zika virus, were also validated. As three of the five hit drugs were calcium inhibitors, additional types of calcium inhibitors that confirmed that calcium is essential for JEV infection, most likely during viral replication, were utilized. Adaptive mutant analysis uncovered that replacement of Q130, located in transmembrane domain 3 of the nonstructural NS4B protein, which is relatively conserved in flaviviruses, with R or K conferred JEV resistance to manidipine, a voltage-gated Ca²⁺ channel (VGCC) inhibitor, without an apparent loss of the viral growth profile. Furthermore, manidipine was indicated to protect mice against JEV-induced lethality by decreasing the viral load in the brain, while it abrogated the histopathological changes associated with JEV infection. This study provides five antiflavivirus candidates and identifies cytoplasmic calcium to be a novel antiviral target for the treatment of JEV infection. The findings reported here provide therapeutic possibilities for combating infections caused by flaviviruses.

IMPORTANCE No approved therapy for the treatment of Japanese encephalitis virus infection is currently available. Repurposing of approved drugs would accelerate the development of a therapeutic stratagem. In this study, we screened a library of FDA-approved drugs and identified five hit drugs, especially calcium inhibitors, exerting antiflavivirus activity that blocked viral replication. The in vivo efficacy and toxicity of manidipine were investigated with a mouse model of JEV infection, and the viral target was identified by generating an adaptive mutant.

Antihypertensive drugs

Successful treatment of hypertension is possible with limited side effects given the availability of multiple antihypertensive drug classes. This review describes the various pharmacological classes of antihypertensive drugs, under two major aspects: their mechanisms of action and side effects. The mechanism of action is analysed through a pharmacological approach, i.e. the molecular receptor targets, the various sites along the arterial system, and the extra-arterial sites of action, in order to better understand in which type of hypertension a given pharmacological class of antihypertensive drug is most indicated. In addition, side effects are described and explained through their pharmacological mechanisms, in order to better understand their mechanism of occurrence and in which patients drugs are contra-indicated. This review does not address the effectiveness of monotherapies in large randomized clinical trials and combination therapies, since these are the matters of other articles of the present issue. Five major pharmacological classes of antihypertensive drugs are detailed here: beta-blockers, diuretics, angiotensin converting enzyme inhibitors, angiotensin II receptor antagonists, and calcium channel blockers. Four additional pharmacological classes are described in a shorter manner: renin inhibitors, alpha-adrenergic receptor blockers, centrally acting agents, and direct acting vasodilators.

Enantioselective determination of R-(-)-manidipine and S-(+)-manidipine in human plasma by a sensitive and selective chiral LC-MS/MS assay

A sensitive and selective liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay method has been developed and validated for the enantioselective determination of manidipine in human plasma using isotope-labeled compounds as internal standards. After solid-phase extraction, R-(-)-manidipine and S-(+)-manidipine were chromatographed on a Chiralpack IC-3 C₁₈ column using a isocratic mobile phase composed of 2 mm ammonium bicarbonate and acetonitrile (15:85, v/v). The precursor ion to product ion transitions for the enantiomers and internal standards were monitored in the multiple reaction monitoring and positive ionization mode using an API-4000 mass spectrometer. The method was linear over the concentration range of 0.05-10.2 ng/mL for both enantiomers. The precision and accuracy results over five concentration levels in five different batches were well within the acceptance limits. The mean extraction recovery was >80% for both enantiomers. A variety of stability tests were executed in plasma and in neat samples, which complies with the FDA guidelines. After complete validation, the method was successfully applied to a pharmacokinetic study of a manidipine 20 mg oral dose in 10 healthy South India subjects under fasting conditions. The assay reproducibility is shown through incurred samples reanalysis of 20 subject plasma samples.

Calcium channel blockers and hypertension

Effective treatment of high blood pressure (BP) represents a key strategy for reducing the burden of hypertension-related cardiovascular and renal diseases. In spite of these well-established concepts, hypertension remains poorly controlled worldwide. In order to improve BP control in patients with hypertension, several interventions have been proposed, among which (1) preferred use of more effective, sustained, and well-tolerated antihypertensive drug aimed to ensure adherence to prescribed medications and (2) extensive use of rational, integrated, and synergistic combination therapies, even as first-line strategy, aimed to achieve the recommended BP targets. Within the possible antihypertensive drug classes currently available for the clinical management of hypertension, both in monotherapy and in combination therapy, drugs inhibiting the renin-angiotensin system and calcium channel blockers (CCBs) have demonstrated to be effective and safe in lowering BP levels and achieving the recommended BP targets with a good tolerability profile. In particular, CCBs have been one of the most widely used classes of antihypertensive agents in the last 20 years, based on their effectiveness in reducing BP levels, good tolerability, and abundant evidence on reducing cardiovascular and renal consequences of hypertension. This article provides an updated overview of the evidence supporting the use of CCBs-based antihypertensive regimen, both in monotherapy and in combination therapies with different classes of antihypertensive drugs.

Manidipine plus delapril in patients with Type 2 diabetes and hypertension: reducing cardiovascular risk and end-organ damage

In patients with hypertension and diabetes, atherothrombosis is a leading cause of morbidity and mortality, and there is now compelling evidence demonstrating that lowering elevated blood pressure (BP) is one of the most beneficial aims of therapy in this high-risk population. Indeed, major international guidelines have set a target BP goal of 130/80 mmHg in high-risk patients and recommend combination treatment with two or more drug classes to help achieve this objective. Manidipine plus delapril is a fixed-dose combination of a third-generation dihydropyridine calcium antagonist and an angiotensin-converting enzyme inhibitor, which is effective in mild-to-moderately hypertensive patients with an inadequate response to monotherapy. It is also effective in the long-term (50 weeks) management of essential hypertension. Comparative studies have demonstrated that manidipine plus delapril is as effective as enalapril plus hydrochlorothiazide (HCTZ) in patients with hypertension that is unresponsive to monotherapy, and as effective as ramipril plus HCTZ, valsartan plus HCTZ, irbesartan plus HCTZ and olmesartan plus HCTZ in patients with essential hypertension and Type 2 diabetes. In addition, manidipine plus delapril exhibited renoprotective effects in normotensive Type 2 diabetic patients, and improved fibrinolytic function (significantly more than irbesartan plus HCTZ) in hypertensive patients with Type 2 diabetes. Manidipine 10 mg plus delapril 30 mg once daily was generally well tolerated, with no unexpected adverse effects and evidence of a low incidence of ankle edema. Thus, manidipine plus delapril is a fixed-dose combination treatment that significantly reduces elevated BP with once-daily administration. It is well tolerated and has ancillary properties, such as nephroprotective activity and improvement of fibrinolytic balance, which may help reduce cardiovascular morbidity and mortality, particularly in high-risk patients, such as those with Type 2 diabetes mellitus.

Excellent tolerance to cilnidipine in hypertensives with amlodipine - induced edema

BACKGROUND

Ankle edema is a common adverse effect of amlodipine, an L-type calcium channel blocker (CCB). Cilnidipine is a newer L/N-type CCB, approved for treatment of essential hypertension.

AIM

This study was designed to determine whether cilnidipine can produce resolution of amlodipine-induced edema while maintaining adequate control of hypertension.

MATERIALS AND METHODS

A prospective study was performed on 27 patients with essential hypertension with amlodipine-induced edema. Concomitant nephropathy, cardiac failure, hepatic cirrhosis, or other causes of edema, and secondary hypertension were excluded by appropriate tests. Amlodipine therapy was substituted in all the cases with an efficacy-equivalent dose of cilnidipine. Clinical assessment of ankle edema and measurement of bilateral ankle circumference, body weight, blood pressure, and pulse rate were performed at onset of the study and after 4 weeks of cilnidipine therapy.

RESULTS

At completion of the study, edema had resolved in all the patients. There was a significant decrease in bilateral ankle circumference and body weight (P < 0.001). There was no significant change in mean arterial blood pressure and pulse rate.

CONCLUSIONS

Therapy with cilnidipine resulted in complete resolution of amlodipine-induced edema in all the cases without significant worsening of hypertension or tachycardia. Cilnidipine is an acceptable alternative antihypertensive for patients with amlodipine-induced edema.

Effect of grapefruit juice on the disposition of manidipine enantiomers in healthy subjects

AIM

To examine the effect of grapefruit juice, an inhibitor of CYP3A4 in the small intestine, on the disposition of manidipine enantiomers in healthy subjects.

METHODS

A randomized cross-over study with at least a 2-week wash-out period was performed. Seven healthy male volunteers received an oral 40-mg dose of racemic manidipine after an overnight fast with either grapefruit juice (GFJ) or water, as a control study. Plasma concentrations of (S)- and (R)-manidipine were monitored up to 10 h after the dosing.

RESULTS

The plasma concentrations of (S)-manidipine were significantly higher (P<0.001) than those of (R)-manidipine in the control phase with an S/R ratio for the AUC0-infinity of 1.62 (95% confidence interval 1.52, 1.73). GFJ significantly increased Cmax and AUC0-infinity of (S)-manidipine by 2.4-fold (P<0.01) and 2.3-fold (P<0.01), respectively, and Cmax and AUC0-infinity of (R)-manidipine were increased by 3.4-fold (P<0.01) and 3.0-fold (P<0.01), respectively. There were significant differences (P<0.01) in GFJ-mediated percentage increases in Cmax and AUC0-infinity of (S)-manidipine compared with those of (R)-manidipine. The S/R ratio for AUC0-infinity was significantly decreased from 1.6 to 1.2 during the GFJ phase (P<0.01).

CONCLUSION

These results indicate that the stereoselective disposition of manidipine was altered by GFJ, as an inhibitor of CYP3A4. GFJ appears to affect this metabolic disposal of (R)-manidipine to a greater extent than that of (S)-manidipine.

Effect of Manidipine as Compared to Atenolol on Platelet Aggregation in Elderly Patients with Isolated Systolic Hypertension and Type II Diabetes Mellitus

This study was done to evaluate the effect of treatment with manidipine as compared with atenolol on thrombin-mediated platelet aggregation in elderly patients with isolated systolic hypertension and type II diabetes mellitus. After a 2-week washout placebo period, 60 elderly patients (aged 65-80 years) with isolated systolic hypertension (SBP > 140 mm Hg and DBP < 90 mm Hg) were randomly assigned to manidipine 10 mg or atenolol 50 mg 6-week treatment according to a double-blind, crossover design. Thirty patients had a concomitant well-controlled type 2 diabetes mellitus (HbA1c < or = 6.5%). At the end of the washout and of each treatment period, blood pressure (BP) (by mercury sphygmomanometer) and platelet aggregation (by Born-type aggregometer) were evaluated. Blood samples were collected using sodium citrate as anticoagulant, and platelet aggregation was induced by 2 different concentrations of ADP and collagen. Manidipine and atenolol produced a significant BP reduction in both diabetic and nondiabetic patients, with no difference between treatments. Despite the similar BP effect, in diabetic patients manidipine produced a significant reduction in platelet aggregation induced by both doses of either ADP or collagen. In nondiabetic hypertensives, manidipine inhibited platelet aggregation only at the highest doses of both inducers. The difference in the platelet inhibitory effect of manidipine between diabetic and nondiabetic subjects was statistically significant (P < 0.05) at both inducer concentrations. No changes in platelet aggregation were observed in the atenolol group. These data indicate that, unlike atenolol, manidipine inhibits platelet aggregation in elderly hypertensive patients, expecially in those with associated type II diabetes mellitus. The clinical impact of this positive effect in terms of prevention of cardiovascular complications in these high-risk patients remains to be clarified.

Manidipine versus enalapril monotherapy in patients with hypertension and type 2 diabetes mellitus: A multicenter, randomized, double-blind, 24-week study

BACKGROUND

Blood pressure reduction is associated with a reduced risk for cardiovascular events and death, particularly in patients with both hypertension and type 2 diabetes mellitus.

OBJECTIVE

The aim of this study was to compare the antihypertensive efficacy, tolerability, and effect on metabolic risk factors of manidipine, a new dihydropyridine calcium channel antagonist, and enalapril, a widely used angiotensin-converting enzyme inhibitor, in patients with mild to moderate essential hypertension and type 2 diabetes.

METHODS

This multicenter, double-blind trial compared manidipine and enalapril in patients with type 2 diabetes and hypertension (diastolic blood pressure [DBP] 90-104 mm Hg, systolic blood pressure [SBP] < or =190 mm Hg). Following a 3-week, single-blind placebo run-in period, eligible patients were randomized to receive either manidipine 10 mg or enalapril 10 mg once daily for 24 weeks. The dose was doubled after 3 weeks in patients who had not responded to treatment (DBP > or =90 mm Hg). The primary efficacy end point was change in DBP from baseline to the end of the study. Secondary outcomes were the responder rate (DBP <90 mm Hg and/or a DBP reduction of > or =10 mm Hg) at the end of the study. Other secondary measures were changes from baseline to the end of the study in heart rate and in the following measures obtained by ambulatory blood pressure monitoring (ABPM): 24-hour, daytime, and nighttime mean DBP and SBP, and the trough:peak ratio. Blood glucose, glycosylated hemoglobin (HbA1c), total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, uric acid, and creatinine were measured at the end of the placebo run-in period and the end of treatment. The study had 80% power to detect a between-treatment difference in mean sitting DBP of >3 mm Hg.

RESULTS

One hundred twenty-four patients were enrolled in the study. After the placebo run-in period, 13 patients were excluded from the study: 4 for DBP values outside the specified limits, 7 at their request, and 2 for adverse events. Thus, 111 patients met the eligibility criteria and were randomized to treatment (53 manidipine, 58 enalapril). The population consisted of 61 men and 50 women with a mean (SD) age of 62 (11) years and a body mass index of 28.2 (2.4) kg/m2. Among patients who completed the study, drug doses were doubled in 67.6% (25/37) of patients in the manidipine group and 60.0% (24/40) of patients in the enalapril group (P = NS). Similar reductions in blood pressure were observed in both groups, from a mean (SD) of 164 (12)/97.5 (5) mm Hg at baseline to 141 (12)/84.5 (6) mm Hg at the end of the study in the manidipine group (P < 0.01), and from 159 (12)/98 (4) mm Hg to 139 (12)/86 (8) mm Hg in the enalapril group (P < 0.01). The proportion of responders was 66.7% (32/48) in the manidipine group and 60.0% (30/50) in the enalapril group; the difference between groups was not significant. Twenty-four-hour ABPM revealed significant (P < 0.01) and similar reductions in blood pressure in both groups, with a trough:peak ratio of approximately -50%. Neither drug affected heart rate. Among the statistically significant changes in metabolic parameters, significant reductions in HbA(1c) (from 6.7% [1.4%] to 6.2% [1.1%]) and blood glucose concentrations (from 152 [44] to 143 [44] mg/dL) were observed only in the manidipine group (P < 0.05). The incidence of adverse events was similar between groups.

CONCLUSIONS

In the present study, manidipine was as metabolically neutral and as effective as enalapril in reducing blood pressure in hypertensive patients with type 2 diabetes, providing a sustained 24-hour antihypertensive effect.

Effect of delapril-manidipine combination vs irbesartan-hydrochlorothiazide combination on fibrinolytic function in hypertensive patients with type II diabetes mellitus

The aim of this double-blind, double-dummy, parallel group study was to compare the effects of delapril-manidipine combination vs a irbesartan-hydrochlorothiazide combination on plasma tissue plasminogen activator (t-PA) and plasmogen activator inhibitor type I (PAI-l) activities in hypertensive patients with type II diabetes mellitus. After a 4-week run-in placebo period, 80 patients (37 male and 43 female), aged 41-65 years, were randomly allocated to an 8-week treatment with delapril 30 mg once daily or irbesartan 150 mg once daily. Thereafter, manidipine l0 mg once daily was added to delapril treatment and hydrochlorothiazide 12.5 mg to irbesartan treatment for a further 8 weeks. Blood pressure (BP), plasma t-PA and PAI-l activities were evaluated at the end of the run-in period, after 4-week monotherapy treatments, and at the end of the combination treatment periods. Both combination treatments, delapril-manidipine and irbesartan-hydrochlorothiazide, produced a greater reduction in systolic BP/diastolic BP (SBP/DBP) values (-27.6/21.8 mmHg and -26.4/20.2 mmHg, respectively) than the respective monotherapies (-15.2/11.7 mmHg with delapril and -16.3/11.3 mmHg with irbesartan). Delapril monotherapy significantly decreased plasma PAI-l activity (-10.4 IU/mI; P<0.05). The addition of manidipine produced a significant increase in t-PA activity (+0.27 IU/mI); P<0.05). Irbesartan monotherapy did not significantly affect the fibrinolytic balance, whereas the addition of hydrochlorothiazide worsened it, producing a significant increase in PAI-l activity (+9.5 IU/ml; P<0.05). In hypertensive patients with type II diabetes mellitus, the combination delapril-manidipine may determine a greater improvement of the fibrinolytic function than the respective monotherapy, while the association irbesartan-hydrochlorothiazide may worsen it.

Manidipine: a review of its use in the management of hypertension

Manidipine is a lipophilic, third-generation dihydropyridine calcium channel antagonist with a high degree of selectivity for the vasculature, thereby inducing marked peripheral vasodilation with negligible cardiodepression. In addition, manidipine does not significantly affect norepinephrine levels, suggesting a lack of sympathetic activation. It has a gradual onset of action and a long duration of action enabling once daily administration. Furthermore, manidipine dilates both the efferent and the afferent renal arterioles and appears to have beneficial renal effects unrelated to its antihypertensive effect. Once-daily oral manidipine is an effective and generally well tolerated antihypertensive agent for younger and elderly adult patients with mild-to-moderate hypertension. In particular, in a large double-blind trial, the incidence of ankle oedema was significantly lower in manidipine than in amlodipine recipients. Manidipine is also effective in hypertensive patients with comorbidities, such as type 2 diabetes mellitus and/or renal impairment, and appears to improve insulin sensitivity without affecting metabolic function. Thus, manidipine represents a first-line treatment option for patients with essential mild-to-moderate hypertension.

Therapeutic profile of manidipine and lercanidipine in hypertensive patients

Manidipine and lercanidipine are considered effective and safe in the treatment of chronic arterial hypertension and are equipotent in reducing blood pressure (BP) levels. Their main side effect is ankle-foot edema. After a 2-week placebo run-in period, these 2 drugs were compared in a controlled parallel-group study lasting 3 months, involving 53 patients with mild-to-moderate essential hypertension (26 assigned to manidipine and 27 to lercanidipine). At the end of the active treatment period, BP was significantly reduced in comparison with the end of the placebo phase in both the manidipine and the lercanidipine groups, without significant differences between the 2 drugs. Daytime BP was significantly reduced by 5.5%/5.6% with manidipine and by 3.8%/6.6% with lercanidipine, while smaller reductions were seen at nighttime. The smoothness index was the same with both drugs. Unlike lercanidipine, manidipine significantly reduced both basal (-30%) and minimal vascular resistance (-39%), qualifying it as a potent vasodilator. Despite vasodilation, heart rate was not increased but was even slightly reduced by treatment. Ankle-foot edema was observed with both drugs but was less pronounced with manidipine, probably because of greater postcapillary dilatation. In conclusion, manidipine and lercanidipine are both effective and safe in mild-to-moderate essential hypertension, although the former seems to have a more favorable tolerability profile than the latter.

Effect of manidipine on gene expression and protein level of oxidative stress-related proteins: p22phox and HO-1: relevance for antihypertensive and anti-remodeling effects

Oxidative stress (OxSt) is a major damaging factor in arterial hypertension and its long-term complications. This is why considerable attention is paid to the possible effects of antihypertensive drugs on OxSt. Manidipine is a dihydropiridine calcium channel blocker with reported nephroprotective activities, but no information is available on its effect on OxSt and related mechanisms. This study assessed the effect of manidipine on normal subjects' monocyte gene and protein expression of OxSt-related proteins such as p22(phox), a NAD(P)H oxidase system subunit, critical in generating O2-, and heme oxygenase-1 (HO-1), induced by and protective from OxSt, and compared manidipine with the ACE inhibitor captopril and the calcium channel blocker nifedipine, in the presence and absence of sodium arsenite (NaAsO2) as an inducer of OxSt.Co-incubation of manidipine with NaAsO2 dose-dependently decreased p22(phox) mRNA production from basal: 0.87 +/- 0.1 d.u., 0.69 +/- 0.06 and 0.66 +/- 0.09 at 100, 300 and 500 nM respectively versus 0.99 +/- 0.2, P < 0.04, while HO-1 mRNA production was increased by the same concentrations of the drug: 0.87 +/- 0.1 d.u., 0.92 +/- 0.1, 0.98 +/- 0.1 respectively versus 0.63 +/- 0.07; P < 0.03. Monocyte p22(phox) mRNA production was reduced both by manidipine and captopril: 0.48 +/- 0.04 d.u. and 0.43 +/- 0.08, respectively versus 0.58 +/- 0.07, P < 0.006, while no changes were induced by nifedipine (0.61 +/- 0.07, P = ns). Manidipine increased monocyte HO-1 mRNA production (1.6 +/- 0.4 versus 1.2 +/- 0.4, P < 0.008), while nifedipine and captopril showed no effect (1.2 +/- 0.3 and 1.1 +/- 0.3, respectively). The effects of M on p22(phox) and HO-1 gene expression in the presence of OxSt were also paralleled by the same effects at protein level. In conclusion, manidipine decreases p22(phox) and increases HO-1 mRNA production and protein level. The manidipine-induced increase of HO-1 gene and protein expression seems to be a peculiar effect of this drug since it is not observed with captopril and nifedipine. This effect, together with the reduction of p22(phox) mRNA production, could play a role in its protective mechanism against OxSt.