Pranidipine, a novel calcium antagonist, once daily, for the treatment of hypertension: a multicenter, double-blind, placebo-controlled dose-finding study

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.

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.

Comparative Effects of Pranidipine with Amlodipine in Rats with Heart Failure

The aim of the present study was to compare the cardioprotective properties of long-acting calcium channel antagonist pranidipine with amlodipine in rat model of heart failure induced by autoimmune myocarditis. Twenty-eight days after immunization the surviving rats were randomized for the oral administration of low-dose amlodipine (1 mg/kg/day), high-dose amlodipine (5 mg/kg/day), pranidipine (0.3 mg/kg/day) or vehicle (0.5% methylcellulose). After oral administration for 1 month, the animals underwent echocardiography and hemodynamic analysis. Histopathology, immunohistochemistry, and Western immunoblotting were carried out in the heart samples. Both pranidipine and high-dose amlodipine increased survival rate. Although the heart rate did not differ among the four groups, left ventricular end-diastolic pressure was significantly decreased and +/-dP/dt was increased in the pranidipine- and high-dose amlodipine-treated rats, but not in low-dose amlodipine-treated rats. In comparison to amlodipine treatment, pranidipine treatment significantly reduced myocyte size and central venous pressure. Furthermore, both pranidipine and high-dose amlodipine treatment significantly reduced myocardial protein levels of atrial natriuretic peptide and inducible nitric oxide synthase, whereas pranidipine only significantly decreased tumor necrosis factor-alpha, and improved sarcoplasmic reticulum Ca2+ ATPase2 protein levels. We conclude that pranidipine ameliorates the progression of left ventricular dysfunction and cardiac remodeling in rats with heart failure after autoimmune myocarditis in a lower dose when compared to amlodipine and which may be a clinically potential therapeutic agent for the treatment of heart failure.

Long-acting calcium channel antagonist pranidipine prevents ventricular remodeling after myocardial infarction in rats

The purpose of this study was to examine the effects of the long-acting calcium channel antagonist pranidipine on ventricular remodeling, systolic and diastolic cardiac function, circulating humoral factors, and cardiac mRNA expression in myocardial infarcted rats. Myocardial infarction (MI) was produced by ligation of the coronary artery in Wistar rats. Three mg/kg per day of pranidipine was randomly administered to the infarcted rats. Hemodynamic measurements, Doppler echocardiographic examinations, analyses of the plasma levels of humoral factors, and myocardial mRNA expression were performed at 4 weeks after myocardial infarction. Left ventricular end-diastolic pressure (LVEDP) and central venous pressure (CVP) increased to 24.2 +/- 1.2mmHg and 5.4 +/- 0.6 mmHg. Pranidipine reduced LVEDP and CVP to 13.6 +/- 1.4mmHg (P < 0.01) and 2.5 +/- 0.4mmHg (P < 0.01). The weight of the left and right ventricles in MI was significantly higher than in the sham-operated rats (sham, 2.02 +/- 0.04 and 0.47 +/- 0.02g/kg; MI, 2.18 +/- 0.05 and 0.79 +/- 0.04g/ kg; P < 0.01). Left ventricular end-diastolic dimension (LVDd) in MI increased to 10.3 +/- 0.3mm (P < 0.01) (sham, 6.4 +/- 0.3mm). Pranidipine prevented an increase in the weight of the left and right ventricles (2.02 +/- 0.04 and 0.6 +/- 0.03g/kg, P < 0.01) and LVDd (7.9 +/-0.2mm, P < 0.01 to MI). Plasma renin activity (PRA), and plasma epinephrine, norepinephrine, and dopamine concentrations in MI were higher than those of the sham-operated rats. Pranidipine decreased the PRA and plasma cathecolamine levels of the myocardial infarcted rats to the level of the sham-operated rats. Moreover, the rats in MI showed systolic dysfunction, shown by decreased fractional shortening (sham, 31 +/- 2% vs MI, 15 +/- 1%; P < 0.01) and diastolic dysfunction shown by the E-wave deceleration rate (sham, 12.8 +/- 1.1 m/s2; MI, 32.6 +/- 2.1 m/s2; P < 0.01). Pranidipine significantly prevented systolic and diastolic dysfunction. The increases in beta-myosin heavy chain (MHC), alpha-skeletal actin, and atrial natriuretic polypeptide mRNAs in the noninfarcted left ventricle and right ventricle at 4 weeks after the myocardial infarction were significantly suppressed by the treatment with pranidipine. On the other hand, depressed alpha-MHC was restored to normal levels by pranidipine in both regions. In conclusion, pranidipine prevents the left ventricular remodeling process accompanied by systolic and diastolic dysfunction, and inhibits abnormal cardiac gene expression after myocardial infarction.