Efficacy of methylene blue in a murine model of amlodipine overdose

INTRODUCTION

Amlodipine overdoses have significant cardiac toxicity and are difficult to treat. Methylene blue has potential as a treatment for overdoses.

METHODS

A randomized controlled study of methylene blue as a treatment for amlodipine toxicity was conducted in C57Bl/6 mice. A baseline echocardiography was followed by gavage administration of amlodipine (90 mg/kg). Five minutes after gavage, animals received either vehicle solution (controls) or methylene blue (20 mg/kg) by intra-peritoneal injection. Animals were continuously monitored, and cardiac parameters were acquired every 15 min up to two hours.

RESULTS

Only 50% of control animals survived to the two-hour endpoint compared to 83% that received methylene blue. Amlodipine delivery induced significant reduction in left ventricular ejection fraction (EF), fractional shortening (FS), stroke volume (SV), and cardiac output (CO) in the vehicle treated animals relative to animals in the treatment group (p < 0.05 vehicle versus Methylene blue for EF, FS, SV, CO, and HR).

DISCUSSION

The amlodipine dose induced cardiotoxicity that were effects were more pronounced in the untreated group. 50% vehicle controls quickly progressed into heart failure (within 90 min of exposure) and did not survive the two h observation endpoint. Distinctly, only one animal from the Methylene blue treatment group did not survive (83% survival) the study. Additionally, the surviving animals from the Methylene blue group displayed significantly higher ejection fraction, fractional shortening, stroke volume, and cardiac output compared to vehicle group, indicating that methylene blue preserved cardiac function.

CONCLUSION

In this mouse model of amlodipine overdose, methylene blue decreased cardiac toxicity.

Development and Validation of an HPLC Method Using an Experimental Design for Analysis of Amlodipine Besylate and Enalapril Maleate in a Fixed-dose Combination

Objectives

The aim of this study was to develop and optimize a simple, cost-effective, and robust high-performance liquid chromatography (HPLC) method by taking an experimental design approach to the assay and dissolution analysis of amlodipine besylate and enalapril maleate from a fixed-dose combination tablet.

Materials and Methods

The chromatographic analysis was performed on a C18 column (4.6x250 mm id., particle size of 5 μm). The injection volume was 5 μL, and the detection wavelength was 215 nm. A Box-Behnken design was used to test the robustness of the method. The flow rate (1, 1.2, and 1.4 mL/min), column temperature (25°C, 30°C, and 35°C), methanol ratio of the mobile phase (5, 10, and 15%), and pH of the mobile phase (2.8, 3, and 3.2) were selected as independent variables. The method was validated according to International Conference on Harmonization guidelines. Dissolution of the tablets was performed by using USP apparatus 2 and analyzed using the optimized HPLC method. Multivariate linear regression analysis and ANOVA were used in the statistical evaluation.

Results

Linear models were fitted for all variables. The flow rate was the most significant factor affecting the APIs' concentrations. The optimized method included the following parameters: Column temperature of 25°C, 10% methanol as the mobile phase, pH of 2.95, and flow rate of 1.205 mL/min. Retention times were 3.8 min and 7.9 min for enalapril and amlodipine, respectively. The method was found to be linear in the range of 0.8-24 μg/mL (R² >0.999) and 1.6-48 μg/mL (R² >0.999) for amlodipine and enalapril, respectively. Both APIs were dissolved more than 85% within 10 min.

Conclusion

The experimental design was proved as a useful tool for the determination and separation of enalapril maleate and amlodipine besylate in dosage forms. The optimized method can be used for in vitro performance and quality control tests of fixed-dose tablet combinations containing enalapril maleate and amlodipine besylate.

Effectiveness and Effect on Renal Parameters of Amlodipine vs. Other Dihydropyridine Calcium Channel Blockers in Patients with Essential Hypertension: Retrospective Observational Study Based on Real-World Evidence from Electronic Medical Records

Introduction

The renoprotective effects of dihydropyridine calcium channel blockers (CCBs) have been established as non-inferior to other classes of antihypertensive drugs. Studying their effect on renal outcome parameters, specifically for amlodipine as monotherapy, in real-world settings can further help in expanding its usage among Indian patients. This study was performed to assess the effects of amlodipine and other dihydropyridine CCBs (cilnidipine, benidipine and azelnidipine) on renal parameters and effectiveness in blood pressure reduction in Indian patients.

Methods

The retrospective data of adult patients (> 18 years) with essential hypertensive who were prescribed amlodipine (n = 92), cilnidipine (n = 91), benidipine (n = 70) or azelnidipine (n = 71) as monotherapy were analyzed. The renal outcomes, serum creatinine, estimated glomerular filtration rate (eGFR), blood urea nitrogen (BUN), microalbumin, urine albumin-to-creatinine ratio (UACR), sodium and potassium levels, and mean changes in BP were analyzed from baseline to 12 months. Appropriate statistical methods were used to determine the significance (p value < 0.05).

Results

From baseline to the end of the study, mean serum creatinine changed from 0.98 ± 0.17 to 1.07 ± 0.28 mg/dL with amlodipine, 0.97 ± 0.18 to 1.13 ± 0.50 mg/dL with cilnidipine, 0.98 ± 0.30 to 0.97 ± 0.27 mg/dL wi th benidipine, and 0.99 ± 0.23 to 0.98 ± 0.25 mg/dL with azelnidipine (p = 0.01). The mean microalbumin and UACR were reduced from baseline to the end of the study (p = 0.06 and p > 0.05). No significant changes were observed in BUN, sodium or potassium levels. Overall, for all CCBs, the mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) values were reduced from baseline to the end of the study (p = 0.002). At the end of the study, the average dose of amlodipine was 7.25 mg, and the average reduction in SBP and DBP per mg dose was 1.54 and 0.57 mmHg. The corresponding numbers for the other CCBs were as follows: cilnidipine, 14.28 mg, 0.26 and 0.01; benidipine, 5.71 mg, 0.41 and 0.11; azelnidipine, 15.88 mg, 0.13 and 0.06.

Conclusion

Amlodipine and other CCBs demonstrated good efficacy and similar effects on renal parameters from baseline to end of study. Amlodipine also showed higher potency by demonstrating greater BP reduction at a lower dose. Thus, amlodipine can remain a preferred choice among CCBs, even with the advent of the newer CCBs.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40119-021-00224-8.

Hypertension in Pheochromocytoma and Paraganglioma: Evaluation and Management in Pediatric Patients

PURPOSE OF REVIEW

The rare catecholamine-secreting tumors, pheochromocytomas and paragangliomas (PPGL), account for a minority of cases of secondary hypertension in pediatrics. As such, perioperative blood pressure (BP) management in pediatric patients presents a distinct challenge. This review will expand the practitioner's knowledge of antihypertensive treatment options for the pediatric patient with PPGL with a focus on literature in the past several years.

RECENT FINDINGS

There continue to be only small case series and single-center experiences to provide guidelines regarding BP management. While phenoxybenzamine has been more routinely used, selective α₁-blockers, such as doxazosin, as well as calcium channel blockers, have also been utilized with success in pediatric patients. While the concept of obligatory α-adrenergic blockade for adult patients has been recently challenged, international guidelines and current practice patterns among pediatric clinicians continue to support preoperative α-adrenergic blockade to ensure the best possible patient outcomes. Selective α₁-blockers and calcium channel blockers are becoming more commonly used given the high cost, limited availability, and undesirable side effect profile of phenoxybenzamine.

Fixed-dose combination amlodipine-celecoxib for treatment of hypertension and osteoarthritis pain: an up-to-date evaluation

Introduction: A fixed-dose combination of amlodipine and celecoxib, branded in the USA as Consensi®, was recently granted a US Food and Drug Administration (FDA)-approved indication for treatment of comorbid hypertension and osteoarthritis.Areas covered: A PubMed and Medline search was conducted for clinical trials published through December 2020 in the English language using keywords amlodipine, celecoxib, combination product, consensi, hypertension, osteoarthritis, and pill burden. Although no clinical trials have been published in the peer-reviewed literature, results from two phase 3 clinical trials reported to ClinicalTrials.gov suggest that amlodipine-celecoxib has similar short-term efficacy compared with amlodipine alone in reducing blood pressure and a comparable adverse event profile to the individual components administered alone.Expert opinion: Despite the pill burden reduction and a body of evidence supporting the efficacy and safety of the individual drugs, the role of amlodipine-celecoxib in the management of patients with hypertension-osteoarthritis remains in question. This is in no small part because the combination product is very costly relative to the generic components, provides limited flexibility for dose-adjustment, and lacks long-term data on safety and efficacy.

Cardioprotective Effects of Mebudipine in a Rat Model of Doxorubicin-Induced Heart Failure

Background

Mebudipine, a dihydropyridine calcium-channel blocker (CCB), shows greater time- and voltage-dependent inhibitory effects than nifedipine. Its significant negative chronotropic effects without having considerable negative inotropic properties may make it a suitable candidate for the pharmacotherapy of heart failure (HF). This study aimed to investigate the possible beneficial action of mebudipine in a rat model of HF.

Methods

The present study carried out in the Department of Pharmacology at the Iran University of Medical Sciences during the years of 2009-2011. An experimental model of HF was induced in male Wistar rats using doxorubicin (DOX). The rats were divided into five groups with seven animals in each group: normal control group, DOX-induced HF control groups, and treatment groups. The animals were administered DOX for 15 days. A consistent deterioration occurred after a four-week rest period. The animals were then treated with intraperitoneal mebudipine (0.5 mg/kg) and intraperitoneal amlodipine (0.35 mg/kg), as well as an equal volume of distilled water for 15 days. The plasma levels of big endothelin-1 (BET-1), creatine kinase-myocardial band (CK-MB), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), and alanine aminotransferase (ALT), as well as the clinical status (heart rate and blood pressure), were assessed before and after treatment. Statistical analysis was performed with SPSS software using parametric and nonparametric ANOVA.

Results

Mebudipine and amlodipine reversed the increased plasma BET-1 values in the treated animals when compared with the HF control group (0.103 and 0.112 vs 0.231 pg/mL, respectively). The increased plasma levels of AST, ALT, CK-MB, and LDH were also reversed in the HF animals that received mebudipine or amlodipine.

Conclusion

The administration of mebudipine to HF animals, akin to amlodipine, palliated the clinical and biochemical signs of the disease in the present study. The abstract was presented in the Iranian Congress of Physiology and Pharmacology as a poster and published in the Scientific Information Database as a supplement (2015; Vol 22).

Pharmacokinetic comparison between a fixed-dose combination of fimasartan/amlodipine/hydrochlorothiazide 60/10/25 mg and a corresponding loose combination of fimasartan/amlodipine 60/25 mg and hydrochlorothiazide 25 mg in healthy subjects

For the treatment of hypertension, fixed-dose combinations (FDCs) of antihypertensive drugs can provide complementary benefits from improved compliance and cost-effectiveness compared with loose combinations of corresponding drugs. A new FDC of fimasartan/amlodipine/hydrochlorothiazide 60/10/25 mg is undergoing clinical development. A randomized, open-label, single-dose, 3-period, 3-sequence, partially replicated crossover phase 1 study was conducted to compare the pharmacokinetics (PKs) between the FDC of fimasartan/amlodipine/hydrochlorothiazide 60/10/25 mg and a loose combination of a dual-combination FDC (fimasartan/amlodipine 60/10 mg) and hydrochlorothiazide 25 mg. Sixty healthy subjects were randomized, and 55 subjects completed the study. Serial blood samples were collected, and plasma concentrations of fimasartan, amlodipine and hydrochlorothiazide were measured to analyze PK parameters. The PK profiles of the FDC were similar to those of the loose combinations. The geometric mean ratios (GMRs) and 90% confidence intervals (CIs) of the FDC to loose combinations for the maximum plasma concentration (C_max) and area under the curve until the last measurable time point (AUC_last) were within the conventional bioequivalent range of 0.80 to 1.25. The GMRs and 90% CIs of fimasartan, amlodipine and hydrochlorothiazide were 1.0163 (0.8681–1.1898), 0.9595 (0.9256–0.9946), and 1.1294 (1.0791–1.1821) for C_max and 1.0167 (0.9347–1.1059), 0.9575 (0.9317–0.9841), and 1.0561 (1.0170–1.0967) for AUC_last, respectively. Both the FDC and loose combinations were well tolerated. In conclusion, the FDC of fimasartan/amlodipine/hydrochlorothiazide 60/10/25 mg showed similar PK profiles to those of the corresponding loose combination, and both treatments were well tolerated.

Perindopril/amlodipine-induced thrombotic microangiopathy

This is the first report on a case of perindopril/amlodipine-induced thrombotic microangiopathy (TMA) syndrome. A 48-year-old female was admitted complaining of nettle rash all over the body, bloody urine, and weakness shortly after starting antihypertensive therapy with perindopril/amlodipine. Shortly thereafter, she developed pronounced hemiparesis, somnolence, and sensorimotor aphasia. Laboratory findings were compatible with microangiopathic hemolytic anemia and thrombocytopenia. She was diagnosed with TMA. Cessation of perindopril/amlodipine therapy and treatment with plasma exchange and systemic corticosteroids resulted in full recovery. Very seldom perindopril/amlodipine may cause hematologic abnormalities, probably through an immunological mechanism, but there were no reports of causing TMA so far. In our case, the symptoms began shortly after the start of perindopril/amlodipine use. The clinical course of TMA in the case was compatible with TMA related to an acute, immune-mediated drug reaction. The most important thing is to promptly recognize TMA and its induction by a drug because distinctive treatment and cessation of the suspected drug can prevent severe outcome, as it was avoided in our patient.

Differential effects on out-of-hospital cardiac arrest of dihydropyridines: real-world data from population-based cohorts across two European countries

AIMS

Various drugs increase the risk of out-of-hospital cardiac arrest (OHCA) in the general population by impacting cardiac ion channels, thereby causing ventricular tachycardia/fibrillation (VT/VF). Dihydropyridines block L-type calcium channels, but their association with OHCA risk is unknown. We aimed to study whether nifedipine and/or amlodipine, often-used dihydropyridines, are associated with increased OHCA risk, and how these drugs impact on cardiac electrophysiology.

METHODS AND RESULTS

We conducted a case-control study with VT/VF-documented OHCA cases with presumed cardiac cause from ongoing population-based OHCA registries in the Netherlands and Denmark, and age/sex/index date-matched non-OHCA controls (Netherlands: PHARMO Database Network, Denmark: Danish Civil Registration System). We included 2503 OHCA cases, 10 543 non-OHCA controls in Netherlands, and 8101 OHCA cases, 40 505 non-OHCA controls in Denmark. To examine drug effects on cardiac electrophysiology, we performed single-cell patch-clamp studies in human-induced pluripotent stem cell-derived cardiomyocytes. Use of high-dose nifedipine (≥60 mg/day), but not low-dose nifedipine (<60 mg/day) or amlodipine (any-dose), was associated with higher OHCA risk than non-use of dihydropyridines [Netherlands: adjusted odds ratios (ORadj) 1.45 (95% confidence interval 1.02-2.07), Denmark: 1.96 (1.18-3.25)] or use of amlodipine [Netherlands: 2.31 (1.54-3.47), Denmark: 2.20 (1.32-3.67)]. Out-of-hospital cardiac arrest risk of (high-dose) nifedipine use was not further increased in patients using nitrates, or with a history of ischaemic heart disease. Nifedipine and amlodipine blocked L-type calcium channels at similar concentrations, but, at clinically used concentrations, nifedipine caused more L-type calcium current block, resulting in more action potential shortening.

CONCLUSION

High-dose nifedipine, but not low-dose nifedipine or any-dose amlodipine, is associated with increased OHCA risk in the general population. Careful titration of nifedipine dose should be considered.

Population pharmacokinetic modelling to quantify the magnitude of drug-drug interactions between amlodipine and antiretroviral drugs

PURPOSE

Drug-drug interactions (DDIs) with antiretroviral drugs (ARVs) represent an important issue in elderly people living with HIV (PLWH). Amlodipine is a commonly prescribed antihypertensive drug metabolized by CYP3A4, thus predisposed to a risk of DDIs. Guidance on the management of DDIs is mostly based on theoretical considerations derived from coadministration with other CYP3A4 inhibitors. This study aimed at characterizing the magnitude of DDIs between amlodipine and ARV drugs in order to establish dosing recommendations.

METHODS

A population pharmacokinetic analysis was developed using non-linear mixed effect modelling (NONMEM) and included 163 amlodipine concentrations from 55 PLWH. Various structural and error models were compared to characterize optimally the concentration-time profile of amlodipine. Demographic and clinical characteristics as well as comedications were tested as potential influential covariates. Model-based simulations were performed to compare amlodipine exposure (i.e. area under the curve, AUC) between coadministered ARV drugs.

RESULTS

Amlodipine concentration-time profile was best described using a one-compartment model with first-order absorption and a lag-time. Amlodipine apparent clearance was influenced by both CYP3A4 inhibitors and efavirenz (CYP3A4 inducer). Model-based simulations revealed that amlodipine AUC increased by 96% when coadministered with CYP3A4 inhibitors, while efavirenz decreased drug exposure by 59%.

CONCLUSION

Coadministered ARV drugs significantly impact amlodipine disposition in PLWH. Clinicians should adjust amlodipine dosage accordingly, by halving the dosage in PLWH receiving ARV with inhibitory properties (mainly ritonavir-boosted darunavir), whereas they should double amlodipine doses when coadministering it with efavirenz, under appropriate monitoring of clinical response and tolerance.

Calcium Channel Blockers in Conjunction with Standard Iron-Chelating Agents for β-Thalassemia Major: Systematic Literature Search

Thalassemia is a genetic mutation of the α- or β-globin chains that lead to defective erythropoiesis. This study aimed to collect evidences from all published studies that investigated the clinical effectiveness of calcium channel blockers (CCBs) in conjunction with chelation therapy for reducing iron overload in patients with thalassemia. A systematic search was conducted in PubMed, Institute for Scientific Information (ISI) Web of Science, Scopus, Cochrane Central Register of Controlled Trials, and Virtual Health Library. Original studies reporting the use of CCBs in patients with thalassemia were included for meta-analysis. A total of five randomized studies including 210 patients were included with a follow-up period of 3-12 months. There was no significant difference between amlodipine and control groups in increasing the heart T2* magnetic resonance imaging (MRI) [mean difference (MD) 95% confidence interval (95% CI) = -1.9 (-4.4 to 0.5), p = 0.119] or reducing the liver iron concentration [MD 95% CI = -0.046 (-0.325 to 0.2), p = 0.746]. Although there were no serious adverse events reported in the included trials, further studies are recommended to strengthen our findings.

Smart UV spectrophotometric methods based on simple mathematical filtration for the simultaneous determination of celecoxib and ramipril in their pharmaceutical mixtures with amlodipine: A comparative statistical study

Two newly introduced pharmaceutical mixtures of amlodipine/celecoxib and amlodipine/ramipril were developed to manage hypertension and the associated osteoarthritis. The current work presents three newly developed UV spectrophotometric methods depending on minimal mathematical manipulations on the zero-order spectrum namely: absorption correction, induced dual-wavelength, and Fourier self deconvoluted method; for the simultaneous determination of celecoxib and ramipril in their pharmaceutical combined dosage forms with amlodipine. In absorption correction and induced dual-wavelength method, celecoxib and ramipril were determined at 253 and 222 nm for absorption correction and (251-270 nm) and (222-230 nm) for induced dual-wavelength method, respectively from the zero-order spectrum after calculating the absorption correction and equality factors for amlodipine. Amlodipine itself was determined at 361 nm from the zero-order spectrum in both methods. In Fourier self deconvoluted method, celecoxib and amlodipine zero-order spectra were deconvoluted, using the spectrophotometer software built-in Fourier wavelet function, and then was determined at 360 and 269 nm, respectively. The proposed methods were simple, accurate, and sensitive requiring minimal mathematical manipulations saving the time needed for analysis. The methods were linear over the range of (5-60 μg/ml), (5-30 μg/ml), and (5-110 μg/ml) for each of amlodipine, celecoxib, and ramipril, respectively. The limit of detection was in the range of (0.5781-0.7132 μg/ml) for amlodipine, (0.6497-1.0450 μg/ml) for celecoxib, and (0.0001-0.0003 μg/ml) for ramipril that indicated the sensitivity of these suggested methods. All methods were validated as per ICH recommendations regarding linearity, range, accuracy, precision, and selectivity. A statistical comparative study executed for the proposed methods with each other and with the reported methods showed no significant difference between the proposed methods and the reported methods.

Bioequivalence of levamlodipine besylate tablets in healthy Chinese subjects: a single-dose and two-period crossover randomized study

Background

Levamlodipine, a calcium channel blocker, has been show act as a cardiovascular drug. To compare the pharmacokinetic parameters between levamlodipine (test formulation) at a single dose of 5 mg and amlodipine (reference formulation) at a single dose of 10 mg, the bioequivalence study was carried out.

Methods

A single-dose randomized, open-label, two-period crossover study was designed in healthy Chinese subjects. 48 subjects were divided into fasted and fed groups equally. The subjects randomly received the test or reference formulations at the rate of 1:1. Following a 21-day washout period, the alternative formulations were received. The blood samples were collected at 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 24, 36, 48, 72, 96, 120, 144, 168 h later. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was applied to determine the plasma concentrations of levamlodipine. Adverse events were recorded.

Results

The 90% confidence intervals (CIs) of the ratio of geometric means (GMRs) of C_max, AUC_0-t, and AUC_0-∞ under both fasted and fed conditions were within the prespecified bioequivalence limits between 80 ~ 125%. Under fasted conditions, 24 subjects were enrolled and completed the study. The mean C_max was (2.70 ± 0.49) ng/mL, AUC_0-t was (141.32 ± 36.24) ng × h/mL and AUC_0-∞ was (157.14 ± 45.65) ng × h/mL after a single dose of 5 mg levamlodipine. The mean C_max was (2.83 ± 0.52) ng/mL, AUC_0-t was (153.62 ± 33.96) ng × h/mL and AUC_0-∞ was (173.05 ± 41.78) ng × h/mL after a single dose of 10 mg amlodipine. Under fed conditions, 24 subjects were enrolled and completed the study. The mean C_max was (2.73 ± 0.55) ng/mL, AUC_0-t was (166.93 ± 49.96) ng × h/mL and AUC_0-∞ was (190.99 ± 70.89) ng × h/mL after a single dose of 5 mg levamlodipine. The mean C_max was (2.87 ± 0.81) ng/mL AUC_0-t was (165.46 ± 43.58) ng × h/mL and AUC_0-∞ was (189.51 ± 64.70) ng × h/mL after a single dose of 10 mg amlodipine. Serious adverse event was not observed.

Conclusion

The trial confirmed that levamlodipine at a single dose of 5 mg and amlodipine at a single dose of 10 mg were bioequivalent under both fasted condition and fed condition.

Trial registration

Cinicaltrials, NCT04411875. Registered 3 June 2020 - Retrospectively registered

Supplementary Information

The online version contains supplementary material available at 10.1186/s40360-020-00459-6.

Postmortem fatal and non-fatal concentrations of amlodipine

Amlodipine is a dihydropyridine calcium channel blocker widely used in the treatment of high blood pressure and coronary heart disease. Intoxication can lead to reflex tachycardia following massive hypotension and death. The objective of this work was to study the post-mortem concentrations of amlodipine in 62 patients in order to determine whether the use of the reference concentrations from the living patients was applicable in postmortem setting, and to define more precisely the fatal and non-fatal postmortem concentrations of amlodipine. The amlodipine concentrations were measured in femoral whole blood by LC-MS/MS validated method. When sufficient information was available, the data were classified into 2 different groups, based on the conclusions of the autopsy and toxicological results: G1: non-toxic death and G2: fatal poisoning involving amlodipine alone or as part of a multidrug poisoning. The median concentration of amlodipine [1st quartile - 3rd quartile] of the whole population (n = 62) was 81 [42-134] ng/mL. Twenty-two cases were classified as G1 and thirteen as G2. The observed median [1st quartile - 3rd quartile] concentration of amlodipine was 66 [40.5-79.5] ng/mL in G1 and 240 [170-404] ng/mL in G2. The median concentrations observed in "non-toxic" deaths (66 ng/mL) were three times higher than those usually observed in living patients. Amlodipine distribution ratio between plasma and whole blood concentrations seems insufficient to explain this difference and postmortem redistribution from organs should be considered, and could suggest the same redistribution pattern for other drugs belonging to the same family.

Amlodipine alleviates cisplatin-induced nephrotoxicity in rats through gamma-glutamyl transpeptidase (GGT) enzyme inhibition, associated with regulation of Nrf2/HO-1, MAPK/NF-κB, and Bax/Bcl-2 signaling

BACKGROUND

The therapeutic utility of the effective chemotherapeutic agent cisplatin is hampered by its nephrotoxic effect. We aimed from the current study to examine the possible protective effects of amlodipine through gamma-glutamyl transpeptidase (GGT) enzyme inhibition against cisplatin nephrotoxicity.

METHODS

Amlodipine (5 mg/kg, po) was administered to rats for 14 successive days. On the 10th day, nephrotoxicity was induced by a single dose of cisplatin (6.5 mg/kg, ip). On the last day, blood samples were collected for estimation of kidney function, while kidney samples were used for determination of GGT activity, oxidative stress, inflammatory, and apoptotic markers, along with histopathological evaluation.

RESULTS

Amlodipine alleviated renal injury that was manifested by significantly diminished serum creatinine and blood urea nitrogen levels, compared to cisplatin group. Amlodipine inhibited GGT enzyme, which participates in the metabolism of extracellular glutathione (GSH) and platinum-GSH-conjugates to a reactive toxic thiol. Besides, amlodipine diminished mRNA expression of NADPH oxidase in the kidney, while enhanced the anti-oxidant defense by activating Nrf2/HO-1 signaling. Additionally, it showed marked anti-inflammatory response by reducing expressions of p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor-kappa B (NF-κB), with subsequent down-regulation of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and vascular cell adhesion molecule-1 (VCAM-1). Moreover, amlodipine reduced Bax/Bcl-2 ratio and elevated hepatocyte growth factor (HGF), thus favoring renal cell survival.

CONCLUSIONS

Effective GGT inhibition by amlodipine associated with enhancement of anti-oxidant defense and suppression of inflammatory signaling and apoptosis support our suggestion that amlodipine could replace toxic GGT inhibitors in protection against cisplatin nephrotoxicity.

High performance liquid chromatographic assay of amlodipine, valsartan and hydrochlorothiazide simultaneously and its application to pharmaceuticals, urine and plasma analysis

A Simple, Specific, Precise, Accurate, Linear, Rugged, Robust High Performance Liquid Chromatographic method of analysis for simultaneous determination of assay of Amlodipine, Valsartan and Hydrochlorothiazide drugs in the pharmaceuticals tablet formulations using Pioglitazone as a common internal standard was developed and validated. The assay was accomplished using a mixture of acetonitrile & methanol in the volume ratio of 20:80 v/v (mobile phase B) and Ammonium acetate buffer (Mobile phase A) in gradient flow as mobile phase on an Hibar RP-18e, 250 × 4.6 mm, 5µ as chromatographic column at a flow rate of 1.300 mLmin-1, injection volume 10 µL and at a wavelength 235 nm with UV detector. Linearity of the analytical method was evaluated at a concentration range of 2.5-45.3 µg/ml for Amlodipine, 32.0-720.1 µg/ml for valsartan and 5.0-112.6 µg/ml for Hydrochlorothiazide respectively with Correlation coefficient (r) value more than 0.9997. The limit of detection (LOD) for Amlodipine, Valsartan and Hydrochlorothiazide was found to be 1.1 µg/ml, 8.0 µg/ml & 1.0 µg/ml respectively. Specificity, Method Precision, System Precision, Ruggedness, Robustness, Recovery, Stability of analytical solution, Filter paper selection study, Stress testing (Force Degradation) at various conditions were performed as per the ICH (Q2) recommendations. The chromatographic method may also be applied for simultaneous estimation of analytes in plasma and urine.

An enhanced first derivative synchronous spectrofluorimetric method for determination of the newly co-formulated drugs, amlodipine and celecoxib in pharmaceutical preparation and human plasma

BACKGROUND

A new combination of amlodipine and celecoxib has been recently introduced in order to relieve the symptoms of osteoarthritis and help treat hypertension that commonly associated with osteoarthritis.

OBJECTIVE

The current study is the first to develop and optimize a sensitive, simple and accurate first derivative synchronous spectrofluorimetric method for the simultaneous determination of amlodipine and celecoxib in bulk powder, pharmaceutical preparation and spiked human plasma.

METHOD

The method implies the use of synchronous methodology using Δλ = 100 nm and measuring the fluorescence amplitudes of the first derivative each at the zero-crossing point of the other. For amlodipine and celecoxib, the emission wavelengths were at 455 nm and 368 nm, after excitation at 367 nm and 264 nm, respectively.

RESULTS

The method was found to be linear over a wide concentration ranges of (5-600 ng/ml), (100-2000 ng/ml) with lower limits of detection of (1.16 ng/ml) and (17.16 ng/ml) for amlodipine and celecoxib, respectively. Enhancement of the fluorescence intensity was achieved by complex formation between the studied drugs and the surfactant sodium dodecyl sulfate and optimizing other experimental conditions. The method was further extended for application for determination of the studied drugs in spiked human plasma with excellent % recoveries of (95.20 ± 6.095) and (98.67 ± 6.394) for amlodipine and celecoxib, respectively. Validation of the method was successfully implemented according to recommendations delivered by guidelines of the International Conference on Harmonization.

Amlodipine Compared with Benidipine in the Management of Hypertension: A Systematic Review and Meta-Analysis

INTRODUCTION

Benidipine and amlodipine are two well-known drugs used in hypertensive patients with chronic kidney disease (CKD).

AIM

In this systematic review we aimed to compare benidipine and amlodipine in terms of efficacy in the management of hypertensive patients.

METHODS

We searched PubMed, Cochrane CENTRAL, SCOPUS and Web of Science for relevant clinical trials and excluded observational studies. Quality appraisal was evaluated according to GRADE and we assessed the risk of bias using the Cochrane's risk of bias tool. We included the following outcomes: Systolic blood pressure, diastolic blood pressure, heart rate, estimated glomerular filtration rate (eGFR), and urinary albumin/creatinine ratio. Data were pooled as mean differences (MD) with relative 95% confidence intervals (CI).

RESULTS

Eight studies were eligible for our meta-analysis. We found no significant difference between both drugs regarding systolic (MD = - 0.21 [- 1.48, 1.89], (P = 0.81) and diastolic (MD = 0.01[- 0.51, 0.53], (P = 0.97)) blood pressure measurements. The overall heart rate did not differ as well (MD = - 0.03 [- 1.63, 1.57], (P = 0.97)). We found that benidipine was statistically better than amlodipine in terms of eGFR (MD = 1.07 [0.43, 1.71], (P = 0.001)), and urinary albumin/creatinine ratio (MD = - 43.41 [- 53.53, - 33.29], (P < 0.00001)).

CONCLUSIONS

Finally we conclude that benidipine seems to show more positive and promising results in the management of hypertensive patients with chronic kidney disease.

Calcium channel blocker induced gingival enlargement following implant placement in a fibula free flap reconstruction of the mandible: a case report

Background

Gingival tissue enlargement is a common side effect of antiepileptic medications (e.g. phenytoin and sodium valproate), immunosuppressing drugs (e.g. cyclosporine) and calcium channel blockers (e.g. nifedipine, verapamil, amlodipine) (Murakami et al. 2018, Clin Periodontol 45:S17–S27, 2018). The clinical and histological appearances of lesions caused by these drugs are indistinguishable from one another (Murakami et al. 2018, Clin Periodontol 45:S17–S27, 2018). Drug-induced gingival enlargement is rarely seen in edentulous patients.

Case presentation

This case presents a 72-year-old female with a history of squamous cell carcinoma of the floor of the mouth treated with surgical excision and fibula-free flap reconstruction. Following the uncovering of osseointegrated implants placed in the fibular-free flap, the patient developed gingival enlargement of the floor of the mouth. Cessation of amlodipine and switching to an alternative medication lead to a resolution of the enlarged tissue.

Conclusions

This case illustrates that gingival enlargement can occur around dental implants, most notably in rehabilitation cases in patients who have had head and neck cancer. Clinicians should be aware of the risk of gingival enlargement in hypertensive patients taking calcium channel blockers prior to implant placement.

Pharmacokinetic interactions of esaxerenone with amlodipine and digoxin in healthy Japanese subjects

Background

To investigate the effects of coadministration of esaxerenone with amlodipine on the pharmacokinetics (PK) of each drug, and of esaxerenone on the PK of digoxin.

Methods

In three open-label, single-sequence, crossover studies, healthy Japanese males received single oral doses of esaxerenone 2.5 mg (Days 1, 15), with amlodipine 10 mg/day (Days 8–18) (Study 1, N = 24); single doses of amlodipine 2.5 mg (Days 1, 21), with esaxerenone 5 mg/day (Days 8–25) (Study 2; N = 20); or digoxin 0.25 mg/day (Days 1–15) with esaxerenone 5 mg/day (Days 11–15) (Study 3; N = 20). PK parameters and safety were assessed.

Results

Study 1: esaxerenone peak plasma concentration (C_max) and time to C_max were unaltered by amlodipine coadministration, but mean half-life was slightly prolonged from 18.5 to 20.9 h. Geometric least-squares mean (GLSM) ratios for C_max, area under the plasma concentration–time curve (AUC) from zero to last measurable concentration and from zero to infinity for esaxerenone + amlodipine versus esaxerenone were 0.958, 1.154, and 1.173, respectively. Study 2: corresponding GLSM ratios for amlodipine + esaxerenone versus amlodipine were 1.099, 1.185, and 1.214. Study 3: esaxerenone did not markedly alter digoxin PK. GLSM ratios for C_max, trough plasma concentration, and AUC during a dosing interval for digoxin versus esaxerenone + digoxin were 1.130, 1.088, and 1.072, respectively.

Conclusions

No drug–drug interactions are expected during combination therapy with esaxerenone and either amlodipine or digoxin, based on a lack of any clinically relevant PK changes.

Trial registration

Studies 1 and 2: JapicCTI-163379 (registered on 20 September 2016); Study 3: JapicCTI-163443 (registered on 24 November 2016).

Valsartan Versus Amlodipine Effect on Left Ventricular Multidirectional Deformation and Adipocytokines Levels in Hypertensive Patients: Speckle Tracking Echocardiography

INTRODUCTION

Structural and functional properties of the left ventricle (LV) wall have been reported to be altered in hypertension, even at early stages of the disease. Abnormal adipokine levels affect blood pressure regulation. Hypo-adiponectinaemia and hyper-leptinaemia were reported in hypertension.

AIM

To evaluate the effects of valsartan versus amlodipine on LV deformation also, on plasma adiponectin and leptin levels in hypertensive individuals.

METHODS

LV strain was measured by two-dimensional speckle tracking echocardiography, plasma levels of adiponectin and leptin was determined in 30 healthy individuals served as control group and in 200 hypertensive patients before and after treatment for 6 months with either valsartan 160 mg or amlodipine 10 mg.

RESULTS

Compared to control group longitudinal strain was significantly affected in hypertensive patients, adiponectin was significantly lower while TNF-α, hs-CRP and leptin levels were significantly higher in hypertensive group. A significant improvement in LV functions, along with a decrease in leptin and increase in adiponectin levels in valsartan group compared to amlodipine group.

CONCLUSIONS

Our results indicate that valsartan is superior to amlodipine when it comes to affecting the hormonal function of human adipose tissue. Valsartan has a beneficial effect on LV deformation and function presented in GLS.

Pharmacokinetics and bioequivalence of fixed-dose combination of candesartan cilexetil/amlodipine besylate (16/10 mg) versus coadministration of individual formulations in healthy subjects

This study compared the pharmacokinetics of a fixed-dose combination (FDC) of candesartan (16 mg) and amlodipine (10 mg) versus coadministration of individual formulations to clarify the bioequivalence of the FDC. In this randomized, open-label, single-dose, 2-treatment, 2-way crossover study, healthy Korean volunteers received a single dose of candesartan (16 mg) with amlodipine (10 mg) as either an FDC or single agents concomitantly administered, with a 2-week washout period. Serial blood samples were collected up to 72 hours after dosing for each treatment period, and plasma concentrations of candesartan and amlodipine were measured using a validated liquid chromatography-tandem mass spectrometry method. A total of 39 subjects completed the study. The geometric mean ratios (GMRs) and 90% confidence intervals (CIs) for the area under the plasma concentration-time curve from time 0 to the last measurement (AUC_0-t) and the peak plasma concentration (C_max) for candesartan were 1.0182 (0.9562–1.0841) and 0.9492 (0.8726–1.0324), respectively. The GMR and 90% CI for the AUC_0-t and C_max for amlodipine were 1.0552 (1.0255–1.0857) and 1.0668 (1.0259–1.1094), respectively. In conclusion, the new FDC formulation of candesartan (16 mg) and amlodipine (10 mg) was bioequivalent to the concomitant administration of single agents. A single dose of candesartan/amlodipine as the FDC or as single agents was well tolerated.

Therapeutic Potential of Dihydropyridine Calcium Channel Blockers on Oxidative Injury Caused by Organophosphates in Cortex and Cerebellum: An In Vivo Study

This study was designed to investigate the effects of amlodipine (AM), a dihydropyridine calcium channel blocker, on the oxidative damage induced by diazinon (DZN) in the rat cortex and cerebellum. Forty-two rats were randomly divided into six groups. The rats were treated intraperitoneally with normal saline (group 1), AM (9 mg/kg; group 2), DZN (32 mg/kg; group 3) and different doses of AM (3, 6, and 9 mg/kg; groups 4, 5, and 6, respectively) with DZN. After 14 days, the cerebellum and cortex tissues were removed for biochemical and histological experiments. DZN significantly decreased acetylcholinesterase activity (AChE; 57%, p < 0.001 and 39.1%, p < 0.05), depleted total antioxidant capacity (TAC; 46.2%, p < 0.01 and 44.7%, p < 0.05), and increased lactate dehydrogenase activity (LDH; 96%, p < 0.001 and 202%, p < 0.001), nitric oxide (NO; 130%, p < 0.001 and 74.4%, p < 0.001), and lipid peroxidation levels (LPO; 35.6%, p < 0.001 and 128.7%, p < 0.001), in the cerebellum and cortex tissues, respectively. In addition, DZN induced structural alterations in the cerebellum and cortex. Following AM administration, a remarkable improvement was observed in LDH activity and some of the oxidative markers, such as NO and LPO; however, no significant changes were found in AChE activity when the DZN group was compared with the AM-treated groups. This study suggests that AM may prevent DZN-induced neurotoxicity via improvement of the oxidative/antioxidant balance in the cerebellum and cortex tissues.