Influence of CYP2D6*5 and *10 polymorphism on the pharmacokinetics of nebivolol in healthy Chinese subjects

Clinical pharmacokinetics of nebivolol: a systematic review

Nebivolol is a beta-1 receptor blocker used to treat hypertension, heart failure, erectile dysfunction, vascular disease, and diabetes mellitus. This review investigated the data regarding pharmacokinetic (PK) parameters, drug-drug interactions, dextrorotatory (D), and levorotatory (L) stereoisomers of nebivolol. The articles related to the PK of nebivolol were retrieved by searching the five databases; Google Scholar, PubMed, Cochrane Library, ScienceDirect, and EBSCO. A total of 20 studies comprising plasma concentration-time profile data following the nebivolol's oral and intravenous (IV) administration were included. The area under the concentration-time curve from zero to infinity (AUC0-∞) was 15 times greater in poor metabolizers (PMs) than in extensive metabolizers (EMs). In hypertensive patients, L-nebivolol expressed a higher maximum plasma concentration (Cmax) than D-nebivolol, i.e. 2.5 ng/ml vs 1.2 ng/ml. The AUC0-∞ of nebivolol was 3-fold greater in chronic kidney disease (CKD). The clearance (CL) was increased in obese than in controls from 51.6 ± 11.6 L/h to 71.6 ± 17.4 L/h when 0.5 mg/ml IV solution was infused. Nebivolol showed higher Cmax, AUC0-∞ and half-life (t1/2) when co-administered with bupropion, duloxetine, fluvoxamine, paroxetine, lansoprazole, and fluoxetine. This concise review of nebivolol would be advantageous in assessing all PK parameters, which may be crucial for clinicians to avoid drug-drug interactions, prevent adverse drug events and optimize the dosage regimen in diseased patients diagnosed with hypertension and cardiovascular disorders.

Diltiazem efficacy and CYP2D6 gene polymorphism in patients with atrial fibrillation with rapid ventricular response

BACKGROUND

Diltiazem stands out as one of the front-line drugs administered in the emergency department to achieve acute rate control in patients suffering from atrial fibrillation with rapid Ventricular Response. One of the cytochrome enzymes involved in the metabolism of diltiazem is cytochrome P450 2D6 (CYP2D6). Interindividual differences can act on drug metabolism and thus drug efficacy due to the genetic polymorphism induced by the CYP2D6 enzyme. This study explores the association between the efficacy of diltiazem and the genetic polymorphism of CYP2D6 in patients with atrial fibrillation with rapid ventricular response.

RESULTS

87 out of 93 individuals with ventricular rate > 120 beats/min constituted the patient cohort. The patients were administered 0.25 mg/kg diltiazem intravenously. As a second dose, 0.35 mg/kg diltiazem was administered to patients who reportedly did not receive adequate drug efficacy. Heart rate control was considered to be achieved in patients whose heart rate fell below 110 beats/min and did not rise above 110 beats/min for 2 h. CYP2D6 *2, *3, *4 and *10 represent allele variants and *1 represents wild type (wt) allele. Achieving rate control after one or two doses of diltiazem in normal allele (wt/wt) carriers proved significantly higher than wt/*2, wt/*4 and wt/*10 heterozygous variant carriers. No significant difference was noted in wt/*3 heterozygous variant carriers.

CONCLUSION

The presence of *2, *4 and *10 alleles was observed to significantly compromise the drug efficacy. *3 allele was found to bear no relation to the effect of diltiazem on achieving rate control.

New Data for Nebivolol after In Silico PK Study: Focus on Young Patients and Dosage Regimen

Nebivolol (NEB) is a highly selective β1 receptor antagonist with a distinct pharmacological profile. This drug is approved for the treatment of hypertension in the US, and hypertension and heart failure in Europe. Here, we review observations based on age dependence and explore new drug regimens with in-silico studies, to achieve better efficacy and safety. The clinical data were obtained from six published literature reports. Then the data were used for model building, evaluation, and simulation. A two-compartment model with first-order absorption, lag time, linear elimination, and the following covariates: age and genotype were the ones best describing our population. Simulation of different dose regimens resulted in an increase chance of efficacy and safety when the dose regimen was altered to 6 mg every 36 h. It is worth noting that our population in this study constituted of young and healthy individuals. Studies regarding the effects of NEB according to age are scarce; however, they are needed to further improve efficacy and safety, and reduce adverse effects.

Antiretroviral Treatment and Antihypertensive Therapy

The presence of hypertension among the population with human immunodeficiency virus (HIV) has become a new threat to the health and well-being of people living with this disease, in particular, among those who received antiretroviral therapy. The estimated prevalence of high blood pressure in HIV-infected patients is significantly higher than the rate observed in HIV-uninfected subjects. The approach to the HIV-positive patient requires the assessment of individual cardiovascular risk and its consideration when designing the individualized target. On the other hand, the numerous pharmacological interactions of antiretroviral (ARV) drugs are essential elements to take into account. Serum levels of any kind of antihypertensive drugs may be influenced by the coadministration of protease inhibitors, non-nucleoside reverse transcriptase inhibitor, or other antiretroviral. Similarly, plasma concentrations of antiretroviral drugs can be increased by the concomitant use of calcium channel blockers or diuretics. In this regard, the treatment of high blood pressure in HIV patients should be preferentially based on ACE inhibitors or thiazide/thiazide-like diuretics or their combination.

Han Chinese specific cytochrome P450 polymorphisms and their impact on the metabolism of anti-hypertensive drugs with adrenoreceptor blocking properties

Introduction: Cytochrome P450 (CYP) is a monooxygenase superfamily mediating the elimination of anti-hypertensive drugs. Polymorphisms of CYP would lead to differential drug efficacy. Building relationships between genotype and phenotype will benefit individual medical treatment of hypertension.Areas covered: The review systematically summarizes the polymorphisms of four CYPs (CYP2C9, CYP2C19, CYP2D6, and CYP3A4) concentrated distributed in the Han Chinese population. Moreover, the activity of variants on metabolizing anti-hypertensive drugs are reviewed, especially drugs with adrenoceptor blocking properties, as well as their clinical relevancies.Expert opinion: The polymorphisms of CYP can cause stratification in drug exposure of antihypertensive drugs. Although the clinical relevance has been built partially, the translational medicine still lacks reliable data support. Furthermore, the studies have demonstrated that even the same CYP variant will exhibit different catalytic capability for different drugs, which is another obstacle to hinder its application. With the deepening of multiomics research and structural biology, nucleotide polymorphisms can be combined with transcriptome, proteome, metabolome and molecular structure analyses to study the susceptibility to hypertension and drug efficacy. A complete data chain would be further estabolished by combining studies of pharmacokinetics-pharmacodynamics, which can effectively promote the precise application of anti-hypertensive drugs.

Pharmacogenetic factors affecting β-blocker metabolism and response

INTRODUCTION

β-blockers are among the most widely prescribed of all drugs, used for treatment of a large number of cardiovascular diseases. Herein we evaluate literature pertaining to pharmacogenetics of β-blocker therapy, provide insight into the robustness of the genetic associations, and determine the appropriateness for translating these genetic associations into clinical practice.

AREAS COVERED

A literature search was conducted using PubMed to collate evidence on associations between CYP2D6, ADRB1, ADRB2, and GRK5 genetic variation and drug-response outcomes in the presence of β-blocker exposure. Pharmacokinetic, pharmacodynamic, and clinical outcomes studies were included if genotype data and β-blocker exposure were documented.

EXPERT OPINION

Substantial data suggest that specific ADRB1 and GRK5 genotypes are associated with improved β-blocker efficacy and have potential for use to guide therapy decisions in the clinical setting. While the data do not justify ordering a CYP2D6 pharmacogenetic test, if CYP2D6 genotype is available in the electronic health record, there may be clinical utility for understanding dosing of β-blockers.