rs622342A > C in SLC22A1 is associated with metformin pharmacokinetics and glycemic response
DRUG METABOLISM AND PHARMACOKINETICS
Authors: Naja, Khaled; El Shamieh, Said; Fakhoury, Rajaa
Abstract
Polymorphisms in SLC22A1 lead to variability in metformin clinical efficacy. Sixty-three Lebanese patients with type 2 diabetes who administered metformin, were followed up for six months and genotyped for rs622342A>C. The area under the plasma concentration-time curve and the maximum concentration of metformin was highest in CC patients (P <= 0.03). There was a significant difference between groups in the percentage decrease in fasting blood sugar (FBS) and glycated hemoglobin (HbA1c). Going into the same direction, rs622342C was associated with decrease in FBS levels after three and six months of treatment (P <= 0.02), whereas with HbA1c, the decrease was noticed after six months (beta = -2.78; P = 0.03). In contrast, the serum levels of lactate and creatinine did not vary significantly according to rs622342A>C genotypes. The rs622342A>C in SLC22A1 may be associated with metformin pharmacokinetics and variability in therapeutic efficacy. (C) 2019 The Japanese Society for the Study of Xenobiotics. Published by Elsevier Ltd. All rights reserved.
Effects of Comedication and Genetic Factors on the Population Pharmacokinetics of Lamotrigine: A Prospective Analysis in Chinese Patients With Epilepsy
FRONTIERS IN PHARMACOLOGY
Authors: Wang, Zhan-zhang; Zhang, Yue-feng; Huang, Wen-can; Wang, Xi-pei; Ni, Xiao-jiao; Lu, Hao-yang; Hu, Jin-qing; Deng, Shu-hua; Zhu, Xiu-qing; Xie, Huan-shan; Chen, Hong-zhen; Zhang, Ming; Qiu, Chang; Wen, Yu-guan; Shang, De-wei
Abstract
Lamotrigine (LTG) is a second-generation anti-epileptic drug widely used for focal and generalized seizures in adults and children, and as a first-line medication in pregnant women and women of childbearing age. However, LTG pharmacokinetics shows high interindividual variability, thus potentially leading to therapeutic failure or side effects in patients. This prospective study aimed to establish a population pharmacokinetics model for LTG in Chinese patients with epilepsy and to investigate the effects of genetic variants in uridine diphosphate glucuronosyltransferase (UGT) 1A4, UGT2B7, MDR1, ABCG2, ABCC2, and SLC22A1, as well as non-genetic factors, on LTG pharmacokinetics. The study population consisted of 89 patients with epilepsy, with 419 concentrations of LTG. A nonlinear mixed effects model was implemented in NONMEM software. A one-compartment model with first-order input and first-order elimination was found to adequately characterize LTG concentration. The population estimates of the apparent volume of distribution (V/F) and apparent clearance (CL/F) were 12.7 L and 1.12 L/h, respectively. The use of valproic acid decreased CL/F by 38.5%, whereas the co-administration of rifampicin caused an increase in CL/F of 64.7%. The CL/F decreased by 52.5% in SLC22A1-1222AA carriers. Patients with the ABCG2-34AA genotype had a 42.0% decrease in V/F, whereas patients with the MDR1-2677TT and C3435TT genotypes had a 136% increase in V/F. No obvious genetic effect of UGT enzymes was found relative to the concentrations of LTG in Chinese patients. Recommended dose regimens for patients with different gene polymorphisms and comedications were estimated on the basis of Monte Carlo simulations and the established model. These findings should be valuable for developing individualized dosage regimens in adult and adolescent Chinese patients 13-65 years of age.