Minkyung Oh

Inje University Paik Hospital, Sŏul, Seoul, South Korea

Are you Minkyung Oh?

Claim your profile

Publications (8)21.06 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective. The objective of this study was to evaluate the effects of voglibose on the pharmacokinetics of metformin. Methods. A randomized, open-label, two-way crossover study with a 7-day washout period was conducted. All subjects were given an oral dose of metformin with or without voglibose 3 x daily for 7 days. Plasma concentrations of metformin on day 7 were measured using high performance liquid chromatography (HPLC) with UV detection for pharmacokinetic assessment Vital signs and adverse events were monitored, and physical examinations and laboratory tests were conducted to evaluate safety. Results. 22 subjects completed the study. The geometric mean ratios for Css,max of metformin (metformin plus voglibose vs. metformin only) were 0.98 (90% CI, 0.92 - 1.05; p > 0.05) and for AUCtau, the ratio was 0.99 (90% CI, 0.92 - 1.06; p > 0.05). There were no significant differences in adverse drug reactions between metformin with and without voglibose. However, the incidence of adverse events was higher in period 1 than in period 2 (16 cases vs. 1 case, p < 0.001). Conclusions. Co-administration of metformin and voglibose had no statistically or clinically significant effects on the pharmacokinetics of metformin in healthy subjects. The pharmacodynamic interaction study to evaluate the effect of metformin on the pharmacodynamics of voglibose is in progress.
    International journal of clinical pharmacology and therapeutics 08/2014; · 1.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to compare pharmacokinetic characteristics of fixed-dose combination (FDC) of two different salt form of amlodipine, amlodipine adipate/valsartan and amlodipine besylate/ valsartan, in healthy Korean volunteers under fasting conditions. A randomized, open-label, single-dose, two-treatment, two-way crossover study with a 14-day wash-out period was conducted. Plasma samples were collected for up to 144 hours for amlodipine and 24 hours for valsartan. Plasma concentrations of amlodipine and valsartan were analyzed using a validated ultra-performance liquid chromatography tandem mass-spectrometry. A non-compartmental method was used to calculate pharmacokinetic parameters. Vital signs and adverse events were monitored and physical examinations, laboratory tests, and electrocardiograms were conducted to evaluate safety. 44 subjects completed the study. The 90% CIs for the geometric mean ratio of Cmax and the AUC0-t were 93.5 - 100.4% and 93.2 - 98.3% for amlodipine, and 92.1 - 121.3% and 94.1 - 115.2% for valsartan, respectively. 17 adverse events occurred in 15 subjects during the study; 5 and 7 adverse drug reactions from the 5 and 6 subjects were considered to probably be related to the test and reference treatments respectively. All adverse drug reactions were in line with those known for the reference drug. All subjects recovered fully with no sequelae. A FDC of amlodipine adipate/valsartan and amlodipine besylate/ valsartan combination tablets met the regulatory criteria for bioequivalence. In addition, no significant difference was observed in the safety assessments between two treatments. Thus, the newly developed FDC of amlodipine adipate/valsartan seems to be interchangeable with amlodipine besylate valsartan combination.
    International journal of clinical pharmacology and therapeutics 07/2014; · 1.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Long-term data on lead complication rates are limited for both the axillary and subclavian venous approaches for permanent pacemaker implantation. Methods and Results: We conducted a single-center, retrospective, nonrandomized comparison. We reviewed the patients who had consented to receiving a permanent pacemaker implant. A superficial landmark or radiographic contrast guiding was used for the axillary venous approach, whereas conventional landmarks were used for the subclavian venous approach. From January 1992 to December 2005, we analyzed 1,161 permanent pacemaker leads in 655 patients [subclavian venous approach (group I: 338 patients, 542 leads) and axillary venous approach (group II: 317 patients, 619 leads)]. Baseline characteristics of the patients did not differ. However, DDD-pacemakers and atrial leads were used more often in group II than in group I (94% vs. 62% and 49% vs. 40%, P<0.01). During the 8-year follow-up, lead complication rates were lower in group II (17 leads, 3%) than in group I (31 leads, 6%) (P=0.03), and group II had a better complication-free survival curve than group I with a 49% relative risk reduction in lead complication rates (hazard ratio =0.51; 95% confidence interval, 0.27-0.94; P=0.03). Conclusions: The axillary venous approach for permanent pacemaker implantation has better long-term efficacy and lower lead complication rates than the subclavian venous approach.
    Circulation Journal 03/2014; · 3.58 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We evaluated the effect of CYP2C19 genotype over time on the antiplatelet response of clopidogrel in healthy subjects. Seventy subjects for a pharmacodynamic study and twenty two subjects for a pharmacokinetic and pharmacodynamic study took 300 mg clopidogrel on the first day and 75 mg once daily for 6 consecutive days. The subjects with CYP2C19 poor metabolizer (PM, n = 22) and intermediate metabolizer (IM, n = 37) had significantly delayed time to inhibition of platelet aggregation (IPA) compared with CYP2C19 extensive metabolizer (EM, n = 33) (12 vs. 9 vs. 2 h as median Tmax , P < 0.05) after a 300 mg of clopidogrel. During maintenance dose of clopidogrel, IPA values of only CYP2C19 PM subjects were gradually decreased from 30.0 ± 21.9% on day 2 to 23.7 ± 16.6% on day 8 (P > 0.05 for time effect; P < 0.05 for time and genotype interaction effect). CYP2C19 PM had decreased Cmax and AUC of thiol metabolite compared with CYP2C19 EM (0.42 and 0.37 fold on day 1, P < 0.01; 0.39 and 0.34 fold on day 7, P < 0.01, respectively). Delayed time to reach maximal IPA as well as decreased IPA may influence the increased risk of the acute cardiac events in CYP2C19 PM and IM.
    The Journal of Clinical Pharmacology 11/2013; · 2.84 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The primary objective of this study was to evaluate the effects of Ginkgo biloba extracts (GBE) on the pharmacokinetics of cilostazol and its metabolites. Secondary objective was to assess the effect of GBE on pharmacodynamics of cilostazol. A randomized, double-blind, two-way crossover study was conducted with 34 healthy Korean subjects. All subjects were given an oral dose of cilostazol (100 mg) plus GBE (80 mg) or cilostazol (100 mg) plus placebo twice daily for 7 days. Plasma concentrations of cilostazol and its active metabolites (3,4-dehydrocilostazol and 4'-trans-hydroxycilostazol) were measured using liquid chromatography tandem mass spectroscopy (LC-MS/MS) on day 7 for pharmacokinetic assessment. ADP-induced platelet aggregation and bleeding time were measured at baseline and on day 7 for pharmacodynamic assessment. The geometric mean ratios of AUCτ for cilostazol plus GBE versus cilostazol plus placebo were 0.96 (90% CI, 0.89-1.03; p=0.20) for cilostazol; 0.96 (90% CI, 0.90-1.02; p=0.30) for 3,4-dehydrocilostazol; and 0.98 (90% CI, 0.93-1.03; p=0.47) for 4'-trans-hydroxycilostazol, respectively. The change of aggregation after administration of cilostazol plus GBE seemed to be 1.31 times higher compared with cilostazol plus placebo without statistical significance (p=0.20). There were no significant changes in bleeding time and adverse drug reaction between the treatments. Co-administration of GBE showed no statistically significant effects on the pharmacokinetics of cilostazol in healthy subjects. The long-term large cohort clinical study seems to be remained to evaluate the possible pharmacodynamic interaction between cilostazol and GBE, since there was remarkable, but no statistically significant, increase of platelet aggregation inhibition.
    British Journal of Clinical Pharmacology 09/2013; · 3.69 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective: Fentanyl, a μ-opioid receptor agonist, is a substrate of P-glycoprotein. Its metabolism is catalyzed by CYP3A4 and CYP3A5. The aim of this study was to investigate the association between postoperative fentanyl consumption and genetic polymorphisms of μ-opioid receptor (OPRM1), ABCB1 (gene encoding P-glycoprotein), CYP3A4 and CYP3A5 in Korean patients. Methods: 196 female patients scheduled to undergo total abdominal hysterectomy or laparoscopic assisted vaginal hysterectomy under general anesthesia were enrolled in this study. Intravenous patient-controlled analgesia with fentanyl was provided postoperatively. Cumulative fentanyl consumption was measured during the first 48 hours postoperatively. The severity of pain at rest was assessed with the visual analogue scale. OPRM1 118A>G, ABCB1 2677G>A/T, ABCB1 3435C>T, CYP3A4*18 and CYP3A5*3 variant alleles were genotyped. The effects of genetic and non-genetic factors on fentanyl requirements were evaluated with multiple linear regression analysis. Results: The 24-hour cumulative fentanyl doses were significantly associated with pain core, weight and type of surgery (p < 0.05). The 48-hour cumulative fentanyl doses were significantly associated with pain score, type of surgery and history of PONV or motion sickness (p < 0.05). Genetic polymorphisms were not associated with fentanyl requirements. Conclusion: In Korean gynecologic patients, no association was found between genetic factors and postoperative fentanyl consumption.
    International journal of clinical pharmacology and therapeutics 04/2013; · 1.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The effect of CYP2C9 and vitamin K epoxide reductase complex subunit 1 (VKORC1) genotypes was evaluated for the early-phase and steady-state warfarin dosing in Korean patients with mechanical heart valve replacement. The genotypes of CYP2C9 variants including CYP2C9*3, CYP2C9*13, and CYP2C9*14, and VKORC1 1173C>T were assessed for the association with warfarin dosing in 265 patients whose data were collected for warfarin dose; international normalized ratio (INR), comedication, comorbidity, and other clinical characteristics. In the early phase of warfarin therapy, the combined genotypes of CYP2C9 and VKORC1 caused statistically significant difference in warfarin dose from day 7 of warfarin dosing and the subsequent time course of dose increase showed significant difference among the three different genotypes (P<0.001). Compared with patients with CYP2C9 wild type, the patients with heterozygous CYP2C9 variants have delayed time to reach stable dose [adjusted hazard ratio (HRadj): 0.48; 95% confidence interval (CI): 0.27-0.85] and tended to have high risk for the first INR greater than 3.5 (HRadj: 1.64; 95% CI: 0.98-2.75). The patients with the VKORC1 CT genotype showed no significant difference in the time to reach stable dose but statistically significant low HR for time to first INR greater than 3.5 compared with those with VKORC1 TT genotype (HRadj: 0.25; 95% CI: 0.13-0.51). The observed warfarin maintenance dose was best explained by a model including covariates of age, weight, concurrent congestive heart failure/cardiomyopathy, INR-increasing drugs, aspirin, dietary supplements, and CYP2C9 and VKORC1 genotypes (R=0.56). The heterozygous CYP2C9 and VKORC1 genotypes influence warfarin dosing in an early phase as well as steady state of warfarin therapy in Korean patients with mechanical heart valve replacement.
    Pharmacogenetics and Genomics 12/2008; 19(2):103-12. · 3.61 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The role of the genetically polymorphic CYP3A5 in the metabolism of CYP3A substrates is unclear. We investigated the contributions of the CYP3A4 and CYP3A5 isoforms to the metabolism of the phosphodiesterase type 5 inhibitors (PDE5Is) sildenafil, udenafil, and vardenafil. In vitro incubation studies of sildenafil N-demethylation, udenafil N-dealkylation, and vardenafil N-deethylation were conducted using recombinant CYP3A enzymes and 15 human liver microsome (HLM) preparations with predetermined CYP3A5 genotypes. Recombinant CYP3A4 and CYP3A5 both produced N-desalkyl metabolites of sildenafil, udenafil, and vardenafil. The catalytic efficiency (Cl(int) = V(max)/apparent K(m)) of the rCYP3A5 isoform for vardenafil N-deethylation was about 3.2-fold that of rCYP3A4, whereas the intrinsic clearance rates for N-dealkylation of both sildenafil and udenafil were similar between rCYP3A5 and rCYP3A4. The metabolite formation activity was higher in HLMs heterozygous for the CYP3A5*3 allele (n = 9) than in HLMs homozygous for CYP3A5*3 (n = 6). These findings suggest that CYP3A5 and CYP3A4 play a significant role in the metabolism of PDE5Is. The genetic polymorphism of CYP3A5 may contribute to interindividual variability in the disposition of PDE5Is, especially vardenafil. Further in vivo studies are needed to confirm the effects of CYP3A5 genotypes on the pharmacokinetics of PDE5Is.
    Drug metabolism and disposition: the biological fate of chemicals 07/2008; 36(6):986-90. · 3.74 Impact Factor