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Rapid Quantitation of Flecainide in Human Plasma for Therapeutic Drug Monitoring Using Liquid Chromatography and Time-of-Flight Mass Spectrometry. Ther Drug Monit 2020; 41:391-395. [PMID: 30520831 DOI: 10.1097/ftd.0000000000000586] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Measurement of flecainide is useful to optimize dosage and minimize risks of toxicity. Furthermore, there is a need for urgent sample analysis when flecainide is used in transplacental therapy for fetal tachycardia. To this end, we have developed and validated a rapid assay for the measurement of flecainide in human plasma or serum, using a small sample volume (50 µL). METHODS After a simple deproteination with zinc sulfate and methanol, prepared samples were injected onto a short (30 mm) analytical column and eluted using a rapid gradient elution. Detection was performed using time-of-flight mass spectrometry. Flecainide was quantified using flecainide-D4 as internal standard, with both compounds extracted from the total ion chromatogram using a ±5 ppm extraction window based on the theoretical m/z values for the protonated ions. RESULTS The assay was linear over a putative therapeutic range (100-1500 mcg/L). Between- and within-assay imprecision and accuracy were <4.6% and 94.8%-110.0%, respectively. Matrix effects were minimal and were compensated for by flecainide-D4. There were no effects due to hemolysis or lipemia, and no carryover was apparent. Total analysis time was just 1.2 minutes (72 seconds). CONCLUSIONS We have developed and validated a rapid method for the analysis of flecainide. The method is particularly suited for flecainide therapeutic drug monitoring, when analyzing samples from mothers receiving flecainide for the treatment of fetal tachycardia.
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Doki K. Use of Pharmacogenetic Information for Therapeutic Drug Monitoring of an Antiarrhythmic Drug. YAKUGAKU ZASSHI 2018; 138:1145-1150. [DOI: 10.1248/yakushi.18-00114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Kosuke Doki
- Department of Pharmaceutical Sciences, Faculty of Medicine, University of Tsukuba
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Tamargo J, Le Heuzey JY, Mabo P. Narrow therapeutic index drugs: a clinical pharmacological consideration to flecainide. Eur J Clin Pharmacol 2015; 71:549-67. [PMID: 25870032 PMCID: PMC4412688 DOI: 10.1007/s00228-015-1832-0] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 03/04/2015] [Indexed: 12/19/2022]
Abstract
PURPOSE The therapeutic index (TI) is the range of doses at which a medication is effective without unacceptable adverse events. Drugs with a narrow TI (NTIDs) have a narrow window between their effective doses and those at which they produce adverse toxic effects. Generic drugs may be substituted for brand-name drugs provided that they meet the recommended bioequivalence (BE) limits. However, an appropriate range of BE for NTIDs is essential to define due to the potential for ineffectiveness or adverse events. Flecainide is an antiarrhythmic agent that has the potential to be considered an NTID. This review aims to evaluate the literature surrounding guidelines on generic substitution for NTIDs and to evaluate the evidence for flecainide to be considered an NTID. METHODS A review of recommendations from various regulatory authorities regarding BE and NTIDs, and publications regarding the NTID characteristics of flecainide, was carried out. RESULTS Regulatory authorities generally recommend reduced BE limits for NTIDs. Some, but not all, regulatory authorities specify flecainide as an NTID. The literature review demonstrated that flecainide displays NTID characteristics including a steep drug dose-response relationship for safety and efficacy, a need for therapeutic drug monitoring of pharmacokinetic (PK) or pharmacodynamics measures and intra-subject variability in its PK properties. CONCLUSIONS There is much evidence for flecainide to be considered an NTID based on both preclinical and clinical data. A clear understanding of the potential of proarrhythmic effects or lack of efficacy, careful patient selection and regular monitoring are essential for the safe and rational administration of flecainide.
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Affiliation(s)
- Juan Tamargo
- Department of Pharmacology, School of Medicine, University Complutense, 28040, Madrid, Spain,
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Doki K, Sekiguchi Y, Kuga K, Aonuma K, Homma M. Serum flecainide S/R ratio reflects the CYP2D6 genotype and changes in CYP2D6 activity. Drug Metab Pharmacokinet 2015. [PMID: 26195225 DOI: 10.1016/j.dmpk.2015.04.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The aims of this study were to clarify whether the ratio of S- to R-flecainide (S/R ratio) in the serum flecainide concentration was associated with the stereoselectivity of flecainide metabolism, and to investigate the effects of the cytochrome P450 (CYP) 2D6 (CYP2D6) genotype and CYP2D6 inhibitor on the serum flecainide S/R ratio. In vitro studies using human liver microsomes and cDNA-expressed CYP isoforms suggested that variability in the serum flecainide S/R ratio was associated with the stereoselectivity of CYP2D6-mediated flecainide metabolism. We examined the serum flecainide S/R ratio in 143 patients with supraventricular tachyarrhythmia. The S/R ratio was significantly lower in intermediate metabolizers and poor metabolizers (IMs/PMs) than in extensive metabolizers (EMs) identified by the CYP2D6 genotype. The cut-off value for the S/R ratio to allow the discrimination between CYP2D6 EMs and IMs/PMs was 0.99. The S/R ratio in patients with co-administration of bepridil, a potent CYP2D6 inhibitor, was lower than 0.99, regardless of the CYP2D6 genotype status. Other factors, including age, sex, body weight, and renal function, did not affect the serum flecainide S/R ratio. This study suggests that the serum flecainide S/R ratio reflects the CYP2D6 genotype and changes in CYP2D6 activity on co-administration of a CYP2D6 inhibitor.
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Affiliation(s)
- Kosuke Doki
- Department of Pharmaceutical Sciences, Faculty of Medicine, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8575, Japan.
| | - Yukio Sekiguchi
- Department of Internal Medicine, Faculty of Medicine, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8575, Japan.
| | - Keisuke Kuga
- Department of Internal Medicine, Faculty of Medicine, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8575, Japan.
| | - Kazutaka Aonuma
- Department of Internal Medicine, Faculty of Medicine, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8575, Japan.
| | - Masato Homma
- Department of Pharmaceutical Sciences, Faculty of Medicine, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8575, Japan.
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Doki K, Sekiguchi Y, Kuga K, Aonuma K, Kohda Y, Homma M. Stereoselective analysis of flecainide enantiomers using reversed-phase liquid chromatography for assessing CYP2D6 activity. Biomed Chromatogr 2014; 28:1193-8. [PMID: 24523024 DOI: 10.1002/bmc.3143] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 12/13/2013] [Accepted: 12/25/2013] [Indexed: 11/08/2022]
Abstract
Stereoselective analyses of flecainide enantiomers were performed using reversed-phase high-performance liquid chromatography (HPLC) equipped with a polysaccharide-based chiral column (Chiralpak AS-RH) and fluorescence detector. Excitation and emission wavelengths were set at 300 and 370 nm, respectively. Flecainide enantiomers in serum and urine were extracted using diethyl ether. The mobile phase solution, comprising 0.1 m potassium hexafluorophosphate and acetonitrile (65:35, v/v), was pumped at a flow rate of 0.5 mL/min. The recoveries of flecainide enantiomers were greater than 94%, with the coefficients of variation (CVs) <6%. The calibration curves of flecainide enantiomers in serum and urine were linear in the concentration range 5-500 ng/mL and 0.75-15 µg/mL (r > 0.999), respectively. CVs in intra-day and inter-day assays were 1.8-5.8 and 3.4-7.5%, respectively. In a pharmacokinetic study, the ratios of (S)- to (R)-flecainide (S/R ratio) in the area under the curve and the amount of flecainide enantiomers excreted in urine were lower in a subject carrying CYP2D6*10/*10 than in subjects carrying CYP2D6*1/*2. The S/R ratio of trough serum flecainide concentration ranged from 0.79 to 1.16 in patients receiving oral flecainide. The present HPLC method can be used to assess hepatic flecainide metabolism in a pharmacokinetic study and therapeutic drug monitoring.
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Affiliation(s)
- Kosuke Doki
- Department of Pharmaceutical Sciences, Faculty of Medicine, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki, 305-8575, Japan
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SCN5A promoter haplotype affects the therapeutic range for serum flecainide concentration in Asian patients. Pharmacogenet Genomics 2013; 23:349-54. [DOI: 10.1097/fpc.0b013e328361fb8d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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CYP2D6 genotype affects age-related decline in flecainide clearance: a population pharmacokinetic analysis. Pharmacogenet Genomics 2013; 22:777-83. [PMID: 22941032 DOI: 10.1097/fpc.0b013e3283588fe5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To investigate the association between age-related decline in flecainide clearance and CYP2D6 genotype, we conducted a population pharmacokinetic analysis of flecainide using routine therapeutic drug monitoring data. METHODS Population pharmacokinetic analysis was performed on retrospective data from 163 genotyped patients treated with oral flecainide for supraventricular tachyarrhythmias. The CYP2D6 genotype was categorized as CYP2D6 homozygous extensive metabolizers (hom-EMs; n=57), heterozygous extensive metabolizers (het-EMs; n=79), and intermediate metabolizers and poor metabolizers (IMs/PMs; n=27). RESULTS Population pharmacokinetic analysis revealed that estimated glomerular filtration rate, body weight, female sex, and aging were important factors for estimating flecainide clearance. The metabolic clearance was decreased age dependently in a curvilinear fashion, where the lower clearance was observed in greater than 60 years for het-EMs and greater than 55 years for IMs/PMs. The reduction in metabolic clearance in elderly (70 years) patients compared with middle-aged (52 years) patients was different among the CYP2D6 genotype groups: 22.1 and 49.5% in CYP2D6 het-EMs and IMs/PMs, respectively, and no change in hom-EMs. A 11.4% reduction in estimated glomerular filtration rate in elderly patients compared with middle-aged patients corresponded to 6.1% decline in flecainide clearance. Overall, the age-related decline in flecainide clearance was 6.1% in hom-EMs, 16.3% in het-EMs, and 28.9% in IMs/PMs groups. CONCLUSION This study suggests that CYP2D6 genotype is a determinant factor of age-related decline in flecainide clearance.
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Heath B, Cui Y, Worton S, Lawton B, Ward G, Ballini E, Doe C, Ellis C, Patel B, McMahon N. Translation of flecainide- and mexiletine-induced cardiac sodium channel inhibition and ventricular conduction slowing from nonclinical models to clinical. J Pharmacol Toxicol Methods 2011; 63:258-68. [DOI: 10.1016/j.vascn.2010.12.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Revised: 12/20/2010] [Accepted: 12/21/2010] [Indexed: 10/18/2022]
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Doki K, Homma M, Kuga K, Aonuma K, Kohda Y. Effects of CYP2D6 genotypes on age-related change of flecainide metabolism: involvement of CYP1A2-mediated metabolism. Br J Clin Pharmacol 2010; 68:89-96. [PMID: 19660006 DOI: 10.1111/j.1365-2125.2009.03435.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
AIMS The aim of this study was to clarify the effects of CYP2D6 genotype on age-related change in flecainide metabolism in patients with supraventricular tachyarrhythmias. An in vitro study using microsomes was performed to identify other CYPs responsible for age-related change in flecainide metabolism. METHODS The study population comprised 111 genotyped patients: CYP2D6-homozygous extensive metabolizers (hom-EMs, n= 34), heterozygous EMs (het-EMs, n= 56), and intermediate and poor metabolizers (IMs/PMs, n= 21). Serum concentrations of flecainide and its metabolites [m-O-dealkylated flecainide (MODF) and m-O-dealkylated lactam of flecainide] were determined by use of a high-performance liquid chromatography. Metabolic ratio (MR) was expressed as serum concentrations of flecainide to its metabolites. In vitro formation of MODF was examined in human liver microsomes and cDNA-expressed CYP isoforms. RESULTS MR was higher in elderly patients (> or =70 years) than in middle-aged patients (<70 years). The increase of MR in elderly patients differed among CYP2D6 genotypes: 1.6-fold in het-EMs [4.3, 95% confidence interval (CI) 2.8, 5.7 vs. 2.7, 95% CI 2.3, 3.1, P < 0.05], 1.5-fold in IMs/PMs (6.0, 95% CI 4.5, 7.6 vs. 4.1, 95% CI 2.9, 5.4, P < 0.05), and no change in hom-EMs. The in vitro study using microsomes revealed that both CYP2D6 and CYP1A2 were involved in the formation of MODF. MODF formation in CYP2D6 PM microsomes increased as CYP1A2 activity increased. CONCLUSIONS The results suggest that patients with poor CYP2D6-mediated metabolism (het-EMs and IMs/PMs) showed age-related reduction in flecainide metabolism because metabolism was taken over by CYP1A2, whose activity decreases with age.
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Affiliation(s)
- Kosuke Doki
- Department of Pharmaceutical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan
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Doki K, Homma M, Kuga K, Aonuma K, Sakai S, Yamaguchi I, Kohda Y. Gender-associated differences in pharmacokinetics and anti-arrhythmic effects of flecainide in Japanese patients with supraventricular tachyarrhythmia. Eur J Clin Pharmacol 2007; 63:951-7. [PMID: 17665182 DOI: 10.1007/s00228-007-0348-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Accepted: 07/05/2007] [Indexed: 12/26/2022]
Abstract
OBJECTIVE We examined the effect of gender-associated differences in pharmacokinetics on the anti-arrhythmic effects of flecainide in Japanese patients with supraventricular tachyarrhythmia and in healthy subjects. METHODS The study population comprised 72 outpatients (52 males and 20 females) treated with oral flecainide for supraventricular tachyarrhythmias. Serum flecainide concentrations were determined by use of high-performance liquid chromatography. The anti-arrhythmic efficacy of flecainide was assessed for at least 2 months through evaluation of symptomatology, electrocardiograms, and Holter monitoring. Pharmacokinetics of flecainide after a single 50-mg dose was examined in 14 healthy subjects (7 males and 7 females). RESULTS The daily dose of flecainide did not differ between males and females (2.87 +/- 0.68 versus 2.92 +/- 0.90 mg/kg). The serum flecainide concentration was significantly lower in males than in females (315 +/- 151 versus 408 +/- 184 ng/mL, P < 0.05). Clinically relevant efficacy of flecainide was achieved significantly (P < 0.05) less often in male patients (31 of 52; 60%) than in female patients (19 of 20; 95%). We confirmed that nonrenal clearance of flecainide among healthy subjects was significantly higher in males than in females (0.77 +/- 0.16 versus 0.57 +/- 0.06 L h(-1) kg(-1), P < 0.05). CONCLUSIONS Our results suggest that the anti-arrhythmic efficacy of flecainide differed between males and females because of gender-associated differences in pharmacokinetics.
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Affiliation(s)
- Kosuke Doki
- Department of Pharmaceutical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ten-nodai 1-1-1, Tsukuba, Ibaraki, 305-8575, Japan
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Doki K, Homma M, Kuga K, Kawano S, Aonuma K, Yamaguchi I, Kohda Y. Impact of serum flecainide level on control of atrial fibrillation in a case treated with cardiac resynchronization therapy. J Clin Pharm Ther 2007; 32:409-11. [PMID: 17635343 DOI: 10.1111/j.1365-2710.2007.00837.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A 72-year-old male patient with dilated cardiomyopathy was treated with oral flecainide (100 mg/day) for persistent atrial fibrillation (AF) that could not be converted to sinus rhythm by electrical cardioversion. Initiation of flecainide treatment provided sinus rhythm without prolongation of QRS and QTc, bradycardia and first-degree atrioventricular block at a serum flecainide level of 438 ng/mL. Then, he received cardiac resynchronization therapy (CRT). Dose reduction to 50 mg/day because of stabilization of heart rate after CRT produced AF at a serum flecainide level of 270 ng/mL. Electrical cardioversion did not restore the AF to a sinus or pacing rhythm. Dose escalation of flecainide (to 100 mg/day) restored the pacing rhythm at a serum flecainide level of 401 ng/mL. This case suggests that in the Japanese population, serum flecainide level should be maintained at >300 ng/mL to control AF even after effective CRT.
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Affiliation(s)
- K Doki
- Department of Pharmaceutical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
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Doki K, Homma M, Kuga K, Kusano K, Watanabe S, Yamaguchi I, Kohda Y. Effect of CYP2D6 genotype on flecainide pharmacokinetics in Japanese patients with supraventricular tachyarrhythmia. Eur J Clin Pharmacol 2006; 62:919-26. [PMID: 16944116 DOI: 10.1007/s00228-006-0188-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Accepted: 07/18/2006] [Indexed: 12/20/2022]
Abstract
OBJECTIVE To examine the effect of CYP2D6 genotype on the pharmacokinetics of flecainide, we conducted a population pharmacokinetic analysis of the data collected during routine therapeutic drug monitoring of Japanese patients with supraventricular tachyarrhythmia. METHODS Population analysis was performed on retrospective data from 58 patients with normal kidney and liver function treated with oral flecainide for supraventricular tachyarrhythmia. Serum concentrations of flecainide were determined by high-performance liquid chromatography. CYP2D6 genotyping for extensive metabolizer (EM), intermediate metabolizer (IM) and poor metabolizer (PM) alleles was conducted by allele-specific polymerase chain reaction (PCR) and stepdown PCR. WinNonMix was used to estimate oral clearance (CL/F) of flecainide with a one-compartment model for first-order absorption. RESULTS Body weight, age, sex, serum creatinine concentration (Scr), and CYP2D6 genotype influenced flecainide pharmacokinetics. The CL/F was affected by age (30% reduction in > or =70 years old) and sex (24% reduction in females). The ratios of CL/F for the five CYP2D6 genotypes were: 1.00 (EM/EM), 0.89 (EM/IM), 0.84 (EM/PM), 0.79 (IM/IM), 0.73 (IM/PM). A model including these five covariates reduced the interpatient variability of CL/F from 32.9% (base model) to 17.8%. Using a Bayesian method we estimated that the CL/F in IMs was significantly lower than in homozygous EMs (0.25+/-0.05 l h(-1) kg(-1) vs. 0.37+/-0.08 l h(-1) kg(-1), P<0.05) among male patients under 70 years old. CONCLUSIONS CYP2D6 genotype, even in IMs, as well as body weight, age, sex, and Scr influence flecainide pharmacokinetics in Japanese patients with supraventricular tachyarrhythmia.
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Affiliation(s)
- Kosuke Doki
- Department of Pharmaceutical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ten-nodai 1-1-1, Tsukuba, Ibaraki, 305-8575, Japan
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