| 1. |
- Carlsson, Björn, et al.
(författare)
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Enantioselective Analysis of Citalopram and Metabolites in Adolescents
- 2001
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Ingår i: Therapeutic drug monitoring. - : Ovid Technologies (Wolters Kluwer Health). - 0163-4356. ; 23, s. 658-
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Tidskriftsartikel (refereegranskat)abstract
- Studies of the antidepressant effect and pharmacokinetics of citalopram have been performed in adults, but the effects on children and adolescents have only been studied to a minor extent despite its increasing use in these age groups. The aim of this study was to investigate a group of adolescents treated for depression, with respect to the steady-state plasma concentrations of the enantiomers of citalopram and its demethylated metabolites desmethylcitalopram and didesmethylcitalopram. Moreover, the authors studied the genotypes for the polymorphic cytochrome P450 enzymes CYP2D6 and CYP2C19 in relation to the different enantiomers. The S/R ratios of citalopram and desmethylcitalopram found in this study of 19 adolescents were similar to studies involving older patients. The concentrations of the R-(-)- and S-(+)-enantiomers of citalopram and desmethylcitalopram were also in agreement with values from earlier studies, the R-(-)-enantiomer (distomer) being the major enantiomer. The results indicate that the use of oral contraceptives may have some influence on the metabolism of citalopram. This might be because of an interaction of the contraceptive hormones with the CYP2C19 enzyme.
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| 2. |
- Chang, Ming, et al.
(författare)
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CYP2C19*17 affects R-warfarin plasma clearance and warfarin INR/dose ratio in patients on stable warfarin maintenance therapy
- 2015
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Ingår i: European Journal of Clinical Pharmacology. - : Springer Science and Business Media LLC. - 0031-6970 .- 1432-1041. ; 71:4, s. 433-439
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Tidskriftsartikel (refereegranskat)abstract
- We aimed to assess the influence of CYP2C19*17 on R-warfarin clearance as well as the effect of CYP2C19, CYP2C8, CYP2C9, and VKORC1 polymorphisms together with non-genetic factors on warfarin international normalized ratio (INR)/daily dose. One hundred fifty Caucasian Italian outpatients with data on steady-state plasma concentrations of S- and R-warfarin were genotyped for CYP2C19 (*2, *3, *4, *17), CYP2C9 (*2, *3), CYP2C8*3, and VKORC1*2. The statistical analysis was performed on the effect of genotypes/haplotypes, age, sex, and body weight on the clearance of warfarin enantiomers and dose-normalized INR. R-warfarin clearance was 32 % higher in carriers of CYP2C19*17 than in carriers of CYP2C19*2 (mean 2.5 mL/min, 95 % confidence interval (CI) 2.3-2.8 vs. 1.9 mL/min, 95 % CI 1.7-2.2; P (post hoc) = 0.01). Patients with CYP2C19*1/*1 genotype had an intermediate clearance (mean 2.1 mL/min, 95 % CI 1.8-2.4). The genotypes of VKORC1, CYP2C9, and CYP2C19, together with non-genetic factors (age, sex, and body weight) explained 52 % of the variability in warfarin INR/daily dose, of which CYP2C19 genotypes accounted for 7 %. This is the first study to include the gain-of-function CYP2C19*17 allele when assessing the impact of CYP2C19 polymorphisms on the clearance of warfarin enantiomers. CYP2C19 genotypes influenced the clearance of R-warfarin and contributed significantly to the variability in INR/daily dose, indirectly indicating a clinical relevance of R-warfarin.
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| 3. |
- Dahl, Marja-Liisa, et al.
(författare)
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Cytochromes P450
- 2006
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Ingår i: Psychopharmacogenetics. - : M Springer science + Businesss Media Inc.
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Bokkapitel (refereegranskat)
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| 4. |
- De Fazio, Salvatore, et al.
(författare)
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Role of CYP3AS in abnormal clearance of methadone
- 2008
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Ingår i: The Annals of Pharmacotherapy. - 1060-0280 .- 1542-6270. ; 42:6, s. 893-897
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To report a case of unusually low concentrations of methadone in a polydrug abuser during maintenance treatment with methadone. CASE SUMMARY: A 25-year-old man (weight 55 kg, height 165 cm) with a 12-year history of polydrug abuse was admitted to an opiates withdrawal methadone program. At the time of our observation, he was using both cannabinoids and heroin; no other medical conditions were discovered. Within the opiates withdrawal methadone program, under medical supervision, the patient started methadone therapy (20 mg/day). Two weeks later, an Abuscreen assay for methadone screening in the urine was negative and, to prevent the development of withdrawal symptoms, the dose of methadone was increased to 60 mg/day. One day later, the patient was asked to collect another urine sample in the presence of a nurse. The Abuscreen for methadone in urine remained negative. Evaluation of urinary samples collected over 24 hours documented low concentrations of methadone and high levels of 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (the primary metabolite of methadone). Evaluation for the presence of the most common polymorphisms in the cytochrome P450 and P-glycoprotein genes showed that the patient was heterozygous for the CYP3A5*1 allele and for 2 single nucleotide polymorphisms in the P-glyooprotein gene (1236C/T and 3435C/T). DISCUSSION: In this patient, poor methadone adherence was ruled out because of the presence of physicians and nurses during both methadone maintenance treatment and Abuscreen screening. Moreover, because the patient reported only heroin and cannabis at the time of evaluation, drug interactions were ruled out as possible causes for the rapid clearance of methadone. CONCLUSIONS: In this case, CYP3A5 polymorphism may have played a role in the rapid methadone metabolism.
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| 5. |
- De Luca, C., et al.
(författare)
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Idiopathic environmental intolerances (IEI) : from molecular epidemiology to molecular medicine
- 2010
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Ingår i: Indian Journal of Experimental Biology. - 0019-5189. ; 48:7, s. 625-635
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Forskningsöversikt (refereegranskat)abstract
- Inherited or acquired impairment of xenobiotics metabolism is a postulated mechanism underlying environment-associated pathologies such as multiple chemical sensitivity, fibromyalgia, chronic fatigue syndrome, dental amalgam disease, and others, also collectively named idiopathic environmental intolerances (IEI). In view of the poor current knowledge of their etiology and pathogenesis, and the absence of recognised genetic and metabolic markers of the diseases. They are often considered "medically unexplained syndromes",. These disabling conditions share the features of polysymptomatic multi-organ syndromes, considered by part of the medical community to be aberrant responses triggered by exposure to low-dose organic and inorganic chemicals and metals, in concentrations far below average reference levels admitted for environmental toxicants. A genetic predisposition to altered biotransformation of environmental chemicals, drugs, and metals, and of endogenous low-molecular weight metabolites, caused by polymorphisms of genes coding for xenobiotic metabolizing enzymes, their receptors and transcription factors appears to be involved in the susceptibility to these environment-associated pathologies, along with epigenetic factors. Free radical/antioxidant homeostasis may also be heavily implicated, indirectly by affecting the regulation of xenobiotic metabolizing enzymes, and directly by causing increased levels of oxidative products, implicated in the chronic damage of cells and tissues, which is in part correlated with clinical symptoms. More systematic studies of molecular epidemiology, toxico- and pharmaco-genomics, elucidating the mechanisms of regulation, expression, induction, and activity of antioxidant/detoxifying enzymes, and the possible role of inflammatory mediators, promise a better understanding of this pathologically increased sensitivity to low-level chemical stimuli, and a solid basis for effective individualized antioxidant- and/or chelator-based treatments.
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| 6. |
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| 7. |
- Gokalp, Osman, et al.
(författare)
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Mild hypoglycaemic attacks induced by sulphonylureas related to CYP2C9, CYP2C19 and CYP2C8 polymorphisms in routine clinical setting
- 2011
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Ingår i: European Journal of Clinical Pharmacology. - : Springer Science and Business Media LLC. - 0031-6970 .- 1432-1041. ; 67:12, s. 1223-1229
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Tidskriftsartikel (refereegranskat)abstract
- To evaluate the impact of polymorphisms in the cytochrome P450 (CYP) 2C9, 2C19 and 2C8 genes on the risk of mild hypoglycaemic attacks in patients treated with sulphonylureas. One hundred and eight type 2 diabetic patients (50 men, 58 women), treated with oral antidiabetics, including at least one from the sulphonylurea group (glimepiride n = 50, gliclazide n = 46, or glipizide n = 12) for 3 months or longer, were included in the study. Symptoms of hypoglycaemia (sweating, tremor, anxiety and palpitations) during a 3 month period were recorded and confirmed by home glucose measurements. Gender, age, body mass index, creatinine clearance, HbA1c, oral antidiabetic dose and concomitant medication were assessed together with functional CYP2C9, CYP2C19 and CYP2C8 polymorphisms, analysed by real-time PCR methods. Fifteen patients (eight men, seven women) reported hypoglycaemia symptoms which were validated by their home glucose measurements (< 70 mg/dl). Heterozygosity and homozygosity for CYP2C9 variant alleles (*2 or *3) tended to be more frequent among patients who reported hypoglycaemic attacks (60 and 7%) than those who did not (39 and 3%). Similarly, the CYP2C8*1/*3 genotype tended to be more frequent in patients with (47%) than without (27%) hypoglycaemia, while no such trend was observed for CYP2C19 variants. However, only in the gliclazide group a significant association between CYP2C9 genotype and hypoglycaemic attacks was observed (P = 0.035). None of the other covariates showed any significant association with the risk of hypoglycaemic attacks. CYP2C9 polymorphisms leading to decreased enzyme activity show a modest impact on the risk of mild hypoglycaemia attacks during oral antidiabetic treatment, with a significant association in patients treated with gliclazide.
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| 8. |
- Gunes, Arzu, et al.
(författare)
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ABCB1 polymorphisms influence steady-state plasma levels of 9-hydroxyrisperidone and risperidone active moiety
- 2008
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Ingår i: Therapeutic Drug Monitoring. - 0163-4356 .- 1536-3694. ; 30:5, s. 628-633
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Tidskriftsartikel (refereegranskat)abstract
- Risperidone is metabolized to its active metabolite, 9-hydroxy risperidone, mainly by the cytochrome P450 enzymes CYP2D6 and 3A4. Its antipsychotic effect is assumed to be related to the active moiety, that is, the sum of risperidone and 9-hydroxyrisperidone. Both risperidone and 9-hydroxyrisperidone are substrates of P-glycoprotein (P-gp), a transport protein involved in drug absorption, distribution, and elimination. The aim of the present study was to evaluate the influence of polymorphisrns in genes encoding CYP3A5 and P-gp (ABCB1) on the steady-state plasma levels of risperidone, 9-hydroxyrisperidone, and the active moiety, taking CYP2D6 genotype status into account. Forty-six white patients with schizophrenia treated with risperidone (1-10 mg/d) in monotherapy for 4-6 weeks were genotyped, and their plasma concentrations of risperidone and 9-hydroxyrisperidone were measured. Dose-corrected plasma concentrations (C/D) of risperidone, 9-hydroxyrisperidone, and active moiety showed up to 68-, 9-, and 10-fold interindividual variation, respectively. Six patients carried 1 CYP3A5*1 allele and therefore were likely to express the CYP3A5 enzyme. The CYP3A5 genotype did not influence risperidone, 9-hydroxyrisperidone, or active moiety C/Ds. The CYP2D6 genotype in these 46 patients was again associated with risperidone C/D (P = 0.001) but not with 9-hydroxyrisperidone C/D or active moiety C/D, as previously shown by our group in 37 of these patients. Patients homozygous for the ABCB1 3435T/2677T/1236T haplotype had significantly lower C/Ds of 9-hydroxyrisperidone (P = 0.026) and active moiety (P = 0.028) than patients carrying other ABCB1 genotypes. In conclusion, our results confirmed the significant effect of CYP2D6 genotype oil the steady-state plasma levels of risperidone and showed that ABCB1 polymorphisins have a moderate effect oil those of 9-hydroxyrisperidone and the active moiety.
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| 9. |
- Gunes, Arzu, et al.
(författare)
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Association between HTR2C and HTR2A polymorphisms and metabolic abnormalities in patients treated with olanzapine and clozapine
- 2009
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Ingår i: Journal of Clinical Psychopharmacology. - 0271-0749 .- 1533-712X. ; 29:1, s. 65-68
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Tidskriftsartikel (refereegranskat)abstract
- Serotonin 2C and 2A receptor (5-HT2C and 5-HT2A) antagonisms are hypothesized to play a role in the metabolic adverse effects induced by olanzapine and clozapine. Associations between polymorphisms in 5-HT2C and 5-HT2A receptor coding genes, HTR2C and HTR2A, with antipsychotic-induced weight gain have been reported. The impact of HTR2C and HTR2A polymorphisms on body mass index (BMI), glucose-insulin homeostasis, and blood lipid levels was evaluated in 46 patients with schizophrenia or schizoaffective disorder and treated with olanzapine (n = 28) or clozapine (n = 18) for at least 6 months. Olanzapine-treated patients with HTR2C haplotype C (-759C, -697C, and 23Ser) had higher BMI (P = 0.029) and C peptide levels (P = 0.029) compared with patients with haplotype B (-759T, -697C, and 23Cys). The frequency of patients homozygous for the HTR2C haplotype A (-759C, -697G, and 23Cys) was significantly higher among clozapine-treated patients with obesity (BMI >/= 30 kg/m) compared with nonobese patients (P = 0.015; odds ratio, 28; 95% confidence interval, 2-380). Patients carrying the HTR2A haplotype 2 (-1438A, 102T, and 452His) had significantly higher C peptide levels compared with haplotype 3 (-1438A, 102T, and 452Tyr) carriers in the olanzapine group (P = 0.034) and in the overall study population (P = 0.019). None of the haplotypes were associated with serum levels of insulin, triglycerides, and cholesterol or with homeostasis model assessment index for insulin resistance. In conclusion, both HTR2C and HTR2A gene polymorphisms seem to be associated with the occurrence of metabolic abnormalities in patients treated with olanzapine or clozapine.
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| 10. |
- Gunes, Arzu, et al.
(författare)
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Further evidence for association between 5-HT2C receptor gene polymorphisms and extrapyramidal side effects in male schizophrenic patients
- 2008
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Ingår i: European Journal of Clinical Pharmacology. - : Springer Science and Business Media LLC. - 0031-6970 .- 1432-1041. ; 64:5, s. 477-482
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Tidskriftsartikel (refereegranskat)abstract
- RATIONALE: Antipsychotic-induced extrapyramidal side effects (EPS) are still a major problem in the treatment of schizophrenia. Serotonin 2C receptors (5-HT(2C)) have regulatory effects on dopaminergic pathways in brain regions involved with EPS. Polymorphisms in the 5-HT(2C) gene (HTR2C) have been suggested to be associated with the risk of developing EPS. OBJECTIVE: Our purpose was to evaluate the impact of polymorphisms in the HTR2C gene on the occurrence of EPS in male schizophrenic patients. METHODS: Ninety-nine male Caucasian chronic schizophrenic patients on long-term treatment with classical antipsychotics were genotyped for the -997 G/A, -759 C/T, -697 G/C and Cys23Ser polymorphisms of HTR2C. EPS (dystonia, parkinsonism, tardive dyskinesia) were assessed by the Simpson-Angus Scale and the Abnormal Involuntary Movement Scale. Fifty-one patients had current or previous history of EPS, whereas 48 patients had no symptoms or history of EPS. To rule out a possible association between HTR2C polymorphisms and schizophrenia, 112 healthy male volunteers were also genotyped. RESULTS: Allele frequencies of -997A, -759T and -697C did not differ between the groups, whereas patients with EPS had a significantly (p = 0.025) higher frequency of the 23Ser allele (0.29) than did patients without EPS (0.15) or healthy volunteers (0.13). A similar trend was observed for a haplotype including the -997G, -759C, -697C and 23Ser alleles (p = 0.04). CONCLUSIONS: Results confirm previously reported associations between the HTR2C 23Ser allele and EPS occurrence and suggest the novel finding of an HTR2C haplotype association with EPS in male chronic schizophrenic patients.
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| 11. |
- Gunes, Arzu, et al.
(författare)
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Influence of genetic polymorphisms, smoking, gender and age on CYP1A2 activity in a Turkish population
- 2009
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Ingår i: Pharmacogenomics (London). - : Future Medicine Ltd. - 1462-2416 .- 1744-8042. ; 10:5, s. 769-778
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: To study the variation in CYP1A2 activity in relation to smoking, gender, age and CYP1A2 polymorphisms. MATERIALS & METHODS: CYP1A2 activity was determined by plasma paraxanthine:caffeine ratio (17X:137X) 4 h after the intake of a standardized cup of coffee in 146 Turkish healthy volunteers. Seven CYP1A2 polymorphisms (-3860G>A, -3113G>A, -2467del/T, -739T>G, -729C>T, -163C>A and 5347T>C) were analyzed. RESULTS: The 17X:137X ratios were increased in smokers (p < 0.0001) and tended to be higher in men both among nonsmokers (p = 0.051) and smokers (p = 0.064). Age-related differences were observed only among nonsmoking women (p = 0.024). The -163C>A polymorphism correlated with 17X:137X ratios only in smokers (p = 0.006). Furthermore, increased 17X:137X ratios were observed in CYP1A2 haplotype H4 (-3860G, -3113G, -2467del, -739T, -729C, -163A and 5347T) carriers in the overall study population (p = 0.026). Multiple regression analyses including smoking, gender, -163C>A genotype and age revealed a significant influence of smoking (p < 0.0001) and gender (p = 0.002) in the overall study population. However, in nonsmokers only the influence of gender remained significant (p = 0.021), while in smokers the influence of the -163C>A genotype held the statistical significance (p = 0.019). The influence of haplotype H4 remained significant (p = 0.028) in the overall study population in similar analyses. CONCLUSION: Smoking has the strongest impact on CYP1A2 activity, while gender and haplotype H4 showed marginal effects. The influence of the -163C>A polymorphism on CYP1A2 activity in smokers suggests an effect on the inducibility of the enzyme.
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| 12. |
- Gunes, Arzu, 1975-
(författare)
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Pharmacogenetics and Antipsychotic Treatment in Schizophrenia with Special Focus on Adverse Drug Reactions
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Genetically determined differences in drug metabolism and disposition and drug targets play a pivotal role in the interindividual variability in the clinical outcome of antipsychotic treatment. The aim of this thesis was to study the impact of polymorphisms in genes involved in the pharmacokinetics and pharmacodynamics of antipsychotics, with special focus on their extrapyramidal and metabolic adverse effects. Polymorphisms in serotonin 2A and 2C receptor coding genes (HTR2A and HTR2C) were found to be associated with the risk to develop extrapyramidal side effects (EPS) in patients on short term perphenazine treatment. A further study in a larger group of patients on long term treatment with various classical antipsychotics confirmed the association between occurrence of EPS and HTR2C polymorphisms. In another study, dose corrected steady state serum clozapine and N-desmethylclozapine concentrations (C/D) and insulin elevation during clozapine therapy were found to correlate with CYP1A2 but not with CYP2D6 polymorphisms. Furthermore, HTR2C and HTR2A polymorphisms were found to have significant influences on BMI and C-peptide levels in patients treated with olanzapine and clozapine. Evaluation of the impact of polymorphisms in genes encoding CYP3A4, CYP3A5 and P-glycoprotein (ABCB1) in addition to CYP2D6 on the steady state plasma levels of risperidone, 9-hydroxyrisperidone and their active moiety revealed a significant influence of ABCB1 genotype on 9-hydroxyrisperidone and active moiety C/Ds, while CYP2D6 genotype associated with risperidone C/Ds but not with 9-hydroxyrisperidone or active moiety C/D. We have shown that polymorphisms in genes involved in the pharmacokinetics and the pharmacodynamics of antipsychotic drugs play a role in the occurrence of adverse effects, both EPS and metabolic disturbances, induced by antipsychotic treatment. Genotyping for HTR2A, HTR2C, CYP1A2, CYP2D6 and ABCB1 polymorphisms may therefore potentially provide useful information to identify patients at higher risk to develop EPS or metabolic adverse during schizophrenia treatment with antipsychotic drugs.
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| 13. |
- Gunes, Arzu, et al.
(författare)
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Serotonin and dopamine receptor gene polymorphisms and the risk of extrapyramidal side effects in perphenazine-treated schizophrenic patients
- 2007
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Ingår i: Psychopharmacology. - : Springer Science and Business Media LLC. - 0033-3158 .- 1432-2072. ; 190:4, s. 479-484
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Tidskriftsartikel (refereegranskat)abstract
- Rationale: Perphenazine, a classical antipsychotic drug, has the potential to induce extrapyramidal side effects (EPS). Dopaminergic and serotonergic pathways are involved in the therapeutic and adverse effects of the drug. Objectives: To evaluate the impact of polymorphisms in the dopamine D 2 and D3 and serotonin 2A and 2C receptor genes (DRD2, DRD3, HTR2A, and HTR2C) on short-term effects of perphenazine monotherapy in schizophrenic patients. Materials and methods: Forty-seven Estonian inpatients were evaluated before and after 4-6 weeks of treatment by Simpson-Angus rating scale, Barnes scale, and Positive and Negative Symptom Scale. Genotyping was performed for common DRD2, DRD3, HTR2A, and HTR2C gene polymorphisms, previously reported to influence receptor expression and/or function. Results: Most of the patients (n = 37) responded to the treatment and no significant association was observed between the polymorphisms and antipsychotic response. The 102C allele of HTR2A and the -697C and 23Ser alleles of HTR2C were more frequent among patients with EPS (n = 25) compared to patients without EPS (n = 22) (p = 0.02, 0.01, and 0.02, respectively). The difference between patients with and without EPS in variant allele frequencies remained significant after multiple model analyses including age, gender, and duration of antipsychotic treatment as covariants. There was no significant association between EPS occurrence and polymorphisms in the DRD2 and DRD3 genes. Conclusions: An association was observed between polymorphisms in HTR2A and HTR2C genes and occurrence of acute EPS in schizophrenic patients treated with perphenazine monotherapy. Larger study populations are needed to confirm our findings.
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| 14. |
- Güzey, C., et al.
(författare)
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Antipsychotic-induced extrapyramidal symptoms in patients with schizophrenia : associations with dopamine and serotonin receptor and transporter polymorphisms
- 2007
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Ingår i: European Journal of Clinical Pharmacology. - : Springer Science and Business Media LLC. - 0031-6970 .- 1432-1041. ; 63:3, s. 233-241
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Tidskriftsartikel (refereegranskat)abstract
- Background: Little is known about the influence of polymorphisms of the dopamine and serotonin system on the risk for extrapyramidal symptoms (EPS) during treatment with antipsychotic drugs. Methods: Of 119 subjects with schizophrenia treated with antipsychotics, 63 had current or previous EPS (acute dystonia, parkinsonism, tardive dyskinesia), and 56 had no such symptoms. All subjects were genotyped for a total of eight dopamine and serotonin receptor and transporter polymorphisms: the Taq1A polymorphism of the dopamine D2 receptor (DRD2) gene, the Msc1 polymorphism of the dopamine D3 receptor (DRD3) gene, the variable number of tandem repeat (VNTR) polymorphism of the dopamine transporter (DAT1) gene, four polymorphisms (102T/C, His452Tyr, 516 C/T, and Thr25Asn) of the serotonin 5-HT2A receptor (5HTR2A) gene, and the 5HTTLPR polymorphism of the serotonin transporter (5HTT) gene. Results: The frequency of the A1 allele of the DRD2 Taq1A polymorphism was significantly higher in the EPS group than in the control group [16% vs. 7%, P=0.040; odds ratio (OR) 2.4; 95% confidence interval (CI) 1.1-5.7]. Also, the 9 repeat allele of the DAT1 VNTR polymorphism was significantly more common in the EPS group (42% vs. 28%, P=0.030; OR 1.9; 95% CI 1.1-3.3). Being a carrier of both DRD2 Taq1A A1 and DAT1 VNTR 9 repeat alleles was also significantly associated with the occurrence of EPS (19% vs. 6%, P=0.040; OR 4.0; 95% CI 1.05-15.2) No significant differences in allele frequencies were found for the other polymorphisms. Conclusion: Presence of the Taq1A A1 allele of the DRD2 and the 9 repeat allele of the DAT1 VNTR polymorphisms might be risk factors for EPS caused by antipsychotic drugs.
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| 15. |
- Hamberg, Anna Karin, et al.
(författare)
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A PK-PD model for predicting the impact of age, CYP2C9, and VKORC1 genotype on individualization of warfarin therapy
- 2007
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Ingår i: Clinical Pharmacology and Therapeutics. - : Springer Science and Business Media LLC. - 0009-9236 .- 1532-6535. ; 81:4, s. 529-538
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to characterize the relationship between warfarin concentrations and international normalized ratio (INR) response and to identify predictors important for dose individualization. S- and R-warfarin concentrations, INR, and CYP2C9 and VKORC1 genotypes from 150 patients were used to develop a population pharmacokinetic/pharmacodynamic model in NONMEM. The anticoagulant response was best described by an inhibitory E(MAX) model, with S-warfarin concentration as the only exposure predictor for response. Delay between exposure and response was accounted for by a transit compartment model with two parallel transit compartment chains. CYP2C9 genotype and age were identified as predictors for S-warfarin clearance, and VKORC1 genotype as a predictor for warfarin sensitivity. Predicted INR curves indicate important steady-state differences between patients with different sets of covariates; differences that cannot be foreseen from early INR assessments alone. It is important to account for CYP2C9 and VKORC1 genotypes and age to improve a priori and a posteriori individualization of warfarin therapy.
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| 16. |
- Holmgren, Per, et al.
(författare)
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Enantioselective analysis of citalopram and its metabolites in postmortem blood and genotyping for CYD2D6 and CYP2C19
- 2004
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Ingår i: Journal of Analytical Toxicology. - : Oxford University Press (OUP). - 0146-4760 .- 1945-2403. ; 28:2, s. 94-104
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Tidskriftsartikel (refereegranskat)abstract
- Citalopram, a selective serotonin reuptake inhibitor, is one of the most commonly found drugs in Swedish forensic autopsy cases. Citalopram is a racemic drug with 50:50 of the S- and R- enantiomers. Enantioselective analysis of citalopram and its metabolites desmethylcitalopram and didesmethylcitalopram were performed in femoral blood from 53 autopsy cases by a chiral high-performance liquid chromatography (HPLC) method. The mean (± standard deviation) S/R ratio for citalopram was 0.67 ± 0.25 and for desmethylcitalopram, 0.68 ± 0.20. We found increasing S/R ratios with increasing concentrations of citalopram. We also found that high citalopram S/R ratios were associated with a high parent drug-to-metabolite ratio and may be an indicator of recent intake. Citalopram is metabolized by cytochrome P450 (CYP) 3A4, 2C19, and 2D6. Genotyping for the polymorphic CYP2C19 and CYP2D6 revealed no poor metabolizers regarding CYP2C19 and only 2 (3.8%) poor metabolizers regarding CYP2D6. The presence of drugs metabolized by and/or inhibiting these enzymes in several of the cases suggests that such pharmacokinetic interactions are a more important (practical) problem than metabolic deficiency. Enantioselective analysis of citalopram and its metabolites can provide additional information when interpreting forensic toxicology results and might be a necessity in the future.
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| 17. |
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| 18. |
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| 19. |
- Korkina, L., et al.
(författare)
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The chemical defensive system in the pathobiology of idiopathic environment-associated diseases
- 2009
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Ingår i: Current drug metabolism. - 1389-2002 .- 1875-5453. ; 10:8, s. 914-931
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Forskningsöversikt (refereegranskat)abstract
- Chemical defensive system consisting of bio-sensoring, transmitting, and responsive elements has been evolved to protect multi-cellular organisms against environmental chemical insults (xenobiotics) and to maintain homeostasis of endogenous low molecular weight metabolites (endobiotics). Both genetic and epigenetic defects of the system in association with carcinogenesis and individual sensitivity to anti-tumor therapies have been intensely studied. Recently, several non-tumor human pathologies with evident environmental components such as rather rare functional syndromes (multiple chemical sensitivity, chronic fatigue, Persian Gulf, and fibromyalgia now collectively labeled as idiopathic environmental intolerances) and common diseases (vitiligo and systemic lupus erythematosus) have become subjects of the research on the impaired metabolism and detoxification of xenobiotics and endogenous toxins. Here, we collected and critically reviewed epidemiological, genetic, and biochemical data on the involvement and possible role of cytochrome P450 super family enzymes, glutathione-S-transferase isozymes, catechol-O-methyl-transferase, UDP-glucuronosyl transferases, and proteins detoxifying inorganic and organic peroxides (catalase, glutathione peroxidase, and peroxiredoxin) in the above pathologies. Genetic predisposition assessed mainly by single nucleotide polymorphism and gene expression analyses revealed correlations between defects in genes encoding xenobiotic-metabolizing and/or detoxifying enzymes and risk/severity of these syndromes/diseases. Proteome analysis identified abnormal expression of the enzymes. Their functions were affected epigenetically leading to metabolic impairment and, as a consequence, to the negative health outcomes shared by some of these pathologies. Data obtained so far suggest that distinct components of the chemical defensive system could be suitable molecular targets for future pathogenic therapies.
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| 20. |
- Kubo, K., et al.
(författare)
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Population differences in S-warfarin pharmacokinetics among African Americans, Asians and whites : their influence on pharmacogenetic dosing algorithms
- 2017
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Ingår i: The Pharmacogenomics Journal. - : NATURE PUBLISHING GROUP. - 1470-269X .- 1473-1150. ; 17:6, s. 494-500
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Tidskriftsartikel (refereegranskat)abstract
- Using population pharmacokinetic analysis (PPK), we attempted to identify predictors of S-warfarin clearance (CL(S)) and to clarify population differences in S-warfarin pharmacokinetics among a cohort of 378 African American, Asian and white patients. Significant predictors of CL(S) included clinical (age, body weight and sex) and genotypic (CYP2C9*2,*3 and *8) factors, as well as African American ethnicity, the median CL(S) being 30% lower in the latter than in Asians and whites (170 versus 243 and 250 ml h(-1), P<0.01). The plasma S-warfarin (Cp(S)) time courses following the genotype-based dosing algorithms simulated using the PPK estimates showed African Americans with CYP2C9*1/*1 and any of the VKORC1 genotypes would have an average Cp(S) at steady state 1.5-1.8 times higher than in Asians and whites. These results indicate warfarin dosing algorithms should be evaluated in each respective ethnic population. Further study of a large African American cohort will be necessary to confirm the present findings.
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| 21. |
- Magliulo, Laura, et al.
(författare)
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Do CYP3A and ABCB1 genotypes influence the plasma concentration and clinical outcome of donepezil treatment?
- 2011
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Ingår i: European Journal of Clinical Pharmacology. - : Springer Science and Business Media LLC. - 0031-6970 .- 1432-1041. ; 67:1, s. 47-54
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Tidskriftsartikel (refereegranskat)abstract
- Purpose The aim of our study was to evaluate the impact of CYP3A4, CYP3A5, and ABCB1 polymorphisms on donepezil disposition and clinical outcome. Methods Fifty-four Italian patients diagnosed with probable mild to moderate Alzheimer's disease, treated with donepezil (37 patients 5 mg/day, 17 patients 10 mg/day) were genotyped for CYP3A4 (*1B, *3, and *4), CYP3A5 (*2, *3, and *6) and ABCB1 (3435C>T, 2677G>T/A, and 1236C>T) polymorphisms. All patients were evaluated for the degree of cognitive impairment with Mini Mental State Examination (MMSE) screening test at baseline (before treatment) and after at least 3 months of donepezil treatment at stable dose, when the drug plasma levels were measured. Results Three patients carried one detrimental CYP3A4 allelic variant, and 12 carried one functional CYP3A5*1 allele. No statistically significant association was found between CYP3A4 or CYP3A5 genotypes and plasma donepezil concentrations, or between genotypes and clinical response (as measured by change in MMSE score). Nine ABCB1 haplotypes were observed, the most common being 1236C/2677G/3435C (46%) and 1236T/2677T/3435T (41%). Patients homozygous for the T/T/T haplotype had slightly though not significantly lower plasma donepezil concentration-to-dose ratios than those carrying other genotypes [median (95% CI) 0.18 (0.13-0.45) vs. 0.31 (0.30-0.44) mg/l/mg/kg, respectively]. These patients also showed a slightly better clinical response (as measured by change in MMSE score) than the other genotype groups [median (95% CI) 0 (-1.3 to 3.3) vs. -1.0 (-2.1 to 0.0), respectively]. Conclusions Our data suggest that the CYP3A4 and CYP3A5 polymorphisms are unlikely to influence donepezil metabolism and/or clinical outcome. On the other hand, the ABCB1 polymorphisms may play a role in donepezil disposition and clinical outcome.
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| 22. |
- Mao, Mao, et al.
(författare)
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Flavin-containing monooxygenase 3 polymorphisms in 13 ethnic populations from Europe, East Asia and sub-Saharan Africa : frequency and linkage analysis
- 2009
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Ingår i: Pharmacogenomics (London). - : Future Medicine Ltd. - 1462-2416 .- 1744-8042. ; 10:9, s. 1447-1455
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: To investigate intra- and inter-ethnic differences in three widespread (E158K, V257M and E308G) and two African-specific (D132H and L360P) flavin-containing monooxygenase 3 (FMO3) polymorphisms. MATERIALS & METHODS: Allele frequencies were determined by TaqMan allelic discrimination assay in 2152 healthy volunteers from Europe (Swedes, Italians and Turks), East Asia (Japanese) and sub-Saharan Africa (nine ethnic groups covering eastern, southern and western regions), followed by haplotype and linkage analysis. RESULTS: Significant subpopulation differences (p < 0.001) in allele frequencies were found for E158K, V257M and E308G in Europeans and regional differences (p < 0.01) for D132H among Africans. No carrier of P360 was identified. Cis-linkage between G308 and K158 was confirmed with the compound variant (K158/G308) being found in a high proportion (12.0-38.3%) of non-African subjects, but rarely (1.3%) among Africans. CONCLUSIONS: Distribution of functionally relevant FMO3 polymorphisms varies not only between ethnicities but also within. The K158/G308 variant may have potential clinical importance primarily in non-African populations due to its low prevalence in Africa.
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| 23. |
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| 24. |
- Mao Söderberg, Mao
(författare)
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Clinical Pharmacogenetics of Olanzapine : with Focus on FMO Gene Polymorphisms
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Pharmacogenetics is the study of variability in drug response attributed to genetic variation. Olanzapine (OLA) is a widely used antipsychotic drug for schizophrenia treatment. The pharmacokinetics of OLA display large inter-individual variation leading to multiple-fold differences in drug exposure between patients at a given dose. This variation in turn gives rise to the need of individualized dosing in order to avoid concentration-dependent adverse effects and therapeutic failure. The observed variability has been partially explained by environmental and physiological factors. Genetically determined differences in drug metabolism represent a less studied source of variability. Precluded contribution by cytochrome P450 (CYP) 2D6 calls for evaluation of the other major OLA metabolizing enzymes. The objective of this thesis was to study pharmacogenetic influence of flavin-containing monooxygenase (FMO) 1 and 3, CYP1A2 and uridine diphosphate-glucuronosyltransferase (UGT) 1A4 on therapeutic OLA exposure. We conducted genetic association studies applying gene re-sequencing and genotyping of candidate and tagging SNPs.Patients carrying the FMO1*6 allele displayed increased dose-adjusted concentrations (C/Ds) of OLA, in serum as well as cerebrospinal fluid. Patients who were homozygous for the FMO3 K158-G308 compound variant showed reduced C/Ds of OLA N-oxide metabolite, but no alteration in OLA exposure. This compound variant is expected to have clinical relevance primarily for non-African populations, since low frequencies were detected among native Africans. Deviation in OLA exposure was observed in carrier of a rare FMO3 mutation, predicted in silico to affect gene splicing. Reduced OLA exposure was observed in UGT1A4*3 carriers. The CYP1A2 -163(A) (CYP1A2*1F) variant was not associated with increase in CYP1A2-catalyzed OLA metabolism or reduction in OLA exposure. Correlations were detected for two cis-acting variants within the inter-genetic region of the CYP1A cluster and a trans-acting variant located upstream the locus encoding aryl hydrocarbon receptor. The inconsistent data reported for CYP1A2*1F could be explained by presence of ethnic specific haplotype structures incorporating the -163(A) variant.A continuously improved understanding of the wide range of factors that can influence pharmacokinetics and pharmacodynamics will increase the likelihood of achieving optimal treatment response for individual patients.
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| 25. |
- Melkersson, Kristina I., et al.
(författare)
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Impact of CYP1A2 and CYP2D6 polymorphisms on drug metabolism and on insulin and lipid elevations and insulin resistance in clozapine-treated patients
- 2007
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Ingår i: Journal of Clinical Psychiatry. - : Physicians Postgraduate Press, Inc. - 0160-6689 .- 1555-2101. ; 68:5, s. 697-704
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Adverse metabolic effects of atypical antipsychotics have increasingly been recognized. Recently, we found that levels of insulin and triglycerides increased by increasing serum clozapine concentration in clozapine-treated patients. As these insulin and triglyceride elevations probably are drug concentration-dependent, they also would be expected to be drug metabolism-related. The genetically polymorphic cytochromes P450 CYP1A2 and CYP2D6 catalyze the metabolism of clozapine. The aim of this study was to evaluate the impact of CYP1A2 and CYP2D6 polymorphisms on serum drug and metabolite levels and on insulin and triglyceride elevations and insulin resistance in patients receiving clozapine. METHOD: Seventeen clozapine-treated patients were genotyped for CYP1A2 and CYP2D6 by polymerase chain reaction-based methods. Serum concentrations of clozapine and its N-desmethylmetabolite, blood glucose, and serum levels of insulin, C-peptide, triglycerides, and cholesterol were analyzed, and homeostasis model assessment index for insulin resistance (HOMA-IR) was determined. RESULTS: Clozapine and N-desmethylclozapine concentration-to-dose (C/D) ratios were significantly higher in patients carrying 2 CYP1A2 single nucleotide polymorphisms (SNPs), previously suggested to cause low enzyme activity, compared to those with no such SNPs (p < .05). In contrast, clozapine and N-desmethylclozapine C/D ratios were not related to the CYP2D6 genotype. Furthermore, patients with elevated insulin levels more frequently carried CYP1A2*1C and/or *1D alleles, had higher clozapine and N-desmethylclozapine C/D ratios, and had higher lipid levels and HOMA-IR, compared to patients with normal insulin levels (p < .05). CONCLUSION: CYP1A2 variants *1C and *1D seem to be associated with higher serum clozapine concentrations and an increased risk of developing insulin and lipid elevations and insulin resistance on a given dose of clozapine.
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| 26. |
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| 27. |
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| 28. |
- Scordo, Maria Gabriella
(författare)
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Cytochrome P450 2C9, 2C19 and 2D6 genetic polymorphisms : evaluation of genotyping as a tool for individualised treatment
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Recent advances in the understanding of drug metabolism and the molecular biology of CYPs have generated great expectations regarding the use of pharmacogenetic testing as a tool to individualize drug treatment. The individual pharmacogenetic constitution might in principle predict the response to drugs, hormones and toxins. Therefore, a simple phenotyping or genotyping test before treatment with a compound subject to polymorphic metabolism could be of value in selecting the dosage schedule, thus enhancing therapeutic efficacy and preventing toxicity. Many antipsychotics and antidepressants are mainly metabolised through CYP2D6. CYP2C9 and CYP2C19 are involved in the metabolism of warfarin, phenytoin and fluoxetine. All these three enzymes are highly polymorphic. The general aims of this thesis were to elucidate the impact of polymorphic CYP isoenzymes on the metabolism of psychoactive drugs (risperidone, fluoxetine) and anticoagulants (warfarin), characterised by a narrow therapeutic range and the potential risk for drug-drug interactions, to investigate the role of CYP polymorphism as a risk factor for the appearance of psychoactive drug- induced side-effects, and to evaluate the potential usefulness of genotyping as a tool for individualising the therapy. CYP2D6 genotype appears to partially explain the broad variability in the steady state plasma levels of risperidone and fluoxetine, but its usefulness in predicting clinical effects remains to be clarified. A significant relationship has been found in our studies between CYP2C9 genotype and warfarin dose requirement and clearance, as well as between CYP2C9 genotype and fluoxetine active moiety. Furthermore, our findings suggest that PMs of CYP2D6 are more prone to EPS during treatment with classical antipsychotics. Similarly, CYP2C9 and CYP2C19 genetically impaired metabolic activity seems to represent a predisposing factor for phenytoin toxicity. CYP2D6 genotyping can today be recommended as a complement to the determination of plasma concentrations when aberrant metabolic capacity (poor or ultrarapid) is suspected, while its usefulness in predicting clinical effects must be further explored. Therapeutic drug monitoring still represents a better tool for individualization of dosage of CYP2D6 substrates. On the other hand CYP2C9 genotype may be of value in choosing the right dose, andlor avoiding potentially harmful drugs in selected subgroups of patients with genetically impaired metabolic activity. The next step should involve prospective studies of impotant drugs to establish the clinical utility of genotype specific dosage-schedules.
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| 29. |
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| 30. |
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| 31. |
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| 32. |
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| 33. |
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| 34. |
- Spina, Edoardo, et al.
(författare)
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Drug Interactions in Epilepsy
- 2004
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Ingår i: The Treatment of Epilepsy, 2nd ed. - : Blackwell Science, Oxford. ; , s. 120-133
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 35. |
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| 36. |
- Spina, Edoardo, et al.
(författare)
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Le interazioni farmacologiche degli psicofarmaci
- 2003
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Ingår i: Trattato di psicofarmacologia clinica. - : Il Pensiero Scientifico Edotire, Roma. ; , s. 449-482
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 37. |
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| 38. |
- Spina, Edoardo, et al.
(författare)
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Pharmacogenetics of Psychopharmacological Agents
- 2003
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Ingår i: Proceedings from 15th IFCC_FESCC European Congress of Clinical Chemistry Laboratory medicine EUROMEDLAB 2003. ; , s. 137-142
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 39. |
- Takahashi, Harumi, et al.
(författare)
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Correlations between the enantio- and regio-selective metabolisms of warfarin
- 2017
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Ingår i: Pharmacogenomics (London). - : Future Medicine Ltd. - 1462-2416 .- 1744-8042. ; 18:2, s. 133-142
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To clarify whether the activities of multiple CYPs associated with warfarin metabolism would be correlated with each other. Methods: Oral clearances (CLpo) of warfarin enantiomers were estimated in 378 Chinese, Caucasians and African-Americans. The partial metabolic clearances (CLm) for 7-hydroxywarfarin enantiomers were also measured. In addition, CLpo and CLm were determined in a patient on warfarin and rifampicin. Results: Correlations between CLpo for warfarin enantiomers existed across the three populations. In addition, there was a significant correlation between the CLm for 7-hydroxylation of warfarin enantiomers. Under induced conditions by rifampicin, there were significant correlations between the enantio-and regio-selective metabolisms of warfarin. Conclusion: Metabolic activities of CYP2C9, CYP1A2 and CYP3A4 may be regulated by common transcriptional mechanism(s).
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| 40. |
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| 41. |
- Varsaldi, Federica, et al.
(författare)
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Impact of the CYP2D6 polymorphism on steady-state plasma concentrations and clinical outcome of donepezil in Alzheimer's disease patients
- 2006
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Ingår i: European Journal of Clinical Pharmacology. - : Springer Science and Business Media LLC. - 0031-6970 .- 1432-1041. ; 62:9, s. 721-726
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The aims of this study were to evaluate the impact of the CYP2D6 polymorphism on both the steady-state plasma concentrations (Cp) and the clinical outcome of donepezil, a selective acetylcholinesterase inhibitor used in the treatment of Alzheimer's disease (AD). Methods: Forty-two patients of Caucasian ethnicity affected by probable AD were included in the study. All had been receiving therapy with donepezil for at least 3 months: 31 patients with 5 mg/day and 11 patients with 10 mg/day. The CYP2D6 genotype was analysed, and donepezil Cp was measured by using high-performance liquid chromatography. Results: On the basis of their CYP2D6 genotype, 30 patients could be classified as homozygous extensive metabolizers (EM), 10 as heterozygous EM and 2 as ultrarapid metabolizers (UM). No poor metabolizer was found. The dose and body weight-corrected median donepezil Cp were slightly, though not significantly, lower in homozygous than in heterozygous EM (0.33 vs. 0.41 ng/ml/mg/kg, respectively). The latter group consistently showed a better clinical response to treatment, as measured by change in Mini-Mental State Examination score (median: 1.40 vs. -1.30, respectively). UM patients had lower Cp than EM patients and showed no clinical improvement. Conclusions: Our preliminary data suggest that the CYP2D6 polymorphism influences both donepezil metabolism and therapeutic outcome and that a knowledge of a patient's CYP2D6 genotype together with donepezil concentration measurements might be useful in the context of improving the clinical efficacy of donepezil therapy.
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