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CYP2D6 subfamily isoenzymes play an important role in the biotransformation of haloperidol, and their activity may influence the efficacy and safety of haloperidol. The use of haloperidol is often associated with the occurrence of adverse drug reactions (ADRs), such as dyskinesia, acute dystonia, and orthostatic hypotension. Previous studies have demonstrated the relationship between theTo evaluate the association ofThe study involved 100 male patients with AIPD (average age 41.4 ± 14.4 years) who received haloperidol by injections in a dose of 5-10 mg/day. The efficacy profile was assessed using a validated psychometric PANSS scale (Positive and Negative Syndrome Scale). Therapy safety was assessed using the internationally validated UKU (Side-Effect Rating Scale) and SAS (Simpson-Angus Scale for Extrapyramidal Symptoms) scales. Genotyping was performed with the real-time polymerase chain reaction.We revealed the statistically significant results in terms of therapy safety evaluation (dynamics of the UKU scores: (It can be concluded that patients with the

BACKGROUND: Previous studies have shown that haloperidol biotransformation occurs with participation of the CYP2D6 isoenzyme. The CYP2D6 gene is highly polymorphic, which may contribute to differences in its activity and in the haloperidol biotransformation rates across different individuals, resulting in variable drug efficacy and safety profiles. PURPOSE: The study aimed to investigate the correlation of the 1846G> A polymorphism of CYP2D6 gene with the efficacy and safety rates of haloperidol in patients with alcoholic hallucinoses. MATERIAL AND METHODS: One hundred male patients received 5–10 mg/day haloperidol by injections for 5 days. The efficacy and safety assessments were performed using the validated psychometric scales PANSS, UKU, and SAS. For genotyping, the real-time polymerase chain reaction was performed. RESULTS: We revealed no statistically significant results in terms of haloperidol efficacy in patients with different genotypes (dynamics of the PANSS scores: (GG) −13.00 [−16.00; −11.00], (GA) −15.00 [−16.75; −13.00], p = 0,728). Our findings revealed the statistically significant results in terms of treatment safety evaluation (dynamics of the UKU scores: (GG) 8.00 [7.00; 10.00], (GA) 15.0 [9.25; 18.0], p < 0.001; dynamics of the SAS scores: (GG) 11.0 [9.0; 14.0], (GA) 14.50 [12.0; 18.0], p < 0.001. CONCLUSION: These results suggest that genotyping for common CYP3A variants might have the potential to guide benzodiazepine withdrawal treatment. The effect of of the 1846G>A polymorphism of CYP2D6 gene on the safety profile of haloperidol was demonstrated in a group of 100 patients with alcoholic hallucinoses.

The evolution of evidence and availability of Clinical Pharmacogenetic Implementation Consortium (CPIC) guidelines have enabled assessment of pharmacogenetic actionability and clinical implementation. However population-level actionability is not well characterized. We leveraged the Alabama Genomic Health Initiative (AGHI) to evaluate population-level pharmacogenetic actionability. Participants (>18 years), representing all 67 Alabama counties, were genotyped using the Illumina Global Screening array. Using CPIC guidelines, actionability was evaluated using (1) genotype data and genetic ancestry, (2) prescribing data, and (3) combined genotype and medication data. Of 6,331 participants, 4,230 had genotype data and 3,386 had genotype and prescription data (76% female; 76% White/18% Black (self-reported)). Genetic ancestry was concordant with self-reported race. For CPIC level A genes, 98.6% had an actionable genotype (99.4% Blacks/African; 98.5% White/European). With the exception of DPYD and CYP2C19, the prevalence of actionable genotypes by gene differed significantly by race. Based on prescribing, actionability was highest for CYP2D6 (70.9%), G6PD (54.1%), CYP2C19 (53.5%), and CYP2C9 (47.5%). Among participants prescribed atenolol, carvedilol, or metoprolol, approximately 50% had an actionable ADRB1 genotype, associated with decreased therapeutic response, with higher actionability among Blacks compared to Whites (62.5% vs 47.4%; p

Background In recent years, the incidence rate of vivax malaria recurrence still had 3.1% in Yunnan Province population after eradication therapy using primaquine (PQ). In order to understand the specific failure reasons for preventing vivax malaria relapses, a preliminary exploration on the CYP2D6 enzyme activity was carried out in the vivax malaria patients in Yunnan Province population by analysing mutational polymorphism in the coding region of CYP2D6 gene. Methods Blood samples were collected from vivax malaria patients with suspected relapse (SR) and non-relapsed (NR) malaria in Yunnan Province. The DNA fragments containing 9 exons regions of human CYP2D6 gene were amplified by performing PCR and sequenced. The sequencing results were aligned by using DNAStar 11.0 to obtain the coding DNA sequence (CDS) of CYP2D6 gene. DnaSP 6.11.01 software was used to identify mutant polymorphisms and haplotypes of the CDS chain. The waterfall function of GenVisR package in R was utilized to visualize the mutational landscape. The alleles of CYP2D6 gene were identified according to the criteria prescribed by Human Cytochrome P450 (CYP) Allele Nomenclature Committee Database and the CYP2D6 enzyme activity was predicted based on diploid genotype. Results A total of 320 maternal CDS chains, including 63 from SR group and 257 from NR group, were obtained. Twelve mutant loci, including c.31 (rs769259), c.100 (rs1065852), c.271 (rs28371703), c.281 (rs28371704), c.294 (rs28371705), c.297 (rs200269944), c.336 (rs1081003), c.408 (rs1058164), c.505 (rs5030865), c.801 (rs28371718), c.886 (rs16947), and c.1,457 (rs1135840) were observed on the 640 CDS chains (including 320 maternal and 320 paternal chains). The high-frequency mutation at rs1135840 (0.703) and low-frequency mutation, such as rs28371703, were detected only in the SR group. The frequency of mutant rs1058164 and rs1135840 were significantly increased in the SR group ($${x}^{2}$$ x 2 = 4.468, 5.889, P $${x}^{2}$$ x 2 = 3.911, P $${x}^{2}$$ x 2 = 10.050, P Conclusion In the patients receiving PQ dosage in Yunnan Province population, both rs1135840 single nucleotide polymorphism and *10 allele form was common in the CYP2D6 gene. Low-frequency mutation sites, such as rs28371703, were only presented in patients with vivax malaria relapse.

This study of a cohort of 1-year treatment-compliant survivors of a suicide attempt examined for the first time whether a high CYP2D6-CYP2C19 metabolic capacity (pharmacogenes related to psychopathology, suicide, and attempt severity) and/or polypharmacy treatments predicted repeat suicide attempts, adjusting for sociodemographic and clinical factors as confounders. Of the 461 (63% women) consecutively hospitalized patients who attempted suicide and were evaluated and treated after an index attempt, 191 (67.5% women) attended their 6- and 12-month follow-up sessions. Clinicians were blinded to the activity scores (AS) of their genotypes, which were calculated as the sum of the values assigned to each allele (CYP2C19 *2, *17; CYP2D6 *3, *4, *4xN, *5, *6, *10, wtxN). No differences were found in polypharmacy prescription patterns and the variability of CYP2D6 and CYP2C19 genotypes between adherents and dropouts, but the formers were older, with a higher frequency of anxiety and bipolar disorders and fewer alcohol and substance use disorders. The risk of reattempts was higher for CYP2D6 ultrarapid (AS > 2) metabolizers (β = 0.561, p = 0.005) and violent suicide survivors (β = −0.219, p = 0.042) if the attempt occurred during the first 6-month period, individuals with an increased number of MINI DSM-IV Axis I mental disorders (β = 0.092, p = 0.032) during the second 6-month period and individuals with a combined high CYP2D6-CYP2C19 metabolic capacity (AS > 4) (β = 0.345, p = 0.024) and an increased use of drugs other than antidepressants, anxiolytics-depressants and antipsychotics-lithium (β = 0.088, p = 0.005) in multiple repeaters during both periods. CYP2D6 and CYP2C19 rapid metabolism and polypharmacy treatment for somatic comorbidities must be considered to prevent the severe side effects of short-term multiple suicide reattempts after a previous attempt.

Brexpiprazole is an oral antipsychotic agent indicated for use in patients with schizophrenia or as adjunctive treatment for major depressive disorder. As obesity (body mass index ≥35 kg/m2 ) has the potential to affect drug pharmacokinetics and is a common comorbidity of both schizophrenia and major depressive disorder, it is important to understand changes in brexpiprazole disposition in this population. This study uses a whole-body physiologically based pharmacokinetic model to compare the pharmacokinetics of brexpiprazole in obese and normal-weight (body mass index 18-25 kg/m2 ) individuals known to be cytochrome P450 2D6 extensive metabolizers (EMs) and poor metabolizers (PMs). The physiologically based pharmacokinetic simulations demonstrated significant differences in the time to effective concentrations between obese and normal-weight individuals within metabolizer groups according to the label-recommended titration. Simulations using an alternative dosing strategy of 1 week of twice-daily dosing in obese EMs or 2 weeks of twice-daily dosing in obese poor metabolizers, followed by a return to once-daily dosing, yielded more consistent plasma concentrations between normal-weight and obese patients without exceeding the area under the plasma concentration-time curve observed in the normal-weight EMs. These alternative dosing strategies reduce the time to effective concentrations in obese patients and may improve clinical response to brexpiprazole.

Atomoxetine (ATX) is a neurological drug widely used for the treatment of attention deficit-hyperactivity disorder. Liver injury has been documented in patients administered ATX. The mechanism of ATX's toxic action is less clear. This study is aimed to characterize reactive metabolites of ATX in vitro and in vivo to assist our understanding of the mechanisms of ATX hepatotoxicity. A hydroxylated metabolite, along with an O-dealkylation metabolite, was found in ATX-supplemented rat liver microsome incubations. Additionally, two glutathione (GSH) conjugates and two N-acetylcysteine (NAC) conjugates were observed in rat liver microsome incubations containing ATX, NADPH, and GSH or NAC. The corresponding GSH conjugates and NAC conjugates were found in bile and urine of ATX-treated rats, respectively. Recombinant P450 enzyme incubation study demonstrated that CYP2D6 dominated the metabolic activation of ATX. The insights gained from this study may be of assistance to illuminate the mechanisms of ATX-induced hepatotoxicity.

The cytochrome P450 (CYP) 2D6 enzyme exhibits large interindividual differences in metabolic activity. Patients are commonly assigned a CYP2D6 phenotype based on their CYP2D6 genotype, but there is a lack of consensus on how to translate genotypes into phenotypes, causing inconsistency in genotype‐based dose recommendations. The aim of this study was to quantify and compare the impact of different CYP2D6 genotypes and alleles on CYP2D6 metabolism using a large clinical data set. A population pharmacokinetic (popPK) model of tedatioxetine and its CYP2D6‐dependent metabolite was developed based on pharmacokinetic data from 578 subjects. The CYP2D6‐mediated metabolism was quantified for each subject based on estimates from the final popPK model, and CYP2D6 activity scores were calculated for each allele using multiple linear regression. The activity scores estimated for the decreased function alleles were 0.46 (CYP2D6*9), 0.34 (CYP2D6*10), 0.01 (CYP2D6*17), 0.65 (CYP2D6*29), and 0.21 (CYP2D6*41). The CYP2D6*17 and CYP2D6*41 alleles were thus associated with the lowest CYP2D6 activity, although only the difference to the CYP2D6*9 allele was shown to be statistically significant (p = 0.02 and p = 0.05, respectively). The study provides new in vivo evidence of the enzyme function of different CYP2D6 genotypes and alleles. Our findings suggest that the activity score assigned to CYP2D6*41 should be revisited, whereas CYP2D6*17 appears to exhibit substrate‐specific behavior. Further studies are needed to confirm the findings and to improve the understanding of CYP2D6 genotype–phenotype relationships across substrates.

BackgroundThe relapsing nature ofPlasmodium vivaxinfection is a major barrier to its control and elimination. Factors such as adequate dosing, adherence, drug quality, and pharmacogenetics can impact the effectiveness of radical cure ofP. vivaxand need to be adequately evaluated. CYP2D6 pathway mediates the activation of primaquine (primaquine) into an active metabolite(s) in hepatocytes, and impaired activity has been linked to a higher risk of relapse.Cases presentationThree patients diagnosed withP. vivaxmalaria presented repeated relapses after being initially treated with chloroquine (25 mg/kg) and primaquine (3.5 mg/kg in 14 days) at a non-endemic travel clinic. Recurring episodes were subsequently treated with a higher dose of primaquine (7 mg/kg in 14 days), which prevented further relapses in two patients. However, one patient still presented two episodes after a higher primaquine dose and was prescribed 300 mg of chloroquine weekly to prevent further episodes. Impaired CYP2D6 function was observed in all of them.ConclusionLack of response to primaquine was associated with impaired CYP2D6 activity in three patients presenting multiple relapses followed in a non-endemic setting. Higher primaquine dosage was safe and effectively prevented relapses in two patients and should be further investigated as an option in Latin America. It is crucial to investigate the factors associated with unsuccessful radical cures and alternative therapeutic options.

BACKGROUND Previous studies have shown that cytochrome P450 2D6 (CYP2D6) is involved in the metabolism of fluvoxamine, the activity of which is highly dependent, inter alia, on the polymorphism of the gene encoding it. The objective of our study was to investigate the effect of 1846G>A polymorphism of the CYP2D6 gene on the efficacy and safety of fluvoxamine, using findings on CYP2D6 enzymatic activity and on CYP2D6 expression level in patients with depressive disorders comorbid with alcohol use disorder. STUDY QUESTION Efficacy and safety of fluvoxamine depend on the polymorphism of CYP2D6 gene in patients with major depressive disorder. STUDY DESIGN Our study enrolled 96 male patients with depressive disorders comorbid with alcohol use disorder. Patients were examined on days 1, 9, and 16 of fluvoxamine therapy. MEASURES AND OUTCOMES Treatment efficacy was evaluated using the validated psychometric scales. Therapy safety was assessed using the UKU Side-Effect Rating Scale. For genotyping and estimation of the microRNA (miRNA) plasma levels, we performed the real-time polymerase chain reaction. The activity of CYP2D6 was evaluated using the HPLC-MS/MS method by the content of the endogenous substrate of given isoenzyme and its metabolite in urine (6-hydroxy-1,2,3,4-tetrahydro-β-carboline/pinoline ratio). RESULTS Our study revealed the statistically significant results for the treatment efficacy evaluation [the Hamilton Depression Rating Scale scores at the end of the treatment course: (GG) 2.0 (1.0-4.0) and (GA) 5.0 (4.0-7.0), P < 0.001]. Analysis of the results of the pharmacotranscriptomic part of the study did not show the statistically significant difference in the hsa-miR-370-3p plasma levels in patients with different genotypes: (GG) 26.9 (15.0-32.2), (GA) 31.8 (22.7-33.7), P = 0.247. In addition, we evaluated the relationship between the CYP2D6 enzymatic activity (as evaluated by 6-hydroxy-1,2,3,4-tetrahydro-β-carboline/pinoline ratio measurement) and the hsa-miR-370-3p plasma concentration: rs = -0.243, P = 0.017. CONCLUSIONS The effect of genetic polymorphism of the CYP2D6 gene on the efficacy and safety profiles of fluvoxamine was demonstrated in a group of 96 patients with depressive disorders comorbid with alcohol use disorder.

Sejung Hwang,1 Dae Young Lee,2 Joo-Youn Cho,1,3 Jae-Yong Chung,4 In-Jin Jang,1 Kyung-Sang Yu,1,3 SeungHwan Lee1 1Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Republic of Korea; 2Drug Metabolism and Pharmacokinetics (DMPK), Drug Evaluation, Dong-A ST Research Institute, Gyonggi-do, Republic of Korea; 3Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea; 4Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Bundang Hospital, Seongnam, Republic of KoreaCorrespondence: SeungHwan LeeDepartment of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of KoreaTel +82-2-2072-2343Fax +82-2-2072-0720Email leejh413@snu.ac.krPurpose: DA-8031 is a novel selective serotonin reuptake inhibitor for the treatment of premature ejaculation. This study investigated the pharmacokinetics, safety and tolerability of multiple oral doses of DA-8031. In addition, a genetic analysis was explored to evaluate the effect of genetic polymorphisms on the pharmacokinetics of DA-8031.Subjects and Methods: A dose block-randomized, double-blind, placebo-controlled study was conducted in 3 dose groups with 20, 30 and 40 mg of DA-8031. Healthy male subjects were randomized to DA-8031 or placebo at a 4:1 ratio in each dose group of 10 subjects by oral administration once daily for 7 consecutive days. Serial blood and urine samples were collected for the pharmacokinetic evaluation, and the pharmacokinetic-related genes were analyzed by DMETTM plus. A safety evaluation was conducted including adverse events (AEs) monitoring and 12-lead electrocardiogram (ECG).Results: The plasma DA-8031 concentration reached the maximum concentration (Cmax) in 2.2 to 3.0 h and was eliminated with a mean half-life of 25.5 to 26.7 h at steady state. The accumulation index of DA-8031 ranged 2.3 to 2.8. The systemic exposure of DA-8031 of the CYP2D6 intermediate metabolizer (IM) was significantly higher compared to the CYP2D6 poor metabolizer (PM). There were no clinically significant QTc interval changes, and all the adverse events were mild.Conclusion: After multiple oral doses of DA-8031 20, 30, and 40 mg in this study, the systemic exposure of DA-8031 increased in a more than dose-proportional manner with the increasing doses, and DA-8031 was generally well tolerated. In addition, the genetic polymorphisms of CYP2D6 have an impact on the pharmacokinetics of DA-8031.Keywords: selective serotonin reuptake inhibitors, clinical pharmacology, phase 1 study, pharmacogenomics

Introduction Pharmacogenetic testing is proposed to minimize adverse effects when considered in combination with pharmacological knowledge of the drug. As yet, limited studies in clinical settings have investigated the predictive value of pharmacokinetic (pk) gene variation on therapeutic drug levels as a probable mechanism of adverse effects, nor considered the combined effect of pk gene variation and drug level on antidepressant treatment response. Methods Two depression cohorts were investigated for the relationship between pk gene variation and antidepressant serum concentrations of amitriptyline, venlafaxine, mirtazapine and quetiapine, as well as treatment response. For the analysis, 519 patients (49% females; 46.6±14.1 years) were included. Results Serum concentration of amitriptyline was associated with CYP2D6 (higher concentrations in poor metabolizers compared to normal metabolizers), of venlafaxine with CYP2C19 (higher concentrations in intermediate metabolizers compared to rapid/ultrarapid metabolizers) and CYP2D6 (lower metabolite-to-parent ratio in poor compared to intermediate and normal metabolizers, and intermediate compared to normal and ultrarapid metabolizers). Pk gene variation did not affect treatment response. Discussion The present data support previous recommendations to reduce starting doses of amitriptyline and to guide dose-adjustments via therapeutic drug monitoring in CYP2D6 poor metabolizers. In addition, we propose including CYP2C19 in routine testing in venlafaxine-treated patients to improve therapy by raising awareness of the risk of low serum concentrations in CYP2C19 rapid/ultrarapid metabolizers. In summary, pk gene variation can predict serum concentrations, and thus the combination of pharmacogenetic testing and therapeutic drug monitoring is a useful tool in a personalized therapy approach for depression.

The metabolic activity of the polymorphic CYP2D6 enzyme is dependent on the CYP2D6 genotype; however, the guidelines for translating the genotype into phenotype, which are of relevance for adequate drug dose personalization, are ambiguous. In the present study, retrospective therapeutic drug monitoring data from 4,700 CYP2D6 genotyped patients treated with risperidone, venlafaxine, and/or aripiprazole were analyzed to quantify the effect of CYP2D6 genotype on the CYP2D6 metabolic activities, as measured by metabolic ratios of these substrates. The patients were categorized into diplotypes based on the presence of normal function (CYP2D6Norm), nonfunctional (CYP2D6Nonf), and decreased function (CYP2D6Decr; i.e., CYP2D6*9, CYP2D6*10, and CYP2D6*41) CYP2D6 haplotypes. Significant correlations between the metabolic ratios were observed in patients (n = 77-103) cotreated with risperidone and venlafaxine, risperidone and aripiprazole, or venlafaxine and aripiprazole (ρ = 0.874, 0.785, and 0.644, respectively; P

PURPOSE The aim of this study was to investigate the potential dose-dependent CYP2D6 inhibition by bupropion (BUP) in patients with depression. METHODS Patients combining BUP with venlafaxine were included from a therapeutic drug monitoring (TDM) database at the Diakonhjemmet Hospital (Oslo, Norway). The O/N-desmethylvenlafaxine metabolic ratio measured in TDM samples was used as a biomarker for CYP2D6 phenotype and was compared between patients treated with BUP 150 mg/d and 300 mg/d or greater. In addition, reference groups of venlafaxine-treated patients genotyped as CYP2D6 poor metabolizers (PMs, no CYP2D6 activity) and normal metabolizers (NMs, fully functional CYP2D6 activity) were included. FINDINGS A total of 221 patients were included in the study. The median O/N-desmethylvenlafaxine metabolic ratio was significantly higher in patients treated with BUP 150 mg/d (n = 59) versus 300 mg/d or greater (n = 34, 1.77 vs 0.96, P < 0.001). In CYP2D6 NMs (n = 62) and PMs (n = 66), the median metabolic ratios were 40.55 and 0.48, respectively. For patients treated with BUP 150 mg/d, 11 (19%) of the 59 patients were phenoconverted to PMs, whereas this was the case for 17 (50%) of the 34 patients treated with BUP 300 mg/d or greater. CONCLUSIONS Bupropion exhibits a clear dose-dependent CYP2D6 inhibitory effect during treatment of patients with depression. This finding is of clinical relevance when adjusting dosing of CYP2D6 substrates during comedication with BUP. Half of the patients treated with high-dose BUP are converted to CYP2D6 PM phenotype. Because of the variability in CYP2D6 inhibition, TDM of CYP2D6 substrates should be considered to provide individualized dose adjustments during comedication with BUP.

Cytochrome P450 2D6 (CYP2D6) O-demethylates codeine to the active drug, morphine. However, the utility of testing for CYP2D6 metabolizer status in patients receiving codeine in real-world clinical practice is poorly defined. Using data from a DNA bank linked to de-identified electronic health records, we studied 157 patients with a baseline pain score higher than 4 (0-10 scale) who received codeine. Based on CYP2D6 genotyping, 69 were classified as poor/intermediate and 88 as normal/ultrarapid CYP2D6 metabolizers. Pain response was defined as a score of 4 or lower while receiving codeine. In a propensity-score adjusted model, poor/intermediate metabolizers had lower odds (OR = 0.35, p = 0.02) of achieving a pain response than normal/ultrarapid metabolizers. To discriminate between codeine responders and nonresponders, a score including CYP2D6 phenotype and clinical variables was built. The response rate was 38.5% among patients in the high, 17.3% in the intermediate, and 9.4% in the low-score groups, respectively (p = 0.001).

Background Accumulating evidence suggest that compromised CYP2D6 enzyme activity caused by gene mutation could contribute to primaquine failure for the radical cure of vivax malaria. The current study aims to preliminarily reveal the association between the recurrence of vivax malaria in Yunnan Province and CYP2D6 gene mutation by analysing polymorphisms in the entire coding region of human CYP2D6 gene. Methods Blood samples were collected from patients with vivax malaria, who received "chloroquine and 8-day course of primaquine therapy" in Yunnan Province. The suspected relapsed cases were determined by epidemiological approaches and gene sequence alignment. PCR was conducted to amplify the CYP2D6 gene in the human genome, and the amplified products were then sequenced to compare with the non-mutation “reference” sequence, so as to ensure correct sequencing results and to determine 9 exon regions. Subsequently, the DNA sequences of 9 exons were spliced into the coding DNA sequence (CDS), which, by default, is known as maternal CDS. The paternal CDS was obtained by adjusting the bases according to the sequencing peaks. The mutation loci, haplotypes (star alleles), genotypes and odds ratios (OR) of all the CDSs were analysed. Results Of the119 maternal CDS chains in total with 1491 bp in length, 12 mutation sites in the 238 maternal and paternal CDS chains were detected. The c.408G > C mutation was most frequently detected in both suspected relapsed group (SR) and non-relapsed group (NR), reaching 85.2% (75/88) and 76.0% (114/150), respectively. The c.886C > T mutation was most closely related to the recurrence of vivax malaria (OR = 2.167, 95% CI 1.104–4.252, P Χ2 = 16.177, P Conclusion Mutation of CYP2D6*10 allele accounts for the highest proportion of vivax malaria cases in Yunnan Province. The mutations of c. 886C > T and CYP2D6*2 allele, which correspond to impaired PQ metabolizer phenotype, are most closely related to the relapse of vivax malaria. In addition, the genotype *4/*4 with null CYP2D6 enzyme function was only detected in the SR group. These results reveal the risk of defected CYP2D6 enzyme activity that diminishes the therapeutic effect of primaquine on vivax malaria.

Rationale Cytochrome P450 2D (CYP2D) enzymes metabolize many addictive drugs, including methamphetamine. Variable CYP2D metabolism in the brain may alter CNS drug/metabolite concentrations, consequently affecting addiction liability and neuropsychiatric outcomes; components of these can be modeled by behavioral sensitization in rats. Methods To investigate the role of CYP2D in the brain in methamphetamine-induced behavioral sensitization, rats were pretreated centrally with a CYP2D irreversible inhibitor (or vehicle) 20 h prior to each of 7 daily methamphetamine (0.5 mg/kg subcutaneous) injections. In vivo brain microdialysis was used to assess brain drug and metabolite concentrations, and neurotransmitter release. Results CYP2D inhibitor (versus vehicle) pretreatment enhanced methamphetamine-induced stereotypy response sensitization. CYP2D inhibitor pretreatment increased brain methamphetamine concentrations and decreased the brain p-hydroxylation metabolic ratio. With microdialysis conducted on days 1 and 7, CYP2D inhibitor pretreatment exacerbated stereotypy sensitization and enhanced dopamine and serotonin release in the dorsal striatum. Day 1 brain methamphetamine and amphetamine concentrations correlated with dopamine and serotonin release, which in turn correlated with the stereotypy response slope across sessions (i.e., day 1 through day 7), used as a measure of sensitization. Conclusions CYP2D-mediated methamphetamine metabolism in the brain is sufficient to alter behavioral sensitization, brain drug concentrations, and striatal dopamine and serotonin release. Moreover, day 1 methamphetamine-induced neurotransmitter release may be an important predictor of subsequent behavioral sensitization. This suggests the novel contribution of CYP2D in the brain to methamphetamine-induced behavioral sensitization and suggests that the wide variation in human brain CYP2D6 may contribute to differential methamphetamine responses and chronic effects.

There is limited evidence to support pharmacogenetic (PGx) testing in children. We conducted a retrospective review of PGx testing among 452 patients at an academic children's hospital to determine the potential utility of PGx in diseases of childhood and to identify targets for future pediatric pharmacogenetic research. An actionable gene-drug pair associated with the 28 genes tested (Clinical Pharmacogenetics Implementation Consortium (CPIC) level A or B, Pharmacogenomics Knowledge Base (PharmGKB) level 1A or B, or US Food and Drug Administration (FDA) recommendation and a PharmGKB level) was present in 98.7% of patients. We identified 203 actionable gene-drug-diagnosis groups based on the indications for each actionable drug listed in Lexicomp. Among patients with an actionable gene-drug-diagnosis group, 49.3% had a diagnosis where the drug was a therapeutic option and PGx could be used to guide treatment selection. Among patients with an associated diagnosis, 30.9% had a prescription for the actionable drug allowing PGx guided dosing. Three genes (CYP2C19, CYP2D6, and CYP3A5) accounted for all the gene-drug-diagnosis groups with matching diagnoses and prescriptions. The most common gene-drug-diagnosis groups with matching diagnoses and prescriptions were CYP2C19-citalopram-escitalopram-depression 3.3% of patients tested; CYP2C19-dexlansoprazole-gastritis-esophagitis 3.1%; CYP2C19-omeprazole-gastritis-esophagitis 2.4%; CYP2D6-atomoxetine-attention deficit hyperactivity disorder 2.2%; and CYP2C19-citalopram-escitalopram-obsessive-compulsive disorder 1.5%. PGx could be used to guide selection of current treatment options or medication dosing in almost half (48.7%) of pediatric patients tested. Mood disorders and gastritis/esophagitis are promising targets for future study of PGx testing because of the high prevalence of these diagnoses and associated actionable gene-drug pairs in the pediatric population.

Introduction Genetic variation is known to affect enzymatic activities allowing differentiating various metabolizer types (e. g., slow or rapid metabolizers), in particular CYP2C19 and CYP2D6. Methods PGx-testing was conducted in adult major depressive disorder inpatients admitted to the Vitos Klinik Eichberg between 11/2016 and 7/2017 (n=108, 57% female). We conducted a two-sided Z-Test (p=0.05) to analyze and compare frequencies of CYP2D6, CYP2C19, CYP3A4, CYP3A5 and CYP2C9 metabolizer groups with other European and psychiatric inpatient cohorts. The HLA-A and –B genes were also analyzed. Results Non-normal metabolizer status of CYP2D6 were present in 47%. More specifically, 35 % were intermediate, 7% poor and 4% ultra-rapid metabolizers. 68% were CYP2C19 non-normal metabolizers. 8% were ultra-rapid and 31% rapid metabolizers. Notably, only 13% were NM for CYP2C19 and NM for CYP2D6 (activity score of 1 or more). For CYP2C9 we found 16% to be intermediate metabolizers, 1.0% poor metabolizer. CYP3A4 and CYP3A5 genetic polymorphisms were present in 25% and 19% respectively. HLA-B TAG- SNPs for *15:01 was positive in 25 patients, showing the need for different Tag-SNPs in Caucasians. HLA-B *57:01 TAG-SNP was positive in 8% of the patients, HLA-A TAG-SNP for *31:01 in Caucasians was positive in 9%. Z-Test showed statistical significance for our results. Discussion Our results suggest that our psychiatric inpatients were enriched with genotypes consistent with non-normal drug metabolism compared to reference populations. We therefore conclude that pharmacogenetic testing should be implemented in clinical practice to guide drug therapy.

The aim of this study was to investigate the effects of paroxetine, a potent inhibitor of CYP2D6, on the pharmacokinetics of atomoxetine and its two metabolites, 4-hydroxyatomoxetine and N-desmethylatomoxetine, in different CYP2D6 genotypes. Twenty-six healthy subjects were recruited and divided into CYP2D6*wt/*wt (*wt=*1 or *2, n = 10), CYP2D6*wt/*10 (n = 9), and CYP2D6*10/*10 groups (n = 7). In atomoxetine phase, all subjects received a single oral dose of atomoxetine (20 mg). In paroxetine phase, after administration of a single oral dose of paroxetine (20 mg) for six consecutive days, all subjects received a single oral dose of atomoxetine with paroxetine. Plasma concentrations of atomoxetine and its metabolites were determined up to 24 h after dosing. During atomoxetine phase, there were significant differences in Cmax and AUC0−24 of atomoxetine and N-desmethylatomoxetine among three genotype groups, whereas significant differences were not found in relation to CYP2D6*10 allele after administration of paroxetine. AUC ratios of 4-hydroxyatomoxetine and N-desmethylatomoxetine to atomoxetine were significantly different among three genotype groups during atomoxetine phase (all, P

Many academic institutions are collecting blood samples from patients seeking treatment for coronavirus disease 2019 (COVID‐19) to build research biorepositories. It may be feasible to extract pharmacogenomic (PGx) information from biorepositories for clinical use. We sought to characterize the potential value of multigene PGx testing among individuals hospitalized with COVID‐19 in the United States. We performed a cross‐sectional analysis of electronic health records from consecutive individuals hospitalized with COVID‐19 at a large, urban academic health system. We characterized medication orders, focusing on medications with actionable PGx guidance related to 14 commonly assayed genes (CYP2C19, CYP2C9, CYP2D6, CYP3A5, DPYD, G6PD, HLA‐A, HLA‐B, IFNL3, NUDT15, SLCO1B1, TPMT, UGT1A1, and VKORC1). A simulation analysis combined medication data with population phenotype frequencies to estimate how many treatment modifications would be enabled if multigene PGx results were available. Sixty‐four unique medications with PGx guidance were ordered at least once in the cohort (n = 1,852, mean age 60.1 years). Nearly nine in 10 individuals (89.7%) had at least one order for a medication with PGx guidance and 427 patients (23.1%) had orders for 4 or more actionable medications. Using a simulation, we estimated that 17 treatment modifications per 100 patients would be enabled if PGx results were available. The genes CYP2D6 and CYP2C19 were responsible for the majority of treatment modifications, and the medications most often affected were ondansetron, oxycodone, and clopidogrel. PGx results would be relevant for nearly all individuals hospitalized with COVID‐19 and would provide the opportunity to improve clinical care.

This study aimed to evaluate the influence of CYP2D6 activity and cachexia progression on the enantiomeric alteration of plasma tramadol and its demethylated metabolites in head and neck cancer patients. Fifty-three head and neck cancer patients receiving oral tramadol were enrolled. The plasma concentrations of tramadol, O-desmethyltramadol (ODT), and N-desmethyltramadol (NDT) enantiomers were determined. The CYP2D6 activity score (AS) and degree of cachexia progression were assessed according to genotype and the Glasgow Prognostic Score (GPS), respectively. The enantiomeric ratio of NDT was (+)-form dominant in all patients. CYP2D6 AS had negative correlations with the plasma concentrations of (+)-NDT and (−)-NDT. The plasma concentrations of (+)-tramadol and (+)-ODT were higher in patients with GPS 1 or 2 than in those with GPS 0. Lower metabolic ratios to NDT enantiomers were observed in patients with GPS 1 or 2. In patients with GPS 1 or 2, the plasma (−)-tramadol was associated with the incidence of central nervous system symptoms. In conclusion, CYP2D6 AS partially explained the contribution of CYP2D6 activity to plasma tramadol and its demethylated metabolite enantiomers. Additionally, cachexia progression elevated the plasma (+)-tramadol and (+)-ODT levels through the reduction of N-demethylation of (+)-tramadol.

Recent CYP2D6 phenotype standardization efforts by CYP2D6 activity score (AS) are based on limited pharmacokinetic (PK) and pharmacodynamic (PD) data. Using data from two independent clinical trials of metoprolol, we compared metoprolol PK and PD across CYP2D6 AS with the goal of determining whether the PK and PD data support the new phenotype classification. S‐metoprolol apparent oral clearance (CLo), adjusted for clinical factors, was correlated with CYP2D6 AS (P

Pharmacogenetic (PGx) testing is a tool to identify patients at a higher risk of adverse events or treatment failure. The concern for unwanted side effects can limit medication adherence, particularly in children and adolescents. We conducted a pragmatic study to evaluate the acceptability and feasibility and gather pilot data on the utility of PGx testing in a child and adolescent psychiatry clinic. Both physicians and families participated in the study and answered pre‐survey and post‐survey questionnaires to examine their attitudes toward PGx testing. Patients were randomized into implementation (N = 25) and control groups (N = 24) and underwent PGx testing at the beginning or end of the study, respectively. Clinical consult notes with genotype‐guided recommendations were provided to physicians for their consideration in clinical decisions. Patient‐reported symptom severity and antidepressant‐related side effects were assessed at baseline and for 12 weeks. Both participating physicians and families agreed that PGx testing is a useful tool to improve medication selection. The time from sample collection to having PGx test results was ~ 10 days and 15 days to having consult notes available, which may have impaired test utility in clinical decision making. There were no differences in any clinical end point between the implementation and control arms; however, there were higher antidepressant side effect scores for CYP2D6 poor and intermediate metabolizers after the eighth week of treatment. Our findings revealed benefits and pitfalls with the use of PGx testing in the real‐world clinical setting, which may inform the methodology of a larger trial focused on outcomes.

Venlafaxine (VEN) is a P-glycoprotein (P-gp) substrate, and nifedipine has been described by in vitro and experimental studies as a P-gp inhibitor. The present study aimed to investigate whether nifedipine alters the kinetic disposition of VEN enantiomers and their metabolites in healthy subjects. A crossover study was conducted in 10 healthy subjects phenotyped as extensive metabolizers for cytochrome P450 (CYP) 2D6, CYP2C19, and CYP3A. In phase 1, the subjects received a single oral dose of 150 mg racemic VEN, and in phase 2, a single oral dose of 40 mg nifedipine was administered with the VEN treatment. Plasma concentrations of VEN enantiomers and their metabolites O-desmethylvenlafaxine and N, O- didesmethylvenlafaxine (ODV and DDV, respectively) were evaluated by liquid chromatography with tandem mass spectrometry up to 72 hours after drug administration. Phase 2 was compared with phase 1 using the 90% confidence interval (CI) of the ratio of geometric means for Cmax and area under the curve (AUC). AUC enantiomeric ratios S-(+)/R-(-) were evaluated within each and between phases using the Wilcoxon test (P ≤ .05). The kinetic disposition of VEN was enantioselective (phase 1) with VEN S-(+)/R-(-) AUC ratio median of 2.83 (AUC0-∞ , 526 vs 195 ng·h/mL). However, AUC median did not differ between enantiomers for the metabolites ODV (1971 vs 2226 ng·h/mL) and DDV (199 vs 151 ng·h/mL). The 90%CI of the ratio of geometric means showed that the phases are bioequivalent. A single oral dose of 40 mg nifedipine did not alter VEN enantiomer pharmacokinetics in healthy subjects.

Background: Tramadol is used off-label for medically supervised opioid withdrawal. Tramadol is metabolized by CYP2D6 to an active metabolite with significantly more pharmacologic activity compared ...

Eliglustat is a first-line oral treatment for adults with Gaucher disease type 1 who have cytochrome P450 (CYP) 2D6 extensive, intermediate, or poor metabolizer phenotypes. Per International Conference on Harmonisation (ICH) E14 guidance, a Phase 1 thorough electrocardiographic (ECG) study was done during drug development to assess eliglustat's effects on cardiac repolarization by measuring ECG intervals in healthy adult subjects. Using data from the thorough ECG study, we performed pharmacokinetic/pharmacodynamic-ECG modeling to establish the relationship between eliglustat concentrations and their effects on ECG intervals. We then used that concentration-response relationship to predict the effects of eliglustat on each ECG interval for each CYP2D6 metabolizer phenotype (the main determinant of eliglustat exposure) and in different drug-drug interaction scenarios. These predictions, together with other exposure-related factors, contributed to the CYP2D6 phenotype-based dosing recommendations for eliglustat, including dose adjustments and contraindications when co-administered with drugs metabolized by the CYP2D6 and CYP3A pathways.

The fungal 13-membered cyclodepsipeptides, beauveriolides I and III, were previously reported to be atheroprotective activity in mouse models via inhibiting sterol O-acyltransferase (SOAT) activity. A total of 149 beauveriolide derivatives (BVDs) synthesized combinatorially were evaluated in in silico absorption, distribution, metabolism and excretion (ADME) analysis and inhibitory activity toward the two SOAT isozymes, SOAT1 and SOAT2. Hence, only 11 BVDs exhibited SOAT2-selective inhibition. Among these, we chose BVD327, which had the highest ADME score, for further evaluation. BVD327 administration (50 mg/kg/d, per os (p.o.)) significantly decreased atherosclerotic lesions in the aorta and heart (25.4 ± 6.9 and 20.6 ± 2.9%, respectively) in apolipoprotein E knockout (Apoe-/-) mice fed a cholesterol-enriched diet (0.2% cholesterol and 21% fat) for 12 weeks. These findings indicate that beauveriolide derivatives can be used as anti-atherosclerotic agents.

ObjectiveTo assess CYP2D6 genotype prevalence in chronic pain patients treated with tramadol or codeine.DesignProspective cohort study.SettingGeneral hospital, pain management unit.SubjectsPatients with chronic pain, treated with codeine or tramadol.MethodsPatients’ pain was assessed at baseline (numeric rating scale [NRS]; 0–10). Prescription of codeine or tramadol was selected randomly. The assessment of patients’ response to the drug in terms of pain relief and adverse effects was performed after 24 hours. Reduction of pain intensity of >50% or an NRS ResultsSeventy-six consecutive patients were studied (20 males, 56 females), aged 21–85 years. Thirty-four received tramadol and 42 codeine. The main genotypes of CYP2D6 identified were the wt/wt (35.5%), the *4/wt (17.1%), and the *6/wt (10.5%). Adverse effects were common, especially in carriers of *9/*9, *5/*5, *5/*4, and *10/*10, as well as in variants including the 4 allele (*4/*1 [38.4%] and *4/*4 [42.8%]).ConclusionsGenotyping can facilitate personalized pain management with opioids, as specific alleles are related to decreased efficacy and adverse effects.

OBJECTIVE: To describe the usage patterns of antidepressants with published CYP2D6- and CYP2C19-based prescribing guidelines among depressed primary care patients and estimate the proportion of patients taking antidepressants not recommended for them based on their CYP2C19 and CYP2D6 genotype-predicted metabolizer status. METHODS: Medication use and pharmacogenetic testing results were collected on 128 primary care patients enrolled in a 10-year depression cohort study. At each 12-month interval, we calculated the proportion of patients that: (1) reported use of one or more of the 13 antidepressant medications (i.e. amitriptyline, citalopram, escitalopram, clomipramine, desipramine, doxepin, fluvoxamine, imipramine, nortriptyline, paroxetine, sertraline, trimipramine, venlafaxine) with published CYP2D6- and CYP2C19-based prescribing guidelines, (2) were taking an antidepressant that was not recommended for them based on their CYP2C19 and CYP2D6 genotype-predicted metabolizer phenotype, and (3) switched medications from the previous 12-month interval. RESULTS: The annual proportion of individuals taking an antidepressant with a CYP2D6- and CYP2C19-based prescribing guidelines ranged from 45 to 84%. The proportion of participants that used an antidepressant that was not recommended for them, based on available CYP2D6 and CYP2C19 metabolizer phenotype, ranged from 18 to 29% and these individuals tended to switch medications more frequently (10%) compared to their counterparts taking medication aligned with their metabolizer phenotype (6%). CONCLUSION: One-quarter of primary care patients used an antidepressant that was not recommended for them based on CYP2D6- and CYP2C19-based prescribing guidelines and switching medications tended to be more common in this group. Studies to determine the impact of CYP2D6 and CYP2C19 genotyping on reducing gene-antidepressant mismatches are warranted.

What is known and objective Nebivolol, a selective β1 adrenoreceptor antagonist, is predominantly metabolized by cytochrome P450 (CYP)2D6 and shows a wide interindividual variability in pharmacokinetics. The present study was conducted to evaluate the effects of the major CYP2D6 polymorphisms on nebivolol disposition in healthy Chinese volunteers. Methods Twenty-eight volunteers were enrolled and classified as CYP2D6*1/*1, CYP2D6*1/*10, CYP2D6*10/*10 and CYP2D6*5 carriers according to their genotypes. The concentration of nebivolol was determined by high-performance liquid chromatography-tandem mass spectrometry. The association between the pharmacokinetic parameters and genotypes was evaluated using the unpaired t test or analysis of variance. Results and discussion We evaluated the effects of CYP2D6*5 and *10 polymorphism on the pharmacokinetics of nebivolol. Plasma nebivolol peak concentration and area under the curve (AUC(0-48 h) and AUC(0-∞) ) were significantly higher in subjects with CYP2D6*5 and CYP2D6*10/*10 polymorphism than those in subjects with wild-type CYP2D6 (CYP2D6*1/*1), whereas its plasma clearance was significantly lower in the CYP2D6*10/*10 and CYP2D6*5 carriers. No significant differences in the peak time and terminal half-life of nebivolol were observed among CYP2D6*10/*10, CYP2D6*1/*1 and CYP2D6*5 carriers. What is new and conclusion Both CYP2D6*5 and *10 polymorphism altered the pharmacokinetics of nebivolol in healthy Chinese volunteers. Further studies are required to investigate the effects of these single-nucleotide polymorphisms on the pharmacokinetics, pharmacodynamics and toxicity of nebivolol.

Background Many drugs with dose-dependent effects on hemodynamic variables are metabolized by cytochrome P450 2D6 (CYP2D6). The aim of this study was to compare prescribed dosages and hemodynamic responses of such drugs in relation to pharmacogenetic variability in CYP2D6 metabolism among patients aged ≥ 70 years exposed to polypharmacy. Materials and Methods We included 173 patients with detailed information about drug use. The patients were retrospectively subjected to CYP2D6 genotyping, which comprised the most common variant alleles encoding reduced, absent, or increased CYP2D6 metabolism. In order to compare dosages across different CYP2D6-metabolized drugs, all prescribed daily doses were harmonized to the ‘percent of a daily defined dose’ (DDD). The mean harmonized DDD was compared between genotype-predicted normal metabolizers (NMs) and patients with reduced or absent CYP2D6 enzyme activity, defined as intermediate or poor metabolizers (IMs/PMs). Blood pressure, pulse, and patient proportions with orthostatism and bradycardia were also compared between genotype subgroups. Results The genotype-predicted phenotype subgroups comprised 79 NMs (45.7%), 75 IMs (43.4%), and 16 PMs (9.2%). There were no differences in dosing of CYP2D6 substrates between NMs and IMs/PMs (p = 0.76). A higher proportion of CYP2D6 IMs/PMs experienced orthostatism (p = 0.03), while there were no significant subgroup differences for the other hemodynamic variables. Conclusion In this real-life clinical setting of patients aged ≥ 70 years, dosing of CYP2D6 substrates were not adjusted according to genotype-predicted CYP2D6 metabolism. The increased occurrence of orthostatism in patients with reduced/absent CYP2D6 metabolism may indicate that individualized dosing based on genotype has the potential to prevent adverse effects in these vulnerable patients. Electronic supplementary material The online version of this article (10.1007/s40266-020-00763-0) contains supplementary material, which is available to authorized users.

This study was aimed to investigate the prevalence of CYP2C9*2 (p.430C > T, rs1799853), CYP2C9*3 (p.1075A > C, rs1057910), CYP4F2*3 (p.1297G > A, rs2108622), CYP2C19*2 (p.681G > A, rs4244285), CYP2C19*3 (p.636G > A, rs4986893), CYP2C19*17 (p.1260C > A, rs12248560), ABCB1 (p.3435C > T, rs1045642), CYP2D6*4 (p.1846G > A, rs3892097), SLCO1B1*5 (p.521T > C, rs4149056) and CES1 (p.1168-33A > C, rs2244613) among Tatars and Balkars ethnic groups living in Russia to provide a basis for future clinical studies concerning on understanding of population-level differences in drug response. The study involved 341 apparently healthy, unrelated, and chronic medication-free volunteers of both sexes of ethnic groups of Tatars and Balkars living in Volga and Caucasus regions of Russia. Genotyping was performed using real-time polymerase chain reaction-based methods. The allelic prevalence of studied markers in ethnic groups were compared with Russians as a largest ethnic group in Russia. Statistically significant differences for the following gene polymorphisms were found between both ethnic groups in respect of different markers and with Russians. Our study shows differences in prevalence of the main relevant pharmacogenetic markers in Tatars and Balkars. These findings should be taken into consideration for personalization algorithms development and pharmacogenetics implementation in regions with ethnic minorities as Russia has.

Purpose Little is known about how many insured patients receive pharmacogenetic testing. We describe trends of single-gene pharmacogenetic testing in a US managed care population, and demographic and clinical characteristics of patients who received a test. Methods We leveraged a random sample of nearly 11 million patients from a data set of paid medical and pharmacy claims to identify patients with at least one claim indicating receipt of at least one of these single-gene pharmacogenetic tests: CYP2C19, CYP2D6, CYP2C9, VKORC1, UGT1A1, and HLA class 1 typing. Results From 1 January 2013 to 30 September 2017, 5712 patients received at least one pharmacogenetic test (55% female; mean age = 43 years). The median number of tests per patient was 3 (mean = 2.7, max = 12); 54% were processed through Managed Medicare/Medicaid, while 45% were processed through commercial insurance. The total number of pharmacogenetic tests received more than doubled from 2013 (n = 1955) to 2015 (n = 4192), then decreased slightly in 2016 (n = 3946). The most common test was CYP2C19 (n = 4719), and “long-term (current) use of other medications” was the most common diagnosis. Conclusion Pharmacogenetic testing through patients’ insurance was low, but more than doubled from 2013 to 2016. This study highlights the need to better understand utilization patterns and insurance coverage for pharmacogenetic tests.

This work aimed to describe and characterize the GnG-PK/PD-AD study and the population of subjects diagnosed with depression and treated with fluoxetine, paroxetine, and venlafaxine recruited in the scope of this project, particularly in terms of antidepressant pharmacokinetics and clinical outcomes and relevant genetic and nongenetic individual factors. 182 subjects diagnosed with depression and treated with these drugs were clinically and therapeutically characterized and submitted to the quantification of drug/metabolite plasma concentrations and genotyping of ABCB1, CYP2C9, CYP2C19, and CYP2D6 genes. Clinical outcomes, including remission and antidepressant adverse effects, were assessed by means of the Hamilton Depression Rating Scale and Antidepressant Side-Effect Checklist, respectively. Most subjects were women (81.9%), suffered from chronic depression (73.6%) and displayed a high prevalence of comorbidities (76.9%), polytherapy (88.5%), and genetic polymorphisms/non-wild-type genotype-predicted phenotypes at the level of CYP2C9, CYP2C19, CYP2D6, and ABCB1 genes (39-78.6%). Noteworthy, most of them were under risk of presenting P-gp, CYP2C9, CYP2C19, and CYP2D6 inhibited due to drug-induced phenoconversion (64.3-98.4%) and 80.8% were at risk of occurrence of at least one antidepressant-drug interaction. Around 40% presented drug plasma concentrations outside of the recommended therapeutic range, 66.5% did not achieve remission of the depressive symptoms and 67.6% presented at least one relevant antidepressant adverse effect. Pharmacokinetics and clinical outcomes with fluoxetine, paroxetine, and venlafaxine were found to be suboptimal and highly variable between subjects. Several genetic and nongenetic factors were identified as potential sources of interindividual variability in the antidepressant outcomes, which deserve to be further investigated. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Background The relationship between a daily dose of olanzapine, its serum concentration, and the genotype of young nonsmoking men treated for schizophrenia or schizophreniform disorder was investigated in day-to-day clinical practice. Pharmacogenetics was also examined for the selected patients. Methods A total of 49 participants were recruited as in-patients at the Mental Health Research Center (Moscow, Russia). Inclusion criteria were patients who had been diagnosed with schizophrenia or schizoaffective disorder (following DSM-IV guidelines) and were being treated with OLZ. A prospective, observational, open-study design was implemented. In line with the literature, patients were only included if they attained steady-state OLZ concentrations lasting for at least 8 days. A liquid chromatographic-tandem mass spectrometric method was developed for analyzing OLZ in human serum. The single cytochrome P450 polymorphisms were genotyped using an amplifier real-time polymerase chain reaction system following standard protocols. Results Evidence indicating that CYP2D6 polymorphism has a significant (P = 0.046) effect on the pharmacokinetics of olanzapine was obtained, confirming the beneficial effects of therapeutic drug monitoring (TDM) for olanzapine. Conclusions TDM should therefore be used as a standard care during olanzapine therapy. TDM is also useful in assessing adherence and may have a role in limiting olanzapine dosage geared at minimizing the risk of long-term toxicity.

CYP2D metabolizes many drugs that act within the brain, and variable expression of CYP2D in the brain may alter local drug and metabolite levels sufficiently to affect behavioral responses. Transgenic mice that express human CYP2D6 (TG) were compared to wild type mice (WT). Following selective inhibition of human CYP2D6 in TG brain, we demonstrated in vivo that human CYP2D6 in the brain was sufficient to alter a drug-induced behavioral response. After a 4-h pre-treatment with intracerebroventricular (i.c.v.) propranolol, CYP2D activity in vivo and in vitro was reduced in TG brain, whereas CYP2D activity in vivo, but not in vitro, was reduced in WT brain. After a 24-h pre-treatment with i.c.v. propranolol, CYP2D activity in vivo and in vitro was reduced in TG brain, whereas CYP2D activity in vivo and in vitro was not changed in WT brain. These results indicate that i.c.v. propranolol irreversibly inhibited human CYP2D6 in TG brain but not mouse CYP2D in TG and WT brain. Pre-treatments with propranolol did not change liver CYP2D activity in vivo or in vitro. Furthermore, 24-h pre-treatment with i.c.v. propranolol resulted in a significant decrease of the haloperidol-induced catalepsy response in TG, but not in WT, without changing serum haloperidol levels in either mouse line. These studies reveal a new tool to selectively and irreversibly inhibit human CYP2D6 in TG brain and indicate that human CYP2D6 has a functional role within the brain sufficient to impact the central nervous system response from peripherally administered drugs.

The growing number of new synthetic opioids (NSO) on the new psychoactive substances (NPS) market bears new challenges in toxicology. As their toxicodynamics and particularly their toxicokinetics are usually unknown, impact on human health is not yet fully understood. Detection of the 2 NSO cyclopentanoyl-fentanyl (CP-F) and tetrahydrofuranoyl-fentanyl (THF-F) was first reported in 2016. Both were involved in several fatal intoxication cases, but no detailed information about their toxicological characteristics is available so far. The main purpose of this study was therefore to investigate the in vitro toxicokinetics and in vivo analytical toxicology of CP-F and THF-F by means of liquid chromatography high-resolution tandem mass spectrometry (LC-HRMS/MS). These studies included metabolic stability, phase I and II metabolism, isozyme mapping, plasma protein binding and detectability in LC-HRMS/MS standard urine screening approaches (SUSA) using rat urine samples. In total, 12 phase I metabolites of CP-F and 13 of THF-F were identified, among them 9 metabolites described for the first time. Overall, N-dealkylations, hydroxylations and dihydroxylations were the main metabolic reactions. The cytochrome P450 (CYP) isozymes mainly involved were CYP2D6 and CYP3A4, leading to elevated drug levels and intoxications in CYP2D6 poor metabolizers. CP-F showed a high plasma protein binding of 99%, which may increase the risk of toxicity by simultaneous intake of other highly bound drugs. Detectability studies showed that neither the parent compounds nor their metabolites were detectable in rat urine using LC-HRMS/MS SUSA. However, a more sophisticated analytical strategy was successfully applied and should be used for analytical confirmation of an intake of CP-F and/or THF-F.

Hyperprolactinemia is a known adverse drug reaction to antipsychotic treatment. Antipsychotic blood levels are influenced by cytochrome P450 enzymes, primarily CYP2D6. Variation in CYP450 genes may affect the risk of antipsychotic-induced hyperprolactinemia. We undertook a systematic review and meta-analysis to assess whether CYP2D6 functional genetic variants are associated with antipsychotic-induced hyperprolactinemia. The systematic review identified 16 relevant papers, seven of which were suitable for the meta-analysis (n = 303 participants including 134 extreme metabolisers). Participants were classified into four phenotype groups as poor, intermediate, extensive, and ultra-rapid metabolisers. A random effects meta-analysis was used and Cohen's d calculated as the effect size for each primary study. We found no significant differences in prolactin levels between CYP2D6 metabolic groups. Current evidence does not support using CYP2D6 genotyping to reduce risk of antipsychotic-induced hyperprolactinemia. However, statistical power is limited. Future studies with larger samples and including a range of prolactin-elevating drugs are needed.

CYP2D6 and CYP3A4, which are members of the cytochrome P450 superfamily of metabolic enzymes, play major roles in the metabolism of commonly available drugs. CYP3A4 is involved in the metabolism of 50% of drugs on the market, whereas CYP2D6 is involved in the metabolism of 25% of them. CYP2D6 exhibits a high degree of polymorphic nature in the human population, causing individual differences in CYP2D6 expression and enzymatic activity. Therefore, accurate prediction of drug metabolism and toxicity require a human adult hepatocyte cell model that mimics individual responses in the average population. HepaRG cells, a human hepatocellular carcinoma cell line, is the only cell line that can differentiate into hepatocyte-like cells with high expression of CYP3A4 but poor expression of CYP2D6. To solve this problem, we developed transgenic HepaRG cell clones expressing either full-length or spliced CYP2D6 at various levels with an easy monitoring system for CYP2D6 expression in living cells under a fluorescent microscope. As CYP2D6 mRNA, protein, and fluorescence intensity were closely correlated among transgenic HepaRG clones, fluorescence levels will provide a simple tool for quality assurance of CYP2D6-expressing HepaRG cells. Thus, the package of transgenic HepaRG cell clones expressing CYP2D6 at various levels will provide an improved hepatocyte model that reflects the average or individual reactions in the human population for in vitro studies of drug metabolism and toxicity involving CYP2D6 and CYP3A4.

This study aims to investigate the different clinically relevant allele variants (allele frequencies) of CYP2D6 gene and to determine whether a specific genotype of CYP2D6 gene (based on genetic polymorphism “allelic types” and combination) have impact on metoprolol effectiveness (clinical outcome) in patients who have acute coronary syndrome (ACS). The study included 250 patients with ACS who were classified into 2 study groups, 125 patients received metoprolol and served as a study group (Group1) and 125 who received no metoprolol therapy (due to contraindication to the medication) and served as a control group (Group 2). Venous blood samples were taken from all participants for DNA extraction. Urine samples were also collected to assess the metabolic ratio using High-performance liquid chromatography (HPLC) technique. There was significant variation in the distribution of Iraqi patients with respect to CYP2D6 allelic polymorphism as compared to similar patients in other countries. Besides, this significant difference existed in patients' outcome in terms of morbidity and mortality in respect to variable genotypes and phenotypes. We recommend a dose individualization of metoprolol in patients with ACS is essential to improve patients' outcome.

The botanical product kratom produces opioid-like effects at high doses and is sometimes used for opioid replacement by individuals with opioid use disorder. Mitragynine, a major alkaloid contained in kratom leaves, has been shown to inhibit multiple cytochromes P450 (CYPs) in vitro, including CYP2D6 and CYP3A. As such, kratom may precipitate pharmacokinetic drug interactions when co-consumed with certain medications. We present a case of a patient taking 150 mg venlafaxine (CYP2D6/3A substrate), 300 mg quetiapine (CYP3A substrate), and a high amount of kratom (~90 g) daily. The patient presented to the emergency department with serotonin syndrome and corrected electrocardiogram abnormalities that may have been secondary to supratherapeutic exposure to venlafaxine and/or quetiapine. The patient's symptoms resolved after discontinuation of venlafaxine and quetiapine. He was amenable to medication therapy for kratom discontinuation and successfully completed an at-home induction with buprenorphine/naloxone. This case report adds to the literature about potential pharmacokinetic kratom-drug interactions and suggests that buprenorphine/naloxone can facilitate recovery from kratom use disorder.

Aims To investigate the longitudinal exposure of English primary care patients to pharmacogenomic drugs to inform design of pre-emptive testing. Methods Sixty-three drugs were identified with dosing guidelines based on variants of 19 pharmacogenes in the Pharmacogenomics Knowledgebase on 01 September 2018. Prescribing of these pharmacogenomic drugs between 1993 and 2017 was summarised for a sample of 648 141 English patients aged 50-99 years on 01 January 2013, registered with Clinical Practice Research Datalink practices during 2011-12. Exposure of patients to pharmacogenomic drugs retrospectively (2, 10, 20 y) and prospectively (5 y) was described. Results During 2011-12, 58% of patients were prescribed at least 1 pharmacogenomic drug, increasing to 80% over the previous 20 years. Multiple exposure was common, with 47% patients prescribed ≥2 pharmacogenomic drugs and 7% prescribed ≥5 pharmacogenomic drugs over the next 5 years. The likelihood of exposure to pharmacogenomic drugs increased with age, with 89% patients ≥70 years prescribed at least 1 pharmacogenomic drug over the previous 20 years. Even among those aged 50-59 years, 71% were prescribed at least 1 pharmacogenomic drug over the previous 20 years. The pharmacogenomic drugs prescribed to the most patients were for pain relief, gastroprotection, psychiatric and cardiovascular conditions. Three pharmacogenes (CYP2D6, CYP2C19 and SLCO1B1) accounted for >95% pharmacogenomic drugs prescribed. Conclusions In primary care patients, exposure to pharmacogenomic drugs is extremely common, multiplicitous and has commenced by relatively early adulthood. A small number of pharmacogenes account for the majority of drugs prescribed. These findings could inform design of pre-emptive pharmacogenomic testing for implementation in primary care.