A Scoping Review of the Evidence Behind Cytochrome P450 2D6 Isoenzyme Inhibitor Classifications

Monitoring Serum Bisoprolol Concentrations in Patients With Heart Failure With Reduced Ejection Fraction: Results of a Pilot Study From Routine Health Care

Bisoprolol is a second-generation, highly selective beta-1 adrenergic receptor antagonist with various beneficial effects in patients with heart failure. Interindividual variability in response to bisoprolol is known, and finding the optimal dose for individual patients with heart failure is still challenging. This pilot study included patients treated with bisoprolol for chronic heart failure with reduced ejection fraction. Between November 2022 and November 2023, one to six blood samples were collected from these patients to determine the trough serum concentration of bisoprolol. At the same time, the values of selected clinical variables were recorded. Bisoprolol concentrations ranged from 1.1 to 65.0 μg/L and correlated with both the daily dose and the dose per kilogram of body weight. However, wide variability in measured serum concentrations of bisoprolol was observed at the same daily dose and in apparent weight-adjusted clearance. Patients classified as NYHA III-IV received a 33% higher dose per kilogram of body weight than patients in NYHA I-II but achieved 165% higher serum concentrations of bisoprolol. An inverse correlation was found between diastolic blood pressure and dose per kilogram of body weight, and a positive correlation between N-terminal pro-B-type natriuretic peptide and both dose per kilogram of body weight and serum bisoprolol concentration. A wide variability in patients' serum concentrations of bisoprolol achieved after taking the same dose has been observed. A significantly higher concentration-to-dose ratio and a significantly lower weight-adjusted apparent clearance were demonstrated in patients with reduced cardiac function, reduced renal function, and taking the combination with amiodarone. These patients may be more prone to overdose with bisoprolol.

Evaluating the Evidence for CYP2C19 Inhibitor Classifications: A Scoping Review

The Food and Drug Administration (FDA) Table of Inhibitors and the Flockhart Table™ are important references for identifying CYP2C19 inhibitors. Accurate inhibitor classification is essential for evaluating phenoconversion and managing drug-drug interactions. The objective of this study was to assess the concordance between inhibitor classifications according to the FDA and Flockhart tables and pharmacokinetic data from the primary literature. A scoping review of PubMed, product labels, and the Drug Interactions Database (DIDB®) up to April 2024 was conducted. Inhibitor-substrate pairs (e.g., fluoxetine-omeprazole) were assigned literature-reported classifications (i.e., weak, moderate, or strong) based on pharmacokinetic data. Concordance between literature-reported and listed classifications was evaluated. Of 90 inhibitor-substrate pairs identified, 66% involved sensitive substrates, which were the focus of our primary analysis. Among sensitive inhibitor-substrate pairs, 36% of FDA-listed and 45% of Flockhart-listed classifications were concordant with the literature. CYP2C19 phenotype appeared to impact concordance, with greater concordance among normal metabolizers for both FDA-listed (42%) and Flockhart-listed (50%) classifications. Steady state status and dosing also appeared to affect concordance. Discrepancies between listed and literature-reported classifications led to the following recommendations: (1) upgrade fluoxetine from moderate to strong in the Flockhart Table™, (2) upgrade fluconazole from moderate to strong in the Flockhart Table™, (3) downgrade omeprazole (and esomeprazole) from moderate to weak in the Flockhart Table™, and (4) include footnotes describing dose-dependent inhibition for fluvoxamine and fluconazole in both tables. These recommendations aim to improve the accuracy of CYP2C19 inhibitor classifications and the clinical utility of these tables.

Synthesis, Experimental and Computational Evaluation of SERAAK1 as a 5-HT2A Receptor Ligand

Many drug discovery efforts have identified potentially promising molecules; however, a common limitation of these reports is the lack of further experimental confirmation of pharmacokinetic properties and behavioral effects of discovered compounds. In this study, we aim to address this limitation. Therefore, we build on our previous virtual screening campaign by synthesizing, analyzing in silico, and evaluating experimentally the SERAAK1 compound, which was initially identified as a ligand for 5-HT1A, 5-HT2A, and D2 receptors. Through these investigations, we discovered that SERAAK1 binds to the orthosteric pocket of the 5-HT2A receptor in a similar mechanism to that known for marketed antipsychotic medications. Molecular dynamics simulations revealed that the SERAAK1 compound remains stable in the orthosteric binding pocket of the 5-HT2A receptor. The determination of the ADMET parameters indicated the directions for further optimization of the compounds. In vivo studies demonstrated the anxiolytic and antidepressant properties of the SERAAK1 compound.

Chronic alcohol intake disrupts cytochrome P450 enzyme activity in alcoholic fatty liver disease: insights into metabolic alterations and therapeutic targets

Introduction

Alcoholic fatty liver disease (AFLD) is a common consequence of chronic alcohol consumption, characterized by lipid accumulation and oxidative stress in the liver. Cytochrome P450 (CYP450) enzymes play essential roles in metabolizing alcohol and other compounds. However, the specific long-term effects of alcohol on these enzymes remain unclear.

Methods

This study the examines influence of prolonged ethanol exposure on CYP450 activity and expression in AFLD using a rat model. Key enzymes such as CYP2E1, CYP2D6, and CYP3A1 were assessed in relation to lipid accumulation and oxidative stress.

Results

Significant alterations were identified in the expression and activity of CYP2E1, CYP2D6, and CYP3A1, which were associated with increased lipid accumulation and oxidative stress in the liver. Additionally, the expression of P-glycoprotein (P-gp) was elevated, suggesting that chronic alcohol intake may impact drug transport and excretion.

Discussion

These findings provide new insights into the molecular mechanisms of AFLD and highlight the potential of CYP450 modulation as a therapeutic target. By elucidating how long-term ethanol exposure disrupts hepatic CYP450 enzyme profiles, this research lays the groundwork for developing personalized therapeutic strategies to improve outcomes for patients with AFLD.

Sex and age effects on prevalence of CYP2C19 and CYP2D6 Phenoconversion risk over time in patients with psychosis

Pharmacogenetics in psychiatry may have benefits for medication treatment success. However, medication regimes leading to drug-drug interactions and potential phenoconversion of actionable pharmacogenetic phenotypes challenge the application of pharmacogenetics. Although polypharmacy is common, its impact in patients with psychosis is understudied, even though these patients might benefit from pharmacogenetics-guided medication adjustment. Here, we investigated the impact of two pharmacogenes relevant in psychiatric practice, CYP2C19 and CYP2D6, and the effect of sex and age. Medication use and predicted occurrence of phenoconversion was examined in a sample of patients with psychosis over a period of approximately six years. Bayesian statistics were applied to examine longitudinal effects. Our results show that women used more medications, including CYP2C19 and CYP2D6 inhibitors and (actionable) substrates. No significant sex or age differences were found for phenoconversion of either enzyme. A sex-effect on CYP2C19 inhibitor use was found but appeared to be driven by weakly inhibiting oral contraceptives, which were reported only in women. The phenoconversion rate for both enzymes appeared to change over time, suggesting that phenoconversion is a dynamic state that may affect patients differently over their lifetime. To further improve treatment in this patient population, long-term and regular updated medication monitoring in (pharmacogenetic) research as well as application in practice are recommended.

Antidepressant Use Trajectories and Risk of Discontinuation After Adolescents and Young Adult Cancer Diagnosis

BACKGROUND

Little is known about the continuity of antidepressant treatment after adolescent and young adult (AYA) cancer diagnosis. Clinical guidelines recommend that past antidepressant use trajectories should inform decisions on discontinuation after cancer diagnosis. We characterized AYAs' antidepressant adherence trajectories before incident cancer diagnosis and assessed any association between their past adherence trajectory and the risk of antidepressant discontinuation up to 1 year afterward.

METHODS

We conducted a retrospective, longitudinal cohort study of AYAs receiving ≥ 2 antidepressant fills 9 months before incident cancer diagnosis (index date). Group-based trajectory modeling was used to estimate latent subgroups of antidepressant adherence before cancer diagnosis, using monthly proportions of days covered (PDC) over the nine-month baseline; IQVIA PharMetrics Plus for Academics US claims, 2006-2020. Discontinuation was defined as ≥ 60-days gap without antidepressants within 1 year post-index date.

RESULTS

We observed three distinct antidepressant adherence trajectory groups before cancer diagnosis: recent start (17% of cohort, mean PDC [range]: 0.25 [0.03-0.49]); gradually increasing (36%, mean PDC [range]: 0.57 [0.22-0.81]); and consistently high (47%, mean PDC [range]: 0.90 [0.62-1.00]). Compared with AYAs exhibiting prior consistently high adherence trajectories, those with recent start (HR, [95% CI] 1.96, [1.46-2.63]) and gradually increasing (HR, [95% CI] 1.52, [1.20-1.93]) trajectories experienced about 2 times the higher risk of antidepressant discontinuation over the year following cancer diagnosis.

CONCLUSION

Past antidepressant trajectory is associated with antidepressant discontinuation after AYA cancer diagnosis. Attention is needed in the psycho-oncologic care of AYAs who recently started antidepressants before cancer diagnosis.

Phytochemical Analysis, Computational Study, and in vitro Assay of Etlingera elatior Inflorescence Extract Towards Inducible Nitric Oxide Synthase

Background

Overproduction of nitric oxide (NO), catalyzed by inducible nitric oxide synthase (iNOS), in the gastric mucosa, contributes to the inflammatory process caused by oxidative stress. Current medications for gastric ulcers, such as proton pump inhibitors and histamine-2 receptor antagonists, have been reported to generate adverse reactions.

Purpose

To obtain the phytochemical profile of Etlingera elatior inflorescence extract, computational studies, and in vitro assay of the extract towards iNOS.

Methods

Fresh E. elatior inflorescence petals collected from West Java, Indonesia, were extracted using ethanol, and their nutritional composition, anthocyanin content, and levels of vitamin C, C3G, and quercetin in the extract were determined. Drug-likeness and ADMET properties were predicted, and the binding affinity and stability of the phytoconstituents towards iNOS were studied using molecular docking and molecular dynamic simulation, and in vitro assay of the extract towards human iNOS.

Results

The extract contains protein 21.81%, fat 0.99%, carbohydrate 38.27%, water 24.56%, and ash 14.37%. The total anthocyanin and vitamin C levels were 47.535 mg/100 g and 985.250 mg/100 g, respectively. The levels of C3G and quercetin were 0.0007% w/w, 0.004% w/w, and 0.0005% w/w, respectively. Drug-likeness and ADMET properties of the constituents showed that most followed Lipinski Rules of Five (Ro5), with few violations. All phytoconstituents occupied the catalytic site by binding to Glu377, and Trp372, similar to S-ethylisothiourea (SEITU) and quinazoline, the iNOS inhibitors. Among these, the flavylium cation of cyanidin, demethoxycurcumin, C3G, cyanidin, and quercetin showed the best binding affinities. Root mean square deviation (RMSD), root mean square fluctuation (RMSF), solvent-accessible surface area (SASA), and radius of gyration (Rg) graphs confirmed the stability of the complexes. E. elatior inflorescence extract inhibited human iNOS with an IC50 value of 24.718 µg/mL.

Conclusion

Etlingera elatior inflorescence may inhibit iNOS activity due to its anthocyanin and flavonoid content. The flavylium cation of cyanidin, demethoxycurcumin, C3G, cyanidin, and quercetin play leading roles in the interaction with iNOS.

A Randomized Hybrid-Effectiveness Trial Comparing Pharmacogenomics (PGx) to Standard Care: The PGx Applied to Chronic Pain Treatment in Primary Care (PGx-ACT) Trial

This trial aimed to identify the effects of providing pharmacogenomic (PGx) results and recommendations for patients with chronic pain treated in primary care practices compared to standard care. An open-label, prospective, largely virtual, type-2 hybrid effectiveness trial randomized participants to PGx or standard care arms. Adults with pain ≥ 3 months who were treated with tramadol, codeine, or hydrocodone enrolled. Alternative analgesics were recommended for CYP2D6 intermediate or poor metabolizers (IM/PMs). Prescribing decisions were at providers' discretion. The trial randomized 253 participants. A modified intent-to-treat primary analysis assessed change in pain intensity over 3 months among IM/PMs (PGx: 49; Standard care: 57). The PGx and standard care arms showed no difference in pain intensity change (-0.10 ± 0.63 vs. -0.21 ± 0.75 standard deviation; p = 0.74) or PGx-aligned care (69% vs. 63%; standardized difference [SD] = 0.13). In IM/PMs, secondary analyses of pain intensity change suggested improvements with PGx-aligned (n = 70; -0.21 ± 0.70) vs. unaligned care (n = 36; -0.06 ± 0.69) (SD = -0.22), with this difference increasing when examining IM/PMs with an analgesic change (aligned: n = 31, -0.28 ± 0.76; unaligned: n = 36, -0.06 ± 0.69; SD = -0.31). This approach to PGx implementation for chronic pain was not associated with different prescribing (i.e., similar proportions of PGx-aligned care) or clinical outcomes. Secondary analyses suggest that prescribing aligned with PGx recommendations showed a small improvement in pain intensity. However, the proportion of patients with a clinically meaningful improvement (≥ 30%) in pain intensity was similar. Future efforts should identify effective implementation methods.

Analysis of serum concentrations of metoprolol and its metabolite α-hydroxymetoprolol in patients with heart failure with reduced ejection fraction: a pilot study in routine health care

BACKGROUND

The cardioselective β-1 receptor antagonist metoprolol is used to treat heart failure. It is metabolized in the liver, primarily by cytochrome 2D6.

RESEARCH DESIGN AND METHODS

In this study, trough serum concentrations of metoprolol and its metabolite α-hydroxymetoprolol were measured in patients with heart failure with reduced ejection fraction.

RESULTS

Concentrations were 1.3-122.9 µg/L for metoprolol and 1.3-125.7 µg/L for α-hydroxymetoprolol, metabolic ratios were 0.11-98.32. The median weight-adjusted apparent clearance of metoprolol was 53.07 (range 3.24-500.0). Metoprolol and α-hydroxymetoprolol concentrations correlated with both daily dose and dose per kilogram of body weight. However, metoprolol concentrations at the same daily dose showed a wide variability. Patients taking 100 mg/day had significantly lower NT-proBNP values than those taking 25 or 50 mg/day. Patients with LVEF ≤ 35% versus > 35% used significantly lower daily doses and doses per kilogram of body weight, although metoprolol concentrations did not differ. A poor cytochrome 2D6 metabolizer phenotype was detected in two patients.

CONCLUSIONS

Metoprolol concentrations showed a wide interindividual variability at the same daily dose. Simultaneous determination of metoprolol and α-hydroxymetoprolol concentrations could identify patients at risk of possible accumulation of metoprolol leading to intoxication or, conversely, patients at risk of underdosing. [Figure: see text].

Asoprisnil as a Novel Ligand Interacting with Stress-Associated Glucocorticoid Receptor

Background/objective: The glucocorticoid receptor (GR) is critical in regulating cortisol production during stress. This makes it a key target for treating conditions associated with hypothalamic-pituitary-adrenal (HPA) axis dysregulation, such as mental disorders. This study explores novel ligands beyond mifepristone for their potential to modulate GR with improved efficacy and safety. By investigating these interactions, we seek to identify new pharmacotherapeutic options for stress-related mental illness. Methods: The ligands asoprisnil, campestanol, and stellasterol were selected based on structural similarities to mifepristone (reference ligand) and evaluated for pharmacological and ADME (absorption, distribution, metabolism, and excretion) properties using the SwissADME database. Molecular docking with AutoDock 4.2.6 and molecular dynamics simulations were performed to investigate ligand-protein interactions with the human glucocorticoid receptor, and binding free energies were calculated using MMPBSA. Results: Pharmacokinetic analysis revealed that asoprisnil exhibited high gastrointestinal absorption and obeyed Lipinski's rule, while mifepristone crossed the blood-brain barrier. Toxicological predictions showed that mifepristone was active for neurotoxicity and immunotoxicity, while asoprisnil, campestanol, and stellasterol displayed lower toxicity profiles. Asoprisnil demonstrated the highest stability in molecular dynamics simulations, with the highest negative binding energy of -62.35 kcal/mol, when compared to mifepristone, campestanol, and stellasterol, with binding energies of -57.08 kcal/mol, -49.99 kcal/mol, and -46.69 kcal/mol, respectively. Conclusion: This makes asoprisnil a potentially favourable therapeutic candidate compared to mifepristone. However, further validation of asoprisnil's interaction, efficacy, and safety in stress-related mental disorders through experimental studies and clinical trials is needed.

Pharmacogenomic insights in psychiatric care: uncovering novel actionability, allele-specific CYP2D6 copy number variation, and phenoconversion in 15,000 patients

Pharmacogenomic testing has emerged as an aid in clinical decision making for psychiatric providers, but more data is needed regarding its utility in clinical practice and potential impact on patient care. In this cross-sectional study, we determined the real-world prevalence of pharmacogenomic actionability in patients receiving psychiatric care. Potential actionability was based on the prevalence of CYP2C19 and CYP2D6 phenotypes, including CYP2D6 allele-specific copy number variations (CNVs). Combined actionability additionally incorporated CYP2D6 phenoconversion and the novel CYP2C-TG haplotype in patients with available medication data. Across 15,000 patients receiving clinical pharmacogenomic testing, 65% had potentially actionable CYP2D6 and CYP2C19 phenotypes, and phenotype assignment was impacted by CYP2D6 allele-specific CNVs in 2% of all patients. Of 4114 patients with medication data, 42% had CYP2D6 phenoconversion from drug interactions and 20% carried a novel CYP2C haplotype potentially altering actionability. A total of 87% had some form of potential actionability from genetic findings and/or phenoconversion. Genetic variation detected via next-generation sequencing led to phenotype reassignment in 22% of individuals overall (2% in CYP2D6 and 20% in CYP2C19). Ultimately, pharmacogenomic testing using next-generation sequencing identified potential actionability in most patients receiving psychiatric care. Early pharmacogenomic testing may provide actionable insights to aid clinicians in drug prescribing to optimize psychiatric care.

Precision pharmacotherapy of atomoxetine in children with ADHD: how to ensure the right dose for the right person?

Non-stimulant atomoxetine is recognized in various current clinical guidelines as an important alternative to stimulants for the pharmacological treatment of attention deficit/hyperactivity disorder (ADHD) in children. While its efficacy and tolerability for core symptoms are established, there is considerable inter-individual variability in response and exposure, highlighting the need for personalized dosing. In this review, we evaluated existing studies and summarized comprehensive evidence supporting the clinical implementation of therapeutic drug monitoring (TDM) and personalized dosing of atomoxetine, organized around a series of logically structured questions. Although there are notable gaps in achieving personalized dosing across multiple critical elements, the available evidence is helpful to endorse personalized dose adjustments based on TDM and CYP2D6 genotyping "whenever possible." We advocate for ongoing improvement and enhancement in clinical practice. Future advancements will rely on a deeper understanding of ADHD, facilitating more precise diagnoses and personalized treatment strategies.

Rational Molecular Design of a Fluorescent Probe for Selectively Sensing Human Cytochrome P450 2D6

Cytochrome P450 2D6 (CYP2D6) is a key enzyme that mediates the metabolism of various drugs and endogenous substances in humans. However, its biological role in drug-drug interactions especially mechanism-based inactivation (MBI), and various diseases remains poorly understood, owing to the lack of molecular tools suitable for selectively monitoring CYP2D6 in complex biological systems. Herein, using a tailored molecular strategy, we developed a fluorescent probe BDPM for CYP2D6. BDPM exhibits excellent specificity and imaging capability for CYP2D6, making it suitable for the real-time monitoring of endogenous CYP2D6 activity in living bio-samples. Therefore, our tailored strategy proved useful for constructing the highly selective and enzyme-activated fluorescent probes. BDPM as a molecular tool to explore the critical roles of CYP2D6 in the pathogenesis of diseases, high-throughput screening of inhibitors and intensive investigation of CYP2D6-induced MBI in natural systems.

New drug combination regimen based on pharmacokinetic characteristics-Erdafitinib combined with sertraline or duloxetine

The aim of this study is to investigate novel strategies for reducing adverse reactions caused by erdafitinib through a drug combination based on its pharmacokinetic characteristics. The spectrum and characterizations of drugs that can inhibit the metabolism of erdafitinib are examined both in vitro and in vivo. The efficacy of combination regimens are then evaluated using subcutaneous xenograft tumor models. The results demonstrated that sertraline and duloxetine, out of more than 100 screened drugs, inhibited the metabolism of erdafitinib through mixed and non-competitive inhibition, respectively. This inhibition primarily occurred via the CYP2C9 and CYP2D6 pathways. The primary alleles of CYP2C9 and CYP2D6 not only determine the metabolic characteristics of erdafitinib but also influence the strength of drug-drug interactions. Co-administration of sertraline or duloxetine with erdafitinib in rats and mice resulted in nearly a three-fold increase in the blood exposure of erdafitinib and its major metabolite M6. When sertraline or duloxetine was combined with 1/3 of the erdafitinib dosage, the anti-proliferative and pro-apoptotic effects on SNU-16 xenografts were comparable to those of the original full dose of erdafitinib. However, the combination regimen significantly mitigated hyperphosphatemia, retinal damage, intestinal villus damage, and gut microbiome dysbiosis. This study utilized pharmacokinetic methods to propose a new formulation of erdafitinib combined with sertraline or duloxetine. The findings suggest that this combination has potential for clinical co-administration based on a database analysis, thereby providing a novel strategy for anti-tumor treatment with fibroblast growth factor receptor (FGFR) inhibitors.

Clinical Pharmacogenetics Implementation Consortium Guideline (CPIC) for CYP2D6, ADRB1, ADRB2, ADRA2C, GRK4, and GRK5 Genotypes and Beta-Blocker Therapy

Beta-blockers are widely used medications for a variety of indications, including heart failure, myocardial infarction, cardiac arrhythmias, and hypertension. Genetic variability in pharmacokinetic (e.g., CYP2D6) and pharmacodynamic (e.g., ADRB1, ADRB2, ADRA2C, GRK4, GRK5) genes have been studied in relation to beta-blocker exposure and response. We searched and summarized the strength of the evidence linking beta-blocker exposure and response with the six genes listed above. The level of evidence was high for associations between CYP2D6 genetic variation and both metoprolol exposure and heart rate response. Evidence indicates that CYP2D6 poor metabolizers experience clinically significant greater exposure and lower heart rate in response to metoprolol compared with those who are not poor metabolizers. Therefore, we provide therapeutic recommendations regarding genetically predicted CYP2D6 metabolizer status and metoprolol therapy. However, there was insufficient evidence to make therapeutic recommendations for CYP2D6 and other beta-blockers or for any beta-blocker and the other five genes evaluated (updates at www.cpicpgx.org).

Exploring Chemotherapy-Induced Peripheral Neuropathy Management Practice Patterns Among Oncology Clinicians

OBJECTIVES

Approximately 60% of cancer survivors receiving neurotoxic chemotherapy experience chemotherapy-induced peripheral neuropathy (CIPN) (eg, hand and foot numbness, tingling, or pain). There is only one recommended pharmacological treatment (duloxetine) and one modestly beneficial nonpharmacological treatment (exercise) for CIPN. However, data suggest national guideline recommendations are not routinely practiced. Further, less is known about nurses' CIPN management practices. The purpose of this convergent mixed methods study was to explore oncology clinicians' self-reported practices and perceptions regarding CIPN prevention and management.

METHODS

Oncology clinicians at three cancer centers completed a survey about their recommendations for CIPN prevention and management in practice. A subset of clinicians also participated in a semi-structured interview to explore their perspectives of and motivations for implementing CIPN assessment, prevention, and management in practice. Quantitative data were described (eg, frequency or median) and qualitative data were analyzed using inductive content analysis.

RESULTS

This study (N = 44 survey responses; n = 9 interviews) resulted in four themes: (1) clinicians primarily recommend gabapentin for CIPN management and often observe cryotherapy used for CIPN prevention, but these interventions are complicated by discomfort, intolerable side effects, and efficacy concerns; (2) clinicians perceive CIPN as troublesome and desire additional information and resources regarding CIPN prevention and management; (3) CIPN-related education provided by clinicians may be limited by patient retention of the amount of education received about cancer treatment and other factors; (4) clinicians use subjective CIPN assessment to screen at each visit for common CIPN symptoms (eg, numbness or tingling) and the impact of symptoms on day-to-day activities.

CONCLUSIONS

Discrepancies persist between evidence-based guidelines on CIPN management and current oncology clinician practices.

IMPLICATIONS FOR NURSING PRACTICE

Clinician involvement is needed when developing education and resources to help oncology clinicians provide the most evidence-based care to potentially prevent and manage their patients' CIPN.

Results of Primary Total Knee Arthroplasty in Patients on Chronic Psychotropic Medications

BACKGROUND

Psychotropic medications are commonly used to treat several mental health conditions. The aim of this study was to determine the impact of psychotropic medications in patients undergoing primary total knee arthroplasty (TKA) with respect to postoperative opioid use, complications, patient-reported outcome measures, and satisfaction.

METHODS

This is a retrospective cohort study of 514 consecutive patients undergoing primary TKA. There were 120 patients (23.3%) who were excluded due to preoperative opioid usage. The remaining 394 patients had a minimum 1-year follow-up. Of those, 133 (34%) were on psychotropic medications preoperatively and were compared to the remaining 261 (66%) patients who were not on psychotropics. Clinical data, satisfaction, Knee Society (KS) scores, Western Ontario McMaster Universities Arthritis Index, Patient-Reported Outcomes Measurement Index Score, Forgotten Joint Scores, Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, postoperative opioid medication usage, and complications were compared.

RESULTS

The study cohort (psychotropic medications) had significantly lower postoperative KS Function, KS Knee, Forgotten Joint Scores, Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, Western Ontario McMaster Universities Arthritis Index, and Patient-Reported Outcomes Measurement Index Score compared to the control group. The study group had a lower overall satisfaction score (Likert scale 1 to 5) and a lower percentage of patients either satisfied or very satisfied (4.55 versus 4.79, P < .001; 92.0 versus 97.24%, P = .03, respectively). Postoperative opioid usage was significantly greater in the study group at both 6.4 weeks (range, 4 to 8) and 12-month follow-up (52.76 versus 13.33%, P < .001; 5.51 versus 0.39%, P = .002, respectively). There were no differences in complications and revisions between the groups.

CONCLUSIONS

Patients on psychotropic medications should be educated on the risk of increased opioid consumption, diminished satisfaction, and patient-reported outcome measures following primary TKA. Given the large number of patients on psychotropic medications undergoing TKA, additional studies are needed to further improve clinical outcomes in this group.

Pain and Opioid use Following Total Knee Arthroplasty: Psycho-Social Factors are More Predictive Than Pharmacogenomics

BACKGROUND

This prospective, observational study was designed to assess the phenotype variation of the genes associated with pain and opioid use following total knee arthroplasty (TKA) in comparison to psycho-social elements.

METHODS

Preoperative demographic data and Patient-Reported Outcomes Measurement Information System-43 scores were obtained on 305 elective TKA patients. Patient visual analog scale pain scores and opioid use were extracted from the hospital record. Following discharge, participants completed a daily log of visual analog scale pain score, and medications used over 30 days. Pharmacogenomic testing was performed for three genes, CYP2D6, COMT, and OPRM1, which are involved in the opioid pathway and pain modulation.

RESULTS

Other than increased pain seen in the COMT high activity group while in the hospital, none of the phenotype variations of the three genes were significantly associated with the participants' pain or opioid use. The Patient-Reported Outcomes Measurement Information System-43 domains of pain interference and anxiety were significantly associated with pain and opioid use using multiple logistic regression.

CONCLUSIONS

Pharmacogenomic testing in this study was not predictive of pain and opioid use following TKA compared with psycho-social variables.

Evaluation of neuroleptic malignant syndrome induced by antipsychotic drugs using spontaneous reporting system

Adverse events (AEs) of antipsychotic drugs include neuroleptic malignant syndrome (NMS), which presents complex clinical symptoms, resulting in a fatal outcome. In this study, the association between antipsychotic drugs and NMS was comprehensively evaluated by cluster and association analyses using the Japanese Adverse Drug Event Report (JADER) database. The analyses were performed using 20 typical antipsychotics (TAPs) alongside 9 atypical antipsychotics (AAPs). The Standardised MedDRA Queries (SMQ) database was used to analyze NMS (SMQ code: 20000044). Reporting odds ratios (RORs) were used for AE signal detection. The relationship between antipsychotic drugs and AEs for NMS was investigated by performing hierarchical cluster analysis using Ward's method. Between April 2004 and September 2021, the total number of JADER reports was 705,294. RORs (95 % confidence interval) of NMS for haloperidol, chlorpromazine, risperidone, and aripiprazole were 12.1 (11.1-13.3), 6.3 (5.7-7.0), 6.2 (5.8-6.6), and 4.7 (4.4-5.1), respectively. Three clusters were formed, with characteristics as follows: Cluster 1 consisted of only TAPs, such as bromperidol and fluphenazine, whilst having a high reporting rate of hypotension, tachycardia, dyskinesia, and dystonia. Cluster 2 consisted of all AAPs alongside several TAPs, such as haloperidol and chlorpromazine, with higher reporting rates of disturbance of consciousness, extrapyramidal disorders (excluding dyskinesia and dystonia), and serotonin syndrome. Cluster 3 consisted of only perphenazine, whilst having a higher reporting rate of coma, leukocytosis, and Parkinsonism. The results of this study may therefore aid in the management of NMS using antipsychotic drugs.

The Evaluation of CYP2D6, CYP2C9, CYP2C19, and CYP2B6 Phenoconversion in Post-Mortem Casework: The Challenge of Forensic Toxicogenetics

In toxicogenetics, an integrative approach including the prediction of phenotype based on post-mortem genotyping of drug-metabolising enzymes might help explain the cause of death (CoD) and manner of death (MoD). The use of concomitant drugs, however, might lead to phenoconversion, a mismatch between the phenotype based on the genotype and the metabolic profile actually observed after phenoconversion. The aim of our study was to evaluate the phenoconversion of CYP2D6, CYP2C9, CYP2C19, and CYP2B6 drug-metabolising enzymes in a series of autopsy cases tested positive for drugs that are substrates, inducers, or inhibitors of these enzymes. Our results showed a high rate of phenoconversion for all enzymes and a statistically significant higher frequency of poor and intermediate metabolisers for CYP2D6, CYP2C9, and CYP2C19 after phenoconversion. No association was found between phenotypes and CoD or MoD, suggesting that, although phenoconversion might be useful for a forensic toxicogenetics approach, more research is needed to overcome the challenges arising from the post-mortem setting.

Role of Dopamine in the Heart in Health and Disease

Dopamine has effects on the mammalian heart. These effects can include an increase in the force of contraction, and an elevation of the beating rate and the constriction of coronary arteries. Depending on the species studied, positive inotropic effects were strong, very modest, or absent, or even negative inotropic effects occurred. We can discern five dopamine receptors. In addition, the signal transduction by dopamine receptors and the regulation of the expression of cardiac dopamine receptors will be of interest to us, because this might be a tempting area of drug development. Dopamine acts in a species-dependent fashion on these cardiac dopamine receptors, but also on cardiac adrenergic receptors. We will discuss the utility of drugs that are currently available as tools to understand cardiac dopamine receptors. The molecule dopamine itself is present in the mammalian heart. Therefore, cardiac dopamine might act as an autocrine or paracrine compound in the mammalian heart. Dopamine itself might cause cardiac diseases. Moreover, the cardiac function of dopamine and the expression of dopamine receptors in the heart can be altered in diseases such as sepsis. Various drugs for cardiac and non-cardiac diseases are currently in the clinic that are, at least in part, agonists or antagonists at dopamine receptors. We define the research needs in order to understand dopamine receptors in the heart better. All in all, an update on the role of dopamine receptors in the human heart appears to be clinically relevant, and is thus presented here.

Metoprolol and CYP2D6: A Retrospective Cohort Study Evaluating Genotype-Based Outcomes

Metoprolol is a medication commonly utilized in select patients to achieve a reduction in heart rate, systolic blood pressure, or other indications. A majority of metoprolol metabolism occurs via CYP2D6. Decreased expression of the CYP2D6 enzyme increases the concentration of metoprolol. Current pharmacogenomics guidelines by the Dutch Pharmacogenomics Working Group recommend slower titrations and dose decreases to minimize adverse effects from poor metabolizers or normal metabolizers taking concomitant medications that are strong inhibitors of CYP2D6 (phenoconverters). This study aimed to evaluate adverse effects such as bradycardia, hypotension, and syncope in patients who are expected to have absent CYP2D6 enzyme activity due to drug–drug or drug–gene interactions. The secondary aims of this study were to evaluate heart rate measurements for the included participants. Retrospective data were collected for individuals with CYP2D6 genotyping results obtained for clinical purposes. Three categories (CYP2D6 normal metabolizers, poor metabolizers, and phenoconverters) were assigned. A total of 325 participants were included. There was no statistically significant difference found in the primary composite outcome between the three metabolizer groups (p = 0.054). However, a statistically significant difference was identified in the incidences of bradycardia between the poor metabolizers and the normal metabolizers or phenoconverters (p < 0.0001). The average heart rates were 2.8 beats per minute (bpm) and 2.6 bpm lower for the poor metabolizer and phenoconverter groups, respectively, compared to the normal metabolizers (p < 0.0001 for both comparisons). This study further supports the role of genetic testing in precision medicine to help individualize patient care as CYP2D6 poor metabolizers taking metoprolol were found to have an increase in bradycardia. Additional research is needed to clarify the dose relationship in this drug–gene interaction.

Nrf2 Regulates the Expression of CYP2D6 by Inhibiting the Activity of Krüppel-Like Factor 9 (KLF9)

AIMS

The aim of the present study is to gain insight into the biology of Parkinson's disease (PD) and cancer to drive translational advances enabling more effective prevention and/or potential treatments.

BACKGROUND

The expression of Cytochrome P450 2D6 (CYP2D6) is correlated with various diseases such as PD and cancer; therefore, exploring its regulatory mechanism at transcriptional levels is of interest. NF-E2-related factor 2 (Nrf2) has been known to be responsible for regulating phase II and phase III drug-metabolizing genes.

OBJECTIVES

The objectives of this study are to investigate the transcriptional regulation of CYP2D6 by Nrf2 and to analyze its role in PD and cancer.

METHODS

Nrf2 was transiently expressed in human hepatoma Hep3B cells, and the expression of CYP2D6 was examined by RT-qPCR. The promoter activity of CYP2D6 and the DNA binding of Nrf2 were examined by luciferase and ChIP assay, respectively. We then investigated the expression and correlation of Nrf2 and CYP2D6 in the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) datasets.

RESULTS

In the present study, we demonstrated that Nrf2 down-regulated CYP2D6 mRNA expression in hepatoma Hep3B cells. Mechanistically, Nrf2 binds to the antioxidant responsive element (ARE) in the proximity of krüppel- like factor 9 (KLF9)-binding site within the -550/+51 of CYP2D6 promoter. The inhibition and activation of Nrf2 enhanced and suppressed KLF9 effects on CYP2D6 expression, respectively. The expression levels of Nrf2 and CYP2D6 were upregulated and downregulated in the PD patient GEO datasets compared to the healthy control tissues, and Nrf2 was negatively correlated with CYP2D6. In liver cancer patients, decreased CYP2D6 levels were apparent and associated with a lower probability of survival.

CONCLUSION

Our work revealed the inhibitory role of Nrf2 in regulating CYP2D6 expression. Moreover, Nrf2- dependent regulation of CYP2D6 can be used as a prognostic factor and therapeutic strategy in PD and liver cancer.

Association of CYP2D6 genotype predicted phenotypes with oxycodone requirements and side effects in children undergoing surgery

Background

Oxycodone is a commonly used oral opioid in children for treating postoperative pain. Highly polymorphic gene CYP2D6 metabolizes oxycodone into its more potent metabolite, oxymorphone. We hypothesized that altered activity due to CYP2D6 polymorphisms will influence oxycodone requirements {relative oxycodone use [oxycodone morphine equivalents (MEq)/total MEq] to maintain analgesia} (primary outcome) and risk for oxycodone induced side-effects such as respiratory depression (RD) and emesis (secondary outcomes). We also explored the influence of genotype availability and provider guidance on oral opioid prescription patterns.

Methods

Patients who underwent Nuss procedure and spine fusion with CYP2D6 genotyping results available preoperatively were included. Data on demographics, genotypes, oral opioids, pain scores, RD and emesis were collected. Univariate and multivariable regression for comparison of CYP2D6 genotype predicted poor, ultrarapid, intermediate metabolizers (PM, UM and IM) phenotype with normal metabolizers (NM) for outcomes were performed. Stratified logistic regression was conducted in low (oxycodone/total MEq <0.5) and high (and oxycodone/total MEq >0.5) oxycodone use groups for RD and emesis, with application of firth correction due to quasi-complete separations. Breslow-Day test was used to evaluate odds ratios for prescribing genotype directed opioid between control group (2012-15) (where providers were alerted to genotyping results availability but not directed to use them while prescribing) and genotype directed groups (2016-18) (where providers were directed to use the genotyping results available to them while prescribing oxycodone after surgery).

Results

Of 193 subjects (age 15.9±0.25 years, 28.5% female, 93.78% White; 101 NM, 76 IM, 10 PM and 6 UM), 77.72% underwent pectus surgery. CYP2D6 phenotype was associated with oxycodone MEq/total MEq requirements (P<0.001). Both PM and UM phenotypes had lower oxycodone requirements compared to NM [-0.316 (SE 0.098), P=0.005 and -0.432 (SE 0.113), P<0.001 respectively]. CYP2D6 phenotype was associated with RD in high use oxycodone group (P=0.018) but not low use oxycodone groups (P=0.634). No phenotype association was found for emesis. Oxycodone was prescribed to 91.24% of NM/IM vs. 66.67% of PM/UM (P=0.129) in control group and 94.64% of NM/IM vs. 28.57% of PM/UM (P<0.001) in the genotype-directed group. PM/UM phenotypes in genotype directed group had a lower chance of being prescribed oxycodone (effect size =-2.775; SE 1.566; P=0.076).

Conclusions

Our findings suggest CYP2D6 genotypes are associated with oxycodone requirements for analgesia and may influence risk for RD. Genotype availability and guidance likely influence oral opioid prescription pattern after surgery. Our findings are limited by small sample size for UM/PM groups.

Pediatric CYP2D6 metabolizer status and post-tonsillectomy nausea and vomiting after ondansetron

The goal of this study was to determine whether CYP2D6 metabolizer status within the ondansetron-treated pediatric tonsillectomy population is associated with risk of postoperative nausea and vomiting (PONV) in the post-anesthesia care unit. We conducted a retrospective cohort study of pediatric patients (<18 years) who underwent tonsillectomy and received ondansetron on the day of the procedure. Data were obtained from BioVU, an institutional biobank that links DNA to de-identified electronic health record data. Subjects were tested for 10 CYP2D6 allelic variants and copy number variation, and genotype data translated into CYP2D6 metabolizer status. The cohort included 652 individuals, 105 (16.1%) of whom had PONV. Rates of PONV were similar across groups: ultrarapid metabolizers (UMs), 1 of 9 (11.1%); normal metabolizers (NMs), 64 of 354 (18.1%); intermediate metabolizers (IMs), 33 of 234 (14.1%); poor metabolizers (PMs), 6 of 39 (15.4%); and ambiguous phenotypes, 1 of 16 (6.3%). In multivariable analysis adjusted for age, sex, and time under anesthesia, CYP2D6 metabolizer status was not associated with PONV, with an odds ratio of 1.37 (95% confidence interval 0.9, 2.1) when comparing PM/IM versus NM/UM. In this large pediatric population, no significant differences were detected for PONV based on CYP2D6 metabolizer status. Further investigation is needed to determine mechanisms for ondansetron inefficacy in children.

Physiologically-based pharmacokinetic modeling of dextromethorphan to investigate interindividual variability within CYP2D6 activity score groups

This study provides a whole‐body physiologically‐based pharmacokinetic (PBPK) model of dextromethorphan and its metabolites dextrorphan and dextrorphan O‐glucuronide for predicting the effects of cytochrome P450 2D6 (CYP2D6) drug‐gene interactions (DGIs) on dextromethorphan pharmacokinetics (PK). Moreover, the effect of interindividual variability (IIV) within CYP2D6 activity score groups on the PK of dextromethorphan and its metabolites was investigated. A parent‐metabolite‐metabolite PBPK model of dextromethorphan, dextrorphan, and dextrorphan O‐glucuronide was developed in PK‐Sim and MoBi. Drug‐dependent parameters were obtained from the literature or optimized. Plasma concentration‐time profiles of all three analytes were gathered from published studies and used for model development and model evaluation. The model was evaluated comparing simulated plasma concentration‐time profiles, area under the concentration‐time curve from the time of the first measurement to the time of the last measurement (AUC_last) and maximum concentration (C_max) values to observed study data. The final PBPK model accurately describes 28 population plasma concentration‐time profiles and plasma concentration‐time profiles of 72 individuals from four cocktail studies. Moreover, the model predicts CYP2D6 DGI scenarios with six of seven DGI AUC_last and seven of seven DGI C_max ratios within the acceptance criteria. The high IIV in plasma concentrations was analyzed by characterizing the distribution of individually optimized CYP2D6 k_cat values stratified by activity score group. Population simulations with sampling from the resulting distributions with calculated log‐normal dispersion and mean parameters could explain a large extent of the observed IIV. The model is publicly available alongside comprehensive documentation of model building and model evaluation.

Keeping pace with CYP2D6 haplotype discovery: innovative methods to assign function

The discovery of haplotypes with unknown or uncertain function in the CYP2D6 pharmacogene is outpacing the capabilities of traditional in vitro and in vivo approaches to characterize their function. This challenge will undoubtedly grow as pharmacogenomic research becomes more inclusive of globally diverse populations. As accurate phenotypic assignment is paramount to the utility of pharmacogenomics, high-throughput technologies are needed for this complex pharmacogene. We describe the evolving landscape of innovative approaches to assign function to CYP2D6 haplotypes and possibilities for adopting these technologies into cohesive processes. Promising approaches include ADME-optimized prediction frameworks, machine learning algorithms, deep mutational scanning and phenoconversion predictions. Implementing these approaches will lead to improved personalization of treatment for patients.

Pharmacogenetics: A Precision Medicine Approach to Combatting the Opioid Epidemic

Ineffective pain control is the most commonly cited reason for misuse of prescription opioids and is influenced by genetics. In particular, the gene encoding the CYP2D6 enzyme, which metabolizes some of the most commonly prescribed opioids (e.g., tramadol, hydrocodone) to their more potent forms, is highly polymorphic and can lead to reduced concentrations of the active metabolites and decreased opioid effectiveness. Consideration of the CYP2D6 genotype may allow for predicting opioid response and identifying patients who are likely to respond well to lower potency opioids as well as those who may derive greater pain relief from non-opioid analgesics versus certain opioids. There is emerging evidence that a CYP2D6-guided approach to pain management improves pain control and reduces opioid consumption and thus may be a promising means for combating opioid misuse. Clinical practice guidelines are available for select opioids and other analgesics to support medication and dose selection based on pharmacogenetic data. This article describes the evidence supporting genotype-guided pain management as a means of improving pain control and reducing opioid misuse and clinical recommendations for genotype-guided analgesic prescribing. In addition, a "how to" guide using patient case examples is provided to demystify the process for implementing pharmacogenetics-guided pain management in order to optimize analgesia and minimize adverse effects. Optimizing pain management through genotype-guided approaches may ultimately provide safer and more effective therapy for pain control while decreasing the risk for opioid misuse.

Clinical Pharmacogenetics Implementation Consortium Guideline for CYP2D6, OPRM1, and COMT Genotypes and Select Opioid Therapy

Opioids are mainly used to treat both acute and chronic pain. Several opioids are metabolized to some extent by CYP2D6 (codeine, tramadol, hydrocodone, oxycodone, and methadone). Polymorphisms in CYP2D6 have been studied for an association with the clinical effect and safety of these drugs. Other genes that have been studied for their association with opioid clinical effect or adverse events include OPRM1 (mu receptor) and COMT (catechol-O-methyltransferase). This guideline updates and expands the 2014 Clinical Pharmacogenetics Implementation Consortium (CPIC) guideline for CYP2D6 genotype and codeine therapy and includes a summation of the evidence describing the impact of CYP2D6, OPRM1, and COMT on opioid analgesia and adverse events. We provide therapeutic recommendations for the use of CYP2D6 genotype results for prescribing codeine and tramadol and describe the limited and/or weak data for CYP2D6 and hydrocodone, oxycodone, and methadone, and for OPRM1 and COMT for clinical use.

How to Integrate CYP2D6 Phenoconversion Into Clinical Pharmacogenetics: A Tutorial

CYP2D6 genotype is increasingly being integrated into practice to guide prescribing of certain medications. The CYP2D6 drug metabolizing enzyme is susceptible to inhibition by concomitant drugs, which can lead to a clinical phenotype that is different from the genotype-based phenotype, a process referred to as phenoconversion. Phenoconversion is highly prevalent but not widely integrated into practice because of either limited experience on how to integrate or lack of knowledge that it has occurred. We built a calculator tool to help clinicians integrate a standardized method of assessing CYP2D6 phenoconversion into practice. During tool-building, we identified several clinical factors that need to be considered when implementing CYP2D6 phenoconversion into clinical practice. This tutorial shares the steps that the University of Florida Health Precision Medicine Program took to build the calculator tool and identified clinical factors to consider when implementing CYP2D6 phenoconversion in clinical practice.

Multi-factorial pharmacokinetic interactions: unraveling complexities in precision drug therapy

Introduction: Precision drug therapy requires accounting for pertinent factors in pharmacokinetic (PK) inter-individual variability (i.e., pharmacogenetics, diseases, polypharmacy, and natural product use) that can cause sub-therapeutic or adverse effects. Although each of these individual factors can alter victim drug PK, multi-factorial interactions can cause additive, synergistic, or opposing effects. Determining the magnitude and direction of these complex multi-factorial effects requires understanding the rate-limiting redundant and/or sequential PK processes for each drug.Areas covered: Perturbations in drug-metabolizing enzymes and/or transporters are integral to single- and multi-factorial PK interactions. Examples of single factor PK interactions presented include gene-drug (pharmacogenetic), disease-drug, drug-drug, and natural product-drug interactions. Examples of multi-factorial PK interactions presented include drug-gene-drug, natural product-gene-drug, gene-gene-drug, disease-natural product-drug, and disease-gene-drug interactions. Clear interpretation of multi-factorial interactions can be complicated by study design, complexity in victim drug PK, and incomplete mechanistic understanding of victim drug PK.Expert opinion: Incorporation of complex multi-factorial PK interactions into precision drug therapy requires advances in clinical decision tools, intentional PK study designs, drug-metabolizing enzyme and transporter fractional contribution determinations, systems and computational approaches (e.g., physiologically-based pharmacokinetic modeling), and PK phenotyping of progressive diseases.