CYP2D6 allele frequency in European Caucasians, Asians, Africans and their descendants

Pharmacogenomics in Pain Management

There is interpatient variability to analgesic administration. Much can be traced to pharmacogenomics variations between individuals. Certain ethnicities are more prone to reduced function of CYP2D6. Weak opioids are subject to interpatient variation based on their CYP2D6 type. Strong opioids have variations based on their transport and individual metabolism. Several cytochrome enzymes have been found to be involved with ketamine but there is no strong evidence of individual polymorphisms manifesting in clinical outcomes. Nonsteroidal anti-inflammatory drugs have adverse outcomes that certain CYP variants are more prone toward. There are now recommendations for dosing based on specific genomic makeup.

MicroRNA hsa-miR-370-3p suppresses the expression and induction of CYP2D6 by facilitating mRNA degradation

Cytochrome P450 2D6 (CYP2D6) participates in the metabolism of approximately 20-25% of prescribed drugs. Genetic polymorphisms influence the expression and/or activity of CYP2D6, and inter-individual differences in drug activation and elimination caused by CYP2D6 genetic variants were reported. However, little is known about the potential modulation of CYP2D6 expression by microRNAs (miRNAs). In the current study, by using in silico prediction of the stabilities of miRNA/mRNA complexes, we screened 38 miRNA candidates that may interact with the transcript of CYP2D6. An inverse correlation between the expression of miRNA hsa-miR-370-3p and the expression of CYP2D6 was observed in human liver tissue samples. Electrophoretic mobility shift assays confirmed that hsa-miR-370-3p was able to directly bind to its cognate target within the coding region of the CYP2D6 transcript. The transfection of hsa-miR-370-3p mimics into the HepG2^CYP2D6 cell line, a genetically modified cell line that overexpresses exogenous CYP2D6, was able to suppress the expression of CYP2D6 significantly at both mRNA and protein levels. The transfection of hsa-miR-370-3p mimics was also able to inhibit endogenous mRNA expression and/or protein production of CYP2D6 in HepaRG cells. Furthermore, in HepaRG, HepG2, and Huh7 cells, dexamethasone-induced expression of CYP2D6 was inhibited by hsa-miR-370-3p mimics. To investigate whether the miRNA mediated suppression is caused by inhibiting protein translation or promoting mRNA degradation, an actinomycin D assay was used to measure the stability of CYP2D6 transcripts. The results indicated that hsa-miR-370-3p mimics facilitated significantly the degradation of CYP2D6 mRNA. In addition, proteomics analyses of proteins isolated from the miRNA/mRNA/protein complex suggested that a group of multifunctional proteins facilitated the interaction between hsa-miR-370-3p and CYP2D6, thereby promoting mRNA degradation.

The blood schizonticidal activity of tafenoquine makes an essential contribution to its prophylactic efficacy in nonimmune subjects at the intended dose (200 mg)

Tafenoquine (TQ) is an 8-aminoquinoline anti-malarial being developed for malaria prophylaxis. It has been generally assumed that TQ, administered prophylactically, acts primarily on the developing exoerythrocytic stages of malaria parasites (causal prophylaxis), and that polymorphisms in metabolic enzymes thought to impact the activity of other 8-aminoquinolines also inhibit this property of TQ. Furthermore, it has been suggested that a diagnostic test for CYP2D6 metabolizer status might be required. In field studies in which metabolic status was not an exclusion criteria, TQ has been shown to exhibit similar prophylactic efficacy as blood schizonticidal drugs (mefloquine). Also, its blood schizonticidal and anti-relapse efficacy is independent of 2D6 metabolizer status. The most reasonable explanation for the field study results, supported by other clinical and non-clinical data, is that TQ is not completely causal and exhibits substantial blood schizonticidal activity at the intended dose. Pharmacokinetic simulations demonstrate that trough concentrations of TQ exceed the proposed MIC of 80 ng/ml in >95% of individuals. Based on these data a companion diagnostic for CP450 enzyme status is not required.

In vitro metabolism of exemestane by hepatic cytochrome P450s: impact of nonsynonymous polymorphisms on formation of the active metabolite 17β-dihydroexemestane

Exemestane (EXE) is an endocrine therapy commonly used by postmenopausal women with hormone‐responsive breast cancer due to its potency in inhibiting aromatase‐catalyzed estrogen synthesis. Preliminary in vitro studies sought to identify phase I EXE metabolites and hepatic cytochrome P450s (CYP450s) that participate in EXE biotransformation. Phase I metabolites were identified by incubating EXE with HEK293‐overexpressed CYP450s. CYP450s 1A2, 2C8, 2C9, 2C19, 2D6, 3A4, and 3A5 produce 17β‐dihydroexemestane (17β‐DHE), an active major metabolite, as well as two inactive metabolites. 17β‐DHE formation in pooled human liver microsomes subjected to isoform‐specific CYP450 inhibition was also monitored using tandem mass spectrometry. 17β‐DHE production in human liver microsomes was unaffected by isoform‐specific inhibition of CYP450s 2A6, 2B6, and 2E1 but decreased 12–39% following inhibition of drug‐metabolizing enzymes from CYP450 subfamilies 1A, 2C, 2D, and 3A. These results suggest that redundancy exists in the EXE metabolic pathway with multiple hepatic CYP450s catalyzing 17β‐DHE formation in vitro. To further expand the knowledge of phase I EXE metabolism, the impact of CYP450 genetic variation on 17β‐DHE formation was assessed via enzyme kinetic parameters. Affinity for EXE substrate and enzyme catalytic velocity were calculated for hepatic wild‐type CYP450s and their common nonsynonymous variants by monitoring the reduction of EXE to 17β‐DHE. Several functional polymorphisms in xenobiotic‐metabolizing CYP450s 1A2, 2C8, 2C9, and 2D6 resulted in deviant enzymatic activity relative to wild‐type enzyme. Thus, it is possible that functional polymorphisms in EXE‐metabolizing CYP450s contribute to inter‐individual variability in patient outcomes by mediating overall exposure to the drug and its active metabolite, 17β‐DHE.

A Study on CYP2C19 and CYP2D6 Polymorphic Effects on Pharmacokinetics and Pharmacodynamics of Amitriptyline in Healthy Koreans

We performed a double-blinded, genotype-based stratification study to explore the pharmacokinetics and pharmacodynamics of amitriptyline according to CYP2C19 and CYP2D6 genotype in Korean subjects. Twenty-four healthy adults were grouped by genotype of CYP2C19 and CYP2D6. After a single dose of 25 mg of amitriptyline, blood samples were collected and anticholinergic effects were measured. The extent of N-demethylation of amitriptyline significantly decreased in subjects carrying two nonfunctional alleles of CYP2C19. The extent of hydroxylation of amitriptyline or nortriptyline was significantly reduced in subjects carrying two CYP2D6 decreased functional alleles compared with those with no or one decreased functional allele. The overall metabolic pathway of amitriptyline was more likely to be dominated by CYP2C19 than CYP2D6. The gene variations of CYP2C19 and CYP2D6 did not change the pharmacodynamic effect. The findings of this study will provide useful information on individualized drug treatment with amitriptyline considering both CYP2D6 and CYP2C19 gene variations.

Genotyping CYP2D6 by three different methods: advantages and disadvantages

BACKGROUND

CYP2D6 belongs to P450 superfamily, and is responsible for the metabolism of 25% of the drugs used clinically. Genetic variability of CYP2D6 affects individual drug or toxic response leading to differences in the drug outcome or toxicity mediating adverse drug effects. The different variant alleles are associated with increased, decreased, or abolished enzyme hydroxylation functions. The CYP2D6*10 (rs1065852, c.100C>T) allele is associated with reduced function and is one of the most studied alleles.

METHODS

The aim of this study was to perform three different methods (PCR-RFLP, TaqMan® Drug Metabolism Genotyping Assays, and Sanger Sequencing) for genotyping alteration c.100C>T, rs1065852 in a group of 24 Portuguese subjects (15 females and 9 males, mean age 70±9 years) and compare the results.

RESULTS

We found 16 samples homozygous for *1 allele and 8 heterozygous for *10 allele.

CONCLUSIONS

The three methods provide concordant results suggesting that any of these techniques is a reliable and sensitive method for genotyping CYP2D6. However, we would recommend the use of TaqMan® Drug Metabolism Assays, given the advantages concerning time spending, straightforwardness, reliability, and accuracy.

Effect of 22 CYP2D6 variants found in the Chinese population on tolterodine metabolism in vitro

Cytochrome P450 2D6 (CYP2D6) is an important member of the cytochrome P450 enzyme superfamily. We recently identified 22 novel variants in the Chinese population using PCR and bidirectional sequencing methods. The aim of this study is to characterize the enzymatic activity of these variants and their effects on the metabolism of the antimuscarinic drug tolterodine in vitro. A baculovirus-mediated expression system was used to express wild-type CYP2D6 and 24 variants (CYP2D6*2, CYP2D6*10, and 22 novel CYP2D6 variants) at high levels. The insect microsomes expressing CYP2D6 proteins were incubated with 0.1-50 μM tolterodine at 37 °C for 30 min and the metabolites were analyzed by high-performance liquid chromatography-tandem mass spectrometry system. Of the 24 CYP2D6 variants tested, 2 variants (CYP2D6*92 and CYP2D6*96) were found to be catalytically inactive, 4 variants (CYP2D6*94, F164L, F219S and D336N) exhibited markedly increased intrinsic clearance values (V_max/K_m) compared with the wild-type (from 66.34 to 99.79%), whereas 4 variants (CYP2D6*10, *93, *95 and E215K) exhibited significantly decreased values (from 49.02 to 98.50%). This is the first report of all these rare alleles for tolterodine metabolism and these findings suggest that more attention should be paid to subjects carrying these infrequent CYP2D6 alleles when administering tolterodine in the clinic.

A review of perioperative anesthesia and analgesia for infants: updates and trends to watch

This review focuses on pharmacokinetics and pharmacodynamics of opioid and non-opioid analgesics in neonates and infants. The unique physiology of this population differs from that of adults and impacts drug handling. Morphine and remifentanil are described as examples of older versus recently developed opiates to compare and contrast pharmacokinetics and pharmacodynamics in infants. Exploration of genetics affecting both pharmacokinetics and pharmacodynamics of opiates is an area of active research, as is the investigation of a new class of mu-opiate-binding agents which seem selective for analgesic pathways while having less activity in pathways linked to side effects. The kinetics of acetaminophen and of ketorolac as examples of parenteral non-steroidal analgesics in infants are also discussed. The growth in regional anesthesia for peri-operative analgesia in infants can fill an important role minimizing intra-operative anesthetic exposure to opioids and transitioning to post-operative care. Use of multi-modal techniques is recommended to decrease undesirable opiate-related side effects in this vulnerable population.

Cancer Drug Delivery

Advancements in cancer drug delivery have led to the development of personalized oncology care through molecularly-driven targeted therapies. Understanding molecular and cellular mechanisms which drive tumor progression and resistance is critical in managing new treatment strategies which have shifted from empiric to biomarker-directed therapy selection. Biomarker-directed therapies have improved clinical outcomes in multiple malignancies as monotherapy and in combination with other treatment modalities, however the changing scope of treatment options presents new opportunities and challenges for research. Furthermore, pharmacogenetics may provide a rationale method of personalizing anticancer drug dosing and supportive care management for oncology patients. This chapter reviews biomarker classifications and pharmacogenetics in anticancer therapy and supportive care. Examples of biomarker-directed therapies and clinical assays, in addition to future directions of molecular profiling in oncology therapy management are discussed.

Codeine use among children in the United States: a nationally representative study from 1996 to 2013

BACKGROUND

Concerns regarding the safety of codeine have been raised. Cases of life-threatening respiratory depression and death in children have been attributed to codeine's polymorphic metabolic pathway. International health agencies recommend restricted use of codeine in children. Despite these recommendations, the epidemiology of codeine use among children remains unknown.

AIMS

Our objective was to examine patterns of codeine use in the US among children.

METHODS

A cross-sectional analysis of children of age 0-17 years from 1996 to 2013 in the US was performed. Data were extracted from MEPS, a nationally representative set of health care surveys. Prevalence rates of codeine use between 1996 and 2013 were examined. Multivariable logistic regression examined relationships between codeine use and patient demographics.

RESULTS

Codeine use remained largely unchanged from 1996 to 2013 (1.08 vs 1.03 million children, respectively). Odds of codeine use was higher in ages 12-17 (OR, 1.40; [1.21-1.61]), outside of the Northeastern US, and among those with poor physical health status (OR, 3.29 [1.79-6.03]). Codeine use was lower in children whose ethnicity was not white and those uninsured (OR, 0.47 [0.34-0.63]). Codeine was most frequently prescribed by emergency physicians (18%) and dentists (14%). The most common condition associated with codeine use was trauma-related pain.

CONCLUSIONS

Pediatric codeine use has declined since 1996; however, more than 1 million children still used codeine in 2013. Health care providers must be made aware of guidelines advising against the use of codeine in children. Codeine is potentially hazardous and safer alternatives to treat children's pain are available.

A Model Based Cost-Effectiveness Analysis of Routine Genotyping for CYP2D6 among Older, Depressed Inpatients Starting Nortriptyline Pharmacotherapy

OBJECTIVE

Genotyping for CYP2D6 has the potential to predict differences in metabolism of nortriptyline. This information could optimize pharmacotherapy. We determined the costs and effects of routine genotyping for old aged Dutch depressed inpatients.

METHODS

With a decision-tree, we modelled the first 12 weeks of nortriptyline therapy. Direct costs of genotyping, hospitalization, therapeutic drug monitoring and drugs were included. Based on genotype, patients could be correctly, sub-, or supratherapeutically dosed. Improvement from sub- or supratherapeutically dosed patients to correctly dosed patients was simulated, assuming that genotyping would prevent under- or overdosing of patients. In the base case, this improvement was assumed to be 35%. A probabilistic sensitivity analysis (PSA) was performed to determine uncertainty around the incremental cost-effectiveness ratio (ICER).

RESULTS

In the base case analysis, costs for genotyping were assumed €200 per test with a corresponding ICER at €1 333 000 per QALY. To reach a €50 000 per QALY cut-off, genotyping costs should be decreased towards €40 per test. At genotyping test costs < €35 per test, genotyping was dominant. At test costs of €17 per test there was a 95% probability that genotyping was cost-effective at €50 000 per QALY.

CONCLUSIONS

CYP2D6 genotyping was not cost-effective at current genotyping costs at a €50 000 per QALY threshold, however at test costs below €40, genotyping could be costs-effective.

Cytochrome P450 2D-mediated metabolism is not necessary for tafenoquine and primaquine to eradicate the erythrocytic stages of Plasmodium berghei

BACKGROUND

Due to the ability of the 8-aminoquinolines (8AQs) to kill different stages of the malaria parasite, primaquine (PQ) and tafenoquine (TQ) are vital for causal prophylaxis and the eradication of erythrocytic Plasmodium sp. parasites. Recognizing the potential role of cytochrome (CYP) 450 2D6 in the metabolism and subsequent hepatic efficacy of 8-aminoquinolines, studies were designed to explore whether CYP2D-mediated metabolism was related to the ability of single-dose PQ and TQ to eliminate the asexual and sexual erythrocytic stages of Plasmodium berghei.

METHODS

An IV P. berghei sporozoite murine challenge model was utilized to directly compare causal prophylactic and erythrocytic activity (asexual and sexual parasite stages) dose-response relationships in C57BL/6 wild-type (WT) mice and subsequently compare the erythrocytic activity of PQ and TQ in WT and CYP2D knock-out (KO) mice.

RESULTS

Single-dose administration of either 25 mg/kg TQ or 40 mg/kg PQ eradicated the erythrocytic stages (asexual and sexual) of P. berghei in C57BL WT and CYP2D KO mice. In WT animals, the apparent elimination of hepatic infections occurs at lower doses of PQ than are required to eliminate erythrocytic infections. In contrast, the minimally effective dose of TQ needed to achieve causal prophylaxis and to eradicate erythrocytic parasites was analogous.

CONCLUSION

The genetic deletion of the CYP2D cluster does not affect the ability of PQ or TQ to eradicate the blood stages (asexual and sexual) of P. berghei after single-dose administration.

Influences of CYP2D6*10 polymorphisms on the pharmacokinetics of iloperidone and its metabolites in Chinese patients with schizophrenia: a population pharmacokinetic analysis

AIM

Iloperidone is an atypical antipsychotic drug that is mainly metabolized by CYP2D6, CYP3A4, and cytosolic enzymes. Previous studies show that extensive and poor metabolizers of CYP2D6 exhibit different plasma concentrations of iloperidone and its metabolites. The aim of this study was to develop a parent-metabolite population pharmacokinetic (PPK) model to quantify the effects of CYP2D6^*10 allele on the pharmacokinetics of iloperidone and its metabolites in Chinese schizophrenia patients.

METHODS

Seventy Chinese schizophrenia patients were enrolled, from whom limited blood samples were collected on d 15 (0 h) and d 28 (0, 4 and 12 h after drug administration). The plasma concentrations of iloperidone and its metabolites M₁ (P-88) and M₂ (P-95) were simultaneously detected using a validated HPLC-MS assay. CYP2D6^*10 (rs1065852) genotyping was performed. A PPK model was developed based on data from the patients using the NONMEM software (version 7.2). A one-compartment model with first-order absorption and elimination was used to describe the pharmacokinetic data related to iloperidone and its metabolites.

RESULTS

Patients with the CYP2D6^*10 T/T genotype had significantly higher concentrations of iloperidone and M₁, and lower concentrations of M₂ than the patients with C/C or C/T genotypes. The CYP2D6^*10 genotype affected the elimination constants for transformation of iloperidone to the metabolites M₁ (K₂₃) and M₂ (K₂₄). The K₂₃ value of the patients with T/T genotype was 1.34-fold as great as that of the patients with C/C or C/T genotype. The K₂₄ value of the patients with C/T and T/T genotypes was 0.693- and 0.492-fold, respectively, as low as that of the patients with C/C genotype.

CONCLUSION

CYP2D6^*10 mutations affect the pharmacokinetics of iloperidone and its metabolites in Chinese schizophrenia patients, suggesting that the clinical doses of iloperidone for patients with CYP2D6^*10 mutations need to be optimized.

Pharmacogenomic implications of the evolutionary history of infectious diseases in Africa

As the common birthplace of all human populations, modern humans have lived longer on the African continent than in any other geographical region of the world. This long history, along with the evolutionary need to adapt to environmental challenges such as exposure to infectious agents, has led to greater genetic variation in Africans. The vast genetic variation in Africans also extends to genes involved in the absorption, distribution, metabolism and excretion of pharmaceuticals. Ongoing cataloging of these clinically relevant variants reveals huge allele-frequency differences within and between African populations. Here, we examine Africa's large burden of infectious disease, discuss key examples of known genetic variation modulating disease risk, and provide examples of clinically relevant variants critical for establishing dosing guidelines. We propose that a more systematic characterization of the genetic diversity of African ancestry populations is required if the current benefits of precision medicine are to be extended to these populations.

Pharmacogenomics of Drug Metabolizing Enzymes and Transporters: Relevance to Precision Medicine

The interindividual genetic variations in drug metabolizing enzymes and transporters influence the efficacy and toxicity of numerous drugs. As a fundamental element in precision medicine, pharmacogenomics, the study of responses of individuals to medication based on their genomic information, enables the evaluation of some specific genetic variants responsible for an individual’s particular drug response. In this article, we review the contributions of genetic polymorphisms to major individual variations in drug pharmacotherapy, focusing specifically on the pharmacogenomics of phase-I drug metabolizing enzymes and transporters. Substantial frequency differences in key variants of drug metabolizing enzymes and transporters, as well as their possible functional consequences, have also been discussed across geographic regions. The current effort illustrates the common presence of variability in drug responses among individuals and across all geographic regions. This information will aid health-care professionals in prescribing the most appropriate treatment aimed at achieving the best possible beneficial outcomes while avoiding unwanted effects for a particular patient.

Impact of CYP2D6, CYP3A5, CYP2C19, CYP2A6, SLCO1B1, ABCB1, and ABCG2 gene polymorphisms on the pharmacokinetics of simvastatin and simvastatin acid

OBJECTIVE

The effects of various polymorphisms in cytochrome P450 (CYP) enzyme and transporter genes on the pharmacokinetics (PK) of simvastatin were evaluated in healthy Korean men.

METHODS

Plasma concentration data for simvastatin and simvastatin acid were pooled from four phase I studies comprising 133 participants. The polymorphisms CYP2D6*4, CYP2D6*5, CYP2D6*14, CYP2D6*41, CYP3A5*3, CYP2C19*2, CYP2C19*3, CYP2A6*7, and CYP2A6*9; SLCO1B1 rs4149056, rs2306283, and rs4149015; ABCB1 rs1128503, rs2032582, and rs1045642; and ABCG2 rs2231142 were evaluated in each participant. Noncompartmental PK results were compared by genotype.

RESULTS

CYP2D6*5 and CYP2D6*14 were found to be associated with a higher area under the curve (AUC) for simvastatin, whereas the AUC of simvastatin acid was significantly increased in patients with the SLCO1B1 rs4149056, ABCG2 rs2231142, and CYP2D6*41 allele variants. Patients with the CYP2D6*41 variant showed a higher peak serum concentration (Cmax) of both simvastatin and simvastatin acid. The SLCO1B1 rs4149056 and rs4149015 polymorphisms were associated with an increased AUC ratio (i.e. ratio of simvastatin acid to simvastatin), whereas the SLCO1B1 rs4149056 and CYP2D6*5 variants were related to a higher Cmax ratio.

CONCLUSION

The CYP2D6*5, CYP2D6*14, CYP2D6*41, CYP3A5*3, SLCO1B1 rs4149056 and rs4149015, and ABCG2 rs2231142 genetic polymorphisms are associated with the PK of both simvastatin and simvastatin acid. This could potentially be used as a basis for individualized simvastatin therapy by predicting the clinical outcomes of this treatment.

CYP2D6 *6/*6 genotype and drug interactions as cause of haloperidol-induced extrapyramidal symptoms

A 66-year-old male Caucasian, received 1 mg of haloperidol orally and rapidly developed severe iatrogenic extrapyramidal symptoms. Treatment was immediately discontinued, and the side effects resolved. Haloperidol is mainly metabolized by Phase I CYP2D6 and to the lesser extent by CYP3A4 and by Phase II UGT2B7 enzymes. Genotyping was performed revealing CYP2D6*6/*6, CYP3A4*1/*1, and UGT2B7 -161 C/T genotypes, implicating poor, extensive and intermediate metabolism, respectively. Of the CYPs, haloperidol is metabolized by CYP2D6 and CYP3A4 primarily. It was the introduction of ciprofloxacin which was a trigger for the development of adverse drug reaction due to inhibition of CYP3A4, which was in presented patient main metabolic pathway for haloperidol since he was CYP2D6 poor metabolizer. Presented case report highlights the importance of genotyping. Pharmacogenetics testing should be considered when drug toxicity is suspected, polymorphic metabolic pathways used and drugs concomitantly applied.

The role of cytochrome P450 pharmacogenomics in chronic non-cancer pain patients

INTRODUCTION

Pharmacogenomics is the field that studies an individualized treatment approach for patients' medication regimen that can impact drug safety, productivity, and personalized health care. Pharmacogenomics characterizes the genetic differences in metabolic pathways which can affect a patient's individual responses to drug treatments. Areas covered: The various responses to pharmacological agents are mainly determined by the different types of genetic variants of the CYP450. CYP2D6 polymorphism is well known for its variation in the metabolism of drugs from many therapeutic arenas, including some analgesic drugs such as codeine, hydromorphone, oxycodone and tramadol. Allele combinations determine the phenotypic expression, characterized as either: extensive metabolizer, intermediate metabolizer, ultra-rapid metabolizer and poor metabolizer. Expert opinion: The Human Genome Project (HGP) revolutionized the future of medicine and the way health care providers approach individualized patient treatment, and chronic pain management is one of those areas. The key findings in the literature appear to be related to the CYP2D6 expression and its high polymorphism influencing the metabolism of opioid medications, and the impact of that on the patient's therapeutic outcome thus exemplifying the importance of genetic testing for CYP2D6 in the process of physician therapeutic decision making.

A service improvement project to review prescribing information provided by general practitioners for new referrals to a UK National Health Service hospital pain clinic: potential implications of CYP2D6 enzyme inhibition

INTRODUCTION

Chronic pain is often managed using co-prescription of analgesics and adjuvants, with concomitant medication prescribed for comorbidities. Patients may have suboptimal response to some analgesics or be at risk of drug interactions or adverse drug reactions (ADRs) due to polypharmacy affecting CYP2D6 enzyme activity. The aim of the service improvement project was to determine the proportion of patients referred to a specialist pain service in the UK National Health Service (NHS) by general practitioners (GPs) who may be at risk of suboptimal analgesic response or ADRs due to CYP2D6 inhibition through polypharmacy. This was achieved by reviewing clinical prescribing information provided by GPs at time of referral. It was hoped that the findings could be used to aid clinical and prescribing decisions without conducting CYP2D6 genotyping or phenotyping.

METHODS

A review of letters from 250 patients referred to an NHS hospital pain service from GPs over a 3-month period was undertaken. Information about current and concomitant medications was analysed to identify the potential for CYP2D6 inhibition and adverse events.

RESULTS

Letters failed to provide information about current pain medication for 20 (8%) patients or non-pain concomitant medication for 54 (21.6%) patients. Of 176 patients, 52 (29.5%) patients with information about non-pain concomitant medication had been prescribed at least one known CYP2D6 inhibitor. A total of 35 (19.9%) patients were identified as being at risk of an adverse drug reaction and 33 (18.75%) patients at risk of suboptimal analgesic response due to co-administration of CYP2D6 inhibitors.

CONCLUSION

The review revealed the need for improved detail in GP referral letters used to transfer care to UK NHS hospital pain clinics. There is a need to consider an individual's CYP2D6 phenotype when prescribing analgesic prodrugs to manage persistent pain. Caution is needed when patients are co-prescribed codeine or tramadol with selective serotonin reuptake inhibitors (SSRIs).

Clinical Utility and Economic Impact of CYP2D6 Genotyping

Pharmacogenetics examines an individual's genetic makeup to help predict the safety and efficacy of medications. Practical application optimizes treatment selection to decrease the failure rate of medications and improve clinical outcomes. Lack of efficacy is costly due to adverse drug reactions and increased hospital stays. Cytochrome P450 2D6 (CYP2D6) metabolizes roughly 25% of all drugs. Detecting variants that cause altered CYP2D6 enzymatic activity identifies patients at risk of adverse drug reactions or therapeutic failure with standard dosages of medications metabolized by CYP2D6. This article discusses the clinical application of pharmacogenetics to improve care and decrease costs.

A new therapeutic option for postoperative pain management with oxycodone HCI injection

Fentanyl is the most commonly used opioid analgesic in intravenous patient-controlled analgesia (IV PCA) in Korea. IV oxycodone was approved for postoperative IV PCA by the Ministry of Food and Drug Safety of Korea in 2013. The approved dosage regimen for postoperative pain relief with IV oxycodone is IV bolus loading of 2 mg followed by PCA composed of demand boluses of 1 mg and no background infusion with an oxycodone concentration of 1 mg/ml. However, a simulation study indicated that the minimum effective analgesic concentration (MEAC, as indicated by relief of pain by administering rescue analgesics) of oxycodone was reached most quickly with a higher loading dose of 0.1 mg/kg and IV PCA with background infusion. Oxycodone is a therapeutic option as an analgesic for postoperative pain management. It is necessary to reduce the analgesic dose of oxycodone in elderly patients because metabolic clearance decreases with age.

Gender based Dosing of Metoprolol in the Elderly using Population Pharmacokinetic Modeling and Simulations

INTRODUCTION

This article seeks to clarify if gender-based differences occur in the pharmacokinetics of metoprolol in the elderly patients. There are a series of physiologic changes that occur in the elderly ranging from decreased hepatic blood flow to increased adiposity causing higher plasma concentrations at therapeutic doses as compared to the healthy young population.

METHODS

Population pharmacokinetic modeling were performed using MONOLIX and Monte-Carlo simulations were conducted using MATLAB. The data was based from a previously published dataset where elderly patients, having multiple comorbidities, were administered a 50mg dose of metoprolol.

RESULTS

Metoprolol was modeled using a one-compartment model and resulted in the following population pharmacokinetic parameters: volume of distribution, V=38L (CV=155%), clearance rates, CL-Men=105L/hour and CL-Women=59.1L/hour (38%), time lag, Tlag=0.469 hour (CV=17%), and the absorption rate constant, Ka=0.235 hr^-1 (CV=23%).

CONCLUSION

Gender stratified doses resulting in an equivalent systemic metoprolol exposure in geriatric patients have been identified. Metoprolol doses resulting a similar AUC in a healthy young male administered 50mg tablet were 15mg for geriatric women and 25mg for geriatric men. Further, Metoprolol doses of 25mg for geriatric women and 50mg for geriatric men resulted in an equivalent AUC to a healthy young males dosed with a 100mg tablet. A 15mg Metoprolol tablet may need to be compounded to account for the gender differences in Metoprolol pharmacokinetics.

Pain Management of Pediatric Musculoskeletal Injury in the Emergency Department: A Systematic Review

Background. Pain management for children with musculoskeletal injuries is suboptimal and, in the absence of clear evidence-based guidelines, varies significantly. Objective. To systematically review the most effective pain management for children presenting to the emergency department with musculoskeletal injuries. Methods. Electronic databases were searched systematically for randomized controlled trials of pharmacological and nonpharmacological interventions for children aged 0-18 years, with musculoskeletal injury, in the emergency department. The primary outcome was the risk ratio for successful reduction in pain scores. Results. Of 34 studies reviewed, 8 met inclusion criteria and provided data on 1169 children from 3 to 18 years old. Analgesics used greatly varied, making comparisons difficult. Only two studies compared the same analgesics with similar routes of administration. Two serious adverse events occurred without fatalities. All studies showed similar pain reduction between groups except one study that favoured ibuprofen when compared to acetaminophen. Conclusions. Due to heterogeneity of medications and routes of administration in the articles reviewed, an optimal analgesic cannot be recommended for all pain categories. Larger trials are required for further evaluation of analgesics, especially trials combining a nonopioid with an opioid agent or with a nonpharmacological intervention.

Influence of CYP2D6 and β2-adrenergic receptor gene polymorphisms on the hemodynamic response to propranolol in Chinese Han patients with cirrhosis

BACKGROUND AND AIM

Propranolol is widely used to prevent gastroesophageal variceal bleeding; however, some patients could not benefit from propranolol. This study is to evaluate the relationship between CYP2D6 and β2-adrenergic receptor (β2-AR) gene polymorphisms and the hemodynamic response to propranolol in Chinese Han patients.

METHODS

The clinical data of patients with gastroesophageal varices undergoing hepatic venous pressure gradient (HVPG) measurement before and 7 days after oral propranolol administration in our department were collected. Four single nucleotide polymorphisms of CYP2D6 and β2-AR genes were detected. The relationship was identified by logistic regression model.

RESULTS

Thirty patients were involved in the analysis. Sixty milligram propranolol twice each day was well tolerated by all the patients. The initial and secondary average of HVPG was 17.4 ± 5.8 mmHg vs. 13.2 ± 4.8 mmHg, respectively (t = 5.726, P < 0.001). Twenty patients responded to propranolol. The mean reduction value of HVPG was 6.6 ± 3.6 mmHg (range from 3 to 19). Genotype analysis showed: 20 homozygotes for C/C188 and 10 for heterozygous C/T188, 8 homozygotes for G/G4268 and 22 heterozygotes for G/C4268, 14 homozygotes for Gly16 and 10 heterozygotes, and 6 homozygotes for Arg16, 27 homozygotes for Gln27 and 3 heterozygotes. The multivariate logistic regression analysis indicated that CYP2D6 (188C>T) genotype was an independent predicting factor for HVPG response to propranolol (P = 0.033).

CONCLUSIONS

CYP2D6 (188C>T) gene polymorphisms influence the hemodynamic response to propranolol in this population of Chinese Han patients with gastroesophageal varices. However, HVPG response cannot be completely predicted from CYP2D6 and β2-AR gene polymorphisms.

POLYMORPHISMS OF DRUG-METABOLIZING ENZYMES CYP1A2, CYP2D6, GST, NAT2 AND TRANSPORTER MDR1 IN POPULATION OF BELARUS: COMPARISON WITH SELECTED EUROPEAN AND ASIAN POPULATIONS

Drug therapeutic efficiency and development of unfavorable pharmacologic responses as well as the disease predisposition are caused first of all by patient’s genetic features. Genetic variations in genes encoding drug-metabolizing enzymes and transporter proteins are essential to understand the ethnic differences in disease occurrence, development, prognosis, therapeutic response and toxicity of drugs. For that reason, it is necessary to establish the normative frequency distribution of genotypes and alleles of these genes in a particular population. Data on frequency of pharmacogenetic polymorphisms in the of Belarus population are limited. The goal of our investigation was to analyze the frequency distribution of genotypes and alleles of genes encoding drug-metabolizing enzymes (CYP1А2, CYP2D6 – I phase; GSTs, NAT2 – II phase) and transporter protein MDR1 in the population of Belarus and comparisons with other ethnic populations. Our results indicate that clinically important genes are genetically highly variable and differ considerably between populations. Differences in allele frequencies across continents should be considered when designing clinical trials of new drugs continents should be considered when designing clinical trials of new drugs.

Relationship between cytochrome P450 polymorphisms and prescribed medication in elderly haemodialysis patients

BACKGROUND

Elderly patients on haemodialysis have a high prevalence of polypharmacy and are at risk of drug-related complications. More than 80 % of all prescribed drugs are metabolized by the cytochrome P450 (CYP) enzyme system. The aims of this study were to describe the prevalence of polymorphism in three CYP isoenzymes and the relationship between CYP polymorphism and prescribed drugs.

METHODS

Fifty-one elderly haemodialysis patients aged ≥65 years were included. CYP-genotyping was carried out in whole blood by a real-time PCR method for detecting common variant alleles in CYP2C9, CYP2C19 and CYP2D6. The allele frequencies were calculated using the Hardy-Weinberg equation.

RESULTS

The overall prevalence of CYP polymorphisms (heterozygous and homozygous) was 77 %. The prevalence of heterozygous carriers of variant alleles coding for defective CYP2D6, CYP2C9 and CYP2C19 was 64, 22 and 55 %, respectively; the prevalence of homozygous carriers was 6 % for each of the CYP2D6, CYP2C9 and CYP2C19 enzymes. The prevalence of the CYP2D6*6, CYP2D6*9 and CYP2D6*41 variant alleles did not differ (p = 0.31) from that in a European Caucasian reference population. Twenty-three patients (45 %) had at least one CYP mutation and used drugs that are metabolized by the CYP isoenzymes. Metoprolol and proton-pump inhibitors were the most commonly used drugs that could be affected by a heterozygous or homozygous mutation.

CONCLUSIONS

Polymorphisms of CYP2C9, CYP2C19 and CYP2D6 are common in elderly haemodialysis patients. Many of these patients have a phenotype with altered CYP enzyme activity and could benefit from close drug monitoring or a drug switch.

A Physiologic Approach to the Pharmacogenomics of Hypertension

Hypertension is a multifactorial condition with diverse physiological systems contributing to its pathogenesis. Individuals exhibit significant variation in their response to antihypertensive agents. Traditional markers, such as age, gender, diet, plasma renin level, and ethnicity, aid in drug selection. However, this review explores the contribution of genetics to facilitate antihypertensive agent selection and predict treatment efficacy. The findings, reproducibility, and limitations of published studies are examined, with emphasis placed on candidate genetic variants affecting drug metabolism, the renin-angiotensin system, adrenergic signalling, and renal sodium reabsorption. Single-nucleotide polymorphisms identified and replicated in unbiased genome-wide association studies of hypertension treatment are reviewed to illustrate the evolving understanding of the disease's complex and polygenic pathophysiology. Implementation efforts at academic centers seek to overcome barriers to the broad adoption of pharmacogenomics in the treatment of hypertension. The level of evidence required to support the implementation of pharmacogenomics in clinical practice is considered.

Primaquine treatment and relapse in Plasmodium vivax malaria

The relapsing peculiarity of Plasmodium vivax is one of the prime reasons for sustained global malaria transmission. Global containment of P. vivax is more challenging and crucial compared to other species for achieving total malaria control/elimination. Primaquine (PQ) failure and P. vivax relapse is a major global public health concern. Identification and characterization of different relapse strains of P. vivax prevalent across the globe should be one of the thrust areas in malaria research. Despite renewed and rising global concern by researchers on this once 'neglected' species, research and development on the very topic of P. vivax reappearance remains inadequate. Many malaria endemic countries have not mandated routine glucose-6-phosphate dehydrogenase (G6PD) testing before initiating PQ radical cure in P. vivax malaria. This results in either no PQ prescription or thoughtless prescription and administration of PQ to P. vivax patients by healthcare providers without being concerned about patients' G6PD status and associated complications. It is imperative to ascertain the G6PD status and optimum dissemination of PQ radical cure in all cases of P. vivax malaria across the globe. There persists a compelling need to develop/validate a rapid, easy-to-perform, easy-to-interpret, quality controllable, robust, and cost-effective G6PD assay. High-dose PQ of both standard and short duration appears to be safe and more effective for preventing relapses and should be practiced among patients with normal G6PD activity. Multicentric studies involving adequately representative populations across the globe with reference PQ dose must be carried out to determine the true distribution of PQ failure. Study proving role of cytochrome P450-2D6 gene in PQ metabolism and association of CYP2D6 metabolizer phenotypes and P. vivax relapse is of prime importance and should be carried forward in multicentric systems across the globe.

Detection of CYP2D6 polymorphism using Luminex xTAG technology in autism spectrum disorder: CYP2D6 activity score and its association with risperidone levels

CYP2D6 is involved in the biotransformation of a large number of drugs, including risperidone. This study was designed to detect CYP2D6 polymorphisms with a Luminex assay, including assessment the relationship of CYP2D6 polymorphisms and risperidone plasma concentration in autism spectrum disorder children (ASD) treated with risperidone. All 84 ASD patients included in this study had been receiving risperidone at least for 1 month. The CYP2D6 genotypes were determined by Luminex assay. Plasma concentrations of risperidone and 9-hydroxyrisperidone were measured using LC/MS/MS. Among the 84 patients, there were 46 (55.42%) classified as EM, 33 (39.76%) as IM, and 4(4.82%) as UM. The plasma concentration of risperidone and risperidone/9-hydroxyrisperidone ratio in the patients were significant differences among the CYP2D6 predicted phenotype group (P = 0.001 and P < 0.0001 respectively). Moreover, the plasma concentration of risperidone and risperidone/9-hydroxyrisperidone ratio in the patients with CYP2D6 activity score 0.5 were significantly higher than those with the CYP2D6 activity score 2.0 (P = 0.004 and P = 0.002 respectively). These findings suggested that the determination of the accurate CYP2D6 genotype-predicted phenotype is essential in the clinical setting and individualization of drug therapy. The use of the Luminex assay for detection of CYP2D6 polymorphisms could help us more accurately identify an individual's CYP2D6 phenotype.

Role of Pharmacogenetics in Improving the Safety of Psychiatric Care by Predicting the Potential Risks of Mania in CYP2D6 Poor Metabolizers Diagnosed With Bipolar Disorder

One of the main concerns in psychiatric care is safety related to drug management. Pharmacogenetics provides an important tool to assess causes that may have contributed the adverse events during psychiatric therapy. This study illustrates the potential of pharmacogenetics to identify those patients for which pharmacogenetic-guided therapy could be appropriate. It aimed to investigate CYP2D6 genotype in our psychiatric population to assess the value of introducing pharmacogenetics as a primary improvement for predicting side effects.A broad series of 224 psychiatric patients comprising psychotic disorders, depressive disturbances, bipolar disorders, and anxiety disorders was included. The patients were genotyped with the AmpliChip CYP450 Test to analyzing 33 allelic variants of the CYP2D6 gene.All bipolar patients with poor metabolizer status showed maniac switching when CYP2D6 substrates such as selective serotonin reuptake inhibitors were prescribed. No specific patterns were identified for adverse events for other disorders.We propose to utilize pharmacogenetic testing as an intervention to aid in the identification of patients who are at risk of developing affective switching in bipolar disorder treated with selective serotonin reuptake inhibitors, CYP2D6 substrates, and inhibitors.

Pharmacogenetics of treatment response in psoriatic arthritis

TNF-blocking agents, non-biological disease-modifying anti-rheumatic drugs (nbDMARDs) and non-steroidal anti-inflammatory drugs (NSAIDs) are commonly prescribed treatments in psoriatic arthritis. A large proportion of patients do not respond to these medications, although unfortunately clinically useful biomarkers that predict future response are currently lacking. Several candidate gene polymorphisms have been associated with responses to biologic therapies and nbDMARDs; however, replication and validation of these variants in large prospective psoriatic arthritis cohorts are required before translating these to clinical practice. In this review, we discuss the advances made in pharmacogenetics of treatment response in psoriatic arthritis to date, with focus on biologic therapies approved for use, nbDMARDs and NSAIDs, as well as outline emerging methodologies to obtain data that will help inform a future precision medicine approach in this condition.

Factors affecting the development of adverse drug reactions to β-blockers in hospitalized cardiac patient population

The aim of the present study was to undertake a study on the prevalence of cytochrome P450 2D6 (CYP2D6) poor metabolizer alleles (*3, *4, *5, and *6) on a Montenegrin population and its impact on developing adverse drug reactions (ADRs) of β-blockers in a hospitalized cardiac patient population. A prospective study was conducted in the Cardiology Center of the Clinical Center of Montenegro and included 138 patients who had received any β-blocker in their therapy. ADRs were collected using a specially designed questionnaire, based on the symptom list and any signs that could point to eventual ADRs. Data from patients' medical charts, laboratory tests, and other available parameters were observed and combined with the data from the questionnaire. ADRs to β-blockers were observed in 15 (10.9%) patients. There was a statistically significant difference in the frequency of ADRs in relation to genetically determined enzymatic activity (P<0.001), with ADRs' occurrence significantly correlating with slower CYP2D6 metabolism. Our study showed that the adverse reactions to β-blockers could be predicted by the length of hospitalization, CYP2D6 poor metabolizer phenotype, and the concomitant use of other CYP2D6-metabolizing drugs. Therefore, in hospitalized patients with polypharmacy CYP2D6 genotyping might be useful in detecting those at risk of ADRs.

Cancer pharmacogenomics: implications on ethnic diversity and drug response

The goal of pharmacogenomic research is to discover and validate genetic variants that are predictive of drug response, for eventual implementation into clinical practice. Cancer pharmacogenomics provides the opportunity to analyze two sets of DNA, that of the tumor (somatic) and that of the host (germline). Germline variants are inherited variations and are often associated with the pharmacokinetic behavior of a drug, including drug disposition and ultimately drug efficacy and/or toxicity, whereas somatic mutations are often useful in predicting the pharmacodynamic response to drugs. Pharmacoethnicity, or ethnic diversity in drug response or toxicity, is an increasingly recognized factor accounting for interindividual variations in anticancer drug response. Pharmacoethnicity is often determined by germline pharmacogenomic factors and the distribution of single nucleotide polymorphisms across various populations, but it may also be influenced by nongenetic factors, such as environmental factors. This review aims to elucidate the importance of pharmacoethnicity in cancer pharmacogenomic research and implementation, focusing solely on germline variants.

Pharmacogenetics in Central American healthy volunteers: interethnic variability

Ethnicity is one of the major factors involved in interindividual variability to drug response. This study aims to describe the frequency of the most relevant pharmacogenetic biomarkers and metabolic phenotypes in Central American healthy volunteers and to determine its interethnic variability. Twenty-six original research articles on allelic, genotypes or metabolic phenotype frequencies were analyzed, in which a total number of 7611 Central American healthy volunteers were included (6118 were analyzed for genotype and 1799 for metabolic phenotype). No reports were available for population from Belize and Honduras. The CYP2D6*4 and *5 frequencies in Amerindian populations from Costa Rica have shown to be among the highest frequencies so far reported in the world. Furthermore, NAT2*5 and *6 presented higher frequencies in admixed populations than in Amerindians, but, inversely, the NAT2*7 was more frequent in Amerindians compared to an admixed population. Likewise, different patterns of distribution have been shown in HLA-A*02, *03 and HLA-B*07 among Native populations from Latin America. Reports on Central American populations were also found for the CYP2C19, LDLR, CYP2E1, MDR1, G6PD, TP53, CYP1A2, CYP3A4 and CYP3A5 biomarkers, but no data were available for the other 91 pharmacogenetic biomarkers revised in Central American populations. Differences in the frequency of some pharmacogenetic biomarkers and metabolic phenotypes were found, showing interethnic variability within Central American and with other Latin American populations.

Contribution of ABCB1 and CYP2D6 Genotypes to the Outcome of Tamoxifen Adjuvant Treatment in Premenopausal Women With Breast Cancer

Recent pre-clinical evidence suggests that the active metabolite of tamoxifen, endoxifen, is a substrate for efflux pump P-glycoprotein. The aim of our study was to evaluate, if the polymoprhisms within ABCB1 gene alter tamoxifen adjuvant treatment efficacy in premenopausal women. Totally 71 premenopausal women with estrogen receptor positive breast cancer indicated for tamoxifen adjuvant treatment were followed retrospectively for median period of 56 months. The gentic polymorphisms of CYP2D6 and ABCB1 were analyzed and potential covariates as tumor grading, staging, age at the diagnosis, comedication, quantitative positivity of ER or PR were also evaluated. Cox proportional-hazards regression model indicated that patients carrying at least one variant allele in ABCB1 rs1045642 had significantly longer time to event survival compared to wild type subjects. Non-significant trend was noted for better treatment outcome of patients carrying at least one variant allele in the SNP rs2032582, while for the CYP2D6 polymorphism poor metabolizer phenotype resulted in worse outcome in comparison to extensive metabolizers subjects with HR of 4.04 (95 % CI 0.31-52.19). Similarly, patients using CYP2D6 inhibitors had non-significantly shorter time-to-event as compared to never users resulting in hazard ratio of 2.06 (95 % CI 0.40-10.63). ABCB1 polymorphisms may affect outcome of tamoxifen adjuvant treatment in premenopausal breast cancer patiens. This factor should be taken into account in addition to the CYP2D6 polymorphism or phenotypic inhibition of CYP2D6 activity.

CYP2D6 allele distribution in Macedonians, Albanians and Romanies in the Republic of Macedonia

Cytochrome P450 2D6 (CYP2D6) is an enzyme of great importance for the metabolism of clinically used drugs. More than 100 variants of the CYP2D6 gene have been identified so far. The aim of this study was to investigate the allele distribution of CYP2D6 gene variants in 100 individuals of each of the Macedonian, Albanian and Romany population, by genotyping using long range polymerase chain reaction (PCR) and a multiplex single base extension method. The most frequent variants and almost equally distributed in the three groups were the fully functional alleles *1 and *2. The most common non functional allele in all groups was *4 that was found in 22.5% of the Albanians. The most common allele with decreased activity was *41 which was found in 23.0% of the Romany ethnic group, in 11.0% of the Macedonians and in 10.5% of the Albanians. Seven percent of the Albanians, 6.0% of the Romani and 4.0% of the Macedonians were poor metabolizers, while 5.0% of the Macedonians, 1.0% of Albanians and 1.0% of the Romanies were ultrarapid metabolizers. We concluded that the CYP2D6 gene locus is highly heterogeneous in these groups and that the prevalence of the CYP2D6 allele variants and genotypes in the Republic of Macedonia is in accordance with that of other European populations.

Efficacy of Pregabalin in Acute Postoperative Pain Under Different Surgical Categories: A Meta-Analysis

The efficacy of pregabalin in acute postsurgical pain has been demonstrated in numerous studies; however, the analgesic efficacy and adverse effects of using pregabalin in various surgical procedures remain uncertain. We aim to assess the postsurgical analgesic efficacy and adverse events after pregabalin administration under different surgical categories using a systematic review and meta-analysis of randomized controlled trials.A search of the literature was performed between August 2014 to April 2015, using PubMed, Ovid via EMBASE, Google Scholar, and ClinicalTrials.gov with no limitation on publication year or language. Studies considered for inclusion were randomized controlled trials, reporting on relevant outcomes (2-, 24-hour pain scores, or 24 hour morphine-equivalent consumption) with treatment with perioperative pregabalin.Seventy-four studies were included. Pregabalin reduced pain scores at 2 hours in all categories: cardiothoracic (Hedge's g and 95%CI, -0.442 [-0.752 to -0.132], P = 0.005), ENT (Hedge g and 95%CI, -0.684 [-1.051 to -0.316], P < 0.0001), gynecologic (Hedge g, 95%CI, -0.792 [-1.235 to -0.350], P < 0.0001), laparoscopic cholecystectomy (Hedge g, 95%CI, -0.600 [-0.989 to -0.210], P = 0.003), orthopedic (Hedge g, 95%CI, -0.507 [-0.812 to -0.202], P = 0.001), spine (Hedge g, 95%CI, -0.972 [-1.537 to -0.407], P = 0.001), and miscellaneous procedures (Hedge g, 95%CI, -1.976 [-2.654 to -1.297], P < 0.0001). Pregabalin reduced 24-hour morphine consumption in gynecologic (Hedge g, 95%CI, -1.085 [-1.582 to -0.441], P = 0.001), laparoscopic cholecystectomy (Hedge g, 95%CI, -0.886 [-1.652 to -0.120], P = 0.023), orthopedic (Hedge g, 95%CI, -0.720 [-1.118 to -0.323], P < 0.0001), spine (Hedge g, 95%CI, -1.016 [-1.732 to -0.300], P = 0.005), and miscellaneous procedures (Hedge g, 95%CI, -1.329 [-2.286 to -0.372], P = 0.006). Pregabalin resulted in significant sedation in all surgical categories except ENT, laparoscopic cholecystectomy, and gynecologic procedures. Postoperative nausea and vomiting was only significant after pregabalin in miscellaneous procedures.Analgesic effects and incidence of adverse effects of using pregabalin are not equal in different surgical categories.