Epigenetic and sex differences in opioid use disorder in chronic pain: A real-world study linked with OPRM1 DNA methylation.

Opioid use disorder (OUD) is a multifaceted condition influenced by sex, genetic and environmental factors that could be linked with epigenetic changes. Understanding how these factors interact is crucial to understand and address the development and progression of this disorder. Our aim was to elucidate different potential epigenetic and genetic mechanisms between women and men that correlate with OUD under real-world pain unit conditions. Associations between analgesic response and the DNA methylation level of the opioid mu receptor (OPRM1) gene (CpG sites 1-5 selected in the promoter region) were evaluated in 345 long opioid-treated chronic non cancer pain: cases with OUD (n = 67) and controls (without OUD, n = 278). Cases showed younger ages, low employment status and quality of life, but higher morphine equivalent daily dose and psychotropic use, compared to the controls. The patients with OUD showed a significant decrease in OPRM1 DNA methylation, which correlated with clinical outcomes like pain relief, depression and different adverse events. Significant differences were found at the five CpG sites studied for men, and exclusively in women for CpG site 3, in relation to OUD diagnosis. These findings support the importance of epigenetics and sex as biological variables to be considered toward efficient OUD understanding and therapy development.

Clinical prediction of opioid use disorder in chronic pain patients: a cohort-retrospective study with a pharmacogenetic approach.

BACKGROUND: Opioids are widely used in chronic non-cancer pain (CNCP) management. However, they remain controversial due to serious risk of causing opioid use disorder (OUD). Our main aim was to develop a predictive model for future clinical translation that include pharmacogenetic markers. METHODS: An observational study was conducted in 806 pre-screened Spanish CNCP patients, under long-term use of opioids, to compare cases (with OUD, N.=137) with controls (without OUD, N.=669). Mu-opioid receptor 1 (OPRM1, A118G, rs1799971) and catechol-O-methyltransferase (COMT, G472A, rs4680) genetic variants plus cytochrome P450 2D6 (CYP2D6) liver enzyme phenotypes were analyzed. Socio-demographic, clinical and pharmacological outcomes were also registered. A logistic regression model was performed. The model performance and diagnostic accuracy were calculated. RESULTS: OPRM1-AA genotype and CYP2D6 poor and ultrarapid metabolizers together with three other potential predictors: 1) age; 2) work disability; 3) oral morphine equivalent daily dose (MEDD), were selected with a satisfactory diagnostic accuracy (sensitivity: 0.82 and specificity: 0.85), goodness of fit (P=0.87) and discrimination (0.89). Cases were ten-year younger with lower incomes, more sleep disturbances, benzodiazepines use, and history of substance use disorder in front of controls. CONCLUSIONS: Functional polymorphisms related to OPRM1 variant and CYP2D6 phenotypes may predict a higher OUD risk. Established risk factors such as young age, elevated MEDD and lower incomes were identified. A predictive model is expected to be implemented in clinical setting among CNCP patients under long-term opioids use.

Pharmacogenetics May Prevent Psychotropic Adverse Events in Autism Spectrum Disorder: An Observational Pilot Study.

INTRODUCTION: Up to 73% of individuals with autism spectrum disorder (ASD) and intellectual disability (ID) currently have prescriptions for psychotropic drugs. This is explained by a higher prevalence of medical and psychiatric chronic comorbidities, which favors polypharmacy, increasing the probability of the appearance of adverse events (AEs). These could be a preventable cause of harm to patients with ASD and an unnecessary waste of healthcare resources. OBJECTIVE: To study the impact of pharmacogenetic markers on the prevention of AE appearance in a population with ASD and ID. METHODS: This is a cross-sectional, observational study (n = 118, 72 participants completed all information) in the ASD population. Sociodemographic and pharmacological data were gathered. The Udvalg for Kliniske Undersøgelser Scale (UKU Scale) was used to identify AEs related to the use of psychotropic medication. Polymorphisms of DOP2, ABCB1, and COMT were genotyped and correlated with the AE to find candidate genes. Furthermore, a review of all medications assessed in a clinical trial for adults with autism was performed to enrich the search for potential pharmacogenetic markers, keeping in mind the usual medications. RESULTS: The majority of the study population were men (75%) with multiple comorbidities and polypharmacy, the most frequently prescribed drugs were antipsychotics (69%); 21% of the participants had four or more AEs related to psychotropic drugs. The most common were "Neurological" and" Psychiatric" (both 41%). Statistical analysis results suggested a significant correlation between the neurological symptoms and the DOP2 genotype, given that they are not equally distributed among its allelic variants. The final review considered 19 manuscripts of medications for adults with ASD, and the confirmed genetic markers for those medications were consulted in databases. CONCLUSION: A possible correlation between neurologic AEs and polymorphisms of DOP2 was observed; therefore, studying this gene could contribute to the safety of this population's prescriptions. The following studies are underway to maximize statistical power and have a better representation of the population.

CYP2D6 Genotype and Pharmacovigilance Impact on Autism Spectrum Disorder: A Naturalistic Study with Extreme Phenotype Analysis.

The long-term use of psychopharmacology medications in autism spectrum disorder (ASD) hitherto remains controversial due to a lack of evidence about safety and tolerability. In this regard, genotyping the metabolizing enzyme cytochrome P450 (CYP) 2D6, especially its extreme phenotypes, could help to prevent drug-related adverse reactions or adverse events (AEs). There are several medications warranting CYP2D6 screening that are consumed by people with ASD, such as risperidone and aripiprazole to name a few. A naturalistic observational study was carried out in participants with ASD to analyze the influence of the CYP2D6 phenotype in drug tolerability using a local pharmacovigilance system created for this study. In this case, AEs were identified from participants' electronic health records (EHRs) and paper registries. Other variables were collected: socio-demographic information, comorbidities, and psychopharmacology prescriptions (polypharmacy defined as ≥4 simultaneous prescriptions) and doses. The genetic analysis included allelic discrimination (CYP2D6*1, *2, *3, *4, *5, *6, *10, *17, and *41) and copy number variations. All of these were used to determine theoretical phenotypes of the metabolic profiles: poor (PM); intermediate (IM); normal (NM); and ultra-rapid (UM). Sex differences were analyzed. A total of 71 participants (30 ± 10 years old, 82% male, 45% CYP2D6 NM phenotype (32 participants)) with a median of 3 (IQR 2-4) comorbidities per person, mainly urinary incontinence (32%) and constipation (22%), were included. CYP2D6 UM showed the highest rate of polypharmacy, whilst, IM participants had the highest rates of neurological and psychiatric AEs, even worse if a CYP2D6 inhibitor drug was prescribed simultaneously. CYP2D6 pharmacogenomics and the monitoring of new antipsychotic prescriptions may make a difference in medication safety in adults with ASD. Particularly in those with psychopharmacology polymedication, it can help with AE avoidance and understanding.

Long-term deprescription in chronic pain and opioid use disorder patients: Pharmacogenetic and sex differences.

More than half of patients with opioid use disorder for chronic non-cancer pain (CNCP) reduced their dose through a progressive opioid withdrawal supported by a rotation to buprenorphine and/or tramadol. The aim of this research is to analyse the long-term effectiveness of opioid deprescription taking into account the impact of sex and pharmacogenetics on the inter-individual variability. A cross-sectional study was carried out from October 2019 to June 2020 on CNCP patients who had previously undergone an opioid deprescription (n = 119 patients). Demographic, clinical (pain, relief and adverse events) and therapeutic (analgesic use) outcomes were collected. Effectiveness (< 50 mg per day of morphine equivalent daily dose without any aberrant opioid use behaviour) and safety (number of side-effects) were analysed in relation to sex differences and pharmacogenetic markers impact [OPRM1 genotype (rs1799971) and CYP2D6 phenotypes]. Long-term opioid deprescription was achieved in 49 % of the patients with an increase in pain relief and a reduction of adverse events. CYP2D6 poor metabolizers showed the lowest long-term opioid doses. Here, women showed a higher degree of opioid deprescription, but increased use of tramadol and neuromodulators, as well as an increased number of adverse events. Long-term deprescription was successful in half of the cases. Understanding sex and gender interaction plus a genetic impact could help to design more individualized strategies for opioid deprescription.

Sex Differences in Oxycodone/Naloxone vs. Tapentadol in Chronic Non-Cancer Pain: An Observational Real-World Study.

Despite the large body of research on sex differences in pain, there is a lack of translation to real-world pain management. Our aim was to analyse the sex differences in the analgesic response to oxycodone/naloxone (OXN) and tapentadol (TAP), in comparison with other opioids (OPO) commonly prescribed for chronic non-cancer pain (CNCP). An observational and cross-sectional study was conducted on ambulatory CNCP patients (n = 571). Sociodemographic, clinical (pain intensity, relief, and quality of life), safety (adverse events (AEs), adverse drug reactions), hospital frequentations and pharmacological (morphine equivalent daily dose (MEDD)) variables were collected. Multiple linear regressions were carried out to assess the association between sex and outcomes. Sex differences were observed, with lower female tolerability and higher hospital frequentation, especially in the OXN group (OR AEs report = 2.8 [1.8−4.4], p < 0.001). Here, females showed higher hospital use (23% hospital admission, 30% prescription change, p < 0.05), requiring a higher MEDD (127 ± 103 mg/day, p < 0.05), compared to OXN men. Regardless of the opioid group, CNCP women were significantly older than men (three years), with significantly higher benzodiazepine use (OR = 1.6 [1.1−2.3]), more constipation (OR = 1.34 [0.93−1.90]) and headache (OR = 1.45 [0.99−2.13]) AEs, than men who were more likely to refer sexual dysfunction (OR = 2.77 [1.53−5.01]), and loss of libido (OR = 1.93 [1.22−3.04]). Sex-differences were found related to poorer female drug tolerability and higher hospital resources, even worst in OXN female users. Other differences related to older female ages and benzodiazepine prescription, need to be further analysed from a gender perspective.

Sex-Differences in Pain and Opioid Use Disorder Management: A Cross-Sectional Real-World Study.

(1) Background: It is essential to focus attention on sex-specific factors which are clinically relevant in pain management, especially with regards to opioid use disorder (OUD) risk. The aim of this study was to explore potential sex-differences in chronic non-cancer pain (CNCP) outpatients. (2) Methods: An observational cross-sectional study was conducted under CNCP outpatients with long-term prescribed opioids (n = 806), wherein 137 patients had an OUD diagnosis (cases, 64% females) and 669 did not (controls, 66% females). Socio-demographic, clinical, and pharmacological outcomes were analyzed. (3) Results: Female controls presented an older age and less intensive pain therapy but higher psychotropic prescriptions and emergency department visits compared to male controls. Meanwhile, cases demonstrated a younger age, higher work disability, double morphine equivalent daily dose, and benzodiazepine use compared with controls. Here, female cases showed an 8% greater substance use disorder (OR 2.04 [1.11-3.76]) and 24% lower tramadol use, while male cases presented a 22% higher fentanyl use (OR 2.97 [1.52-5.81]) and reported the highest number of adverse drug reactions (24%, OR 2.40 [1.12-5.16]) compared with controls. (4) Conclusions: An OUD individual risk profile was evidenced with sex-differences to take into consideration to design equal prevention programs.

Oxycodone/naloxone versus tapentadol in real-world chronic non-cancer pain management: an observational and pharmacogenetic study.

Tapentadol (TAP) and oxycodone/naloxone (OXN) potentially offer an improved opioid tolerability. However, real-world studies in chronic non-cancer pain (CNCP) remain scarce. Our aim was to compare effectiveness and security in daily pain practice, together with the influence of pharmacogenetic markers. An observational study was developed with ambulatory test cases under TAP (n = 194) or OXN (n = 175) prescription with controls (prescribed with other opioids (control), n = 216) CNCP patients. Pain intensity and relief, quality of life, morphine equivalent daily doses (MEDD), concomitant analgesic drugs, adverse events (AEs), hospital frequentation and genetic variants of OPRM1 (rs1799971, A118G) and COMT (rs4680, G472A) genes, were analysed. Test CNCP cases evidenced a significantly higher pain relief predictable due to pain intensity and quality of life (R2 = 0.3), in front of controls. Here, OXN achieved the greatest pain relief under a 28% higher MEDD, 8-13% higher use of pregabalin and duloxetine, and 23% more prescription change due to pain, compared to TAP. Whilst, TAP yielded a better tolerability due the lower number of 4 [0-6] AEs/patient, in front of OXN. Furthermore, OXN COMT-AA homozygotes evidenced higher rates of erythema and vomiting, especially in females. CNCP real-world patients achieved higher pain relief than other traditional opioids with a better tolerability for TAP. Further research is necessary to clarify the potential influence of COMT and sex on OXN side-effects.

The challenge of detecting adverse events in adults with autism spectrum disorder who have intellectual disability.

Adults with autism spectrum disorder (ASD) and associated intellectual disability (ID) take a high number of different psychotropic drugs simultaneously. Nowadays, little is known about this multidrug pattern efficacy and safety. The present study has endeavored to fill this gap creating a local pharmacovigilance system. A 36-month, retrospective and prospective, observational, and multicenter pharmacovigilance study was carried out in adults with ASD and ID (n = 83). Information regarding ongoing medications (polypharmacy: taking simultaneously >4 drugs; safety profile: adverse events' number, adverse drug reactions' number, and affected system; and observed-to-expected [O/E] ratio using the summary of product characteristics), and current diagnoses were recorded. A median of four ongoing medications per participant was registered, half of the sample was under polypharmacy regimen. Regarding all ongoing medications, 50% were antipsychotic drugs, and 47% of participants had >1 antipsychotic prescribed. In contrast, only 64 adverse events were identified from electronic health records, mostly due to risperidone. Half of them were related either to nervous or metabolic systems, and almost a third were not previously described in the corresponding drug summary of products characteristics. Extrapyramidalism, gynecomastia, hypercholesterolemia, and urinary retention were some AEs that occurred more frequently than expected (O/E ratio > 6 times) according to our data. The highest O/E ratio scores (>120 times) were for hypercholesterolemia and rhabdomyolysis caused by valproic acid. According to the number of adverse events and adverse drug reactions reported in electronic health records locally and nationally by clinicians, we need to increase awareness about medications safety. LAY SUMMARY: A 36-month study in adults with autism, ID, and polypharmacy (>4 drugs) was done to investigate drug safety on everyone. A median of four medications per person was registered, half were antipsychotic drugs, and 47% of participants had >1 antipsychotic medication simultaneously. Only 64 adverse events were identified from electronic health records, mostly due to risperidone. Half of them were related to nervous or metabolic systems and a third were not previously described in the drug information sheet.

Therapeutic alliance impact on analgesic outcomes in a real-world clinical setting: An observational study.

A good therapeutic alliance is relevant for healthcare providers exposed to patients' suffering, especially since patients and physicians may understand the painful experience differently. Our aim was to explore the impact of therapeutic alliance on analgesic outcomes in a real-world interdisciplinary pain unit (PU). A cross-sectional observational study was conducted on outpatients (n = 69) using opioids on a long-term basis for the treatment of chronic non-cancer pain, where clinical pharmacologists and pharmacists advised patients about their opioid treatment. Responses to the patient-doctor relationship questionnaire (PDRQ), sociodemographic and clinical information (pain level, quality of life and hospital use) were collected, whereas pharmacology data (analgesic prescription, adverse events, and compliance) were obtained from electronic health records. Patients were predominantly middle-aged (75 % women, 72 % retired), experiencing moderate pain (VAS 40-70 mm) on average, and under a high morphine equianalgesic dosage (95 ± 88 mg per day, mainly tapentadol or fentanyl). Patients with better PDRQ outcomes, and therefore better therapeutic alliance, showed lower pain intensity than patients with worse PDRQ outcomes (pain intensity: high scores 60 ± 47 mm and medium scores 60 ± 45 mm vs. low scores 80 ± 75 mm, p < 0.01). Along with this, pain intensity was lower when patients affirmed that, thanks to the health-care providers, they "gained new insight", "felt better", or "felt content with their doctor's treatment". What´s more, patients who affirmed "I benefit from the treatment" experienced increased pain relief (benefit 40 ± 30 vs. non-benefit 19 ± 26 mm, p = 0.010) and improved quality of life (benefit 33 ± 25 vs. non-benefit 18 ± 16 mm, p = 0.031). However, there was a percentage of patients who did not fully understand the provided information, which is something to be taken into account to improve in clinical routine. Therapeutic alliance supported by pharmacist experts on pain management can be an effective strategy to improve analgesic outcomes. Further efforts are needed to improve communication strategies for pain management. Future directions of research should include the analysis of the role of the pharmacist in poly-professional consultations as related to the advice of patients about their medication, and the mutual trust with the patients.

Personality and psychiatric disorders in chronic pain male affected by erectile dysfunction: prospective and observational study.

The prevalence of personality disorders (PDs) and sexual dysfunction in chronic pain patients is higher than in general population. Our main objective was to analyse the influence of PD in patients with erectile dysfunction and chronic non-cancer pain and their response to andrological treatment. One-hundred one patients were included along 30 months. Pain intensity, quality of life, sexual life quality, anxiety and depression were analysed together with opioid dose. Erectile functioning was measured with the International Index of Erectile Function (IIEF) and PDs with Millon Clinical Multiaxial Inventory (MCMI-III). The mean age was 57 ± 12 years old, with moderate to severe pain, 70% were sexually active and presented moderate to severe ED. PDs were very frequent (31%, cut-off 85 and 84% cut-off 75 scores) mostly anxiety, compulsive, though disorder, somatoform and narcissistic. Self-defeating feature presence was significantly correlated (r = -0.4, 95% CI = -0.605 to -0.145, p = 0.002) with a more severe baseline ED and narcissistic, and a better response to andrological treatment (p = 0.010, d = 1.082). Patients with dysthymia features required significantly higher opioid doses vs. control (238 vs. 102 mg/day, respectively). These findings underline the importance of diagnosing PDs to rigorously treat patients with chronic pain and ED.

Effect of Cytochrome P450 and ABCB1 Polymorphisms on Imatinib Pharmacokinetics After Single-Dose Administration to Healthy Subjects.

BACKGROUND: Validated genomic biomarkers for oncological drugs are expanding to improve targeted therapies. Pharmacogenetics research focusing on the mechanisms underlying imatinib suboptimal response might help to explain the different treatment outcomes and drug safety profiles. OBJECTIVE: To investigate whether polymorphisms in genes encoding cytochrome P450 (CYP) enzymes and ABCB1 transporter affect imatinib pharmacokinetic parameters. METHODS: A prospective, multicenter, pharmacogenetic pilot study was performed in the context of two separate oral imatinib bioequivalence clinical trials, which included 26 healthy volunteers. DNA was extracted in order to analyze polymorphisms in genes CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP3A4, CYP3A5 and ABCB1. Imatinib plasma concentrations were measured by HPLC-MS/MS. Pharmacokinetic parameters were calculated by non-compartmental methods using WinNonlin software. RESULTS: Volunteers (n = 26; aged 24 ± 3 years; 69% male) presented regular pharmacokinetic imatinib data (concentration at 24 h, 436 ± 140 ng/mL and at 72 h, 40 ± 26 ng/mL; AUC0-72 32,868 ± 10,713 ng/mL⋅h; and Cmax 2074 ± 604 ng/mL). CYP2B6 516GT carriers showed a significant reduction of imatinib concentration at 24 h (23%, 391 ng/dL vs 511 ng/dL in 516GG carriers, p = 0.005) and elimination half-life (11%, 12.6 h vs 14.1 h in 516GG carriers, p = 0.041). Carriers for CYP3A4 (*22/*22, *1/*20 and *1/*22 variants) showed a reduced frequency of adverse events compared to *1/*1 carriers (0 vs 64%, p = 0.033). The other polymorphisms analyzed did not influence pharmacokinetics or drug toxicity. CONCLUSION: CYP2B6 G516T and CYP3A4 *20,*22 polymorphisms could influence imatinib plasma concentrations and safety profile, after single-dose administration to healthy subjects. This finding needs to be confirmed before it is implemented in clinical practice in oncological patients under treatment with imatinib.

Gender bias in therapeutic effort: from research to health care.

There are relevant dimensions from a gender perspective related to  therapeutic effort. To illustrate and discuss possible gender bias related  to medicines, through the consumption analysis in women, the  prescription of biological drugs according to sex, the potential gender  inequality in adverse drug reactions, and research with clinical trials, as  well as the decisions of international institutions in the marketing of  medicinal products. There is greater tendency to prescribe pain  relievers, regardless of pain, and drugs for low intensity depressive  symptoms in women than in men. The opposite occurs in the  prescription of statins and adequate doses, and with the greater  probability of prescribing anti-tumor necrosis factor in men than in  women with ankylosing spondylitis, despite a similar disease burden.  Adverse drug reactions are observed more frequently in women than in  men, where determinants such as body weight are having little influence on the dosage. It is currently scarcely considered in the prescription that women have differences in the activity of cytochrome CYPP450 enzymes, which can affect the liver's metabolism rate. There  are even immunological, genetic and epigenetic effects (due to heredity  and uneven gene dosing located in the X and Y chromosomes) that can  influence these differences by sex. Finally, through cases of hormonal  therapy clinical trials, a drug for women's inhibited sexual desire and a  contraceptive for men, gender bias and stereotypes are shown to  influence a potential generation of inequalities, especially in adverse  drug reactions to the detriment of women. In conclusion, health  professionals frequently attribute physical symptoms to women's  emotionality, influencing their greater prescription of symptomatic drugs. Whether the same reason influences the lower prescription of  therapeutic drugs in women than in men should be analyzed. There are  biological determinants to consider due to their influence on a greater pharmacological toxicity in women. Clinical trials should improve  according to the gender recommendations by the Food and Drugs  Administration.

Existen dimensiones relevantes desde una perspectiva de género  relacionadas con el esfuerzo terapéutico. Se pretende ilustrar y traer a  debate posibles sesgos de género relacionados con los medicamentos,  mediante el análisis del consumo en las mujeres, la prescripción de  fármacos biológicos según sexo, la potencial desigualdad de género en  las reacciones adversas a los medicamentos y la investigación con  ensayos clínicos, así como las decisiones de las instituciones  internacionales en la comercialización de medicamentos. Se observa una mayor tendencia a prescribir analgésicos, con independencia del dolor, y fármacos para síntomas depresivos de baja intensidad en mujeres que  en hombres. Lo contrario sucede en la prescripción de estatinas y dosis  adecuadas, y con la mayor probabilidad de prescripción de antifactor de  necrosis tumoral en hombres que en mujeres con espondilitis anquilosante, pese a la similar carga de la enfermedad. Las  reacciones adversas a los medicamentos se observan con más  frecuencia en mujeres que en hombres, donde determinantes como el  peso corporal están influyendo poco en la dosificación. En la actualidad  se considera escasamente en la prescripción que las mujeres presentan  diferencias en la actividad de las enzimas del citocromo CYPP450, que  puede afectar a la velocidad del metabolismo hepático. Incluso hay  efectos inmunológicos, genéticos y epigenéticos (por la herencia y la  dosificación desigual de los genes ubicados en los cromosomas X e Y)  que pueden influir en estas diferencias por sexo. Por último, mediante  los casos de ensayos clínicos de la terapia hormonal, un fármaco para el deseo sexual inhibido de las mujeres y un anticonceptivo para hombres, se muestran sesgos y estereotipos de género que influyen en una  potencial generación de desigualdades, especialmente en las reacciones  adversas a los medicamentos en perjuicio de las mujeres. Concluyendo,  los profesionales sanitarios atribuyen con frecuencia a la emocionalidad  de las mujeres lo que son síntomas físicos, influyendo en la mayor  prescripción de fármacos sintomáticos en ellas. Debe analizarse si la  misma razón influye en la menor prescripción de fármacos terapéuticos en mujeres que en hombres. Existen determinantes biológicos a considerar por su influencia en una mayor toxicidad farmacológica en las mujeres. Los ensayos clínicos deben mejorar atendiendo a las  recomendaciones de género de la Food and Drug Administration.

Gender based differences, pharmacogenetics and adverse events in chronic pain management.

Safety data in chronic non-cancer pain (CNCP) with long-term opioid therapy has been poorly studied and can be differently influenced by gender. Furthermore, pharmacogenetics (PGx) could possibly be used to tailor pain medication based on the individual's genetic background. The aim was to assess whether PGx applied to a pharmacovigilance system could help to improve a patient's security profile. A pharmacovigilance data recording system was conducted over 24 months, including genotyping of OPRM1 variants (opioid receptor, A118G) and COMT (enzyme that degrades catecholamines such as norepinephrine, G1947A). Pain intensity (visual analogue scale, VAS), morphine equivalent daily dose (MEDD), adverse events (AEs) and suspected adverse drug reactions (ADRs) were recorded and analysed by gender. The Ethics Committee approved the study and data were analysed with R 3.6.0 software. A total of 748 patients were recruited in the study (67% female, VAS 62 ± 29 mm, MEDD 119 ± 114 mg/day) reporting a median of 6 (3.5-9) AEs/patient. Women presented more nausea, headaches, insomnia, loss of appetite, weight change, depression and dizziness than men. Analysis by genotype demonstrated that PGx influenced the prevalence of vomiting and depression in men, dizziness in women and sexual dysfunction in both. Physicians notified 150 ADRs mostly in females (79%) related to nervous system disorders. PGx applied to a pharmacovigilance recording system provides important information to achieve a better knowledge about AEs in CNCP pharmacological therapy. OPRM1 and COMT polymorphisms were associated with AEs in CNCP patients that differed according to gender.

OPRM1 Gene Interaction with Sleep in Chronic Pain Patients Treated with Opioids.

BACKGROUND: The experience of chronic non-cancer pain (CNCP) is one of the most common reasons individuals seek medical attention. Patients with CNCP frequently experience concomitant sleep-related problems. OBJECTIVES: The aim was to evaluate sleep problems in opioid naïve CNCP patients, before and after opioid titration, analyzing the influence of OPRM1 gene variants. STUDY DESIGN: A prospective, cohort, observational study. SETTING: This study was performed at the Pain Unit of the Alicante University General Hospital. METHODS: Pain and Medical Outcomes Study Sleep questionnaire (MOS-Sleep) were assessed at baseline and 3 months after opioid titration in 231 opioid naïve CNCP patients. Sleep data was compared with a matched-control group (n = 64). Morphine equivalent daily doses, adverse events, and drugs prescribed for pain were also registered. OPRM1 polymorphism rs1799971 was analyzed by RT-PCR. Ethics Committee approved the study and results were analyzed by R software. RESULTS: After 3 months of opioid titration, patients with CNCP (63 ± 14 years, 64% female, VAS 74 ± 17 mm) significantly decreased pain intensity, anxiety and depression, and increased quality of life. Sleep problems were significantly more frequent in females (P = 0.002). Age, quality of life, anxiety, and depression all influenced sleep disturbances and problems indices, which were significantly different from the control group. Furthermore, the OPRM1 118-GG genotype was also associated with significantly lower sleep adequacy, and more sleep problems. LIMITATIONS: Total number of subjects studied was relatively small and most patients were on other non-opioid centrally-acting medications. CONCLUSIONS: Opioids decreased CNCP severity, improving patients' psychological areas, and quality of life. However, patients with OPRM1 118-GG genotype indicated an increase in sleep problems and worsening sleep pattern while taking opioids. KEY WORDS: OPRM1, pharmacogenetics, MOS-Sleep, opioids, chronic noncancer pain, sleep related problems, sleep problem index SLP-6 and SLP-9.

Health benefits of an adverse events reporting system for chronic pain patients using long-term opioids.

BACKGROUND: Safety data from long-term opioid therapy in the real world has been poorly studied in chronic non-cancer pain (CNCP). The aim was to design a pharmacovigilance data recording system and assess whether participation in this recording system improves pain management, enhancing patient's health status. METHODS: A pharmacovigilance data recording system was conducted during 24 months. Data were self-reported by patients (pain, adverse events [AEs] and healthcare resources use) and physicians (morphine equivalent daily dose [MEDD] prescribed and suspected adverse drug reaction [ADRs]). Outcomes from patients with (case) or without (controls) suspected ADRs and cases follow-up were also compared with Spanish Pharmacovigilance System data. RESULTS: A total of 753 patients were recruited in 897 visits. Fentanyl and tramadol were the most prescribed opioids, 89% with concomitant drugs, pregabalin being the one with the most potential drug interactions. Cases presented significantly higher pain intensity (VAS 67 ± 26 vs 59 ± 30 mm, P < 0.05), number of AEs (8 ± 6 vs 5 ± 3 AEs/patient, P < 0.01), polypharmacy related to pain (65% vs 34%, P < 0.01) and MEDD (139 ± 130 vs 106 ± 99 mg/d, P < 0.01) than controls. Furthermore, cases presented significant higher changes in pharmacological pain therapy due to pain, unplanned emergency visits and hospital admission than controls. Physicians notified 168 suspected ADRs mostly related to neurological or psychiatric events and 8% of them were previously unknown. CONCLUSIONS: This data recording system provided important information to achieve a better control of CNCP pharmacological pain therapy, improving patient's health status and reducing costs to the Health System.

Endothelial nitric oxide synthase gene polymorphisms and erectile dysfunction in chronic pain.

OBJECTIVES: To investigate whether endothelial nitric oxide synthase (eNOS) T786C, 4VNTR and G894 T gene polymorphisms could mediate in andrological treatment response in Spaniards. SUBJECT PATIENTS/METHODS: The study participants were Spaniard males with erectile dysfunction (ED) and chronic pain (n = 105) recruited at the Pain Unit. eNOS polymorphisms were genotyped by quantitative polymerase chain reaction using Taqman specific probes. Statistical analyses were carried out using R-3.2.4 software. RESULTS: A total of 69 patients required andrological treatment and 76% of them improved ED upon iPED5 (20%), testosterone (35%) or iPDE5/testosterone treatment (45%); being significantly better in T786C-CC patients. Multivariate regression analysis indicated that age, opioid daily dose and carriage of T786C-C allele influenced the risk and ED severity in Spaniard chronic pain patients. CONCLUSION: T786C polymorphism at eNOS locus appeared to be a major contributor in the variable erectile function iPDE5/testosterone response in Spaniards.

Pharmacogenetics and prediction of adverse events in prescription opioid use disorder patients.

The threats involved in the long-term opioid treatment of chronic non-cancer pain (CNCP) have increased notably. Strategies to identify at-risk patients are important because there is no clear evidence showing which screening or deprescription programmes are appropriate. Our aim was to evaluate the evidence provided by pharmacogenetics applied to predict an analgesic toxicity profile in prescription opioid use disorder (POUD) patients participating in an opioid deprescription programme. Pharmacogenetic markers were analysed in an observational, prospective deprescription programme for POUD patients (n = 88) treated for CNCP. It consisted of monitoring visits (baseline, follow-up and final), opioid rotation or discontinuation and the recording of adverse events and suspected adverse drug reactions (ADRs). Variants in OPRM1 (A118G), ABCB1 (C3435T), COMT (G472A), OPRD1 (T921C) and ARRB2 (C8622T) genes were tested by real-time PCR. Ethics committee approved the study. Wild-type OPRM1-AA genotype carriers reported a significantly higher number of adverse events than OPRM1-AG/GG (median [p25-75], 7 [5-11] vs 5 [3-9]), particularly gastrointestinal system events (90% vs 63%) such as nausea (33% vs 0%). Suspected ADRs (affecting 17% of the patients) were three times higher in males than in females (30% vs 11%). The deprescription programme was effective and safe, and it achieved a significant progressive reduction in the morphine equivalent daily dose, strong opioids and other analgesics' use, without causing any changes in pain intensity or opiate abstinence syndrome. OPRM1 gene polymorphisms could identify the risk of gastrointestinal adverse events in POUD patients. Deprescription programmes including pharmacogenetic analysis should be considered during the follow-up of this population.

OPRM1 influence on and effectiveness of an individualized treatment plan for prescription opioid use disorder patients.

Screening for opioid use disorder should be considered in chronic non-cancer pain (CNCP) patients with long-term use of opioids. The aim of our study was to assess the effectiveness of an individualized treatment plan (ITP) for prescription opioid dependence that included screening of pharmacogenetic markers. An observational prospective study was performed using prescription opioid-dependent CNCP outpatients (n = 88). Patients were divided into nonresponders, responders, or high responders according to their response to the ITP. Genotyping of OPRM1 (A118G), OPRD1 (T921C), COMT (G472A), ABCB1 (C3435T), and ARRB2 (C8622T) was performed by real-time PCR. Our ITP achieved a significant reduction of the morphine equivalent daily dose (MEDD) in 64% of responders, including 33% of high responders. Nonopioid medication or buprenorphine use was significantly higher at final versus basal visit. 118-AA OPRM1 patients required significantly lower MEDD at basal and final visits. Our ITP showed effectiveness and security in reducing MEDD in opioid-dependent patients, with good conversion to buprenorphine that was more pronounced in 118-AA OPRM1 patients.

ß2­adrenergic receptor functionality and genotype in two different models of chronic inflammatory disease: Liver cirrhosis and osteoarthritis.

The present study was designed to investigate the functional status of ß2 adrenoceptors (ß2AR) in two models of chronic inflammatory disease: liver cirrhosis (LC) and osteoarthritis (OA). The ß2AR gene contains three single nucleotide polymorphisms at amino acid positions 16, 27 and 164. The aim of the present study was to investigate the potential influence of lymphocyte ß2AR receptor functionality and genotype in LC and OA patients. Blood samples from cirrhotic patients (n=52, hepatic venous pressure gradient 13±4 mmHg, CHILD 7±2 and MELD 11±4 scores), OA patients (n=30, 84% Kellgren­Lawrence severity 4 grade, 14% knee replacement joint) and healthy volunteers as control group (n=26) were analyzed. Peripheral blood mononuclear cells (PBMC) were isolated from whole blood and basal and isoproterenol induced adenylate cyclase activity (isoproterenol stimulus from 10­9 to 10­4 mM), and ß2AR allelic variants (rs1042713, rs1042714, rs1800888) were determined. ß2AR functionality was decreased in the two different models of chronic inflammatory disease studied, OA (50% vs. control) and LC (85% vs. control). In these patients, the strength of the ß2AR response to adrenergic stimulation was very limited. Adrenergic modulation of PBMC function through the ß2AR stimulus is decreased in chronic inflammatory processes including LC and OA, suggesting that the adrenergic system may be important in the development of these processes.