Opioid metabolism

Sex differences in the antinociceptive effect of codeine and its peripheral but not central metabolism in adult mice

Codeine is a natural opiate extracted from opium poppy (Papaver somniferum) and used to alleviate mild to moderate pain. The analgesic effect of this molecule results from its metabolism into morphine which is an agonist of the mu opioid receptor. Morphine's major metabolite morphine-3-glucuronide induces both thermal and mechanical hypersensitivies while codeine-6-glucuronide has been proposed to be antinociceptive. However, sex differences in codeine antinociceptive effect and pharmacokinetics were barely studied. To this purpose, we injected male and female mice with codeine (2.5, 5, 10, 20 and 40 mg/kg) and thermal hypersensitivity was assessed 30 min after injection using the Tail Immersion Test. Moreover, both peripheral and central metabolism of codeine were evaluated respectively in the blood or pain-related brain structures in the central nervous system. The amounts of codeine and its metabolites were quantified using the isotopic dilution method by liquid chromatography coupled to a mass spectrometer. Our results show that codeine induces a greater antinociceptive effect in males than females mice independently of the estrous cycle. Moreover, major sex differences were found in the peripheral metabolism of this molecule, with higher amounts of pronociceptive morphine-3-glucuronide and less antinociceptive codeine-6-glucuronide in females than in males. Concerning the central metabolism of codeine, we did not find significant sex differences in pain-related brain structures. Collectively, these findings support a greater codeine antinociceptive effect in males than females in mice. These sex differences could be influenced by a higher peripheral metabolism of this molecule in female mice rather than central metabolism.

Lower Diversity of Amylase-Trypsin Inhibitors and Ex Vivo-Released Opioid-Containing Peptides in Ancestral Compared to Modern Wheat Varieties Assessed by Proteomics and Peptidomics

This study focused on identifying amylase-trypsin inhibitors (ATIs) in seven Norwegian-cultivated wheat varieties, including common wheat and ancestral species, and identifying potentially harmful opioid peptides within the ex vivo digesta of these wheats. LC-MS/MS analysis of tryptic peptides from ATI fractions revealed that the common wheat variety Børsum exhibited the highest diversity of ATIs (n = 24), while they were less represented in tetraploid emmer (n = 11). Hexaploid wheat Bastian showed low diversity and relative abundance of ATIs. Nevertheless, digestion of Mirakel and Bastian by human gastrointestinal juices released the highest number of opioid-containing peptides, representing both gluten exorphins and gliadorphin. In conclusion, emmer had the lowest levels of ATIs, while einkorn and spelt released the fewest opioid-containing peptides after ex vivo digestion. These results point to the potential lower harmful effects of ancestral wheat compared to common hexaploid wheat varieties for wheat-sensitive individuals.

Catalyzing Pharmacogenomic Analysis for Informing Pain Treatment (C-PAIN): A Randomized Trial of Preemptive CYP2D6 Genotyping in Cancer Palliative Care

Background

Cancer patients frequently suffer from pain, often managed with opioids. However, undertreated pain remains a significant concern. Opioid effectiveness varies due to genetic differences in how individuals metabolize some of these medications. While prior research suggests promise in tailoring opioid prescriptions based on CYP2D6 genetic makeup, its application in cancer pain management remains limited. This study investigates the potential benefits of preemptive CYP2D6 genotyping for cancer patients initiating opioid therapy, focusing on codeine, tramadol, and hydrocodone, whose efficacy is demonstrably impacted by CYP2D6 variations.

Methods

This is a randomized, prospective study to evaluate the effects of preemptive pharmacogenomic (PGx) testing on opioid dosing decisions/selections and composite pain score in oncology patients. Patients with metastatic solid tumors for whom near-future opioid therapy is anticipated will be randomized to PGx and control arms, stratified by the presence or absence of bony metastases and history of opioid use. In the PGx arm, patients will be preemptively tested using a panel of pharmacogenomic genetic variants, and providers will receive opioid dosing guidance via an electronic medical record-embedded clinical decision support tool. In the control arm, pain prescribing will occur per standard of care without genotype information.

Planned Outcome

The primary study outcome will be composite pain intensity during the first 45 days after an index opioid prescription for codeine, tramadol, or hydrocodone. Safety will be assessed by comparing opioid-related adverse event rates between the two study arms. Secondary outcomes will include rates of hospitalization/emergency room visits, cumulative morphine equivalents received, and type of first opioid prescribed.

Prolonged post-operative hydrocodone usage due to psychotropic drug interaction

OBJECTIVES

To explore pain outcomes in patients prescribed hydrocodone and psychotropic medications with or without CYP2D6 inhibition activity.

METHODS

Patients hospitalized for lower/limited upper extremity injuries who were prescribed hydrocodone alongside a psychotropic medication were considered for this study (n=224). A subset of these patients (n=178) was prescribed a psychotropic medication known to inhibit CYP2D6, while the remainder (n=46) were prescribed psychotropic medications without CYP2D6 inhibition activity. Patient demographics and pain outcomes were collected by electronic health record review and interviews.

RESULTS

Patients taking a psychotropic inhibitor of CYP2D6 exhibited longer duration of opioid use post-discharge (median 33 days [IQR 10-99]) compared with patients taking a psychotropic non-inhibitor (4 days [2-20], p<0.001). No significant differences were observed with in-hospital pain outcomes, including total dose of hydrocodone administered, duration of hydrocodone use, pain index scores, and the occurrence of common mild/moderate/severe hydrocodone side effects.

CONCLUSIONS

Patients prescribed at least one psychotropic inhibitor of CYP2D6 were more likely to continue using hydrocodone for up to 3 months following surgery. Knowledge of these critical drug-drug interactions could enhance clinical practice and improve patient outcomes. This study highlights negative post-operative pain outcomes in patients prescribed hydrocodone alongside a psychotropic inhibitor of CYP2D6. The results of this study indicate that patients taking psychotropic medications that inhibit CYP2D6 are at increased risk for prolonged hydrocodone use following orthopedic surgery.

Could chronic opioid use be an additional risk of hepatic damage in patients with previous liver diseases, and what is the role of microbiome?

Among illicit drugs, addiction from opioids and synthetic opioids is soaring in an unparalleled manner with its unacceptable amount of deaths. Apart from these extreme consequences, the liver toxicity is another important aspect that should be highlighted. Accordingly, the chronic use of these substances, of which fentanyl is the most frequently consumed, represents an additional risk of liver damage in patients with underlying chronic liver disease. These observations are drawn from various preclinical and clinical studies present in literature. Several downstream molecular events have been proposed, but recent pieces of research strengthen the hypothesis that dysbiosis of the gut microbiota is a solid mechanism inducing and worsening liver damage by both alcohol and illicit drugs. In this scenario, the gut flora modification ascribed to non-alcoholic fatty liver disease performs an additive role. Interestingly enough, HBV and HCV infections impact gut-liver axis. In the end, the authors tried to solicit the attention of operators on this major healthcare problem.

Pharmacokinetics of single dose levobupivacaine after peri-incisional subcutaneous infiltration in anaesthetized domestic pigs

Increasing use of pigs as models in translational research, and growing focus on animal welfare are leading to better use of effective analgesics and anaesthetics when painful procedures are performed. However, there is a gap in basic knowledge such as pharmacokinetics of different anaesthetics in these species. The main objective of our study was to determine the pharmacokinetics of levobupivacaine in domestic pigs. Twelve female grower pigs weighing 31.17 ± 4.6 kg were subjected to general anaesthesia and experimental surgery, at the end of which they received 1 mg/kg levobupivacaine via peri-incisional subcutaneous infiltration. Plasma samples were collected before administration of levobupivacaine and at 0.5, 1, 2, 4, 8, 12, 24 and 48 h thereafter. Concentrations of levobupivacaine were determined by liquid chromatography coupled with tandem mass spectrometry. Following single dose of levobupivacaine, all animals had measurable plasma concentrations 0.5 h after drug administration, with most peak concentrations observed at the 1-h time point. In all 12 animals, levobupivacaine was below the limit of quantification 48 h after drug administration. The mean maximum plasma concentration, area under the curve and half-life were determined to be 809.98 μg/l, 6552.46 μg/l h and 6.25 h, respectively. Plasma clearance, volume of distribution and weight-normalized volume of distribution were 4.41 l/h, 35.57 l and 1.23 l/kg, respectively. Peak plasma concentrations in our study were well below concentrations that were found to produce toxicity in pigs.

Examining the Severity and Progression of Illicitly Manufactured Fentanyl Withdrawal: A Quasi-Experimental Comparison

OBJECTIVE

Illicitly manufactured fentanyl has largely replaced heroin throughout the United States. Characteristics of fentanyl-specific withdrawal are not well understood compared to traditional opioid withdrawal. This study examines opioid withdrawal severity among 2 cohorts of study participants who underwent identical morphine stabilization procedures before and after fentanyl was introduced to the local drug market.

METHODS

The Non-Fentanyl study (n = 103) included participants testing positive for non-fentanyl opioids, and the Fentanyl study (n = 30) included participants testing positive for fentanyl. Both studies completed a 7-day morphine stabilization protocol (30 mg subcutaneous, 4 times daily) and multiple daily self-report and observer-rated assessments of opioid withdrawal and vital signs. Two-way repeated-measures analyses of variance (ANOVAs) examined the effects of study, time, and study × time on daily peak ratings for each outcome.

RESULTS

There were significant elevations in self-report and observer-rated withdrawal scores among the Fentanyl versus Non-Fentanyl study (study × time, P < 0.05) during stabilization days 2-5 and days 2-6, respectively. There was a higher rate of tachycardia among the Fentanyl group compared to the Non-Fentanyl study, and peak diastolic blood pressure was greater among the Fentanyl study compared to the Non-Fentanyl study.

CONCLUSIONS

Individuals with fentanyl exposure were less stabilized by morphine and experienced more severe opioid withdrawal via several metrics compared to persons with non-fentanyl opioid exposure. Withdrawal also remained elevated for several days despite morphine initiation. Adjustments to existing treatment induction protocols may be needed given the permeation of fentanyl into the heroin supply.

Nanotechnology in Pain Management

Chronic pain is a debilitating condition that affects millions of patients worldwide, contributing to a high disease burden and millions of dollars in lost wages, missed workdays, and healthcare costs. Opioids, NSAIDs, acetaminophen, gabapentinoids, muscle relaxants, anticonvulsants, and antidepressants are the most used medications for chronic pain and carry significant side effects, including gastric bleeding, hepatotoxicity, stroke, kidney damage, constipation, dizziness, and arrhythmias. Opioids in particular carry the risk of long-term dependence, drug tolerance, and overdose. In 2022, 81,806 people died from opioid overdose in the United States alone. Alternative treatments for chronic pain are critically needed, and nanotechnology has emerged as a promising means of achieving effective long-term analgesia while avoiding the adverse side effects associated with conventional pharmacological agents. Nanotechnology-based treatments include liposomes, Poly Lactic-co-Glycolic Acid (PLGA) and other polymeric nanoparticles, and carbon-based polymers, which can help mitigate those adverse side effects. These nanomaterials can serve as drug delivery systems that facilitate controlled release and drug stability via the encapsulation of free molecules and protein-based drugs, leading to longer-lasting analgesia and minimizing side effects. In this review, we examine the role of nanotechnology in addressing concerns associated with conventional chronic pain treatments and discuss the ongoing efforts to develop novel, nanotechnology-based treatments for chronic pain such as nanocapacitor patches, gene therapy, the use of both viral and non-viral vectors, CRISPR, and scavengers.

Estimated clinical utility of multi-gene pharmacogenetic testing in a retrospective cohort of gynecology patients

OBJECTIVE

This study aimed to estimate the clinical utility of performing multi-gene pharmacogenetic testing on patients undergoing gynecologic surgery/procedure by evaluating the prescribing rate of Clinical Pharmacogenetics Implementation Consortium (CPIC) level A medications and frequency of drug-gene interactions (DGIs).

METHODS

The electronic health record was queried for 76 current procedural terminology codes to identify gynecologic surgeries/procedures that occurred between 1 January 2015 to 31 December 2020 in patients with at least one of 152 international classification of disease codes. Prescription data for CPIC level A medications was extracted. Those enrolled in the Penn Medicine Biobank were assessed for DGIs.

RESULTS

The cohort consisted of 7798 female patients and 682 were in the biobank. Up to 6 years following their surgery or procedure, 80% were ordered ≥1 CPIC level A medication. Over half (54%) of these medications were ordered within 3 days after their surgery or procedure. The most common CPIC level A medications ordered were ibuprofen (57%) and ondansetron (42%). Overall, 7% of the cohort had ≥1 known or predicted DGI with medications they were prescribed.

CONCLUSION

Multi-gene pharmacogenetic testing may be beneficial to gynecologic surgery/procedure patients by assisting clinicians with prescribing postoperative analgesics and future medications.

Opioid metabolism and drug-drug interaction in cancer

Concomitant use of multiple drugs in most patients with cancer may result in drug-drug interactions (DDIs), potentially causing serious adverse effects. These patients often experience unrelieved cancer-related pain (CRP) during and after cancer treatment, which can lead to a reduced quality of life. Opioids can be used as part of a multimodal pain management strategy when non-opioid analgesics are not providing adequate pain relief, not tolerated, or are contraindicated. However, due to their narrow therapeutic window, opioids are more susceptible to adverse events when a DDI occurs. Clinically relevant DDIs with opioids are usually pharmacokinetic, mainly occurring via metabolism by cytochrome P450 (CYP). This article aims to provide an overview of potential DDIs with opioids often used in the treatment of moderate-to-severe CRP and commonly used anticancer drugs such as chemotherapeutics, tyrosine kinase inhibitors (TKIs), or biologics. A DDI-checker tool was used to contextualize the tool-informed DDI assessment outcomes with clinical implications and practice. The findings were compared to observations from a literature search conducted in Embase and PubMed to identify clinical evidence for these potential DDIs. The limited results mainly included case studies and retrospective reviews. Some potential DDIs on the DDI-checker were aligned with literature findings, while others were contradictory. In conclusion, while DDI-checkers are useful tools in identifying potential DDIs, it is necessary to incorporate literature verification and comprehensive clinical assessment of the patient before implementing tool-informed decisions in clinical practice.

The Role of Pain Medications in Modulating Peripheral Nerve Injury Recovery

Peripheral nerve injuries (PNIs) are common, costly, and cause significant pain. Effective management of PNIs involves tailoring medications to the injury type as well as understanding the pharmacokinetics/pharmacodynamics to support nerve regeneration and reduce pain. Opioids act on opioid receptors to significantly reduce pain for many patients, but there are significant addiction risks and side effects. In addition, opioids may exacerbate pain sensitivity and affect nerve regeneration. Non-steroidal anti-inflammatory drugs or acetaminophen act on cyclooxygenase enzymes and are commonly used for nerve pain, with 34.7% of people using them for neuropathic pain. While effective for mild pain, they are often combined with opioids, gamma-aminobutyric acid (GABA) analogs, lidocaine, or corticosteroids for more severe pain. Corticosteroids, mimicking adrenal hormones like cortisol, treat PNI-related inflammation and pain. Their pharmacokinetics are complex, often requiring local injections in order to minimize systemic risks while effectively treating PNIs. Lidocaine, a common local anesthetic, blocks ion channels in the central nervous system (CNS) and peripheral nerves, providing strong analgesic and anti-inflammatory effects. If used improperly, lidocaine can cause neuronal toxicity instead of anesthetic effect. GABA acts as an inhibitory neurotransmitter in the CNS and its drug analogs like pregabalin and gabapentin can alleviate neuropathic pain by binding to voltage-gated Ca2+ channels, inhibiting neurotransmitter release. These pain medications are commonly prescribed for PNIs despite a limited guidance on their effects on nerve regeneration. This review will discuss these drug's mechanisms of action, pharmacokinetics/pharmacodynamics, and their clinical application to highlight their effect on the PNI recovery.

Understanding the impact of the gut microbiome on opioid use disorder: Pathways, mechanisms, and treatment insights

The widespread use of opioids for chronic pain management not only poses a significant public health issue but also contributes to the risk of tolerance, dependence, and addiction, leading to opioid use disorder (OUD), which affects millions globally each year. Recent research has highlighted a potential bidirectional relationship between the gut microbiome and OUD. This emerging perspective is critical, especially as the opioid epidemic intensifies, emphasizing the need to investigate how OUD may alter gut microbiome dynamics and vice versa. Understanding these interactions could reveal new insights into the mechanisms of addiction and tolerance, as well as provide novel approaches for managing and potentially mitigating OUD impacts. This comprehensive review explores the intricate bidirectional link through the gut-brain axis, focusing on how opiates influence microbial composition, functional changes, and gut mucosal integrity. By synthesizing current findings, the review aims to inspire new strategies to combat the opioid crisis and leverage microbiome-centred interventions for preventing and treating OUD.

Treatment of Pain in Cirrhosis: Advice to Caregivers of Those with Rock Livers

PURPOSE

When one considers the significant role of the liver in medication absorption and metabolism, clinicians must appreciate the important ramifications for medication dosing and monitoring in patients with cirrhosis. For many medications, dose adjustments may be necessary to minimize toxicities or avoid adverse effects from drug accumulation. Clinicians could be well served if they can understand in some detail how pharmacokinetic properties are altered in cirrhosis.

METHODS

A PubMed search of the English medical literature starting with 1980 using keywords cirrhosis, pain management, and analgesics was performed, and additional papers were found using references from the first round of papers.

FINDINGS

Patients with cirrhosis often have significant reductions in first-pass metabolism, altered volumes of distribution, and marked reductions in both renal and hepatic elimination of drugs. These factors may contribute to much higher levels of drug exposure compared to the general population. In terms of drug dosing, FDA labeling is often ambiguous and even incongruous with observed pharmacokinetic changes.

IMPLICATIONS

This article may provide guidance for clinicians to optimize pain management in people living with cirrhosis.

KEY MESSAGE

Current FDA labeling for dosing analgesic drugs in patients with cirrhosis is either vague or not consistent with findings from newer pharmacokinetic research. With this review, we hope to provide insight and guidance to clinicians on how to dose-adjust medications commonly utilized in pain management in these patients.

Case Series: Hepatic and Splenic Titanium Dioxide Deposition in Association With Intravenous Drug Use

ABSTRACT

Titanium dioxide is a versatile compound that is found in a variety of consumer products, medical hardware, and pharmaceuticals. Although oral and topical ingestion of this compound is common, intravenous introduction is much less common. We present three cases where significant titanium dioxide deposits were identified in liver and splenic tissue of three decedents, all of whom died of illicit drug overdose in the same geographic area and had fentanyl and its metabolites in blood on postmortem toxicologic testing. At autopsy, liver sections had a granular texture with fine white stippling grossly, and histologic examination of hepatic and splenic tissues showed scattered patches of black granular material with pink birefringence. Energy-dispersive x-ray spectroscopy performed on these tissues revealed the presences of clusters of titanium dioxide. Immunohistochemical staining of both the liver and spleen with CD68 confirmed the titanium dioxide clusters were within macrophages. Intravenous titanium dioxide nanoparticle elimination studies in rats suggest a time sensitive period for this elimination, with a transient period of pigment deposition between 1-58 days following injection. If a time-dependent link between titanium dioxide pigment deposition within tissues and intravenous drug use can be shown, this could be a valuable tool for Pathologists.

Mitigating Medication Tampering and Diversion via Real-Time Intravenous Opioid Quantification

Opioid tampering and diversion pose a serious problem for hospital patients with potentially life-threatening consequences. The ongoing opioid crisis has resulted in medications used for pain management and anesthesia, such as fentanyl and morphine, being stolen, substituted with a different substance, and abused. This work aims to mitigate tampering and diversion through analytical verification of the administered drug before it enters the patient. We present an electrochemical-based sensor and miniaturized wireless potentiostat that enable real-time intravenous (IV) monitoring of opioids, specifically fentanyl and morphine. The proposed system is connected to an IV drip system during surgery or post-operation recovery. Measurement results of two opioids are presented, including calibration curves and data on the sensor performance concerning pH, temperature, interference, reproducibility, and long-term stability. Finally, we demonstrate real-time fluidic measurements connected to a flow cell to simulate IV administration and a blind study classified using a machine-learning algorithm. The system achieves limits of detection (LODs) of 1.26 µg/mL and 2.75 µg/mL for fentanyl and morphine, respectively, while operating with >1-month battery lifetime due to an optimized ultra-low power 36 µA sleep mode.

Clinical and Adverse Outcomes Associated With Concomitant Use of CYP2D6-Metabolized Opioids With Antidepressants in Older Nursing Home Residents : A Target Trial Emulation Study

BACKGROUND

Limited evidence exists on the safety of pharmacokinetic interactions of cytochrome P450 (CYP) 2D6 (CYP2D6)-metabolized opioids with antidepressants among older nursing home (NH) residents.

OBJECTIVE

To investigate the associations of concomitant use of CYP2D6-metabolized opioids and antidepressants with clinical outcomes and opioid-related adverse events (ORAEs).

DESIGN

Retrospective cohort study using a target trial emulation framework.

SETTING

100% Medicare NH sample linked to Minimum Data Set (MDS) from 2010 to 2021.

PARTICIPANTS

Long-term residents aged 65 years and older receiving CYP2D6-metabolized opioids with a disease indication for antidepressant use.

INTERVENTION

Initiating CYP2D6-inhibiting versus CYP2D6-neutral antidepressants that overlapped with use of CYP2D6-metabolized opioids for 1 day or more.

MEASUREMENTS

Clinical outcomes were worsening pain, physical function, and depression from baseline to quarterly MDS assessments and were analyzed using modified Poisson regression models. The ORAE outcomes included counts of pain-related hospitalizations and emergency department (ED) visits, opioid use disorder (OUD), and opioid overdose and were analyzed with negative binomial or Poisson regression models. All models were adjusted for baseline covariates via inverse probability of treatment weighting.

RESULTS

Among 29 435 identified residents, use of CYP2D6-metabolized opioids concomitantly with CYP2D6-inhibiting (vs. CYP2D6-neutral) antidepressants was associated with a higher adjusted rate ratio of worsening pain (1.13 [95% CI, 1.09 to 1.17]) and higher adjusted incidence rate ratios of pain-related hospitalization (1.37 [CI, 1.19 to 1.59]), pain-related ED visit (1.49 [CI, 1.24 to 1.80]), and OUD (1.93 [CI, 1.37 to 2.73]), with no difference in physical function, depression, and opioid overdose.

LIMITATION

Findings are generalizable to NH populations only.

CONCLUSION

Use of CYP2D6-metabolized opioids concomitantly with CYP2D6-inhibiting (vs. CYP2D6-neutral) antidepressants was associated with worsening pain and increased risk for most assessed ORAEs among older NH residents.

PRIMARY FUNDING SOURCE

National Institute on Aging.

Implementing a pragmatic clinical trial to tailor opioids for chronic pain on behalf of the IGNITE ADOPT PGx investigators

Chronic pain is a prevalent condition with enormous economic burden. Opioids such as tramadol, codeine, and hydrocodone are commonly used to treat chronic pain; these drugs are activated to more potent opioid receptor agonists by the hepatic CYP2D6 enzyme. Results from clinical studies and mechanistic understandings suggest that CYP2D6-guided therapy will improve pain control and reduce adverse drug events. However, CYP2D6 is rarely used in clinical practice due in part to the demand for additional clinical trial evidence. Thus, we designed the ADOPT-PGx (A Depression and Opioid Pragmatic Trial in Pharmacogenetics) chronic pain study, a multicenter, pragmatic, randomized controlled clinical trial, to assess the effect of CYP2D6 testing on pain management. The study enrolled 1048 participants who are taking or being considered for treatment with CYP2D6-impacted opioids for their chronic pain. Participants were randomized to receive immediate or delayed (by 6 months) genotyping of CYP2D6 with clinical decision support (CDS). CDS encouraged the providers to follow the CYP2D6-guided trial recommendations. The primary study outcome is the 3-month absolute change in the composite pain intensity score assessed using Patient-Reported Outcomes Measurement Information System (PROMIS) measures. Follow-up will be completed in July 2024. Herein, we describe the design of this trial along with challenges encountered during enrollment.

The role of drug efflux and uptake transporters in the plasma pharmacokinetics and tissue disposition of morphine and its main metabolites

Morphine is a widely used opioid for the treatment of pain. Differences in drug transporter expression and activity may contribute to variability in morphine pharmacokinetics and response. Using appropriate mouse models, we investigated the impact of the efflux transporters ABCB1 and ABCG2 and the OATP uptake transporters on the pharmacokinetics of morphine, morphine-3-glucuronide (M3G), and M6G. Upon subcutaneous administration of morphine, its plasma exposure in Abcb1a/1b-/-;Abcg2-/--, Abcb1a/1b-/-;Abcg2-/-;Oatp1a/1b-/-;Oatp2b1-/- (Bab12), and Oatp1a/1b-/-;Oatp2b1-/- mice was similar to that found in wild-type mice. Forty minutes after dosing, morphine brain accumulation increased by 2-fold when mouse (m)Abcb1 and mAbcg2 were ablated. Relative recovery of morphine in small intestinal content was significantly reduced in all the knockout strains. In the absence of mOatp1a/1b and mOatp2b1, plasma levels of M3G were markedly increased, suggesting a lower elimination rate. Moreover, Oatp-deficient mice displayed reduced hepatic and intestinal M3G accumulation. Mouse Oatps similarly affected plasma and tissue disposition of subcutaneously administered M6G. Human OATP1B1/1B3 transporters modestly contribute to the liver accumulation of M6G. In summary, mAbcb1, in combination with mAbcg2, limits morphine brain penetration and its net intestinal absorption. Variation in ABCB1 activity due to genetic polymorphisms/mutations and/or environmental factors might, therefore, partially affect morphine tissue exposure in patients. The ablation of mOatp1a/1b increases plasma exposure and decreases the liver and small intestinal disposition of M3G and M6G. Since the contribution of human OATP1B1/1B3 to M6G liver uptake was quite modest, the risks of undesirable drug interactions or interindividual variation related to OATP activity are likely negligible.

Metabolic characterization of the new benzimidazole synthetic opioids - nitazenes

The recent re-emergence and the increasing popularity of nitazenes, a group of new synthetic opioids (NSO) that belong to the benzimidazole chemical class, has raised public health concerns. As a class of potential opioid analgesic agents whose development was discontinued in the 1960s due to their high potential for abuse, very little is known about their metabolism and physiologic disposition. In the current study, three nitazenes-butonitazene, isotonitazene and protonitaze were incubated in human liver microsomes (HLM), human S9 (HS9) fractions and recombinant cytochrome P450 enzymes. All three nitazenes were rapidly metabolized in both HLM and HS9 with over 95% depletion within 60 min. In HLM, butonitazene, isotonitazene and protonitazene had in vitro intrinsic clearance (CLint) (µL/min/mg protein) values of 309, 221 and 216 respectively compared to 150 of verapamil, the positive control. In HS9, CLint values were 217, 139, and 150 for butonitazene, isotonitazene and protonitazene respectively compared to only 35 for testosterone, the control probe substrate. Putative metabolite identified from this study include products of hydroxylation, desethylation, dealkylation, desethylation followed by dealkylation, and desethylation followed by hydroxylation. The metabolic phenotyping showed CYP2D6, CYP2B6 and CYP2C8 and the major hepatic enzymes responsible for the metabolism of nitazenes. Within 30 min of incubation, CYP2D6 depleted butonitazene (99%), isotonitazene (72%) and butonitazene (100%) significantly. The rapid metabolism of nitazenes may be an important factor in accurate and timely detections and quantitation of the unchanged drugs in human matrices following intoxication or in forensic analysis. The involvement of multiple polymorphic CYPs in their metabolism may play important roles in the susceptibility to intoxication and/or addiction, depending on the activity of the metabolites.

Fentanyl Overdose Causes Prolonged Cardiopulmonary Dysregulation in Male SKH1 Mice

Fentanyl overdose is a survivable condition that commonly resolves without chronic overt changes in phenotype. While the acute physiological effects of fentanyl overdose, such as opioid-induced respiratory depression (OIRD) and Wooden Chest Syndrome, represent immediate risks of lethality, little is known about longer-term systemic or organ-level impacts for survivors. In this study, we investigated the effects of a single, bolus fentanyl overdose on components of the cardiopulmonary system up to one week post. SKH1 mice were administered subcutaneous fentanyl at the highest non-lethal dose (62 mg/kg), LD10 (110 mg/kg), or LD50 (135 mg/kg), before euthanasia at 40 min, 6 h, 24 h, or 7 d post-exposure. The cerebral cortex, heart, lungs, and plasma were assayed using an immune monitoring 48-plex panel. The results showed significantly dysregulated cytokine, chemokine, and growth factor concentrations compared to time-matched controls, principally in hearts, then lungs and plasma to a lesser extent, for the length of the study, with the cortex largely unaffected. Major significant analytes contributing to variance included eotaxin-1, IL-33, and betacellulin, which were generally downregulated across time. The results of this study suggest that cardiopulmonary toxicity may persist from a single fentanyl overdose and have wide implications for the endurance of the expanding population of survivors.

Use of CYP2D6 substrates and inhibitors during pain management with analgesic opioids: Drug-drug interactions that lead to lack of analgesic effectiveness

BACKGROUND

Several opioids have pharmacogenetic and drug-drug interactions which may compromise their analgesic effectiveness, but are not routinely implemented into supportive pain management. We hypothesized that CYP2D6 phenotypes and concomitant use of CYP2D6 substrates or inhibitors would correlate with opioid analgesic outcomes.

MATERIALS AND METHODS

An observational cross-sectional study was conducted with 263 adult chronic non cancer pain (CNCP) patients from a real-world pain unit under long-term CYP2D6-related opioid treatment (tramadol, hydromorphone, tapentadol or oxycodone). Metabolizer phenotype (ultrarapid [UM], normal [NM], intermediate [IM] or poor [PM]) was determined by the CYP2D6 genotype. The socio-demographic (sex, age, employment status), clinical (pain intensity and relief, neuropathic component, quality of life, disability, anxiety and depression), pharmacological (opioid doses and concomitant pharmacotherapy) and safety (adverse events) variables were recorded.

RESULTS

The whole population (66 % female, 65 (14) years old, 70 % retired and 63 % attended for low back pain) were classified as PM (5 %), IM (32 %), NM (56 %) and UM (6 %). Multiple linear and logistic regressions showed higher pain intensity and neuropathic component at younger ages when using any CYP2D6 substrate (p = 0.022) or inhibitor (p = 0.030) drug, respectively, with poorer pain relief when CYP2D6 inhibitors (p=0.030) were present.

CONCLUSION

The concomitant use of CYP2D6 substrates or inhibitors during opioid therapy for CNCP may result in lack of analgesic effectiveness. This aspect could be relevant for pharmacological decision making during CNCP management.

Gene polymorphism impact on opioid analgesic usage

Acute pain, moderate-to-severe cancer pain, and persistent malignant pain are all frequently treated with opioids. It is regarded as one of the main tenets of analgesic treatment. The relationship between human opioid sensitivity and genetic polymorphism differences has received little attention up to this point in research. Nonetheless, there is mounting proof that pharmacogenomic diversity could affect how each person reacts to opioids. Finding out how gene polymorphism affects analgesic use is the aim of this investigation, particularly opioids. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses standards were followed in the preparation of the systematic review approach used in this work. Oxycodone, fentanyl, raclopride, tramadol, ketorolac, morphine, ropivacaine, levobupivacaine, subfentanyl, remifentanil, and nortriptyline were the opioid medications used in the study, which was based on 13 publications. From those articles, we reviewed the impact of gene polymorphism on pain management and drug pharmacokinetics. Based on this systematic review, we concluded that gene polymorphism of gene affects analgesic, specifically opioid mechanisms.

Enzalutamide: Understanding and Managing Drug Interactions to Improve Patient Safety and Drug Efficacy

Enzalutamide is an oral androgen receptor signaling inhibitor utilized in the treatment of men with prostate cancer. It is a moderate inducer of the cytochrome P450 (CYP) enzymes CYP2C9 and CYP2C19, and a strong inducer of CYP3A4. It was also shown to be a mild inhibitor of the efflux transporter P-glycoprotein in patients with prostate cancer. Enzalutamide is primarily metabolized by CYP3A4 and CYP2C8. The risk of enzalutamide drug interactions arises primarily when it is coadministered with other drugs that interact with these CYPs, including CYP3A4. In this review, we begin by providing an overview of enzalutamide including its dosing, use in special populations, pharmacokinetics, changes to its prescribing information, and potential for interaction with coadministered drugs. Enzalutamide interactions with drugs from a wide range of medication classes commonly prescribed to patients with prostate cancer are described, including oral androgen deprivation therapy, agents used to treat a range of cardiovascular diseases, antidiabetic drugs, antidepressants, anti-seizure medications, common urology medications, analgesics, proton pump inhibitors, immunosuppressants, and antigout drugs. Enzalutamide interactions with common vitamins and supplements are also briefly discussed. This review provides a resource for healthcare practitioners and patients that will help provide a basis for the understanding and management of enzalutamide drug-drug interactions to inform decision making, improve patient safety, and optimize drug efficacy.

Socioeconomic and racial disparities in revisits, indication, and readmission or reoperation in pediatric tonsillectomy

INTRODUCTION

Pediatric tonsillectomy is a frequent otolaryngologic procedure. This study aimed to characterize disparities in post-tonsillectomy revisits, including emergency department evaluation, readmission, or reoperation as well as indication for revisit.

METHODS

Cases of inpatient and ambulatory pediatric tonsillectomy in New York and Florida in 2016 constituted the analytic sample. Patients were extracted from the State Ambulatory Surgery Databases (SASD) and State Inpatient Databases (SID) and linked to the SID and State Emergency Department Database (SEDD) and SASD. Outcomes include 3 types of revisits within 30 days: ED visits, hospital readmissions, and reoperation. Indication for revisit was also analyzed. Multivariable analysis determined the association of each outcome with gender, age, race/ethnicity, primary payer, urbanicity, and zip code median household income quartile. The Holm Bonferroni test was used to correct for multiple hypothesis testing.

RESULTS

15,264 pediatric tonsillectomies were included. The revisit rate was 6.77% (N = 1,034, 49.1% female; 6 years median age [interquartile range: 5]). The 30-day ED revisit rate was 4.85%, readmission rate was 1.27%, and reoperation rate was 0.65%. On multivariate analysis, Latinx patients (OR = 3.042, 95% CI = 1.393-6.803) and those who identify as other race/ethnicity (OR = 6.116, 95% CI = 1.989-19.245) have greater odds of requiring inpatient care for indications including pain, dehydration, nausea, and vomiting compared to white patients. No significant differences in tier of care for the management of post-tonsillectomy hemorrhage were identified.

CONCLUSION

Disparities in pediatric post-tonsillectomy ED presentation, readmission and reoperation demonstrate opportunities to improve patient safety and equity.

Scholarly literature on nurses and pharmacogenomics: A scoping review

BACKGROUND

Pharmacogenomics is the bioscience investigating how genes affect medication responses. Nurses are instrumental in medication safety. Pharmacogenomics is slowly being integrated into healthcare, and knowledge and understanding of it is now pertinent to nursing practice.

PURPOSE

This paper aims to map the scholarly literature on pharmacogenomics in relation to nurses.

METHODS

A scoping review was conducted in four databases: CINAHL, Embase (Ovid), ProQuest Health and Medicine and PubMed using the search terms pharmacogenomic*, pharmacogenetic*, PGx*, and nurs*, resulting in 263 articles of which 77 articles met the inclusion criteria.

FINDINGS

Most articles (85 %, n = 65) were non-empirical and 12 presented empirical data (15 %, n = 12). The articles were USA-centric (81 %, n = 62) and represented a broad range of nursing specialties.

CONCLUSION

The majority of scholarly literature on nurses and pharmacogenomics is narrative reviews. Further empirical research is warranted to investigate nurses' current knowledge levels and potential involvement with pharmacogenomics in clinical practice.

A Pharmacogenomics-Based In Silico Investigation of Opioid Prescribing in Post-operative Spine Pain Management and Personalized Therapy

Considering the variability in individual responses to opioids and the growing concerns about opioid addiction, prescribing opioids for postoperative pain management after spine surgery presents significant challenges. Therefore, this study undertook a novel pharmacogenomics-based in silico investigation of FDA-approved opioid medications. The DrugBank database was employed to identify all FDA-approved opioids. Subsequently, the PharmGKB database was utilized to filter through all variant annotations associated with the relevant genes. In addition, the dpSNP ( https://www.ncbi.nlm.nih.gov/snp/ ), a publicly accessible repository, was used. Additional analyses were conducted using STRING-MODEL (version 12), Cytoscape (version 3.10.1), miRTargetLink.2, and NetworkAnalyst (version 3). The study identified 125 target genes of FDA-approved opioids, encompassing 7019 variant annotations. Of these, 3088 annotations were significant and pertained to 78 genes. During variant annotation assessments (VAA), 672 variants remained after filtration. Further in-depth filtration based on variant functions yielded 302 final filtered variants across 56 genes. The Monoamine GPCRs pathway emerged as the most significant signaling pathway. Protein-protein interaction (PPI) analysis revealed a fully connected network comprising 55 genes. Gene-miRNA Interaction (GMI) analysis of these 55 candidate genes identified miR-16-5p as a pivotal miRNA in this network. Protein-Drug Interaction (PDI) assessment showed that multiple drugs, including Ibuprofen, Nicotine, Tramadol, Haloperidol, Ketamine, L-Glutamic Acid, Caffeine, Citalopram, and Naloxone, had more than one interaction. Furthermore, Protein-Chemical Interaction (PCI) analysis highlighted that ABCB1, BCL2, CYP1A2, KCNH2, PTGS2, and DRD2 were key targets of the proposed chemicals. Notably, 10 chemicals, including carbamylhydrazine, tetrahydropalmatine, Terazosin, beta-methylcholine, rubimaillin, and quinelorane, demonstrated dual interactions with the aforementioned target genes. This comprehensive review offers multiple strong, evidence-based in silico findings regarding opioid prescribing in spine pain management, introducing 55 potential genes. The insights from this report can be applied in exome analysis as a pharmacogenomics (PGx) panel for pain susceptibility, facilitating individualized opioid prescribing through genotyping of related variants. The article also points out that African Americans represent an important group that displays a high catabolism of opioids and suggest the need for a personalized therapeutic approach based on genetic information.

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.

Development and validation of an LC-MS/MS method for quantifying diamorphine and its major metabolites 6-monoacetylmorphine, morphine, morphine-3-glucuronide, and morphine-6-glucuronide in human plasma

Diamorphine, commonly known as heroin, is a semi-synthetic opioid analgesic. In the context of heroin-assisted treatment for opioid-dependent patients, diamorphine is mostly administered intravenously. However, recent attention has shifted towards intranasal administration as a better-tolerated alternative to the intravenous route. Here, we developed and validated a rapid bioanalytical method for the simultaneous quantification of diamorphine and its major metabolites 6-monoacetylmorphine, morphine, morphine-3-glucuronide, and morphine-6-glucuronide in human plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A straightforward protein precipitation extraction step was used for sample preparation. Chromatographic analyte separation was achieved using a Kinetex EVO C18 analytical column and a mobile phase gradient comprising an aqueous solution of ammonium hydrogen carbonate and methanol supplied with formic acid. Employing positive electrospray ionization and scheduled multiple reaction monitoring, we established a quantification range of 1-1,000 ng/mL for all analytes. Our validation results demonstrate a mean intra-assay accuracy of 91-106% and an intra-assay precision (CV) between 2 and 9% for all analytes and over three validation runs. The method exhibits a high extraction recovery (> 87%) and a negligible matrix effect (99-125%). Furthermore, no interferences with endogenous plasma compounds were detected. Lastly, we applied the method to assess the plasma concentrations of an opioid-dependent patient after the intranasal administration of diamorphine in a clinical study. In summary, we have successfully developed a rapid, highly reliable, and straightforward bioanalytical method for quantifying diamorphine and its metabolites in low amounts of clinical plasma samples.

Evaluating Sedation Strategies for Magnetic Resonance Imaging: A Comprehensive Review of Intravenous Fentanyl, Butorphanol, and Midazolam in Adult and Pediatric Populations

Magnetic resonance imaging (MRI) is a critical diagnostic tool that often requires patient sedation to ensure optimal image quality and patient comfort, particularly in those with anxiety or an inability to remain still. This comprehensive review examines the efficacy, safety, and practical considerations of three commonly used intravenous sedatives, namely, fentanyl, butorphanol, and midazolam, in adult populations undergoing MRI procedures. This review highlights the pharmacological profiles, advantages, and limitations associated with each sedative agent through a detailed analysis of current literature, clinical guidelines, and practice-based evidence. Fentanyl is noted for its potent analgesic properties and rapid onset of action, making it suitable for painful procedures. Butorphanol, with its unique opioid agonist-antagonist activity, presents an alternative with a balance between analgesia and sedation, potentially offering a safer profile for certain patient populations. Midazolam, widely recognized for its anxiolytic and amnestic effects, remains a staple in managing procedure-related anxiety. The review further discusses patient selection criteria, dosing strategies, and the importance of individualized sedation planning to enhance patient experience and procedural outcomes. Future directions highlight the potential of emerging sedation agents and non-pharmacological approaches to improve patient comfort and compliance. The findings underscore the necessity for healthcare providers to adapt sedation practices to the specific needs of each patient, considering both the clinical context and the inherent characteristics of the sedative agents. This review aims to guide clinicians in selecting the most appropriate sedation strategy for adult patients undergoing MRI, optimizing patient care and diagnostic efficacy.

Older adult drug overdose: an application of latent class analysis to identify prevention opportunities

BACKGROUND

Older adult overdose death rates have increased significantly in recent years. However, research for prevention of drug overdose death specific to older adults is limited. Our objective is to identify profiles based on missed intervention points (touchpoints) to inform prevention of future older adult unintentional overdose deaths.

METHODS

We used latent class analysis methods to identify profiles of decedents aged 55 + years in the Illinois Statewide Unintentional Drug Overdose Reporting System. This system collects data on 92.6% of all unintentional overdose deaths in Illinois and includes data from death certificates, coroner/medical examiner, toxicology, and autopsy reports. Data include decedent demographics, circumstances leading up to and surrounding the fatal overdose and details regarding the overdose. Variables in the latent class analysis model included sex, race, alcohol test result, social isolation, recent emergency department (ED) visit, chronic pain, and pain treatment.

RESULTS

We identified three distinct decent profiles. Class 1 (13% of decedents) included female decedents who were in pain treatment, had physical health problems, and had greater likelihood of a recent ED visit before their death. Class 2 (35% of decedents) decedents were most likely to be socially connected (live with others, employed, had social or family relationships) but less likely to have recent healthcare visits. Class 3 (52% of decedents) decedents had higher social isolation (lived alone, unemployed, unpartnered), were mostly male, had fewer known physical health conditions, and more alcohol positivity at time of death. White decedents are clustered in class 1 while Black decedents are predominant in classes 2 and 3.

CONCLUSIONS

These profiles link to potential touchpoint opportunities for substance use disorder screening harm reduction and treatment. Class 1 members were most likely to be reachable in healthcare settings. However, most decedents were members of Classes 2 and 3 with less engagement in the healthcare system, suggesting a need for screening and intervention in different contexts. For Class 2, intervention touchpoints might include education and screening in work or social settings such as senior centers given the higher degree of social connectivity. For Class 3, the most isolated group, touchpoints may occur in the context of harm reduction outreach and social service delivery.

Impact of a Community Pharmacy Pharmacotherapy Follow-up (PTF) service in patients using opioid analgesic

The use of prescribed major opioid analgesics (fentanyl, tapentadol, morphine and oxycodone and combinations) for non-cancer chronic pain is fraught with risks that may generate Negative Medicine Outcomes (NMO). Among the factors associated with these risks, those related to the patient's characteristics and aberrant behavior, the treatment conditions, and the prescription health settings should be evaluated with the aim of minimizing unsafety during the health care process. The present study addresses, from a community pharmacy, the analysis of Drug Related Problems (DRP) and Negative Medicine Outcomes (NMO) in patients using these major opioid analgesics while it aims to demonstrate the role of pharmaceutical care interventions in promoting safety during the use of these molecules. A three step Pharmacotherapeutic Follow-up (PFT) protocol was designed to prevent, detect, and solve DRP and NMO associated with the use of opioid analgesics. 74.6% of the patients used opioid analgesics to treat musculoskeletal pain. Polypharmacy with benzodiazepines (61.9%); antidepressants (57.1%) and antiepileptics (30.2%) was detected in patients using these opioids. The Morisky-Green Adherence test revealed that 30.2% were nonadherent. It was observed, with statistical significance, that in all patients (63), the impact of the 14-week PFT supervised by the community pharmacist achieved an overall reduction in the prevalence of DRP and NMO. While the reduction in the number of DRPs reached 66.7%. Community pharmacies are a strategic point to promote and implement effective opioid stewardship due to both their central role in healthcare services and frequent interaction with patients.

Mechanisms of pain in aging and age-related conditions: Focus on caregivers

Pain is a complex, subjective experience that can significantly impact quality of life, particularly in aging individuals, by adversely affecting physical and emotional well-being. Whereas acute pain usually serves a protective function, chronic pain is a persistent pathological condition that contributes to functional deficits, cognitive decline, and emotional disturbances in the elderly. Despite substantial progress that has been made in characterizing age-related changes in pain, complete mechanistic details of pain processing mechanisms in the aging patient remain unknown. Pain is particularly under-recognized and under-managed in the elderly, especially among patients with Alzheimer's disease (AD), Alzheimer's disease-related dementias (ADRD), and other age-related conditions. Furthermore, difficulties in assessing pain in patients with AD/ADRD and other age-related conditions may contribute to the familial caregiver burden. The purpose of this article is to discuss the mechanisms and risk factors for chronic pain development and persistence, with a particular focus on age-related changes. Our article also highlights the importance of caregivers working with aging chronic pain patients, and emphasizes the urgent need for increased legislative awareness and improved pain management in these populations to substantially alleviate caregiver burden.

Drug-drug interaction perpetrators of oxycodone in patients with cancer: frequency and clinical relevance

AIM

Oxycodone is known to have numerous drug-drug interactions (DDIs) that can potentially decrease efficacy or lead to adverse drug reactions (ADRs). However, there is limited research on the frequency of DDIs associated with oxycodone, which is important in optimising pharmacovigilance and the need for additional research on certain DDIs. In this study, the frequency of pharmacologically and clinically relevant DDI perpetrators was studied in patients with cancer.

METHODS

This was a cross-sectional study using hospital pharmacy records of patients with cancer who were prescribed oxycodone between September 2021 and September 2022. Medication records of patients prescribed oxycodone during a period of ≥ 5 consecutive days (= oxycodone treatment episodes) were reviewed to identify the concomitant use of pharmacologically relevant perpetrators, based on reference sources (Lexicomp®, Micromedex®, the Dutch Kennisbank and the Dutch Commentaren Medicatiebewaking). The clinical relevance was examined by a clinical pharmacologist and a medical oncologist. Additionally, the frequency of double interactions-concomitant oxycodone use with two CYP3A4 and / or CYP2D6 perpetrators-was studied.

RESULTS

Overall, 254 oxycodone treatment episodes were included, of which 227 (89.4%) were found to contain at least one pharmacologically relevant DDI perpetrator. Of these, 210 (82.7%) were considered to be clinically relevant. A total of 80 different pharmacologically relevant perpetrators were identified, with 65 (81.3%) being considered clinically relevant. Double interactions were observed in 21 (8.3%) oxycodone treatment episodes.

CONCLUSION

A high frequency of pharmacologically and clinically relevant perpetrators of oxycodone was observed in our cohort. Moreover, a high number of double interactions involving oxycodone was registered. More intense monitoring of DDIs may be needed to improve medication safety of patients with cancer taking oxycodone.

Pain management considerations in patients living with both pain syndromes and cardiovascular diseases and disorders

Concomitant pain syndromes and cardiovascular disease (CVD) and disorders are associated with significant morbidity, impaired quality of life, and neuropsychiatric disorders. There is an interplay between the mechanisms of pathophysiology of both CVD and pain syndromes. Patients with CVD (and/or disorders) as well as pain syndromes have an increased propensity for drug-drug/disease interactions. Therefore, an understanding of how to use pharmacotherapy to treat pain syndromes, in the context of patients who have diagnoses of CVD and/or disorders, is paramount to patients' success in achieving adequate pain control and appropriately managing CVD and/or disorders, all while decreasing the risk of adverse events (AEs) both from pharmacotherapy to treat pain and CVD (and/or disorders). Based on the appraisal of literature and authors' clinical expertise, it was determined that gabapentinoids, opioids, skeletal muscle relaxants, tricyclic antidepressants, clonidine, serotonin norepinephrine-reuptake inhibitors, dronabinol, carbamazepine, second-generation antipsychotics, non-steroidal anti-inflammatory drugs, aspirin, corticosteroids, and topical anesthetics have the most evidence for use in patients with CVD and/or disorders. However, the literature surrounding the use of pharmacotherapy for pain management is limited to retrospective studies and there is a lack of well-designed, prospective, randomized trials; this also includes head-to-head comparator studies. Unlike many CVD-related pharmacotherapy studies, data studying pain management in patients with CVD lacks standardized outcomes that are consistent among the pool of data. Overall, the decision to prescribe specific pain management therapies in patients with CVD and/or disorders should include assessment of pain severity, type of pain, drug-drug/disease interactions, adjuvant therapies required, and the risk or presence of AEs.

Placental cytochrome P450 methylomes in infants exposed to prenatal opioids: exploring the effects of neonatal opioid withdrawal syndrome on health horizons

Background: Neonatal opioid withdrawal syndrome (NOWS), arises due to increased opioid use during pregnancy. Cytochrome P450 (CYP) enzymes play a pivotal role in metabolizing a wide range of substances in the human body, including opioids, other drugs, toxins, and endogenous compounds. The association between CYP gene methylation and opioid effects is unexplored and it could offer promising insights. Objective: To investigate the impact of prenatal opioid exposure on disrupted CYPs in infants and their anticipated long-term clinical implications. Study Design: DNA methylation levels of CYP genes were analyzed in a cohort of 96 placental tissues using Illumina Infinium MethylationEPIC (850 k) BeadChips. This involved three groups of placental tissues: 32 from mothers with infants exposed to opioids prenatally requiring pharmacologic treatment for NOWS, 32 from mothers with prenatally opioid-exposed infants not needing NOWS treatment, and 32 from unexposed control mothers. Results: The study identified 20 significantly differentially methylated CpG sites associated with 17 distinct CYP genes, with 14 CpGs showing reduced methylation across 14 genes (CYP19A1, CYP1A2, CYP4V2, CYP1B1, CYP24A1, CYP26B1, CYP26C1, CYP2C18, CYP2C9, CYP2U1, CYP39A1, CYP2R1, CYP4Z1, CYP2D7P1 and), while 8 exhibited hypermethylation (CYP51A1, CYP26B1, CYP2R1, CYP2U1, CYP4X1, CYP1A2, CYP2W1, and CYP4V2). Genes such as CYP1A2, CYP26B1, CYP2R1, CYP2U1, and CYP4V2 exhibited both increased and decreased methylation. These genes are crucial for metabolizing eicosanoids, fatty acids, drugs, and diverse substances. Conclusion: The study identified profound methylation changes in multiple CYP genes in the placental tissues relevant to NOWS. This suggests that disruption of DNA methylation patterns in CYP transcripts might play a role in NOWS and may serve as valuable biomarkers, suggesting a future pathway for personalized treatment. Further research is needed to confirm these findings and explore their potential for diagnosis and treatment.

Impact of CYP2D6 and CYP2B6 phenotypes on the response to tramadol in patients with acute post-surgical pain

Tramadol is an important minor opioid prescribed for pain management. In this study, we analyzed the well-known impact of CYP2D6 genetic variation and 60 additional variants in eight candidate genes (i.e., ABCG2, SLCO1B1, CYP2D6, CYP2B6, CYP2C19, CYP2C9, CYP3A5, and CYP3A4) on tramadol efficacy and safety. Some 108 patients with pain after surgery admitted to a post-anesthesia care unit (PACU) and prescribed tramadol were recruited. They were genotyped, and tramadol M1/M2 metabolite concentrations were determined by a newly validated HPLC-MS/MS method. CYP2D6 intermediate (IM) and poor (PM) metabolizers showed lower M1 concentrations adjusted for dose/weight at 30 and 120 min compared to ultrarapid (UM) and normal (NM) metabolizers (univariate p < 0.001 and 0.020, multivariate p < 0.001 and 0.001, unstandardized β coefficients = 0.386 and 0.346, R2  = 0.146 and 0.120, respectively). CYP2B6 PMs (n = 10) were significantly related to a higher reduction in pain 30 min after tramadol intake (univariate p = 0.038, multivariate p = 0.016, unstandardized β coefficient = 0.224, R2  = 0.178), to lower PACU admission time (p = 0.007), and to lower incidence of adverse drug reactions (p = 0.038) compared to the other phenotypes. CYP3A4 IMs and PMs showed a higher prevalence of drowsiness and dizziness (p = 0.028 and 0.005, respectively). Our results suggest that the interaction of CYP2B6 and CYP2D6 phenotypes may be clinically relevant, pending validation of these results in large, independent cohorts. Additional research is required to clarify the impact of CYP3A4 genetic variation on tramadol response.

Efficacy and Safety of Analgesics and Sedatives during Radiofrequency Catheter Ablation of Atrial Fibrillation: A Network Meta-Analysis

Background

Atrial fibrillation is the most common tachyarrhythmia, while catheter ablation is an effective therapy for atrial fibrillation. However, pain and nervousness may occur during the procedure. Moreover, a consensus has still not been reached on which is the best kind of analgesic and sedative to use in these procedures. Therefore, we conducted a network meta-analysis to evaluate the efficacy and safety of analgesics and sedatives used in catheter ablation for atrial fibrillation.

Methods

We searched PubMed, Cochrane Library, Web of Science, EMBASE, China National Knowledge Infrastructure, and Baidu Wenku document download website for randomized controlled trials from their inception to February 26, 2023. Only studies that made comparisons among analgesics or sedatives and involved patients with atrial fibrillation undergoing radiofrequency catheter ablation were included. The efficacy endpoints were Ramsay sedation scores and visual analog scale scores during the radiofrequency catheter ablation for atrial fibrillation. The safety endpoints were the incidence of respiratory depression, hypotension, nausea, and vomiting. Pairwise comparisons and frequency method analyses were conducted. Results were reported as odds ratio (OR), mean difference (MD), and corresponding 95% confidence intervals (CIs). We assessed the risk bias of the studies in accordance with the Cochrane Handbook for Systematic Reviews of Interventions.

Results

Out of the 709 articles initially retrieved, 14 studies, with a total of 1156 participants, were included. In terms of efficacy, patients receiving dexmedetomidine during radiofrequency ablation for atrial fibrillation had higher Ramsay sedation scores than those receiving midazolam plus fentanyl, or its derivatives (MD -0.88, 95% CI [-0.04 to -0.72]). Compared with morphine, dezocine (MD 1.88, 95% CI [1.16 to 2.60]), hydromorphone (MD 4.07, 95% CI [3.56 to 4.58]), butorphanol (MD 3.18, 95% CI [2.38 to 3.96]), and fentanyl or its derivatives (MD 1.57, 95% CI [1.25 to 1.89]) had a better analgesic effect. In terms of safety, propofol (OR 16.46; 95% CI [1.54 to 175.95]) and midazolam plus fentanyl or its derivatives (OR 7.02; 95% CI [1.33 to 36.99]) significantly increased the incidence of respiratory depression compared with dexmedetomidine plus fentanyl or its derivatives. Dexmedetomidine plus fentanyl or its derivatives reduced the incidence of nausea and vomiting compared with fentanyl alone (OR 4.74; 95% CI [1.01 to 22.22]). Propofol was associated with a lower incidence of nausea and vomiting than hydromorphone (OR 0.01; 95% CI [0.00 to 0.59]) and fentanyl or its derivatives (OR 0.01; 95% CI [0.00 to 0.51]). There was no statistically significant difference in the incidence of hypotension between any two strategies.

Conclusions

Hydromorphone and butorphanol had better analgesic effects than fentanyl or its derivates. Dexmedetomidine had better sedative effects. In terms of safety, dexmedetomidine, oxymorphone, and butorphanol were superior. It is necessary to explore the regimen that can consider both the effectiveness and safety during radiofrequency catheter ablation for atrial fibrillation (AF).

The PROSPERO Registration

This study was registered with PROSPERO, number: CRD42023403661.

Quantification of 108 illicit drugs and metabolites in bile matrix by LC-MS/MS for the toxicological testing of sudden death cases

Sudden death could occur after assumption of illicit drugs for recreational purposes in adults or after intoxication in children, and toxicological testing would help identify the cause of the death. Analytical methods sensitive and specific for the quantification of a great number of drugs and metabolites in at least 2 matrices should be used. Bile, collected postmortem, may be considered a specimen alternative to blood and urine to perform toxicological testing because of its extended detection window. The present study proposed a LC-MS/MS method to quantify 108 drugs and metabolites in bile. Compounds belonging to the drugs of abuse classes of amphetamines, benzodiazepines, cocaine derivatives, barbiturates, opioids, z-drugs, and psychedelics were analyzed. The sample preparation is simple and does not require solid-phase extraction. The proposed method showed an appropriate selectivity, specificity, accuracy, and precision of the calibrators and quality controls tested (precision < 15%; accuracy < 100 ± 15%). The sensitivity allowed to identify low amounts of drugs (e.g., morphine limit of detection = 0.2 µg/L; limit of quantification = 1.1 µg/L). There is no significant matrix effect, except for buprenorphine and 11-Nor-9-carboxy-Δ9-tetrahydrocannabinol. Carry-over was not present. Analytes were stable at least for 1 month at - 20 °C. Analyzing 13 postmortem specimens, methadone (50%), and cocaine (37.5%) resulted to be the most prevalent consumed substances; the concentrations quantified in bile resulted to be higher than the ones in blood suggesting bile as a potential new matrix for identifying illicit drugs and their metabolites.

In silico and in vitro metabolism studies of the new synthetic opiate AP-237 (bucinnazine) using bioinformatics tools

The recent emergence of new synthetic opioids (NSOs) compounds in the illicit market is increasingly related to fatal cases. Identification and medical care of NSO intoxication cases are challenging, particularly due to high frequency of new products and extensive metabolism. As the study of NSO metabolism is crucial for the identification of these drugs in cases of intoxication, we aimed to investigate the metabolism of the piperazine NSO AP-237 (= bucinnazine). Two complementary approaches (in silico and in vitro) were used to identify putative AP-237 metabolites which could be used as consumption markers. In silico metabolism studies were realized by combining four open access softwares (MetaTrans, SyGMa, Glory X, Biotransformer 3.0). In vitro experiments were performed by incubating AP-237 (20 µM) in differentiated HepaRG cells during 0 h, 8 h, 24 h or 48 h. Cell supernatant were extracted and analyzed by liquid chromatography coupled to high-resolution mass spectrometry and data were reprocessed using three strategies (MetGem, GNPS or Compound Discoverer®). A total of 28 phase I and six phase II metabolites was predicted in silico. Molecular networking identified seven putative phase I metabolites (m/z 203.154, m/z 247.180, m/z 271.180, two m/z 289.191 isomers, m/z 305.186, m/z 329.222), including four previously unknown metabolites. Overall, this cross-disciplinary approach with molecular networking on data acquired in vitro and in silico prediction enabled to propose relevant candidate as AP-237 consumption markers that could be added to mass spectrometry libraries to help diagnose intoxication.

Opioids and the Kidney: A Compendium

Opioids are a class of medications used in pain management. Unfortunately, long-term use, overprescription, and illicit opioid use have led to one of the greatest threats to mankind: the opioid crisis. Accompanying the classical analgesic properties of opioids, opioids produce a myriad of effects including euphoria, immunosuppression, respiratory depression, and organ damage. It is essential to ascertain the physiological role of the opioid/opioid receptor axis to gain an in-depth understanding of the effects of opioid use. This knowledge will aid in the development of novel therapeutic interventions to combat the increasing mortality rate because of opioid misuse. This review describes the current knowledge of opioids, including the opioid epidemic and opioid/opioid receptor physiology. Furthermore, this review intricately relates opioid use to kidney damage, navigates kidney structure and physiology, and proposes potential ways to prevent opioid-induced kidney damage.

The effect of morphine on rat microglial phagocytic activity: An in vitro study of brain region-, plating density-, sex-, morphine concentration-, and receptor-dependency

Opioids have long been used for clinical pain management, but also have addictive properties that have contributed to the ongoing opioid epidemic. While opioid activation of opioid receptors is well known to contribute to reward and reinforcement, data now also suggest that opioid activation of immune signaling via toll-like receptor 4 (TLR4) may also play a role in addiction-like processes. TLR4 expression is enriched in immune cells, and in the nervous system is primarily expressed in microglia. Microglial phagocytosis is important for developmental, homeostatic, and pathological processes. To examine how morphine impacts microglial phagocytosis, we isolated microglia from adult male and female rat cortex and striatum and plated them in vitro at 10,000 (10K) or 50,000 cells/well densities. Microglia were incubated with neutral fluorescent microbeads to stimulate phagocytosis in the presence of one of four morphine concentrations. We found that the brain region from which microglia are isolated and plating density, but not morphine concentration, impacts cell survival in vitro. We found that 10-12 M morphine, but not higher concentrations, increases phagocytosis in striatal microglia in vitro independent of sex and plating density, while 10-12 M morphine increased phagocytosis in cortical microglia in vitro independent of sex, but contingent on a plating density. Finally, we demonstrate that the effect of 10-12 M morphine in striatal microglia plated at 10 K density is mediated via TLR4, and not μORs. Overall, our data suggest that in rats, a morphine-TLR4 signaling pathway increases phagocytic activity in microglia independent of sex. This may is useful information for better understanding the possible neural outcomes associated with morphine exposures.

Race, Ethnicity, and Sustained Opioid Use After Major Abdominal Surgery for Cancer

Purpose

Sustained opioid use is a well-known complication after surgery. Our objective was to determine whether there is any association between a patient's race or ethnicity and the sustained use of opioids in the year following surgery. Opioid use over the initial 3, 6, and 12 postoperative months was categorized as "sustained early", persistent, and chronic, respectively.

Patients and Methods

Single-institution retrospective study of adults (≥18 years) who had undergone open abdominal surgery for cancer. Multivariable logistic regression was used to evaluate the association between race/ethnicity and opioid use.

Results

Of the 3523 patients included in the study, 2543 (72.2%) were non-Hispanic (NH) White, 476 (13.5%) were Hispanic or Latino, 262 (7.4%) were NH-Black, 186 (5.3%) were Asian, and 56 (1.6%) belonged to other racial or ethnic groups. The overall rates of sustained early, persistent, and chronic opioid use were 15.9%, 7.1%, and 2.6%, respectively. In the multivariable analysis, patient race/ethnicity was associated with sustained early postoperative opioid use (p-value=0.037), with Hispanics/Latinos having significantly higher odds than NH-Whites (OR = 1.382 [95% CI: 1.057-1.808]; p = 0.018). However, neither persistent nor chronic opioid use was associated with race/ethnicity (p = 0.697 and p = 0.443, respectively).

Conclusion

In this retrospective study of adults who had undergone open abdominal surgery, patient race/ethnicity was not consistently associated with the development of sustained opioid use over the first 12 postoperative months.

3-Methoxy-2-phenylimidazo[1,2-b]pyridazines highly active against Mycobacterium tuberculosis and Mycobacterium marinum

A series of 3-methoxy-2-phenylimidazo[1,2-b]pyridazine derivatives which were highly active against autoluminescent Mycobacterium tuberculosis (Mtb) and Mycobacterium marinum (Mm) in an in vitro assay were identified. SAR analysis showed that the most active compounds, which included a phenyl group bearing fluoro substituent(s) at C2, a methoxy function at C3, and a benzyl-heteroatom moiety at C6, exhibited in vitro MIC90 values generally around 0.63-1.26 μM against Mtb and Mm. However, these compounds were inactive against Mtb in vivo (mice), and investigations revealed very short metabolic half-lives (<10 min) when incubated with mouse liver microsomes. Multiple observations of side products produced from oxidative cleavage of the imidazole moiety during the chemical synthesis work suggested that this is a likely metabolic pathway leading to the lack of observed activity in vivo.

Serotonin Syndrome Triggered by an Interaction Between Opioid Analgesics and Cobicistat: A Challenging Diagnostic Case Report

Serotonin syndrome is a clinically diagnosed disorder that may occur secondary to medications that increase the release of endogenous serotonin, impair the reuptake of serotonin from the synaptic cleft, are direct serotonin receptor agonists, or increase the sensitivity of the postsynaptic serotonin receptor. In this case report, we describe the diagnosis of serotonin syndrome in a 60-year-old immunocompromised male. This case is unique, as many of the medications associated with the development of serotonin syndrome in this patient are not typically thought of as being associated with serotonin syndrome, though, in this clinical context, they combined to produce a profound pro-serotonergic effect.

Aversion-associated drug and alcohol seeking in females

Compulsive drug intake is characterized by the continuation of use regardless of negative consequences. This is modeled preclinically using procedures where a negative stimulus is delivered contingently with consumption of the reinforcer. In humans, women and men exhibit different drug taking behavior as it pertains to overall use, withdrawal symptoms, and rate of dependence. In substance use research, females have often been excluded from many studies due to concerns that circulating sex hormones may affect drug seeking behavior. However, the more recent inclusion of females in preclinical studies has identified interesting sex differences in aversion-resistant intake of drugs and alcohol. This review will serve to summarize key findings in aversion-related intake of alcohol, psychostimulants, and opioids in females by examining studies that have included female subjects. Further discussion will examine the effect of intake model, neuroanatomical pathways, and sex hormones in the expression of aversion-resistant drug and alcohol consumption.

Assessment of Drug-Drug Interaction Risk Between Intravenous Fentanyl and the Glecaprevir/Pibrentasvir Combination Regimen in Hepatitis C Patients Using Physiologically Based Pharmacokinetic Modeling and Simulations

INTRODUCTION

An unsafe injection practice is one of the major contributors to new hepatitis C virus (HCV) infections; thus, people who inject drugs are a key population to prioritize to achieve HCV elimination. The introduction of highly effective and well-tolerated pangenotypic direct-acting antivirals, including glecaprevir/pibrentasvir (GLE/PIB), has revolutionized the HCV treatment landscape. Glecaprevir is a weak cytochrome P450 3A4 (CYP3A4) inhibitor, so there is the potential for drug-drug interactions (DDIs) with some opioids metabolized by CYP3A4, such as fentanyl. This study estimated the impact of GLE/PIB on the pharmacokinetics of intravenous fentanyl by building a physiologically based pharmacokinetic (PBPK) model.

METHODS

A PBPK model was developed for intravenous fentanyl by incorporating published information on fentanyl metabolism, distribution, and elimination in healthy individuals. Three clinical DDI studies were used to verify DDIs within the fentanyl PBPK model. This model was integrated with a previously developed GLE/PIB PBPK model. After model validation, DDI simulations were conducted by coadministering GLE 300 mg + PIB 120 mg with a single dose of intravenous fentanyl (0.5 µg/kg).

RESULTS

The predicted maximum plasma concentration ratio between GLE/PIB + fentanyl and fentanyl alone was 1.00, and the predicted area under the curve ratio was 1.04, suggesting an increase of only 4% in fentanyl exposure.

CONCLUSION

The administration of a therapeutic dose of GLE/PIB has very little effect on the pharmacokinetics of intravenous fentanyl. This negligible increase would not be expected to increase the risk of fentanyl overdose beyond the inherent risks related to the amount and purity of the fentanyl received during recreational use.

Enzalutamide Reduces Oxycodone Exposure in Men with Prostate Cancer

BACKGROUND AND OBJECTIVE

Up to 90% of patients with castration-resistant prostate cancer (CRPC) will develop symptomatic bone metastases requiring pain medication, with opioids being the mainstay of therapy in treating moderate and severe pain. Enzalutamide is an androgen receptor antagonist for the treatment of CRPC and a strong inducer of cytochrome P450 (CYP)3A4. Hereby, enzalutamide potentially reduces the exposure of oxycodone, an opioid metabolized by CYP3A4 and CYP2D6. Our objective was to evaluate the potential drug-drug interaction of enzalutamide and oxycodone.

METHODS

A prospective, nonrandomized, open-label, two-arm parallel study was performed. All patients received a single dose of 15 mg normal-release oxycodone. Patients in the enzalutamide arm (ENZ-arm) received enzalutamide 160 mg once daily. Plasma concentrations of oxycodone and its metabolites were quantified using a validated liquid chromatography with tandem mass spectrometry (LC-MS/MS) method.

RESULTS

Twenty-six patients (13 ENZ-arm; 13 control arm) were enrolled in the study. Enzalutamide decreased the mean AUC0-8 h and Cmax of oxycodone with, respectively, 44.7% (p < 0.001) and 35.5% (p = 0.004) compared with the control arm. The AUC0-8 h and Cmax of the active metabolite oxymorphone were 74.2% (p < 0.001) and 56.0% (p = 0.001) lower in the ENZ-arm compared with the control arm. In contrast, AUC0-8 h and Cmax of the inactive metabolites noroxycodone and noroxymorphone were significantly increased by enzalutamide.

CONCLUSION

Co-administration of enzalutamide significantly reduced exposure to oxycodone and its active metabolite oxymorphone in men with prostate cancer. This should be taken into account when prescribing enzalutamide combined with oxycodone.

Optimizing human performance in extreme environments through precision medicine: From spaceflight to high-performance operations on Earth

Humans operating in extreme environments often conduct their operations at the edges of the limits of human performance. Sometimes, they are required to push these limits to previously unattained levels. As a result, their margins for error in execution are much smaller than that found in the general public. These same small margins for error that impact execution may also impact risk, safety, health, and even survival. Thus, humans operating in extreme environments have a need for greater refinement in their preparation, training, fitness, and medical care. Precision medicine (PM) is uniquely suited to address the needs of those engaged in these extreme operations because of its depth of molecular analysis, derived precision countermeasures, and ability to match each individual (and his or her specific molecular phenotype) with any given operating context (environment). Herein, we present an overview of a systems approach to PM in extreme environments, which affords clinicians one method to contextualize the inputs, processes, and outputs that can form the basis of a formal practice. For the sake of brevity, this overview is focused on molecular dynamics, while providing only a brief introduction to the also important physiologic and behavioral phenotypes in PM. Moreover, rather than a full review, it highlights important concepts, while using only selected citations to illustrate those concepts. It further explores, by demonstration, the basic principles of using functionally characterized molecular networks to guide the practical application of PM in extreme environments. At its core, PM in extreme environments is about attention to incremental gains and losses in molecular network efficiency that can scale to produce notable changes in health and performance. The aim of this overview is to provide a conceptual overview of one approach to PM in extreme environments, coupled with a selected suite of practical considerations for molecular profiling and countermeasures.

Synthesis and Modification of Morphine and Codeine, Leading to Diverse Libraries with Improved Pain Relief Properties

Morphine and codeine, two of the most common opioids, are widely used in the clinic for different types of pain. Morphine is one of the most potent agonists for the μ-opioid receptor, leading to the strongest analgesic effect. However, due to their association with serious side effects such as respiratory depression, constriction, euphoria, and addiction, it is necessary for derivatives of morphine and codeine to be developed to overcome such drawbacks. The development of analgesics based on the opiate structure that can be safe, orally active, and non-addictive is one of the important fields in medicinal chemistry. Over the years, morphine and codeine have undergone many structural changes. The biological investigation of semi-synthetic derivatives of both morphine and codeine, especially morphine, shows that studies on these structures are still significant for the development of potent opioid antagonists and agonists. In this review, we summarize several decade-long attempts to synthesize new analogues of morphine and codeine. Our summary placed a focus on synthetic derivatives derived from ring A (positions 1, 2, and 3), ring C (position 6), and N-17 moiety.