Patient-reported pain, satisfaction, adverse effects, and deviations from ambulatory surgery pain medication.

OBJECTIVES: Addressing the challenges of ambulatory surgery involves balancing effective pain relief with minimizing the side effects of pain medication. Due to the heightened risk of opioid abuse, Helsinki University Hospital (Finland) has had a stringent oxycodone prescription policy. This policy prompts an exploration into whether ambulatory surgery patients experience severe post-surgical pain and whether an increase in prescribed opioids would cause elevation in adverse effects. METHODS: This prospective cohort study, with a 1-week follow-up, included 111 adult ambulatory surgery patients (orthopaedics, urology). The patients documented their pain levels within the first postoperative week (using a numerical rating scale [NRS] of 0-10) and pain medication intake up to two days postoperatively. Furthermore, they completed a questionnaire assessing their satisfaction with pain relief, medication-related adverse effects, and adherence to instructions. Medication intake was cross-referenced with the provided instructions and prescriptions. RESULTS: A notable 56% of patients reported experiencing intense pain (NRS ≥5) within a week following surgery. Of these, 52% received a single dose of slow-release oxycodone (5-20 mg) at discharge for use on the night of surgery. Predominantly prescribed pain medications included a combination of paracetamol and codeine (64%) or ibuprofen (62%). Satisfaction rates were high, with 87% expressing satisfaction with pain medication given at hospital discharge and 90% expressing contentment with the prescribed medication. The most common adverse effects were tiredness/grogginess (45%), sleep disturbances (38%), nausea (37%), and constipation (27%). Also, 24% of patients self-reported deviations from medication instructions. A comparison of self-reported and instructed medications revealed that 14% exceeded prescribed dosages, and 28% opted for preparations different from those prescribed. Notably, patients who self-reported deviations from instructions differed from those objectively deviating from instructions. CONCLUSIONS: Although 56% of patients had intense pain, the majority expressed satisfaction with the provided pain relief. Instances of non-adherence to medication instructions were prevalent, often going unnoticed by the patients themselves.

Effect of Oxycodone-Based Multimodal Analgesia on Visceral Pain After Major Laparoscopic Gastrointestinal Surgery: A Randomised, Double-Blind, Controlled Trial.

Purpose: Oxycodone is a potent µ- and κ-opioid receptor agonist that can relieve both somatic and visceral pain. We assessed oxycodone- vs sufentanil-based multimodal analgesia on postoperative pain following major laparoscopic gastrointestinal surgery. Methods: In this randomised double-blind controlled trial, 40 adult patients were randomised (1:1, stratified by type of surgery) to receive oxycodone- or sufentanil-based multimodal analgesia, comprising bilateral transverse abdominis plane blocks, intraoperative dexmedetomidine infusion, flurbiprofen axetil, and oxycodone- or sufentanil-based patient-controlled analgesia. The co-primary outcomes were time-weighted average (TWA) of visceral pain (defined as intra-abdominal deep and dull pain) at rest and on coughing during 0-24 h postoperatively, assessed using the numerical rating scale (0-10) with a minimal clinically important difference of 1. Results: All patients completed the study (median age, 64 years; 65% male) and had adequate postoperative pain control. The mean (SD) 24-h TWA of visceral pain at rest was 1.40 (0.77) in the oxycodone group vs 2.00 (0.98) in the sufentanil group (mean difference=-0.60, 95% CI, -1.16 to -0.03; P=0.039). Patients in the oxycodone group had a significantly lower 24-h TWA of visceral pain on coughing (2.00 [0.83] vs 2.98 [1.26]; mean difference=-0.98, 95% CI, -1.66 to -0.30; P=0.006). In the subgroup analyses, the treatment effect of oxycodone vs sufentanil on the co-primary outcomes did not differ in terms of age (18-65 years or >65 years), sex (female or male), or type of surgery (colorectal or gastric). Secondary outcomes (24-h TWA of incisional and shoulder pain, postoperative analgesic usage, rescue analgesia, adverse events, and patient satisfaction) were comparable between groups. Conclusion: For patients undergoing major laparoscopic gastrointestinal surgery, oxycodone-based multimodal analgesia reduced postoperative visceral pain in a statistically significant but not clinically important manner. Trial Registration: Chinese Clinical Trial Registry (ChiCTR2100052085).

The persistent benefits of decreasing default pill counts for postoperative narcotic prescriptions.

BACKGROUND: In 2017, a university-based academic healthcare system changed the opioid default pill count from 30 to 12 pills. Modifying the electronic default pill count influences short-term clinician prescribing practices. We sought to understand the long-term impact on postoperative opioid prescribing habits after an opioid default pill count reduction. MATERIALS AND METHODS: A retrospective electronic medical record system (EMRS) review was conducted in a healthcare system comprised of seven affiliated hospitals. Patients who underwent a surgical procedure and were prescribed an opioid on discharge between 2017-2021 were evaluated. All prescriptions were converted into morphine equivalents (MME). Analyses were performed with the chi-square test and Bonferonni adjusted t-test. RESULTS: 191,379 surgical procedures were studied. The average quantity of opioids prescribed decreased from 32 oxycodone 5 mg tablets in 2017 to 21 oxycodone 5 mg tablets in 2021 (236 MME to 154 MME, p<0.001). The percentage of patients obtaining a refill within 90 days of surgery varied between 18.3% and 19.9% (p<0.001). Patients with a pre-existing opioid prescription and opioid-naïve patients both had significant reductions in prescription quantities above the default MME (79.7% to 60.6% vs. 65.3% to 36.9%, p<0.001). There was no significant change in refills for both groups (pre-existing 36.7% to 38.3% (p = 0.1) vs naïve 15.0% to 15.3% (p = 0.29)). CONCLUSIONS: The benefits of decreasing the default opioid pill count continue to accumulate long after the original change. Physician uptake of small changes to default EMRS practices represents a sustainable and effective intervention to reduce the quantities of postoperative opioids prescribed without deleterious effects on outpatient opiate requirements.

Tramadol-paracetamol for postoperative pain after spine surgery - A randomized, double-blind, placebo-controlled study.

OBJECTIVES: Multimodal pain management is one component in enhanced recovery after surgery protocol. Here we evaluate the efficacy of tramadol-paracetamol in acute postoperative pain and pain outcome at 12 months after spine surgery in randomized, double-blind, placebo-controlled trial. METHODS: We randomized 120 patients undergoing spine surgery to receive, for add-on pain management, two tramadol-paracetamol 37.5 mg/325 mg (n = 61) or placebo tablets (n = 59) twice a day for 5 postoperative days. In the hospital, multimodal pain management consisted of dexketoprofen and oxycodone. After discharge, patients were prescribed ibuprofen 200 mg, maximum 1,200 mg/day. Pain, analgesic use, and satisfaction with pain medication were followed up with the Brief Pain Inventory questionnaire before surgery and at 1 and 52 weeks after surgery. The primary outcome was patients' satisfaction with pain medication 1 week after surgery. RESULTS: At 1 week after surgery, patients' satisfaction with pain medication was similarly high in the two groups, 75% [interquartile range, 30%] in the placebo group and 70% [40%] in the tramadol-paracetamol group (p = 0.949) on a scale: 0% = not satisfied, 100% = totally satisfied. At 1 week, ibuprofen dose was lower in the placebo group 200 mg [1,000] compared to the tramadol-paracetamol group, 800 mg [1,600] (p = 0.016). There was no difference in the need for rescue oxycodone. Patients in the tramadol-paracetamol group had more adverse events associated with analgesics during the first postoperative week (relative risk = 1.8, 95% confidence interval, 1.2-2.6). CONCLUSION: Add-on pain treatment with tramadol-paracetamol did not enhance patients' satisfaction with early pain management after back surgery.

Neuroplasticity-related genes correlate with individual differences in distinct phases of oxycodone self-administration in male rats.

Opioid use disorder (OUD) is a chronic condition associated with long-lasting molecular and behavioral changes. Animals with prolonged access to opioids develop behaviors similar to human OUD. Identifying associated molecular changes can provide insight to underpinnings that lead to or maintain OUD. In pilot studies, we identified several miRNA targets that are altered by the administration of oxycodone. We selected mir182 for follow up as it was recently shown to be dysregulated in plasma of men administered oxycodone. In addition, mir182 is increased in reward-related brain regions of male rats following exposure to various addictive substances. The present study utilizes a long-access oxycodone self-administration paradigm to examine changes in mir182 and its mRNA targets associated with neuroplasticity, which may be involved in the maintenance of OUD-like phenotype in rats. Male rats were trained to self-administer oxycodone (0.1 mg/kg/infusion, i. v.) for 6 h daily sessions for 12 days. Each animal had a yoked saline control that received matched saline infusions. Animals were then tested on a progressive ratio schedule to measure motivation to obtain a single infusion of oxycodone. Drug seeking was measured following 28 days of forced abstinence using a 90-min cued/test. RTqPCR was utilized to measure mir182 and mRNA targets related to neuroplasticity (wnt3, plppr4, pou3f3, tle4, cacna2d, and bdnf) from the nucleus accumbens. Data revealed that animals responded on a continuum for oxycodone. When divided into two groups termed high- and low responders, animals diverged during self-administration acquisition and maintained differences in behavior and gene expression throughout the study. mir182 was upregulated in the nucleus accumbens of both high and low responders and negatively correlated with tle4, which showed a strong negative correlation with reinstatement behavior. mRNA target levels were correlated with behaviors associated with increased severity of OUD behavior in male rats.

How low can we go? A randomized controlled trial of low-quantity initial opioid prescriptions for shoulder surgery.

BACKGROUND: Orthopedic surgeons are the third most frequent prescribers of opioid medications. Given the current opioid addiction crisis, it is critical to limit opioid prescriptions to the lowest effective dose. In this study, we investigated how the initial opioid prescription after shoulder surgery affects maximum possible opioid consumption. We hypothesized that fewer pills in the initial opioid prescription would lead to less opioid consumption, a lower refill request rate, and fewer post-surgery office contacts for pain. METHODS: In this single-center, prospective, randomized controlled clinical trial, 74 adults who underwent shoulder arthroplasty, rotator cuff repair, or other arthroscopic shoulder procedures were enrolled from December 2020 to July 2022. Follow-up was completed by February 2023. Participants were randomly assigned to receive postoperative prescriptions of seven 5-mg oxycodone pills (n = 20), 15 pills (n = 29), or 23 pills (n = 25). The primary outcome was maximum possible opioid consumption within 2 weeks after surgery, calculated by assuming consumption of all pills in the initial prescription, as well as any refills. Secondary outcomes were the opioid prescription refill request rates, post-surgery pain-related telephone calls or messages to the provider's office ("office contacts") within 2 weeks after surgery, and American Shoulder and Elbow Surgeons pain scores 2 weeks after surgery. Baseline characteristics did not differ among groups except for mean age, which was younger in the 7-pill group (P = .047). RESULTS: Maximum possible opioid consumption increased with the number of pills initially prescribed, with means of 78 morphine milligram equivalents (MME) for the 7-pill group, 118 MME for the 15-pill group, and 199 MME for the 23-pill group (P < .001). None of the secondary outcome measures differed among groups. Refill request rates were 20% for the 7-pill group, 3.4% for the 15-pill group, and 12% for the 23-pill group (P = .20). The proportions of patients with at least 1 office contact were 35% in the 7-pill group, 45% in the 15-pill group, and 28% in the 23-pill group (P = .43). Mean American Shoulder and Elbow Surgeons pain scores were 49 in the 7-pill group, 44 in the 15-pill group, and 40 in the 23-pill group (P = .20). CONCLUSION: After shoulder surgery, an initial prescription of fewer opioid pills was associated with less maximum possible opioid consumption without an increase in the percentage of patients requesting opioid refills or contacting the provider's office for pain-related concerns. An initial postoperative prescription of fewer 5-mg oxycodone pills may be equally or more effective compared with larger quantities for most patients.

Paradoxical potentiation of the exercise pressor reflex by endomorphin 2 in the presence of naloxone.

When contracting muscles are freely perfused, the acid-sensing ion channel 3 (ASIC3) on group IV afferents plays a minor role in evoking the exercise pressor reflex. We recently showed in isolated dorsal root ganglion neurons innervating the gastrocnemius muscles that two mu opioid receptor agonists, namely endomorphin 2 and oxycodone, potentiated the sustained inward ASIC3 current evoked by acidic solutions. This in vitro finding prompted us to determine whether endomorphin 2 and oxycodone, when infused into the arterial supply of freely perfused contracting hindlimb muscles, potentiated the exercise pressor reflex. We found that infusion of endomorphin 2 and naloxone in decerebrated rats potentiated the pressor responses to contraction of the triceps surae muscles. The endomorphin 2-induced potentiation of the pressor responses to contraction was prevented by infusion of APETx2, an ASIC3 antagonist. Specifically, the peak pressor response to contraction averaged 19.3 ± 5.6 mmHg for control (n = 10), 27.2 ± 8.1 mmHg after naloxone and endomorphin 2 infusion (n = 10), and 20 ± 8 mmHg after APETx2 and endomorphin 2 infusion (n = 10). Infusion of endomorphin 2 and naloxone did not potentiate the pressor responses to contraction in ASIC3 knockout rats (n = 6). Partly similar findings were observed when oxycodone was substituted for endomorphin 2. Oxycodone infusion significantly increased the exercise pressor reflex over its control level, but subsequent APETx2 infusion failed to restore the increase to its control level (n = 9). The peak pressor response averaged 23.1 ± 8.6 mmHg for control (n = 9), 33.2 ± 11 mmHg after naloxone and oxycodone were infused (n = 9), and 27 ± 8.6 mmHg after APETx2 and oxycodone were infused (n = 9). Our data suggest that after opioid receptor blockade, ASIC3 stimulation by the endogenous mu opioid, endomorphin 2, potentiated the exercise pressor reflex.NEW & NOTEWORTHY This paper provides the first in vivo evidence that endomorphin 2, an endogenous opioid peptide, can paradoxically increase the magnitude of the exercise pressor reflex by an ASIC3-dependent mechanism even when the contracting muscles are freely perfused.

A dose-ranging study of the physiological and self-reported effects of repeated, rapid infusion of remifentanil in people with opioid use disorder and physical dependence on fentanyl.

RATIONALE: Understanding mechanisms of drug use decisions will inform the development of treatments for opioid use disorder (OUD). Decision-making experiments using neurobehavioral approaches require many trials or events of interest for statistical analysis, but the pharmacokinetics of most opioids limit dosing in humans. OBJECTIVES: This experiment characterized the effects of repeated infusions of the ultra-short acting opioid remifentanil in people with OUD and physical opioid dependence. METHODS: An inpatient study using a within-subjects, single-blind, escalating, within-session, pre-post design was conducted. Seven (3 female) subjects were maintained on oral oxycodone (40-60 mg, 4x/day = 160-240 total mg/day) for seven days prior to the dose-ranging session. Subjects received infusions of three ascending remifentanil doses (0.03, 0.1, 0.3 mcg/kg/infusion in 2 subjects; 0.1, 0.3, 1.0 mcg/kg/infusion in 5 subjects) every minute for 40 min per dose, with infusions administered over 5 s to model naturalistic delivery rates. End tidal carbon dioxide, respiration rate, oxygen saturation (SpO2) and heart rate were measured continuously. Blood pressure (BP), pupil diameter and self-reported drug effects were measured every 5 min. RESULTS: Pupil diameter, SpO2 and systolic BP decreased, and ratings on prototypic subjective effects questionnaire items increased, as a function of remifentanil dose. The number of infusions held because of sedation or physiological parameters exceeding predetermined cutoffs also increased with dose. CONCLUSIONS: This experiment established doses and procedures for the safe delivery of rapid, repeated remifentanil infusions to individuals with OUD and physical fentanyl dependence, which can be applied to the mechanistic study of opioid use decisions.

Oxycodone does not affect placental circulatory physiology during the early first stage of labor-A randomized trial.

INTRODUCTION: Opioids are used for pain relief during the first stage of labor. Oxycodone can cause maternal hypotension that may modify utero- and fetoplacental circulatory physiology. We hypothesized that maternal intravenous (i.v.) oxycodone has no detrimental effect on utero- and fetoplacental hemodynamics during the early first stage of labor. MATERIAL AND METHODS: Twenty-two parturients requiring pain relief during the first stage of labor were randomized in a double-blinded and placebo-controlled study. By Doppler ultrasonography, both uterine artery (Ut) and umbilical vein (UV) volume blood flows (Q), Ut pulsatility index (PI), and Ut vascular resistance (RUt) were calculated. Blood flow velocity waveforms were obtained between uterine contractions. After baseline measurements, women received oxycodone 0.05 mg/kg or a placebo intravenous. Doppler ultrasonography was repeated up to 120 min after the first drug administration. The second dose of oxycodone 0.05 mg/kg was allowed at 60 min to all parturients with contraction pain ≥5/10. Maternal plasma samples were collected at each study phase and after delivery with umbilical cord plasma samples, to measure oxycodone concentrations. CLINICALTRIALS: gov identifier (NCT no. NCT02573831). RESULTS: At baseline, mean QUt and QUV did not differ significantly between the placebo-first (478 mL/min and 57 mL/min/kg) and the oxycodone-first (561 mL/min and 71 mL/min/kg) groups. In addition, RUt and Ut PI were comparable between the groups. Following oxycodone at 60 min, mean QUt and QUV (714 mL/min and 52 mL/min/kg) were similar to the placebo-first (520 mL/min and 55 mL/min/kg) group. Furthermore, all the measured parameters were comparable to the baseline values. At 60 min after the first study drug administration, all the parturients in the placebo-first group needed intravenous oxycodone 0.05 mg/kg. At 120 min, we found no statistically significant change in any of the measured parameters. No significant correlation was found between maternal oxycodone concentration and QUt or QUV. Furthermore, newborn oxycodone concentration did not correlate with QUV. CONCLUSIONS: Oxycodone did not have any detrimental effect on either utero- or fetoplacental circulatory physiology during the early first stage of labor. Maternal plasma oxycodone did not correlate with utero- and fetoplacental hemodynamics. No correlation was found between newborn oxycodone concentration and fetoplacental hemodynamics.

Effects of selective dopamine D3 receptor partial agonist/antagonists on oxycodone self-administration and antinociception in monkeys.

Recent studies suggest that dopamine D3 receptors (D3R) may be a therapeutic target for opioid use disorders (OUD). This study examined the effects of the D3R partial agonist (±)VK4-40 and the D3R-selective antagonist (±)VK4-116, compared to the mu-opioid receptor antagonist naltrexone (NTX), in nonhuman primate models of OUD and antinociception. Adult male and female (N = 4/sex) cynomolgus monkeys were trained to self-administer oxycodone (0.003-0.1 mg/kg/injection) first under a fixed-ratio (FR) and then a progressive-ratio (PR) schedule of reinforcement during daily 1- and 4-hr sessions, respectively. Under the FR schedule, intravenous NTX (0.01-0.1 mg/kg), (±)VK4-116 (1.0-10 mg/kg), and (±)VK4-40 (1.0-10 mg/kg) were studied in combination with the peak oxycodone dose and a dose on the descending limb of the dose-effect curve; NTX and (±)VK4-40 were also studied at the peak of the PR dose-response curve (N = 4). Following saline extinction, each compound was examined on oxycodone-induced reinstatement. Finally, these compounds were assessed in adult male rhesus monkeys (N = 3) in a warm-water (38 °C, 50 °C, 54 °C) tail withdrawal assay. NTX decreased responding on the peak of the FR oxycodone dose-response curve, but increased responding on the descending limb. (±)VK4-40, but not (±)VK4-116, significantly decreased peak oxycodone self-administration; (±)VK4-40 did not increase responding on the descending limb. NTX and (±)VK4-40, but not (±)VK4-116, attenuated oxycodone-induced reinstatement. Under PR responding, NTX and (±)VK4-40 decreased breakpoints. Oxycodone-induced antinociception was attenuated by NTX, but not by (±)VK4-40 or (±)VK4-116. Together, these results suggest that further research evaluating the effects of (±)VK4-40 as a novel pharmacotherapy for OUD is warranted.

The Role of Pharmacogenomics in Opioid Prescribing.

OPINION STATEMENT: Pharmacogenomics is increasingly important to guide objective, safe, and effective individualised prescribing. Personalised prescribing has revolutionised treatments in the past decade, allowing clinicians to maximise drug efficacy and minimise adverse effects based on a person's genetic profile. Opioids, the gold standard for cancer pain relief, are among the commonest medications prescribed in palliative care practice. This narrative review examines the literature surrounding opioid pharmacogenomics and its applicability to the palliative care cancer population. There is currently limited intersection between the fields of palliative care and pharmacogenomics, but growing evidence presents a need to build linkages between the two disciplines. Pharmacogenomic evidence guiding opioid prescribing is currently available for codeine and tramadol, which relates to CYP2D6 gene variants. However, these medications are prescribed less commonly for pain in palliative care. Research is accelerating with other opioids, where oxycodone (CYP2D6) and methadone (CYP2B6, ABCB1) already have moderate evidence of an association in terms of drug metabolism and downstream analgesic response and side effects. OPRM1 and COMT are receiving increasing attention and have implications for all opioids, with changes in opioid dosage requirements observed but they have not yet been studied widely enough to be considered clinically actionable. Current evidence indicates that incorporation of pharmacogenomic testing into opioid prescribing practice should focus on the CYP2D6 gene and its actionable variants. Although opioid pharmacogenomic tests are not widely used in clinical practice, the progressively reducing costs and rapid turnover means greater accessibility and affordability to patients, and thus, clinicians will be increasingly asked to provide guidance in this area. The upsurge in pharmacogenomic research will likely discover more actionable gene variants to expand international guidelines to impact opioid prescribing. This rapidly expanding area requires consideration and monitoring by clinicians in order for key findings with clinical implications to be accessible, meaningfully interpretable and communicated.

Leftover Opioid Analgesics and Disposal Following Ambulatory Pediatric Surgeries in the Context of a Restrictive Opioid-Prescribing Policy.

BACKGROUND: Opioid analgesics are commonly prescribed for postoperative analgesia following pediatric surgery and often result in leftover opioid analgesics in the home. To reduce the volume of leftover opioids and overall community opioid burden, the State of Tennessee enacted a policy to reduce initial opioid prescribing to a 3-day supply for most acute pain incidents. We aimed to evaluate the extent of leftover opioid analgesics following pediatric ambulatory surgeries in the context of a state-mandated restrictive opioid-prescribing policy. We also aimed to evaluate opioid disposal rates, methods of disposal, and reasons for nondisposal. METHODS: Study personnel contacted the parents of 300 pediatric patients discharged with an opioid prescription following pediatric ambulatory surgery. Parents completed a retrospective telephone survey regarding opioid use and disposal. Data from the survey were combined with data from the medical record to evaluate proportion of opioid doses prescribed that were left over. RESULTS: The final analyzable sample of 185 patients (62% response rate) were prescribed a median of 12 opioid doses (interquartile range [IQR], 12-18), consumed 2 opioid doses (IQR, 0-4), and had 10 opioid doses left over (IQR, 7-13). Over 90% (n = 170 of 185) of parents reported they had leftover opioid analgesics, with 83% of prescribed doses left over. A significant proportion (29%, n = 54 of 185) of parents administered no prescribed opioids after surgery. Less than half (42%, n = 71 of 170) of parents disposed of the leftover opioid medication, most commonly by flushing down the toilet, pouring down the sink, or throwing in the garbage. Parents retaining leftover opioids (53%, n = 90 of 170) were most likely to keep them in an unlocked location (68%, n = 61 of 90). Parents described forgetfulness and worry that their child will experience pain in the future as primary reasons for not disposing of the leftover opioid medication. CONCLUSIONS: Despite Tennessee's policy aimed at reducing leftover opioids, a significant proportion of prescribed opioids were left over following pediatric ambulatory surgeries. A majority of parents did not engage in safe opioid disposal practices. Given the safety risks related to leftover opioids in the home, further interventions to improve disposal rates and tailor opioid prescribing are warranted after pediatric surgery.

A limited access oral oxycodone paradigm produces physical dependence and mesocorticolimbic region-dependent increases in DeltaFosB expression without preference.

The abuse of oral formulations of prescription opioids has precipitated the current opioid epidemic. We developed an oral oxycodone consumption model consisting of a limited access (4 h) two-bottle choice drinking in the dark (TBC-DID) paradigm and quantified dependence with naloxone challenge using mice of both sexes. We also assessed neurobiological correlates of withdrawal and dependence elicited via oral oxycodone consumption using immunohistochemistry for DeltaFosB (ΔFosB), a transcription factor described as a molecular marker for drug addiction. Neither sex developed a preference for the oxycodone bottle, irrespective of oxycodone concentration, bottle position or prior water restriction. Mice that volitionally consumed oxycodone exhibited hyperlocomotion in an open field test and supraspinal but not spinally-mediated antinociception. Both sexes also developed robust, dose-dependent levels of opioid withdrawal that was precipitated by the opioid antagonist naloxone. Oral oxycodone consumption followed by naloxone challenge led to mesocorticolimbic region-dependent increases in the number of ΔFosB expressing cells. Naloxone-precipitated withdrawal jumps, but not the oxycodone bottle % preference, was positively correlated with the number of ΔFosB expressing cells specifically in the nucleus accumbens shell. Thus, limited access oral consumption of oxycodone produced physical dependence and increased ΔFosB expression despite the absence of opioid preference. Our TBC-DID paradigm allows for the study of oral opioid consumption in a simple, high-throughput manner and elucidates the underlying neurobiological substrates that accompany opioid-induced physical dependence.

Opiate vs non-opiate prescription medication for pain control after endoscopic sinus surgery for chronic rhinosinusitis.

PURPOSE: Research indicates that most providers give opiates after endoscopic sinonasal surgery. The effectiveness of non-opiate medications after sinonasal surgery is poorly understood and most studies do not assess medication failure. This study compares oral opiate, oral opiate and topical steroid, and oral non-opiate pain control. Patient call-backs are used as a proxy for pain medication failure. MATERIALS AND METHODS: This study compares three medication regiments after sinonasal surgery for 180 adults with chronic rhinosinusitis. Patients were instructed to take acetaminophen for mild pain. For moderate/severe pain, patients used: 1) oxycodone-acetaminophen, 2) oxycodone-acetaminophen + budesonide nasal rinses, or 3) meloxicam + acetaminophen. Patients were instructed to call clinic if pain was not controlled. Descriptive statistics compared cohorts. Chi-square tests compared call-backs between cohorts. Logistic regression adjusted for baseline differences in covariates, comorbidities, and operative sites. RESULTS: Cohorts had similar age, sex distribution, disease features, and extent of surgery. The meloxicam cohort had less subjects with pain disorders. The oxycodone cohort had less subjects with diabetes, septoplasty, and turbinate reduction. After adjusting for baseline differences and using oxycodone as the reference group (n = 50), the odds of calling clinic for poorly controlled pain was 0.18 (95% Confidence Interval (CI): 0.05-0.6) in the meloxicam cohort (n = 45) and 0.19 (95% CI:0.07-0.5) in the oxycodone + budesonide rinses cohort (n = 85). CONCLUSION: In this study, both meloxicam and oxycodone + budesonide rinses were more effective at controlling pain after sinonasal surgery than oxycodone alone.

Elevated customary alcohol consumption attenuates opioid effects.

BACKGROUND: Regular alcohol consumption is on the rise among older adults and has the potential of altering the subjective experience of pain and response to pain medications. This study examined the cognitive, analgesic and side effect response to oxycodone in middle age and older adults with elevated levels of customary alcohol consumption in a human laboratory setting. METHODS: After refraining from alcohol for one day, eligible participants underwent baseline assessment cognition and side effects by means of questionnaires that were repeated at three time points (90 min, 5 and 8 h) following administration of a 10 mg oral dose of oxycodone. Response to pain stimulus (Cold Pressor Test (CPT)), pupil size, and plasma oxycodone were also measured. RESULTS: One hundred twenty-eight adults (age 35-85) completed the study day. Compared to those with lower customary alcohol consumption, participants with elevated alcohol consumption showed attenuated opioid-induced pupil constriction and cognitive decline on objective measures of working memory, sustained attention, inhibitory control, coordination on a simulated driving task, and subjective dysphoric effects with enhanced subjective euphoric effects. Oxycodone pharmacokinetics, pain tolerance to CPT, and Berg balance were impacted comparably between alcohol consumption groups. Women endorsed greater negative drug effects, whereas men endorsed positive drug effects. CONCLUSION: Independent of subject's age, elevated customary alcohol consumption attenuates opioid central effects (i.e., pupil miosis, impaired cognition) and gender influences subjective drug effects. Clinicians should consider alcohol consumption and gender when prescribing opioid medications.

Urban scaling of opioid analgesic sales in the United States.

Opioid misuse is a public health crisis in the United States. The origin of this crisis is associated with a sharp increase in opioid analgesic prescribing. We used the urban scaling framework to analyze opioid prescribing patterns in US commuting zones (CZs), i.e., groups of counties based on commuting patterns. The urban scaling framework postulates that a set of scaling relations can be used to predict health outcomes and behaviors in cities. We used data from the Drug Enforcement Administration's Automated Reports and Consolidated Ordering System (ARCOS) to calculate counts of oxycodone/hydrocodone pills distributed to 607 CZs in the continental US from 2006 to 2014. We estimated the scaling coefficient of opioid pill counts by regressing log(pills) on log(population) using a piecewise linear spline with a single knot at 82,363. Our results show that CZs with populations below the knot scaled superlinearly (ß = 1.36), i.e., larger CZs had disproportionally larger pill counts compared to smaller CZs. On the other hand, CZs with populations above the knot scaled sublinearly (ß = 0.92), i.e., larger CZs had disproportionally smaller pill counts compared to smaller CZs. This dual scaling pattern was consistent across US census regions. For CZs with population below the knot, the superlinear scaling of pills is consistent with the explanation that an increased number of successful matches between prescribers and users will lead to higher prescribing rates. The non-linear scaling behavior observed could be the result of a combination of factors, including stronger health care systems and prescribing regulation in largely populated commuting zones, as well as high availability of other opioids such as heroin in these commuting zones. Future research should explore potential mechanisms for the non-linearity of prescription opioid pills.

An observational cohort study comparing ibuprofen and oxycodone in children with fractures.

OBJECTIVE: To compare the effectiveness and safety of prescribing ibuprofen and oxycodone for at-home management of children's fracture pain. METHODS: A prospective observational cohort was conducted at the Stollery Children's Hospital pediatric emergency department (June 2010-July 2014). Children aged 4-16 years with an isolated fracture discharged home with advice to use either ibuprofen or oxycodone were recruited. RESULTS: A cohort of 329 children (n = 217 ibuprofen, n = 112 oxycodone) were included. Mean age was 11.1 years (SD 3.5); 68% (223/329) were male. Fracture distribution included 80.5% (264/329) upper limb with 34.3% (113/329) requiring fracture reduction. The mean reduction in Faces Pain Score-Revised score (maximum pain-post-treatment pain) for Day 1 was 3.6 (SD 1.9) (ibuprofen) and 3.8 (SD 2.1) (oxycodone) (p = 0.50); Day 2 was 3.6 (SD 1.8) (ibuprofen) and 3.7 (SD 1.6) (oxycodone) (p = 0.56); Day 3 was 3.7 (SD 1.7) (ibuprofen) and 3.3 (SD 1.7) (oxycodone) (p = 0.24). Children prescribed ibuprofen (51.2%, 109/213) experienced less adverse events compared to those prescribed oxycodone (70.5% 79/112) on Day 1 (p = 0.001). Children prescribed ibuprofen (71.8%, 150/209) had their function (eat, play, school, sleep) affected less than those prescribed oxycodone (83.0%, 93/112) (p = 0.03) on Day 1. CONCLUSION: Children prescribed ibuprofen or oxycodone experienced similar analgesic effectiveness for at-home fracture pain. Oxycodone prescribing was associated with more adverse events and negatively impacted function. Oxycodone use does not appear to confer any benefit over ibuprofen for pain relief and has a negative adverse effect profile. Ibuprofen appears to be a safe option for fracture-related pain.

Tapentadol in Cancer Patients with Neuropathic Pain: A Comparison of Methadone, Oxycodone, Fentanyl, and Hydromorphone.

Tapentadol has µ-opioid receptor stimulating and noradrenaline reuptake inhibiting properties, and should be effective for neuropathic pain (NP). However, the efficacy of tapentadol for NP in cancer patients is unclear. Ashiya Municipal Hospital (Hyogo, Japan) enrolled five groups of Japanese cancer patients between January 1, 2013, and December 31, 2019. Patients with NP were administered tapentadol (n = 29), methadone (n = 32), oxycodone (n = 20), fentanyl (n = 26), or hydromorphone (n = 20). The primary endpoint was the difference in the verbal rating scale (VRS) scores between days 0 and 7. The secondary endpoint was the tolerability of each opioid. Before administering opioids among the five groups, there was no significant difference in the VRS score (p = 0.99). The mean reduction in the VRS score on day 7 was significantly greater in the tapentadol group than in the oxycodone group (p = 0.0024) and was larger than that of the methadone, fentanyl, and hydromorphone groups. Regarding safety, the discontinuation rate in the tapentadol group was the lowest of all groups (tapentadol vs. methadone vs. oxycodone vs. fentanyl vs. hydromorphone, 0.0% vs. 6.3% vs. 5.0% vs. 3.8% vs. 10.0%, respectively). This study suggests that tapentadol could be efficacious for cancer patients with NP, and a preferred option in cases that require immediate dose adjustment or for those at high risk for adverse effects. However, the pain intensity was evaluated without pain assessment scales specific to NP. Thus, we think that it is desirable to validate our findings using assessment scales, such as the painDETECT questionnaire in future.

Sex and Estrous Cycle Differences in Analgesia and Brain Oxycodone Levels.

Sex differences in opioid analgesia occur in rodents and humans, and could be due to differences in drug and metabolite levels. Thus, we investigated the sex and cycle differences in analgesia (nociception) from oxycodone in rats and related these to sex and cycle differences in brain and plasma oxycodone and metabolite levels. Since numerous opioids are CYP2D enzyme substrates and variation in CYP2D alters opioid drug levels and response, we also initiated studies to see if the sex and cycle differences observed might be due to differences in brain CYP2D activity. Across oxycodone doses, females in diestrus had higher analgesia (using tail flick latency) compared to males and females in estrus; we also demonstrated a direct effect of estrous cycle on analgesia within females. Consistent with the analgesia, females in diestrus had highest brain oxycodone levels (assessed using microdialysis) compared to males and females in estrus. Analgesia correlated with brain oxycodone, but not brain oxymorphone or noroxycodone levels, or plasma drug or metabolite levels. Propranolol (a CYP2D mechanism-based inhibitor), versus vehicle pre-treatments, increased brain oxycodone, and decreased brain oxymorphone/oxycodone drug level ratios (an in vivo CYP2D activity phenotype in the brain) in males and females in estrus, but not in females in diestrus. Brain oxymorphone/oxycodone inversely correlated with analgesia. Together, both sex and estrous cycle impact oxycodone analgesia and brain oxycodone levels, likely through regulation of brain CYP2D oxycodone metabolism. As CYP2D6 is expressed in human brain, perhaps similar sex and cycle influences also occur in humans.

Sex and heredity are determinants of drug intake in a novel model of rat oral oxycodone self-administration.

The steady rise in prescription opioids such as oxycodone has led to a virulent epidemic of widespread abuse and deaths in the United States; approximately 80% of affected individuals initiate the habitual use of oxycodone by using prescription oral oxycodone. Given the importance of drug pharmacokinetics in determining abuse potential, we designed an oral operant oxycodone self-administration (SA) procedure in rats to model drug intake by most human users/abusers of oxycodone. Key aspects of the model include limited initial drug intake followed by increasing drug concentrations during extended 4-h sessions on alternating days. Sex and genetic predisposition are major determinants of human opiate abuse. Therefore, we studied females in seven inbred strains (WLI, WMI, LEW, DSS, F344, BN and SHR) and both sexes in three of these strains. All strains increased intake across serially increasing doses (0.025-0.2 mg/ml; p < 0.001): the range of intakes at the final concentration of oxycodone was 0.72 ± 0.17-4.84 ± 1.42 mg/kg (mean ± SEM) - a 6.7-fold difference across strains. In LEW, WLI and WMI strains, oxycodone intake increased significantly across all sessions in both sexes. However, in LEW and WMI male rats but not WLI, daily oxycodone intake was significantly lower across all 4-h sessions than females (p < 0.005). The estimated heritability in oxycodone intake was in the range of 0.21-0.41. In summary, our novel operant oral oxycodone SA model captures the strong abuse potential of oral oxycodone and shows dose, sex and strain-specific drug intake that is significantly dependent on heredity.