The relative abuse liability of oral oxycodone, hydrocodone and hydromorphone assessed in prescription opioid abusers

Conversion ratios: Why is it so challenging to construct opioid conversion tables?

Standardizing opioid management is challenging due to the absence of a ceiling dose, the unknown ideal therapeutic plasma level, and the lack of an clear relationship between dose and therapeutic response. Opioid rotation or conversion, which is switching from one opioid, route of administration, or both, to another, to improve therapeutic response and reduce toxicities, occurs in 20-40 percent of patients treated with opioids. Opioid conversion is often needed when there are adverse effects, toxicities, or inability to tolerate a certain opioid formulation. A majority of patients benefit from opioid conversion, leading to improved analgesia and less adverse effects. There are different published ways of converting opioids in the literature. This review of 20 years of literature is centered on opioid conversions and aims to discuss the complexity of converting opioids. We discuss study designs, outcomes and measures, pain phenotypes, patient characteristics, comparisons of equivalent doses between opioids, reconciling conversion ratios between opioids, routes, directional differences, half-lives and metabolites, interindividual variability, and comparison to package insert information. Palliative care specialists have not yet come to a consensus on the ideal opioid equianalgesic table; however, we discuss a recently updated table, based on retrospective evidence, that may serve as a gold standard for practical use in the palliative care population. More robust, well-designed studies are needed to validate and guide future opioid conversion data.

Oxycodone: A Current Perspective on Its Pharmacology, Abuse, and Pharmacotherapeutic Developments

Oxycodone, a semisynthetic derivative of naturally occurring thebaine, an opioid alkaloid, has been available for more than 100 years. Although thebaine cannot be used therapeutically due to the occurrence of convulsions at higher doses, it has been converted to a number of other widely used compounds that include naloxone, naltrexone, buprenorphine, and oxycodone. Despite the early identification of oxycodone, it was not until the 1990s that clinical studies began to explore its analgesic efficacy. These studies were followed by the pursuit of several preclinical studies to examine the analgesic effects and abuse liability of oxycodone in laboratory animals and the subjective effects in human volunteers. For a number of years oxycodone was at the forefront of the opioid crisis, playing a significant role in contributing to opioid misuse and abuse, with suggestions that it led to transitioning to other opioids. Several concerns were expressed as early as the 1940s that oxycodone had significant abuse potential similar to heroin and morphine. Both animal and human abuse liability studies have confirmed, and in some cases amplified, these early warnings. Despite sharing a similar structure with morphine and pharmacological actions also mediated by the μ-opioid receptor, there are several differences in the pharmacology and neurobiology of oxycodone. The data that have emerged from the many efforts to analyze the pharmacological and molecular mechanism of oxycodone have generated considerable insight into its many actions, reviewed here, which, in turn, have provided new information on opioid receptor pharmacology. SIGNIFICANCE STATEMENT: Oxycodone, a μ-opioid receptor agonist, was synthesized in 1916 and introduced into clinical use in Germany in 1917. It has been studied extensively as a therapeutic analgesic for acute and chronic neuropathic pain as an alternative to morphine. Oxycodone emerged as a drug with widespread abuse. This article brings together an integrated, detailed review of the pharmacology of oxycodone, preclinical and clinical studies of pain and abuse, and recent advances to identify potential opioid analgesics without abuse liability.

Use of clinical phenotypes to characterize emergency department patients administered intravenous opioids for acute pain

OBJECTIVE

Individual experience with opioids is highly variable. Some patients with acute pain do not experience pain relief with opioids, and many report no euphoria or dysphoric reactions. In this study, we describe the clinical phenotypes of patients who receive intravenous opioids.

METHODS

This was an emergency department-based study in which we enrolled patients who received an intravenous opioid. We collected 0 to 10 pain scores prior to opioid administration and 15 minutes after. We also used 0 to 10 instruments to determine how high and how much euphoria the patient felt after receipt of the opioid. Using a cutoff point of ≥50% improvement in pain and the median score on the high and euphoria scales, we assigned each participant to one of the following clinical phenotypes: pain relief with feeling high or euphoria, pain relief without feeling high or euphoria, inadequate relief with feeling high or euphoria, and inadequate relief without feeling high or euphoria.

RESULTS

A total of 713 patients were enrolled, 409 (57%) of whom reported not feeling high, and 465 (65%) reported no feeling of euphoria. Median percent improvement in pain was 37.5% (interquartile range, 12.5%-60.0%). One hundred seventy-eight participants (25%) were classified as experiencing pain relief with euphoria or feeling high, 190 (27%) experienced inadequate relief with euphoria or feeling high, 101 (14%) experienced pain relief without euphoria or feeling high, and 244 (34%) reported inadequate relief without euphoria or feeling high.

CONCLUSION

Among patients who receive intravenous opioids in the emergency department, the experiences of pain relief and euphoria are highly variable. For many, pain relief is independent of feeling high.

The novel uncompetitive NMDA receptor antagonist esmethadone (REL-1017) has no meaningful abuse potential in recreational drug users

Esmethadone (REL-1017) is the opioid-inactive dextro-isomer of methadone and a low-affinity, low-potency uncompetitive NMDA receptor antagonist. In a Phase 2, randomized, double-blind, placebo-controlled trial, esmethadone showed rapid, robust, and sustained antidepressant effects. Two studies were conducted to evaluate the abuse potential of esmethadone. Each study utilized a randomized, double-blind, active-, and placebo-controlled crossover design to assess esmethadone compared with oxycodone (Oxycodone Study) or ketamine (Ketamine Study) in healthy recreational drug users. Esmethadone 25 mg (proposed therapeutic daily dose), 75 mg (loading dose), and 150 mg (Maximum Tolerated Dose) were evaluated in each study. Positive controls were oral oxycodone 40 mg and intravenous ketamine 0.5 mg/kg infused over 40 min. The Ketamine study included oral dextromethorphan 300 mg as an exploratory comparator. The primary endpoint was maximum effect (Emax) for Drug Liking, assessed using a bipolar 100-point visual analog scale (VAS). A total of 47 and 51 participants completed the Oxycodone Study and the Ketamine Study, respectively (Completer Population). In both studies, esmethadone doses ranging from therapeutic (25 mg) to 6 times therapeutic (150 mg) had a meaningful and statistically significantly (p < 0.001) lower Drug Liking VAS Emax compared with the positive control. Results were consistent for all secondary endpoints in both studies. In both studies, all doses of esmethadone were statistically equivalent to placebo on Drug Liking VAS Emax (p < 0.05). In the Ketamine Study, Drug Liking VAS Emax scores for esmethadone at all tested doses were significantly lower vs. dextromethorphan (p < 0.05) (exploratory endpoint). These studies indicate no meaningful abuse potential for esmethadone at all tested doses.

Recent trends in the prescription of opioids in the emergency department in patients with urolithiasis

PURPOSE

Pain management is central in the treatment of urolithiasis. We aimed to estimate the impact of the 2017 Department of Health and Human Services declaration of an opioid crisis on prescribing patterns of opioids and NSAIDs in emergency department visits for urolithiasis.

METHODS

The National Health Ambulatory Medical Care Survey (NHAMCS) was queried for emergency department visits of adults with a diagnosis of urolithiasis. The association between urolithiasis and narcotic and NSAIDs prescription patterns was evaluated and compared at pre-declaration (2014-2016) to post-declaration (2017-2018) periods.

RESULTS

Opioids were prescribed in about 211 million (41.1%) out of 513 million emergency department visits, over a 5-year period. Diagnosis of urolithiasis accounted for 1.9% of the visits (6.0 million). The use of opioids was higher in urolithiasis (82.7%) compared to non-urolithiasis diagnosis (40.3%), as well as the use of multiple opioids per visit (p < 0.01 for all). There was an overall decrease in opioid prescriptions in the post-declaration period, - 4.3% for urolithiasis (p = 0.254) and - 5.6% for non-urolithiasis visits (p < 0.05). A decrease in the use of hydromorphone (- 47.5%. p < 0.001), an increase in the use of morphine (+ 59.7% p = 0.006), and an increase of 'other' opioids (+ 98.8%, p < 0.041), were observed. Opioids combined with NSAIDs comprised 72.6% of the opioid prescriptions and 62.3% of all analgesic prescriptions in visits with urolithiasis diagnosis.

CONCLUSIONS

The use of opioids when managing urolithiasis decreased 4.3% after the crisis declaration; however, statistically are not different from pre-declaration numbers. Most often, opioids were prescribed with NSAIDs in urolithiasis patients.

Comparative Study of Opioid Initiation With Tramadol, Short-acting Hydrocodone, or Short-acting Oxycodone on Opioid-related Adverse Outcomes Among Chronic Noncancer Pain Patients

OBJECTIVE

To compare the safety profiles of low and high-dose tramadol, short-acting hydrocodone, and short-acting oxycodone therapies among chronic noncancer pain individuals.

MATERIALS AND METHODS

A retrospective cohort study of individuals with back/neck pain/osteoarthritis with an initial opioid prescription for tramadol, hydrocodone, or oxycodone was conducted using IQVIA PharMetrics Plus claims for Academics database (2006 to 2020). Two cohorts were created for separately studying opioid-related adverse events (overdoses, accidents, self-inflicted injuries, and violence-related injuries) and substance use disorders (opioid and nonopioid). Patients were followed from the index date until an outcome event, end of enrollment, or data end. Time-varying exposure groups were constructed and Cox regression models were estimated.

RESULTS

A total of 1,062,167 (tramadol [16.5%], hydrocodone [61.1%], and oxycodone [22.4%]) and 986,809 (tramadol [16.5%], hydrocodone [61.3%], and oxycodone [22.2%]) individuals were in the adverse event and substance use disorder cohorts. All high-dose groups had elevated risk of nearly all outcomes, compared with low-dose hydrocodone. Compared with low-dose hydrocodone, low-dose oxycodone was associated with a higher risk of opioid overdose (hazard ratio: 1.79 [1.37 to 2.33]). No difference in risk was observed between low-dose tramadol and low-dose hydrocodone (hazard ratio: 0.85 [0.64 to 1.13]). Low-dose oxycodone had higher risks of an opioid use disorder, and low-dose tramadol had a lower risk of accidents, self-inflicted injuries, and opioid use disorder compared with low-dose hydrocodone.

DISCUSSION

Low-dose oxycodone had a higher risk of opioid-related adverse outcomes compared with low-dose tramadol and hydrocodone. This should be interpreted in conjunction with the benefits of pain control and functioning associated with oxycodone use in future research.

The role of opioid transmission in music-induced pleasure

Studies conducted in rodents indicate a crucial role of the opioid circuit in mediating objective hedonic reactions to primary rewards. However, it remains unclear whether opioid transmission is also essential to experience pleasure with more abstract rewards, such as music. We addressed this question using a double-blind within-subject pharmacological design in which opioid levels were up- and downregulated by administering an opioid agonist (oxycodone) and antagonist (naltrexone), respectively, before healthy participants (n = 21) listened to music. Participants also performed a monetary incentive delay (MID) task to control for the effectiveness of the treatment and the specificity of the effects. Our results revealed that the pharmacological intervention did not modulate subjective reports of pleasure, nor the occurrence of chills. On the contrary, psychophysiological (objective) measures of emotional arousal, such as skin conductance responses (SCRs), were bidirectionally modulated in both the music and MID tasks. This modulation specifically occurred during reward consumption, with greater pleasure-related SCR following oxycodone than naltrexone. These findings indicate that opioid transmission does not modulate subjective evaluations but rather affects objective reward-related psychophysiological responses. These findings raise new caveats about the role of the opioidergic system in the modulation of pleasure for more abstract or cognitive forms of rewarding experiences, such as music.

Gabapentin increases the abuse liability of alcohol alone and in combination with oxycodone in participants with co-occurring opioid and alcohol use disorder

BACKGROUND

People who have co-occurring Alcohol Use Disorder (AUD) and Opioid Use Disorder (OUD) carry a higher risk of adverse outcomes, including drug overdose. Early clinical and preclinical studies suggested that gabapentin may be effective in treating both disorders. The present study was designed to assess the effects of gabapentin on the subjective and physiological effects of oxycodone (OXY) and alcohol (ALC), alone and in combination.

METHODS

During an 8-week, inpatient, within-subject, randomized, double-blind, placebo-controlled crossover study, non-treatment seeking participants (N = 13; 12 M/1F; 44.1 ± 3 years of age) with OUD and AUD were maintained on oral morphine (120 mg daily). Under gabapentin (1800 mg/day) and placebo (0 mg/day) maintenance, participants completed nine separate test sessions (three sessions per week) during which they received an oral solution containing 0, 15, or 30 mg/70 kg OXY in combination with 0, 0.5, or 0.75 g/kg ALC. During test sessions, subjective effects and physiological responses were assessed repeatedly on 100-mm visual analog scales (VAS). The primary outcome variable was the VAS rating of drug liking after receiving the drug challenge.

RESULTS

Alcohol alone (but not oxycodone alone) produced dose-related increases in several positive subjective responses, including drug liking. Gabapentin significantly increased drug liking when given in combination with ALC and OXY + ALC (p < 0.05). Gabapentin did not clinically compromise respiration or other vital functions.

CONCLUSIONS

Gabapentin may increase the abuse liability of ALC and OXY + ALC in those with co-occurring OUD and AUD.

Opioid-related overdose and chronic use following an initial prescription of hydrocodone versus oxycodone

Background

Hydrocodone and oxycodone are prescribed commonly to treat pain. However, differences in risk of opioid-related adverse outcomes after an initial prescription are unknown.

This study aims to determine the risk of opioid-related adverse events, defined as either chronic use or opioid overdose, following a first prescription of hydrocodone or oxycodone to opioid naïve patients.

Methods

A retrospective analysis of multiple linked public health datasets in the state of Oregon. Adult patients ages 18 and older who a) received an initial prescription for oxycodone or hydrocodone between 2015–2017 and b) had no opioid prescriptions or opioid-related hospitalizations or emergency department visits in the year preceding the prescription were followed through the end of 2018. First-year chronic opioid use was defined as ≥6 opioid prescriptions (including index) and average ≤30 days uncovered between prescriptions. Fatal or non-fatal opioid overdose was indicated from insurance claims, hospital discharge data or vital records.

Results

After index prescription, 2.8% (n = 14,458) of individuals developed chronic use and 0.3% (n = 1,480) experienced overdose. After adjustment for patient and index prescription characteristics, patients receiving oxycodone had lower odds of developing chronic use relative to patients receiving hydrocodone (adjusted odds ratio = 0.95, 95% confidence interval (CI) 0.91–1.00) but a higher risk of overdose (adjusted hazard ratio (aHR) = 1.65, 95% CI 1.45–1.87). Oxycodone monotherapy appears to greatly increase the hazard of opioid overdose (aHR 2.18, 95% CI 1.86–2.57) compared with hydrocodone with acetaminophen. Oxycodone combined with acetaminophen also shows a significant increase (aHR 1.26, 95% CI 1.06–1.50), but not to the same extent.

Conclusions

Among previously opioid-naïve patients, the risk of developing chronic use was slightly higher with hydrocodone, whereas the risk of overdose was higher after oxycodone, in combination with acetaminophen or monotherapy. With a goal of reducing overdose-related deaths, hydrocodone may be the favorable agent.

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.

Relative potency of intravenous oxymorphone compared to other µ opioid agonists in humans - pilot study outcomes

AIMS

Intravenous (IV) misuse of the µ opioid analgesic oxymorphone has caused significant public health harms; however, no controlled data on its IV abuse potential are available. The primary aims of this pilot study were to directly compare IV oxymorphone to IV oxycodone, morphine, and hydromorphone on a subjective measure of drug liking and to assess relative potency.

METHODS

Participants (n = 6) with opioid use disorder, physical dependence, and current IV use completed this two-site, within-subject, double-blind, placebo-controlled, inpatient pilot study. During each session, one IV dose (mg/70 kg) was administered: oxymorphone (1.8, 3.2, 5.6, 10, 18, 32), hydromorphone (1.8, 3.2, 5.6, 10, 18), oxycodone (18, 32, 56), morphine (18, 32), and placebo. Data were collected before and for 6 h after dosing. Primary outcomes included safety/physiological effects, subjective reports of drug liking, and relative potency estimates.

RESULTS

All active test drugs produced prototypical, dose-related µ opioid agonist effects (e.g., miosis). Oxymorphone was more potent than the comparator opioids on several measures, including drug liking and respiratory depression (p < 0.05). Across abuse-related subjective outcomes, oxymorphone was 2.3-2.8-fold more potent than hydromorphone and 12.5-14-fold more potent than oxycodone (p < 0.05).

CONCLUSIONS

Despite the relatively small sample size, this pilot study detected robust oxymorphone effects. Oxymorphone was far more potent than the comparator opioids, particularly on abuse potential outcomes. Overall, these findings may help explain surveillance reports that demonstrate, after adjusting for prescription availability, oxymorphone is injected at the highest frequency, relative to other prescription opioids.

Why comparative epidemiological indicators suggest that New Zealand is unlikely to experience a severe opioid epidemic

North America (i.e., the United States and Canada) and select other wealthy Commonwealth countries (e.g., Australia, the UK) have been experiencing marked 'opioid epidemics', consisting of elevated opioid use and related (e.g., mortality and morbidity) harms involving both prescription and, increasingly, illicit opioid substances. Multiple commentators have alerted to the possibility of New Zealand becoming home to a similar opioid crisis. In this article, we briefly examine and compare key system-level epidemiological indicators for New Zealand in regards to this situation and prospect. These data suggest that, comparatively, population-level (medical) opioid use, exposure and supply in New Zealand have been low and moderate, mostly involving restrained and lower-risk (e.g., short-duration, few long-acting/high-potency formulations, restricted settings) medical opioid availability, with limited over-time increases and absent the major oscillations in opioid dispensing observed elsewhere. Similarly, illicit opioids have been rather low in availability and use, and do not form primary substances in illicit drug scenes or markets. Correspondingly, opioid-related mortality in New Zealand has been somewhat increasing over-time albeit at comparably low levels, and principally involves methadone, morphine and codeine, i.e. the main opioids medically prescribed. Synthesizing the evidence, New Zealand has not featured the distinct characteristics or system-level drivers that have facilitated the opioid epidemics as have unfolded in other jurisdictions. It appears that New Zealand may have all along engaged in the more measured opioid use practices that other jurisdictions have attempted to revert to post-hoc (but largely when too late) while experiencing extensive adverse consequences related to opioids. On this basis, New Zealand provides for a worthwhile comparative case study towards more moderate opioid utilization and control entailing relatively limited collateral harms (e.g., opioid mortality) on public health compared to elsewhere. Details and characteristics of New Zealand's approach to and experience with opioids should be further examined for future and other jurisdictions' benefit.

Acute administration of oxycodone, alcohol, and their combination on simulated driving-preliminary outcomes in healthy adults

RATIONALE

Epidemiological data indicate that drivers testing positive for an opioid drug are twice as likely to cause a fatal car crash; however, there are limited controlled data available.

OBJECTIVES

The primary aim of this study was to assess the effects of a therapeutic dose range of oxycodone alone and in combination with alcohol on simulated driving performance.

METHODS

Healthy participants (n = 10) completed this within-subject, double-blind, placebo-controlled, randomized outpatient study. Six 7-h sessions were completed during which oxycodone (0, 5, 10 mg, p.o.) was administered 30 min before alcohol (0, 0.8 g/kg (15% less for women), p.o.) for a total of 6 test conditions. Driving assessments and participant-, observer-rated, psychomotor and physiological measures were collected in regular intervals before and after drug administration.

RESULTS

Oxycodone alone (5, 10 mg) did not produce any changes in driving outcomes or psychomotor task performance, relative to placebo (p > 0.05); however, 10 mg oxycodone produced increases in an array of subjective ratings, including sedation and impairment (p < 0.05). Alcohol alone produced driving impairment (e.g., decreased lateral control) (p < 0.05); however, oxycodone did not potentiate alcohol-related driving or subjective effects.

CONCLUSIONS

These preliminary data suggest that acute doses of oxycodone (5, 10 mg) do not significantly impair acuity on laboratory-based simulated driving models; however, 10 mg oxycodone produced increases in self-reported outcomes that are not compatible with safe driving behavior (e.g., sedation, impairment). Additional controlled research is needed to determine how opioid misuse (higher doses; parenteral routes of administration) impacts driving risk.

Evaluation of tradipitant, a selective NK1 antagonist, on response to oxycodone in humans

RATIONALE

Preclinical studies demonstrate that the NK1 receptor is involved in opioid reinforcement and withdrawal expression. Few studies have examined the impact of treatment with NK1 antagonists on opioid response in humans.

OBJECTIVE

To explore the potential for a selective NK1 antagonist, tradipitant, to attenuate the abuse liability and reinforcing and analgesic effects of oxycodone in opioid-experienced individuals.

METHODS

Participants with recreational opioid use, but without opioid physical dependence, were enrolled as inpatients for ~6 weeks (n = 8). A within-subject, double-blind, randomized, placebo-controlled, crossover design was employed. The pharmacodynamic response to intranasal oxycodone across a range of doses (0 to 30 mg) was examined during two counterbalanced maintenance periods (tradipitant 0 or 85 mg/bid). Oxycodone self-administration was assessed with a modified progressive ratio procedure, and analgesia was assessed with the cold pressor test.

RESULTS

Oxycodone produced significant and dose-related increases on a broad array of prototypic opioid measures, including subjective ratings related to abuse liability (e.g., liking) and physiological outcomes (i.e., expired CO₂). Oxycodone self-administration increased with increasing dose, as did analgesia. Tradipitant largely did not alter any of these effects of oxycodone, with the exception of producing a reduction in ratings of desire for opioids.

CONCLUSIONS

Given that the vast majority of oxycodone effects were unchanged by tradipitant, these data do not provide support for the utility of NK1 antagonists as a potential treatment for opioid use disorder.

Analgesic efficacy of morphine sulfate immediate release vs. oxycodone/acetaminophen for acute pain in the emergency department

OBJECTIVE

Previous research demonstrated that administration of Morphine Sulfate Immediate Release (MSIR) results in similar analgesic efficacy to Oxycodone but with significantly lesser degrees of euphoria and reward. The purpose of this study sit to investigate if MSIR combined with Acetaminophen can serve as an opioid analgesic alternative to Oxycodone combined with acetaminophen (Percocet) for acute pain in the Emergency Department (ED).

METHODS

A prospective, randomized, double-blind trial of ED patients aged 18 to 64 years presenting with moderate to severe acute pain as defined by an 11-point numeric rating scale (NRS) with an initial score of ≥5 (0 = no pain and 10 = very severe pain). Patients were randomized to receive either 15 mg MSIR combined with 650 mg of Acetaminophen or 10 mg Oxycodone combined with 650 mg Acetaminophen. Patients were assessed at baseline, 30, 45 and 60 min. The primary outcome was reduction in pain at 60 min. Secondary outcomes include drug likeability and adverse events.

RESULTS

80 patients were enrolled in the study (40 per group). Demographic characteristics were similar between the groups (P > 0.05). Mean NRS pain scores at baseline were 8.44 for the MSIR group and 8.53 for the Percocet group (P = 0.788). Mean pain scores decreased over time but remained similar between the groups: 30 min (6.03 vs. 6.43; P = 0.453), 45 min (5.31 vs. 5.48; P = 0.779), and 60 min (4.22 vs. 4.87; P = 0.346). Reduction in mean NRS pain scores were statistically significant from baseline to 30, 45 and 60 min within each group (P < 0.0001 at each time point for both groups). The largest NRS mean difference was from baseline to 60 min: 4.2 (95% CI: 3.43 to 5.01) for MSIR group and 3.61 (95% CI: 2.79 to 4.43) for Percocet group. No clinically significant changes or any serious adverse events were observed in either group.

CONCLUSION

MSIR provides similar analgesic efficacy as Percocet for short-term pain relief in the ED, similar rates of nausea/vomiting, and lower rates of likeability of the drug.

Relative addictive potential of opioid analgesic agents

Opioid overdoses and deaths continue to be a problem in the USA with a significant portion related to prescribed opioid analgesic agents. The role of pharmacogentic factors in opioid addiction is an active area of research. While all opioid analgesic agents have some addictive potential, it is clear that there are some with greater addictive potential. Oxycodone is the most widely abused opioid analgesic and it appears to predispose to chronic use with high likability by users. Fentanyl and hydromorphone are both very lipophilic allowing rapid penetration into the CNS, but are not rated as highly as other agents. Providers should consider the risk of addiction with the opioids they prescribe and give those with a lower addictive potential.

An evaluation of online discussion relating to nonmedical use of prescription opioids within the UK

AIM

To identify and describe the nature of online discussion relating to prescription opioids within the UK.

METHODS

We performed analysis of posts originating in the UK related to buprenorphine, hydrocodone, oxycodone and tramadol using Social Studio, a web-monitoring platform. The study included posts published between January 2014 and December 2016. The data were cleaned to produce a final dataset consisting only of substantive mentions, which were then categorised by defined themes.

RESULTS

The final dataset included a total of 17 361 substantive mentions (2936 buprenorphine, 2894 hydrocodone, 3826 oxycodone and 7705 tramadol). The most common theme for all 4 drugs was sharing experience or opinion comprising over 90% of mentions for each drug, while discussion related to polysubstance use was present in >1/4 of mentions across drug substances. Mentions related to diversion were more common for hydrocodone and oxycodone (8.1% [6.3-10.1 95% confidence interval] and 7.8% [6.5-9.2], respectively) than buprenorphine or tramadol (4.1 and 3.9% [3.5-4.3], respectively).

CONCLUSION

This investigation shows that there is substantial online discussion relating to a variety of nonmedical use (NMU) behaviours of prescription opioids within the UK, including for hydrocodone, which is not medically available. Web monitoring provides useful data and merits future investigation; this could include expansion to other categories of drugs and a more in-depth analysis of motivations behind NMU, both of which could add timely evidence regarding the current situation in the UK and help inform public health interventions for NMU of prescription drugs.

Opioid-induced Euphoria Among Emergency Department Patients With Acute Severe Pain: An Analysis of Data From a Randomized Trial

BACKGROUND

Parenteral opioids are commonly used to treat acute severe pain. We measured pleasurable sensations in patients administered intravenous analgesics to determine if these sensations were associated with receipt of an opioid, after controlling for relief of pain. Pleasurable sensations not accounted for by relief of pain were considered opioid-induced euphoria.

METHODS

These data were from a randomized study of 1 mg of hydromorphone versus 120 mg of lidocaine for abdominal pain. To assess euphoria, participants were asked to provide a 0 to 10 response to each of these questions: 1) How good did the medication make you feel? 2) How high did the medication make you feel? and 3) How happy did the medication make you feel? Pain at baseline and 30 minutes was also measured on a 0 to 10 scale. To determine the relative importance of pain relief versus medication type, we built three linear regression models in which each euphoria question was the dependent variable and pain relief, medication type, and medication-induced side effects were the independent variables.

RESULTS

Seventy-seven patients received lidocaine and 77 hydromorphone. Hydromorphone patients reported greater pain improvement than lidocaine patients (mean difference = 1.5, 95% confidence interval [CI] = 0.6 to 2.3) and higher scores on all three euphoria questions ("feeling good" difference = 1.9, 95% CI = 0.8 to 3.0; "feeling high" difference = 1.5, 95% CI = 0.4 to 2.7; "feeling happy" difference = 1.7, 95% CI = 0.6 to 2.8). In the regression models, hydromorphone administration (β-coefficient = 0.16, p = 0.03) and pain relief (β-coefficient = 0.45, p < 0.01) were both associated with "feeling good." "Feeling high" and "feeling happy" were associated with pain improvement (p < 0.01) but not with hydromorphone administration (p = 0.07 for "high" and p = 0.06 for "happy"). Medication-induced side effects were not associated with these measures of euphoria.

CONCLUSION

Among emergency department patients with acute pain, hydromorphone-induced euphoria, though measurable, was generally less important for patients than relief of pain.

Oral prescription opioid-seeking behavior in male and female mice

A significant portion of prescription opioid users self-administer orally rather than intravenously. Animal models of opioid addiction have demonstrated that intravenous cues are sufficient to cause drug seeking. However, intravenous models may not characterize oral users, and the preference to self-administer orally appears to be partially influenced by the user's sex. Our objectives were to determine whether oral opioid-associated cues are sufficient for relapse and whether sex differences exist in relapse susceptibility. Mice orally self-administered escalating doses of oxycodone under postprandial (prefed) or non-postprandial (no prefeeding) conditions. Both sexes demonstrated cue-induced reinstatement following abstinence. In separate mice, we found that oral oxycodone cues were sufficient to reinstate extinguished oral oxycodone-seeking behavior following abstinence without prior postprandial or water self-administration training. During self-administration, we incidentally found that female mice earned significantly more mg/kg oxycodone than male mice. Follow-up studies indicated sex differences in psychomotor stimulation and plasma oxycodone/oxymorphone following oral oxycodone administration. In addition, gonadal studies were performed in which we found divergent responses where ovariectomy-enhanced and orchiectomy-suppressed oral self-administration. While the suppressive effects of orchiectomy were identified across doses and postprandial conditions, the enhancing effects of ovariectomy were selective to non-postprandial conditions. These studies establish that (a) oral drug cues are sufficient to cause reinstatement that is independent of prandial conditions and water-seeking behavior, (b) earned oral oxycodone is larger in female mice compared with male mice potentially through differences in psychomotor stimulation and drug metabolism, and (c) gonadectomy produces divergent effects on oral oxycodone self-administration between sexes.

Opioid Prescribing Patterns and Usage Following Cochlear Implantation

OBJECTIVE

To evaluate opioid prescribing patterns following cochlear implantation (CI) and assess factors associated with recurrent opioid use.

STUDY DESIGN

Retrospective cohort study.

SETTING

National pharmaceutical database recording opioid fulfillment (Truven Health Marketscan Commercial Claims and Encounters and Medicare Claims and Encounters database) PARTICIPANTS:: CI recipients who filled opioid prescriptions between January 2011 and December 2016. All patients had no previous opioid prescriptions filled 60 days before implantation and filled at least one opioid prescription within 1 week after surgery. Cohort 1 filled only one prescription and cohort 2 filled more than one prescription in the 12 months following CI. Univariate/multivariate analysis was performed to assess for associations with recurrent opioid use.

MAIN OUTCOME MEASURE(S)

Opioid prescription details and recurrent opioid use.

RESULTS

The study included 98 patients (cohort 1 = 57, cohort 2 (recurrent opioid use) = 41). Hydrocodone 5 mg was most frequently used. The average duration opioids were prescribed was 5.49 days with an average quantity of tablets of 36.1. Recurrent opioid use in cohort 2 was associated with both total morphine milligram equivalents (MME) prescribed/day in the first postoperative week (OR = 1.03, p = 0.01) and use of stronger MME opioids (OR = 7.20, p = 0.05).

CONCLUSION

Prescribing patterns following CI can influence recurrent opioid use in patients. Each additional tablet of hydrocodone 5 mg beyond 8 tablets/d or oxycodone 5 mg beyond 5.33 tablets/d, increases the likelihood of recurrent opioid use by 15 or 22.5%, respectively. Limiting opioids prescribed per day to no more than 40 MME could lower the likelihood of patients becoming recurrent opioid users postoperatively.

Mitigating the Shadow of the Worldwide Opioid Crisis: A Review for the Foot and Ankle Specialist

The foot and ankle physician is no stranger to the difficulties in achieving optimal pain therapy. There remains much confusion and conflicting information available to nonspecialist prescribers regarding opioid therapy as well as great deal of fear or opiophobia during the prescribing and monitoring of opioids worldwide. The role of the lower extremity specialist provider is to responsibly provide pain management to their patients in an error-free environment. The purpose of this article is to explore the central theme of responsible opioid pain management worldwide. This review focuses on the prescribing strategies of opioid analgesics to treat lower-extremity pain. Pharmacology of opioid agents and opioid prescribing strategies will be presented. Then, the concept of multimodal pain relief criteria for selecting appropriate opioid analgesics and use of adjunctive therapies to prevent opioid misuse as presented in the current medical literature is reported. Finally, a commentary and discussion centered on the actions of pharmaceutical companies of promoting their opioid products and the negative outcomes of their actions in the United States that may go worldwide if behaviors of these companies are not recognized by the foot and ankle specialist.

Oxycodone, Hydromorphone, and the Risk of Suicide: A Retrospective Population-Based Case-Control Study

INTRODUCTION

Opioids have been increasingly associated with suicide, but whether they are independent contributors is unclear. Oxycodone and hydromorphone are commonly prescribed high-potency opioids that can differentially affect mood.

OBJECTIVE

The objective of this study was to explore whether oxycodone and hydromorphone are differentially associated with suicide.

METHODS

We conducted a retrospective population-based case-control study in Ontario, Canada, from 1992 to 2014. Using coronial data, we defined case subjects as individuals who died by suicide involving an opioid overdose. Each of these was matched with up to four controls who died of accidental opioid overdose. We ascertained exposure to oxycodone, hydromorphone, and other opioids from postmortem toxicology testing. We used odds ratios and 95% confidence intervals to examine whether opioid-related suicide was disproportionately associated with oxycodone relative to hydromorphone.

RESULTS

We identified 438 suicides and 1212 accidental deaths, each of which involved either oxycodone or hydromorphone but not both. The median age at death was 49 years and 51% were men. After adjusting for a history of self-harm, psychiatric illness, and exposure to other opioids, we found that oxycodone was more strongly associated with suicide than hydromorphone (adjusted odds ratio 1.59; 95% confidence interval 1.20-2.11). In a secondary analysis, we observed a trend of similar magnitude in which combined exposure to oxycodone and hydromorphone was more strongly associated with suicide than hydromorphone alone (adjusted odds ratio 1.68; 95% confidence interval 0.92-3.09).

CONCLUSIONS

While preliminary, these findings support the possibility that some high-potency opioids might independently influence the risk of suicide in susceptible individuals.

Pharmacokinetics and Abuse Potential of Asalhydromorphone, a Novel Prodrug of Hydromorphone, After Intranasal Administration in Recreational Drug Users

OBJECTIVES

Hydromorphone (HM) is a potent μ-opioid receptor agonist with high susceptibility for abuse. A prodrug of hydromorphone, asalhydromorphone (ASAL-HM), has been designed to deter nonoral forms of abuse associated with hydromorphone. This study evaluated the intranasal (IN) pharmacokinetics and exploratory abuse potential of ASAL-HM compared with HM.

DESIGN

Single-center, randomized, double-blind, crossover study.

SETTING

Clinical research site.

SUBJECTS

Healthy adult, nondependent recreational opioid users.

METHODS

Subjects (N = 26) were randomized to receive IN administration of 16.1 mg of ASAL-HM and 8.0 mg of HM (molar-equivalent with respect to hydromorphone). Blood samples were taken through 24 hours postdose, and pharmacodynamic end points (Drug Liking, Feeling High, Take Drug Again, Overall Drug Liking) were assessed through eight hours postdose. Nasal irritation and safety were also assessed.

RESULTS

Relative to IN HM, the rate (Cmax) and extent (area under the curve [AUC0-last, AUC0-inf]) of exposure to hydromorphone following IN ASAL-HM were reduced by ≥50%. Consistent with these findings, scores on "at-the-moment" (i.e., Drug Liking Emax, High Emax) and retrospective (i.e., Take Drug Again, Overall Drug Liking) end points were statistically significantly lower for IN ASAL-HM, with mean/median differences ranging from 11.4 to 25.0 points. ASAL-HM produced greater nasal-related effects, such as nasal burning and facial pain, and a lower incidence of typical opioid-related adverse events such as euphoria, pruritus, and somnolence.

CONCLUSIONS

The novel hydromorphone prodrug ASAL-HM produced marked reductions in hydromorphone exposure and abuse-related effects following IN administration compared with HM. ASAL-HM has desirable molecular features for incorporation into putative abuse-deterrent immediate-release and extended-release hydromorphone products.

Kratom (Mitragyna speciosa): User demographics, use patterns, and implications for the opioid epidemic

BACKGROUND

Kratom, a Southeast Asian plant with opioid-receptor mediated effects, has emerged as a potential substance of abuse, with limited data on its use and effects. This study characterized kratom user demographics, use patterns, and perceived drug effects.

METHODS

A cross-sectional, anonymous online survey was conducted between January and December 2017.

RESULTS

2,798 kratom users - mean age 40 (SD = 12); predominantly White (90 %), female (61 %), and located in the US (97 %) - completed the survey. Kratom was primarily taken orally in doses of 1-3 g (49 %), with daily use (59 %) being most common. Kratom was used for pain (91 %), anxiety (67 %), and depression (65 %), with high ratings of effectiveness. 1,144 (41 %) used kratom to stop or reduce prescription or illicit opioid use, citing decreased opioid withdrawal and craving related to kratom use, with 411 reporting >1-year continuous abstinence from opioids attributed to kratom use. Roughly one-third of respondents reported adverse effects of kratom, largely rated as mild in severity and lasting ≤24 h. Seventeen participants (0.6 %) sought treatment for adverse effects. Fifty-six individuals (2 %) met DSM-5 criteria for a past-year moderate or severe kratom-related substance use disorder (SUD). When asked how troubled they felt regarding their kratom use, the mean (SD) rating was 3.2 (9.8) on a scale from 0 to 100.

CONCLUSION

Kratom is used among White, middle-aged Americans for symptoms of pain, anxiety, depression, and opioid withdrawal. Although regular use was typical, kratom-related SUD and serious adverse effects were uncommon. Additional research on kratom epidemiology and pharmacology is imperative in light of the present opioid epidemic.

Pharmacokinetic and pharmacodynamic considerations in developing a response to the opioid epidemic

Introduction: Opioids continue to be used widely for pain management. Widespread availability of prescription opioids has led to opioid abuse and addiction. Besides steps to reduce inappropriate prescribing, exploiting opioid pharmacology to make their use safer is important.Areas covered: This article discusses the pathology and factors underlying opioid abuse. Pharmacokinetic and pharmacodynamic properties affecting abuse liability of commonly abused opioids have been highlighted. These properties inform the development of ideal abuse deterrent products. Mechanisms and cost-effectiveness of available abuse deterrent products have been reviewed in addition to the pharmacology of medications used to treat addiction.Expert opinion: The opioid crisis presents unique challenges to managing pain effectively given the limited repertoire of strong analgesics. The 5-point strategy to combat the opioid crisis calls for better preventive, treatment, and recovery services, better data, better pain management, better availability of overdose-reversing drugs and better research. There is an urgent need to decrease the cost of abuse deterrent opioids which deters their cost-effectiveness. In addition, discovery of novel analgesics, further insight into central and peripheral pain mechanisms, understanding genomic risk profiles for efficient targeted efforts, and education will be key to winning this fight against the opioid crisis.

Opioid prescribing rates from the emergency department: Down but not out

INTRODUCTION

To examine opioid prescribing rates following emergency department (ED) discharge stratified by patient's clinical and demographic characteristics over an 11-year period.

MATERIAL AND METHODS

We used 3.9 million ED visits from commercially insured enrollees and 15.2 million ED visits from Medicaid enrollees aged 12 to 64 over 2005-2016 from the IBM® MarketScan® Research Databases. We calculated rates of opioid prescribing at discharge from the ED and the average number of pills per opioid prescription filled.

RESULTS

Approximately 15-20% of ED visits resulted in opioid prescriptions filled. Rates increased from 2005 into late 2009 and 2010 and then declined steadily through 2016. Prescribing rates were similar for commercially insured and Medicaid enrollees. Being aged 25-54 years was associated with the highest rates of opioid prescriptions being filled. Hydrocodone was the most commonly prescribed opioid, but rates for hydrocodone prescription filling also fell the most. Rates for oxycodone were stable, and rates for tramadol increased. The average number of pills dispensed from prescriptions filled remained steady over the study period at 18-20.

DISCUSSION

Opioid prescribing rates from the ED have declined steadily since 2010 in reversal of earlier trends; however, about 15% of ED patients still received opioid prescriptions in 2016 amidst a national opioid crisis.

CONCLUSIONS

Efforts to reduce opioid prescribing could consider focusing on the pain types, age groups, and regions with high prescription rates identified in this study.

Cannabinoid modulation of opioid analgesia and subjective drug effects in healthy humans

RATIONALE

Dozens of preclinical studies have reported cannabinoid agonist potentiation of the analgesic effects of μ-opioid agonists.

OBJECTIVES

The aim of this study was to determine if a cannabinoid agonist could potentiate opioid analgesia in humans using several laboratory pain models.

METHODS

Healthy participants (n = 10) with/out current drug use/pain conditions completed this within-subject, double-blind, placebo-controlled, randomized outpatient study. Nine 8-h sessions were completed during which dronabinol (0, 2.5, 5 mg, p.o.) was administered 1 h before oxycodone (0, 5, 10 mg, p.o.) for a total of 9 test conditions. Outcomes included sensory threshold and tolerance from four experimental pain models (cold pressor, pressure algometer, hot thermode, cold hyperalgesia), along with participant- and observer-rated, performance and physiological effects.

RESULTS

Oxycodone produced miosis (p < 0.05) and analgesic responses (e.g., pressure algometer [p < 0.05]), while dronabinol did not (p > 0.05). Depending on the dose combination, dronabinol attenuated or did not alter oxycodone analgesia; for example, dronabinol (2.5 mg) decreased the analgesic effects of oxycodone (10 mg) on pressure tolerance. Conversely, dronabinol increased oxycodone subjective effects (e.g., drug liking) (p < 0.05); oxycodone (5 mg) ratings of "high" were potentiated by 5 mg dronabinol (p < 0.05; placebo = 1.1 [± 0.7]; 5 mg oxycodone = 4.7 [± 2.2]; 5 mg dronabinol = 9.9 [± 8.4]; 5 mg oxycodone + 5 mg dronabinol = 37.4 [± 11.3]).

CONCLUSIONS

This study indicates that dronabinol did not enhance the analgesic effects of oxycodone and increased abuse- and impairment-related subjective effects. These data suggest that dronabinol may not be an effective or appropriate opioid adjuvant; it could potentially increase opioid dose requirements, while increasing psychoactive opioid effects.

Balancing opioid analgesia with the risk of nonmedical opioid use in patients with cancer

The current opioid crisis has brought renewed attention and scrutiny to opioid prescriptions. When patients receiving opioid therapy for pain engage in nonmedical opioid use (NMOU) or diversion, untoward consequences can occur. New evidence suggests that patients with cancer might be at a higher risk of NMOU than was previously thought, but clinical evidence still supports the use of opioid analgesics as the gold standard to treat cancer-related pain, creating a dilemma in patient management. Clinicians are encouraged to adopt a universal precautions approach to patients with cancer receiving opioids, which includes screening all patients; discussing the risks, benefits, adverse effects and alternatives of opioid therapy; and providing education on safe use, storage and disposal. Use of urine drug tests, prescription drug monitoring programmes and close observation of behaviours related to opioid use help to ensure treatment adherence, detect NMOU and support therapeutic decision-making. These measures can optimize the risk-benefit ratio while supporting safe opioid use. In this Review, we examine the role of opioids in cancer pain, the risk of substance use disorder and methods to achieve the right balance between the two in order to ensure safe opioid use.

The association between endogenous opioid function and morphine responsiveness: a moderating role for endocannabinoids

We sought to replicate previous findings that low endogenous opioid (EO) function predicts greater morphine analgesia and extended these findings by examining whether circulating endocannabinoids and related lipids moderate EO-related predictive effects. Individuals with chronic low-back pain (n = 46) provided blood samples for endocannabinoid analyses, then underwent separate identical laboratory sessions under 3 drug conditions: saline placebo, intravenous (i.v.) naloxone (opioid antagonist; 12-mg total), and i.v. morphine (0.09-mg/kg total). During each session, participants rated low-back pain intensity, evoked heat pain intensity, and nonpain subjective effects 4 times in sequence after incremental drug dosing. Mean morphine effects (morphine-placebo difference) and opioid blockade effects (naloxone-placebo difference; to index EO function) for each primary outcome (low-back pain intensity, evoked heat pain intensity, and nonpain subjective effects) were derived by averaging across the 4 incremental doses. The association between EO function and morphine-induced back pain relief was significantly moderated by endocannabinoids [2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine (AEA)]. Lower EO function predicted greater morphine analgesia only for those with relatively lower endocannabinoids. Endocannabinoids also significantly moderated EO effects on morphine-related changes in visual analog scale-evoked pain intensity (2-AG), drug liking (AEA and 2-AG), and desire to take again (AEA and 2-AG). In the absence of significant interactions, lower EO function predicted significantly greater morphine analgesia (as in past work) and euphoria. Results indicate that EO effects on analgesic and subjective responses to opioid medications are greatest when endocannabinoid levels are low. These findings may help guide development of mechanism-based predictors for personalized pain medicine algorithms.

A Benefit Risk Review of Pediatric Use of Hydrocodone/Chlorpheniramine, a Prescription Opioid Antitussive Agent for the Treatment of Cough

Hydrocodone/chlorpheniramine is a prescription opioid licensed in the USA for the relief of cough and upper respiratory symptoms associated with allergy or cold in adults, previously contraindicated in children aged < 6 years. We present findings from a modern benefit risk review of hydrocodone/chlorpheniramine use as an antitussive agent in patients aged 6 to < 18 years. A cumulative search of the manufacturer’s pharmacovigilance database covering 1 January 1900–7 August 2017 identified all individual case safety reports (ICSRs) associated with product family name “hydrocodone/chlorpheniramine.” The search was inclusive of all MedDRA system organ classes, stratified by age (< 18 years). A comprehensive review of the scientific literature was conducted on safety and efficacy of opioids for pediatric treatment of cough. Three hundred and ninety-one ICSRs associated with hydrocodone/chlorpheniramine were identified; 35/391 ICSRs were in patients < 18 years of age; 18 were considered serious. Four fatalities were reported in patients 6 to < 18 years; two fatalities involved co-suspect medication azithromycin and two were poorly documented. Our literature search identified no robust efficacy data for hydrocodone/chlorpheniramine in the relief of cough and upper respiratory symptoms associated with allergy or cold in patients aged 6 to < 18 years. As we found no evidence of hydrocodone/chlorpheniramine efficacy in the pediatric population, we conclude that the benefit risk profile is unfavorable. This evidence contributed to the US Food and Drug Administration’s (FDA’s) recent decision that hydrocodone-containing cough and cold medications should no longer be indicated for treatment of cough in patients < 18 years, highlighting the value of proactive re-evaluation of the benefit risk profile of older established drugs.

Plain Language Summary

People often use medicines containing opioids to treat cough symptoms. The US Food and Drug Administration (FDA) recently decided that cough medicines containing opioids should not be used by children under 18 years old. Part of this decision was a review of the benefits and risks of using cough medicines that contain the opioid hydrocodone in children.

Why was this review carried out? Most cough medicines that doctors can prescribe were approved several decades ago. Since then, rules for the approval of medicines have become stricter. In this review, researchers looked at the safety of hydrocodone, and how well this opioid relieves cough symptoms in children. Up-to-date information and modern research methods were used.

The two key pieces of evidence found were:

We could not locate any clinical trials providing robust evidence for the use of hydrocodone for cough relief in children under 18 years of age. (Outside the scope of this review, a number of clinical trials of hydrocodone-containing cough medicines in adults aged 18 years and over have shown the medicine to be effective in these patients.)

Cough medicines containing opioids can cause harmful side effects in children such as breathing problems. In the research reported here, ten children died after taking a hydrocodone-containing cough medicine. Nine of these deaths were due to overdose.

This evidence was used to draw the following conclusions:

In children under 18 years of age, the risks of using hydrocodone for cough relief are greater than any benefits.

Older medicines should be reviewed regularly to look at their safety and how well they are working using up-to-date evidence.

Prescription Opioid Type and the Likelihood of Prolonged Opioid Use After Orthopaedic Surgery

INTRODUCTION

A common belief is that some narcotic medications have a higher association with prolonged use. We assessed whether the initial opiate type prescribed to postoperative, opiate-naive orthopaedic trauma patients was associated with prolonged opioid use.

METHODS

We studied 17,961 adult, opiate-naive patients treated for a surgical musculoskeletal injury. Discharge prescription in morphine milligram equivalents (MMEs, a standardized dosing unit that allows for comparison across opioid types) was calculated. Opioid prescribing beyond 90 days after injury was defined as prolonged use.

RESULTS

Initial analysis demonstrated a higher likelihood of prolonged use for patients discharged on hydromorphone or morphine versus hydrocodone. However, when we adjusted for discharge MME, only opioid quantity was predictive of prolonged use (P < 0.001). In addition, discharge MME was associated with opioid type (P < 0.01).

DISCUSSION

Persistent opiate use was associated with discharge opioid quantity, not the opioid type. These results highlight the importance of calculating equivalence doses when selecting opioid types and considering amount of narcotics prescribed.

LEVEL OF EVIDENCE

Level III.

Human Abuse Potential of the New Opioid Analgesic Molecule NKTR-181 Compared with Oxycodone

Objective

Evaluate the human abuse potential, pharmacokinetics, pharmacodynamics, and safety of NKTR-181, a novel mu-opioid agonist molecule, relative to oxycodone.

Design

This randomized, single-center, double-blind, active- and placebo-controlled five-period crossover study enrolled healthy, adult, non–physically dependent recreational opioid users.

Setting

Inpatient clinical research site.

Subjects

Forty-two randomized subjects (73.8% male, 81% white, mean age = 25 years).

Methods

The primary objective was to evaluate single orally administered 100, 200, and 400 mg NKTR-181 doses in solution compared with 40 mg oxycodone and placebo solutions using the Drug Liking visual analog scale. Secondary measures included the Drug Effects Questionnaire, Addiction Research Center Inventory/Morphine Benzedrine Group Subscale, Price Value Assessment Questionnaire, Global Assessment of Overall Drug Liking, and Take Drug Again Assessment. Central nervous system mu-opioid effects were assessed using pupillometry. The study included qualifying and treatment phases. Subjects received each of the five treatments using a crossover design.

Results

NKTR-181 at all dose levels had significantly lower Drug Liking E_max than oxycodone (P < 0.0001). Drug Liking scores for oxycodone increased rapidly within 15 minutes and peaked at approximately one hour postdose, whereas Drug Liking (and most secondary abuse potential measures) for all doses of NKTR-181 were comparable with placebo for at least the first hour. Only the 400 mg Drug Liking scores were minimally differentiated vs placebo from one and a half to four hours, but remained significantly lower than oxycodone (P < 0.003). NKTR-181 treatment-related adverse effects were mild and occurred at a lower rate compared with oxycodone.

Conclusions

NKTR-181 demonstrated delayed onset of CNS effects and significantly lower abuse potential scores compared with oxycodone in recreational opioid users.

Readiness and recovery: Transferring between methadone and buprenorphine/naloxone for the treatment of opioid use disorder

Long-acting opioids are prescribed as part of treatment for opioid use disorders; methadone and buprenorphine are well researched and commonly prescribed for the treatment of opioid use disorder. Meta-analysis suggests that buprenorphine has a slightly poorer retention rate in treatment as compared to methadone. Benefits of buprenorphine/naloxone include greater ease in ceasing treatment and less use of illicit opioids while in treatment as compared to methadone. There are a number of qualitative and mixed-method studies that ask patients about their experiences of methadone maintenance and buprenorphine maintenance treatment. This research aimed to understand perspectives of receiving buprenorphine/naloxone for the treatment of opioid use disorder. A qualitative descriptive approach was used. Seven participants with a current diagnosis of opioid use disorder treated with buprenorphine/naloxone were interviewed. Thematic analysis extracted four themes: drivers for opioid substitution treatment change; readiness for buprenorphine/naloxone substitution treatment; absence of effect from buprenorphine/naloxone; and an increased sense of citizenship on buprenorphine/naloxone. This study identified a number of factors influencing participants' decision-making in transferring between methadone and buprenorphine/naloxone for the treatment of their opioid use disorder. Methadone was preferred by those seeking sedation and wishing to continue using other opioids, and buprenorphine/naloxone was most effective for participants no longer wishing to experience sedation and seeing opioid abstinence as an end point in their recovery. Changing treatment expectations are important to consider when determining medication selection and highlight the importance of quality information when determining the most suitable medication for the treatment of opioid use disorder.

Assessment of the Abuse Potential of Cebranopadol in Nondependent Recreational Opioid Users: A Phase 1 Randomized Controlled Study

BACKGROUND

Cebranopadol is a nociceptin/orphanin FQ peptide/opioid receptor agonist with central antinociceptive activity. We hypothesize that this novel mechanism of action may lead to a lower risk of abuse compared with pure μ-opioid peptide receptor agonists.

METHODS

We conducted a single-dose, nested-randomized, double-blind crossover study in nondependent recreational opioid users to evaluate the abuse potential of single doses of cebranopadol relative to hydromorphone immediate release and placebo. The study consisted of a qualification phase and a 7-period treatment phase (cebranopadol 200, 400, and 800 μg; hydromorphone 8 and 16 mg; and 2 placebos). The primary end point was the peak effect of drug liking at this moment, measured by visual analog scale (VAS). Various secondary end points (eg, VAS rating for good drug effects, high, bad drug effects, take drug again, drug similarity, and pupillometry) were also investigated.

RESULTS

Forty-two subjects completed the study. Cebranopadol 200 and 400 μg did not differentiate from placebo on the abuse potential assessments and generated smaller responses than hydromorphone. Responses observed with cebranopadol 800 μg were similar to hydromorphone 8 mg and smaller than hydromorphone 16 mg. The maximum effect for VAS drug liking at this moment was delayed compared with hydromorphone (3 and 1.5 hours, respectively). Cebranopadol administration was safe; no serious adverse events or study discontinuation due to treatment-emergent adverse events occurred.

CONCLUSIONS

These results confirm our hypothesis that cebranopadol, a nociceptin/orphanin FQ peptide/opioid receptor agonist, has lower abuse potential than hydromorphone immediate release, a pure μ-opioid peptide agonist.

Self-reported cumulative medical opioid exposure and subjective responses on first use of opioids predict analgesic and subjective responses to placebo-controlled opioid administration

BACKGROUND AND OBJECTIVES

To expand the evidence base needed to enable personalized pain medicine, we evaluated whether self-reported cumulative exposure to medical opioids and subjective responses on first opioid use predicted responses to placebo-controlled opioid administration.

METHODS

In study 1, a survey assessing cumulative medical opioid exposure and subjective responses on first opioid use was created (History of Opioid Medical Exposure (HOME)) and psychometric features documented in a general sample of 307 working adults. In study 2, 49 patients with chronic low back pain completed the HOME and subsequently rated back pain intensity and subjective opioid effects four times after receiving saline placebo or intravenous morphine (four incremental doses) in two separate double-blinded laboratory sessions. Placebo-controlled morphine effects were derived for all outcomes.

RESULTS

Two HOME subscales were supported: cumulative opioid exposure and euphoric response, both demonstrating high test-retest reliability (Intraclass Correlation Coefficients > 0.93) and adequate internal consistency (Revelle's Omega Total = 0.73-0.77). In study 2, higher cumulative opioid exposure scores were associated with significantly greater morphine-related reductions in back pain intensity (p=0.02), but not with subjective drug effects. Higher euphoric response subscale scores were associated with significantly lower overall perceived morphine effect (p=0.003), less sedation (p=0.04), greater euphoria (p=0.03) and greater desire to take morphine again (p=0.02).

DISCUSSION

Self-reports of past exposure and responses to medical opioid analgesics may have utility for predicting subsequent analgesic responses and subjective effects. Further research is needed to establish the potential clinical and research utility of the HOME.

TRIAL REGISTRATION NUMBER

NCT02469077.

Pharmacokinetics and Abuse Potential of Benzhydrocodone, a Novel Prodrug of Hydrocodone, After Intranasal Administration in Recreational Drug Users

Objective

Developing an acetaminophen-free, immediate-release hydrocodone product remains an unmet medical need; however, new opioid analgesics should not introduce new abuse risks. Benzhydrocodone is a prodrug of hydrocodone that must be metabolized into hydrocodone by enzymes in the intestinal tract to optimally deliver its pharmacologic effects. This study evaluated the intranasal pharmacokinetics and abuse potential of benzhydrocodone active pharmaceutical ingredient (API) compared with hydrocodone bitartrate (HB) API.

Design

Single-center, randomized, double-blind, crossover study.

Setting

Clinical research site.

Subjects

Healthy adult, nondependent, recreational opioid users.

Methods

Subjects (N = 51 Completers) were randomized to receive 13.34 mg of intranasal benzhydrocodone API and 15.0 mg of intranasal HB API (molar-equivalent doses of hydrocodone). Blood samples were taken, and Drug Liking scores (assessed on a bipolar visual analog scale) were obtained throughout each dosing interval. Nasal irritation and safety were assessed.

Results

Peak hydrocodone plasma concentration (Cmax) was 36.0% lower, and total hydrocodone exposures (AUClast and AUCinf) were 20.3% and 19.5% lower, respectively, for benzhydrocodone API compared with HB API (P < 0.0001). All partial AUC values were lower for benzhydrocodone API, with a ≥ 75% reduction in hydrocodone exposure at all time intervals up to one hour postdose (P < 0.0001). Median Tmax of hydrocodone following benzhydrocodone API was delayed by more than one hour compared with HB. Drug Liking score, as assessed by maximal liking (Emax), was significantly lower for benzhydrocodone API vs HB API (P = 0.004), with 45% of subjects showing a ≥ 30% reduction in Drug Liking Emax.

Conclusion

Reductions in hydrocodone exposure and associated decreases in Drug Liking relative to HB suggest that the prodrug benzhydrocodone may deter intranasal abuse.

Preclinical and Clinical Pharmacology of Hydrocodone for Chronic Pain: A Mini Review

Hydrocodone is one of the most prescribed oral analgesic drugs and it is one of the most abused drugs in general population. It is a mu-opioid agonist predominantly metabolized to the O-demethylated product hydromorphone and to the N-demethylated product norhydrocodone. The purpose of the study is to summarize the preclinical and clinical characteristics of hydrocodone. Pharmacokinetic aspect (terminal half-life, maximum serum concentration, and time to maximum serum concentration) of hydrocodone and the influence of metabolic genetic polymorphism in analgesic response to hydrocodone are also illustrated and commented. Literature on experimental preclinical pharmacology investigating analgesic activity in laboratory animals is furtherly discussed. Moreover, the authors discuss and comment on the updated data regarding safety profile and effectiveness of hydrocodone in the treatment of chronic pain. A bibliographic research was carried out (from February 01, 2018 to August 28, 2018) independently by two researchers (blinded to the authors and initially on results) in the major scientific databases and research engines of peer-reviewed literature on life sciences and biomedical topics, starting from January 1990 to August 2018. Analysis of results of clinical studies suggests that abuse-deterrent extended-release (ER) hydrocodone formulations can be effective and they are well tolerated in the treatment of chronic low back pain. Weaker is the evidence of the analgesic effectiveness of ER hydrocodone on other chronic pain syndromes and non-cancer non-neuropathic chronic pain. In these conditions, hydrocodone showed to have positive effects in non-controlled open studies and needs to be further studied to assess the real strength of results.

Effects of ceftriaxone on hydrocodone seeking behavior and glial glutamate transporters in P rats

Hydrocodone (HYD) is one of the most widely prescribed opioid analgesic drugs. Several neurotransmitters are involved in opioids relapse. Among these neurotransmitters, glutamate is suggested to be involved in opioid dependence and relapse. Glutamate is regulated by several glutamate transporters, including glutamate transporter 1 (GLT-1) and cystine/glutamate transporter (xCT). In this study, we investigated the effects of ceftriaxone (CEF) (200 mg/kg, i.p.), known to upregulate GLT-1 and xCT, on reinstatement to HYD (5 mg/kg, i.p.) using the conditioned place preference (CPP) paradigm in alcohol-preferring (P) rats. Animals were divided into three groups: 1) saline-saline group (SAL-SAL); 2) HYD-SAL group; and 3) HYD-CEF group. The CPP was conducted as follows: habituation phase, conditioning phase with HYD (i.p.) injections every other day for four sessions, extinction phase with CEF (i.p.) injections every other day for four sessions, and reinstatement phase with one priming dose of HYD. Time spent in the HYD-paired chamber after conditioning training was increased as compared to pre-conditioning. There was an increase in time spent in the HYD-paired chamber with one priming dose of HYD in the reinstatement test. HYD exposure downregulated xCT expression in the nucleus accumbens and hippocampus, but no effects were observed in the dorsomedial prefrontal cortex and amygdala. Importantly, CEF treatment attenuated the reinstatement effect of HYD and normalized xCT expression in the affected brain regions. These findings demonstrate that the attenuating effect of HYD reinstatement with CEF might be mediated through xCT.

Profile, risk practices and needs of people who inject morphine sulfate: Results from the ANRS-AERLI study

AIMS

In France, a non-negligible proportion of opioid-dependent individuals inject morphine sulfate. Although it has not yet been officially approved as an opioid substitution treatment (OST), some physicians can prescribe its use for people in methadone or buprenorphine treatment failure. Longitudinal data from the ANRS-AERLI study, which evaluated an educational intervention for safer injection called AERLI, provided us the opportunity to better characterize the profile, risk practices and needs of people who inject morphine sulfate (MSI), through comparison with other injectors, and to identify correlates of HIV/HCV risk practices in this group.

METHODS

The national multisite ANRS-AERLI study assessed the impact of AERLI offered in volunteer harm reduction (HR) centers ("with intervention") (n = 113) through comparison with standard HR centers ("without intervention") (n = 127). All participants were scheduled to be followed up for 12 months and have 3 telephone interviews: at baseline, 6 months and 12 months. We compared MSI (n = 79) with other opioid injectors (n = 161) and then used a mixed logistic model to identify factors associated with HIV/HCV risk practices among MSI.

FINDINGS

Of the 240 eligible participants, 79 were regular MSI. They were less likely to use cocaine, crack or buprenorphine and to receive OST than other participants. Conversely, MSI were more likely to inject drugs more than three times a day and to report HIV/HCV risk practices. Among MSI, multivariate analysis showed that those receiving morphine sulfate as an OST were less likely to report such practices than other participants (aOR [95%CI] = 0.11 [0.02-0.61]).

CONCLUSION

Our results show that while MSI use fewer stimulants, they have more HIV/HCV risk practices than other injectors. However, when MSI are prescribed morphine sulfate as a treatment, these practices tend to decrease. Our findings suggest the importance of increasing access to morphine sulfate as a new OST in France.

Nociceptin/orphanin FQ receptors modulate the discriminative stimulus effects of oxycodone in C57BL/6 mice

BACKGROUND

Nociceptin/orphanin FQ (NOP) receptor ligands have shown efficacy as putative analgesics and can modulate the abuse-related effects of opioids, suggesting therapeutic applications. The discriminative stimulus effects of a drug are related to their subjective effects, a predictor of abuse potential. To determine whether activation of NOP receptors could alter the subjective effects of an abused opioid analgesic, a novel oxycodone discrimination was established in mice, characterized with positive and negative controls, and its expression evaluated with a NOP receptor agonist.

METHODS

Adult male C57BL/6 mice were trained to discriminate 1.3 mg/kg oxycodone from vehicle in a two-lever operant procedure. The discrimination was characterized with naloxone challenge, and generalization tests with the μ-opioid receptor agonists, heroin and morphine, and the κ-opioid receptor selective agonist, U50488. Subsequently, effects of the NOP agonist Ro64-6198 were evaluated with and without oxycodone.

RESULTS

Oxycodone generalization occurred in a dose-dependent manner and was reversed by naloxone pretreatment. Heroin and morphine, but not U50488, substituted for oxycodone. Co-treatment of 1 mg/kg Ro64-6198 with the oxycodone training dose reduced % oxycodone lever responding (%OLR) and restored response rates to vehicle control levels. J-113397, a NOP antagonist, reversed these effects. Co-administration of 1 mg/kg Ro64-6198 with a range of oxycodone doses resulted in rightward dose-effect curve shifts in %OLR and response rates compared to oxycodone alone.

CONCLUSIONS

These results provide additional evidence that NOP receptor activation can modulate the subjective effects of opioid analgesics and represent the first characterization of oxycodone's discriminative stimulus effects in mice.

Sweet flowers are slow, and weeds make haste: leveraging methodology from research on tobacco, alcohol, and opioid analgesics to make rapid and policy-relevant advances in cannabis science

The legalization of medical and recreational cannabis use has occurred ahead of science. The current evidence base has poor utility for determining if cannabis products can meet the standards of safety, efficacy, and quality intrinsic to modern medicine, and for informing regulation of cannabis as a legal intoxicant. Individual jurisdictions that pass cannabis reforms may not have adequate resources to support the level of new scientific research needed to inform regulatory actions; this could make it difficult to keep a rapidly growing multi-billion-dollar cannabis industry in check. Further, the present lack of evidence-based regulatory oversight for cannabis parallels the climates that gave rise to the tobacco and prescription opioid epidemics, suggesting that continued omission may result in negative public health consequences. However, translating a methodological framework developed through research on these compounds may promote rapid advances in cannabis science germane to regulatory knowledge gaps. The present review highlights specific advancements in these areas, as well as in alcohol regulation, that are prime for informing policy-relevant cannabis science, and also offers some recommendations for evidence-based regulatory policy. Resulting progress may directly inform both regulation of cannabis in both medical and licit recreational drug frameworks, and new cannabis-related public health initiatives.

Abuse Potential Study of ALO-02 (Extended-Release Oxycodone Surrounding Sequestered Naltrexone) Compared with Immediate-Release Oxycodone Administered Orally to Nondependent Recreational Opioid Users

Objective. To evaluate the abuse potential of ALO-02, an abuse-deterrent formulation comprising pellets of extended-release oxycodone hydrochloride surrounding sequestered naltrexone hydrochloride.

Design. Randomized, double-blind, placebo-/active-controlled, 6-way crossover study, with naloxone challenge, drug discrimination, and treatment phases.

Subjects. Nondependent, recreational opioid users.

Methods. Oral administration of crushed and intact ALO-02, crushed immediate-release (IR) oxycodone, and placebo. Primary endpoints were Drug Liking and High measured on visual analog scales and reported as maximum effect (E_max) and area-under-the-effect-curve from 0 to 2 hours (AUE_0-2h). Other pharmacodynamic, pharmacokinetic and safety assessments were included.

Results. Drug Liking and High (E_max) for crushed oxycodone IR 40 mg were significantly higher compared with placebo, confirming study validity (P < 0.0001). Drug Liking and High (E_max, AUE_0-2h) for crushed ALO-02 (40 mg/4.8 mg and 60 mg/7.2 mg) were significantly lower compared to corresponding doses of crushed oxycodone IR (40 and 60 mg; P < 0.0001). Likewise, Drug Liking and High (E_max and AUE_0-2h) for intact ALO-02 60 mg/7.2 mg were significantly lower compared with crushed oxycodone IR 60 mg (P < 0.0001). Secondary pharmacodynamic endpoints and plasma concentrations of oxycodone and naltrexone were consistent with these results. Fewer participants experienced adverse events (AEs) after ALO-02 (crushed or intact: 71.1–91.9%) compared with crushed oxycodone IR (100%). Most common AEs following crushed ALO-02 and oxycodone IR were euphoric mood, pruritus, somnolence, and dizziness.

Conclusions. The results suggest that ALO-02 (crushed or intact) has lower abuse potential than crushed oxycodone IR when administered orally in nondependent, recreational opioid users.

Characterizing the subjective, observer-rated, and physiological effects of hydromorphone relative to heroin in a human laboratory study

BACKGROUND

This study compared the effects of the several doses of the opioid agonists heroin and hydromorphone across two routes of administration in humans. The goal was to guide development of human laboratory studies of opioid effects and inform subsequent injection pharmacotherapy trials of hydromorphone-assisted treatment.

METHODS

A within-subject (N = 16), double-blind, double-dummy, placebo-controlled, evaluation of acute doses of heroin and hydromorphone was completed at four dose levels (placebo, low, medium, high) across two routes of administration (intravenous, subcutaneous) in non-physically dependent, opioid-experienced individuals. Subject and observer ratings, as well as physiological outcomes, were assessed.

RESULTS

Within each route of administration, heroin and hydromorphone produced effects that were qualitatively similar on most variables across the doses examined. All effects were dose-dependent. The drugs produced different effects on VAS ratings of "Feels Like Heroin," a Heroin Identification Test, observer agonist ratings, and oxygen saturation levels. Drug-dependent differences emerged at the highest doses in all cases. Few significant main effects of Route were identified and their pattern was not uniform. Relative potency calculations across all subject, observer, and physiological outcomes that met analysis criteria revealed similar profiles and resulted in mean heroin:hydromorphone potencies of 3.35:1 and 2.88:1 for the intravenous and subcutaneous routes, respectively, and intravenous:subcutaneous potencies of 0.47:1 and 0.49:1 for heroin and hydromorphone, respectively.

CONCLUSIONS

Hydromorphone produced similar subjective and physiological effects as heroin, but was more potent than heroin. The current findings support the use of hydromorphone as a model for heroin in human laboratory and clinical treatment studies, and help identify appropriate hydromorphone dose conversion ratios to produce effects qualitatively similar to heroin.

Opioid-Induced "Likeability" and "Feeling Good" Are Not Associated With Return Visits to an ED Among Migraine Patients Administered IV Hydromorphone

BACKGROUND

Parenteral opioids are used in more than 50% of emergency department (ED) visits for migraine. Use of opioids for migraine has been associated with subsequent ED visits, perhaps because of opioid-induced euphoria. In this study, we quantify the extent to which nontherapeutic effects of opioids influence migraine outcomes. We hypothesized that "feeling good" and medication likeability would in fact be associated with receipt of opioids (rather than relief of migraine pain) and that receipt of opioids (rather than relief of migraine pain) would be associated with return visits to the ED.

METHODS

During an ED-based clinical trial, migraine patients were randomized to receive hydromorphone 1 mg or prochlorperazine 10 mg + diphenhydramine 25 mg IV. Thirty minutes after medication administration, we asked, (1) How much did you like the medication you received? and (2) How good did the medication make you feel? Participants were asked to provide answers on a 0-10 scale. We also determined 0-10 pain scores at baseline and 1 hour and number of return visits for headache during the subsequent month.

RESULTS

Sixty-three patients received prochlorperazine and 64 hydromorphone. Prochlorperazine pain scores improved by 6.8 (SD: 2.6), hydromorphone by 4.7 (SD: 3.3) (95%CI for difference of 2.1: 1.0, 3.2). On the 0-10 likeability scale, prochlorperazine patients reported a mean of 7.2 (SD: 2.8), hydromorphone 6.9 (SD: 2.9) (95% CI for difference of 0.3: -0.7, 1.3). On the 0-10 feeling good scale, prochlorperazine patients reported a mean of 7.5 (SD: 2.3), hydromorphone 6.8 (SD: 2.8) (95%CI: for difference of 0.7: -0.2, 1.6). In the hydromorphone group, 8/57 (14%, 95%CI: 7, 26%) returned to the ED vs 5/63 (8%, 95%CI: 3,18%) in the prochlorperazine group. In regression modeling, feeling good was independently associated with pain relief (P < .01) but not with medication received (P = .67) or return visits (P = .12). Similarly, medication likeability was independently associated with pain relief (P < .01) but not medication received (P = .12) or return visits (P = .16).

CONCLUSION

We did not detect an association between hydromorphone and medication likeability, feeling good, or return visits to the ED. Headache relief was associated with medication likeability and feeling good.

Effect of FDA Investigation on Opioid Prescribing to Children After Tonsillectomy/Adenoidectomy

BACKGROUND

In August 2012, the Food and Drug Administration investigated the safety of codeine use by children after tonsillectomy and/or adenoidectomy, culminating in a black box warning in February 2013. The objective of this study was to evaluate the association between the investigation and opioid prescribing to children undergoing these surgeries.

METHODS

We identified 362 992 privately insured children in the 2010-2015 Truven MarketScan Commercial Claims and Encounters database who underwent tonsillectomy and/or adenoidectomy. Using an interrupted time series design, we estimated level and slope changes in the proportion of children with ≥1 prescription fills for codeine and ≥1 fills for an alternative opioid, such as hydrocodone, within 7 days of surgery.

RESULTS

The investigation was associated with a significant -13.3 (95% confidence interval: -14.5 to -12.1) percentage point level change in the proportion of children with ≥1 prescription fills for codeine after tonsillectomy and/or adenoidectomy. Despite this drop, 5.1% of children had ≥1 prescription fills for codeine in December 2015. The investigation was not associated with significant level changes in alternative opioid prescribing, although the proportion of children receiving alternative opioids increased during the study period because of other factors.

CONCLUSIONS

The Food and Drug Administration investigation substantially decreased codeine prescribing to children after tonsillectomy and/or adenoidectomy. However, 1 in 20 children undergoing these surgeries were still prescribed codeine in December 2015 despite its well-documented safety and efficacy issues.

The Basic Pharmacology of Opioids Informs the Opioid Discourse about Misuse and Abuse: A Review

Morphine and other opioids are widely used to manage moderate to severe acute pain syndromes, such as pain associated with trauma or postoperative pain, and they have been used to manage chronic pain, even chronic nonmalignant pain. However, recent years have seen a renewed recognition of the potential for overuse, misuse, and abuse of opioids. Therefore, prescribing opioids is challenging for healthcare providers in that clinical effectiveness must be balanced against negative outcomes-with the possibility that neither are achieved perfectly. The current discourse about the dual 'epidemics' of under-treatment of legitimate pain and the over-prescription of opioids is clouded by inadequate or inaccurate understanding of opioid drugs and the endogenous pain pathways with which they interact. An understanding of the basic pharmacology of opioids helps inform the clinician and other stakeholders about these simultaneously under- and over-used agents.