Editorial: A Changing Epidemic and the Rise of Opioid-Stimulant Co-Use

Naloxone Administration and Survival in Overdoses Involving Opioids and Stimulants: An Analysis of Law Enforcement Data from 63 Pennsylvania Counties

Background

In consideration of rising deaths from opioid-stimulant-involved overdoses in the United States, this study explored rates of naloxone administration and survival in opioid overdoses with versus without stimulants co-involved.

Methods

The study used data from the Pennsylvania Overdose Information Network, focusing on 26,635 suspected opioid-involved overdose events recorded by law enforcement and other first responders in 63 Pennsylvania counties from January 2018 to July 2024. Relative frequencies and chi-square tests were first used to compare suspected opioid overdoses with, versus without, stimulants (cocaine or methamphetamine) co-involved. Next, mediation analyses tested naloxone administration as a mediator of the association between stimulant co-involvement (in opioid overdoses) and survival.

Results

Naloxone was reportedly administered in 72.2% of the opioid-no-cocaine overdoses, compared to 55.1% of the opioid-cocaine-involved overdoses, and 72.1% of the opioid-no-methamphetamine overdoses vs. 52.4% of the opioid-methamphetamine-involved overdoses. With respect to survival rates, 18.0% of the opioid-no-cocaine overdoses ended in death, compared to 41.3% of the opioid-cocaine overdoses; 18.1% of the opioid-no-methamphetamine overdoses ended in death, versus 42.9% of the opioid-methamphetamine overdoses. In mediation analyses (adjusted for demographics, county, year, and other drug co-involvement), naloxone administration mediated 38.7% (95% Confidence Interval [CI], 31.3%-46.0%) of the association between cocaine co-involvement and survival and 39.2% (95% CI, 31.3%-47.1%) of the association between methamphetamine co-involvement and survival.

Conclusions

Among suspected opioid overdose events recorded in the Pennsylvania Overdose Information Network, stimulant co-involvement was associated with lower naloxone administration and higher fatality, with naloxone partially mediating the association between stimulant co-involvement and death.

Evolution of the substance use landscape: Implications for contingency management

Contingency management (CM), which involves the delivery of incentives upon meeting behavioral goals, has the potential to improve substance use treatment outcomes. The intervention allows for flexibility through numerous modifiable components including changes to incentive magnitude and schedule, target behavior, and intervention structure. Unfortunately, numerous changes in the substance use landscape have occurred in the past 10 to 15 years: Substances are more potent, overdose risk has increased, new substances and methods of use have been introduced, and substance classes are increasingly being intentionally and unintentionally mixed. These developments potentially undermine CM outcomes. We explored recent substance use changes due to legislative, regulatory, social, and economic factors for four substance classes: stimulants, opioids, tobacco, and cannabis. We discuss potential adjustments to the modifiable components of CM for future research in response to these changes. By continually adapting to the shifting substance use landscape, CM can maintain optimal efficacy.

Changes in injecting versus smoking heroin, fentanyl, and methamphetamine among people who inject drugs in San Diego, California, 2020-2023

BACKGROUND

Amidst an increasingly toxic drug supply in North America, people who inject drugs may be transitioning to smoking them. We aimed to assess changes in injecting and smoking opioids and methamphetamine among a cohort of people who inject drugs from San Diego, California.

METHODS

Over five six-month periods spanning October 2020-April 2023, we assessed prevalence of injecting and smoking opioids or methamphetamine and whether participants used these drugs more frequently by smoking than injecting. Multivariable Poisson regression via generalized estimating equations was used to examine time trends.

RESULTS

Of 362 participants, median age was 40 years; a minority were female (29%), Hispanic/Latinx/Mexican (45%), and housed (33%). Among this cohort, of whom 100% injected (and 84% injected and smoked) in period one (October 2020-April 2021), by period five (November 2022-April 2023), 34% only smoked, 59% injected and smoked, and 7% only injected. By period five, the adjusted relative risk (aRR) of injecting opioids was 0.41 (95% Confidence Interval [CI]: 0.33, 0.51) and the aRR for injecting methamphetamine was 0.50 (95% CI: 0.39, 0.63) compared to period one. Risks for smoking fentanyl rose significantly during period three (aRR=1.44, 95% CI: 1.06, 1.94), four (aRR=1.65, 95% CI: 1.24, 2.20) and five (aRR=1.90, 95% CI: 1.43, 2.53) compared to period one. Risks for smoking heroin and methamphetamine more frequently than injecting these drugs increased across all periods.

CONCLUSIONS

Opioid and methamphetamine injection declined precipitously, with notable increases in smoking these drugs. Research is needed to understand the health consequences of these trends.

Kratom as a potential substance use disorder harm reduction agent

Substance use disorders contribute to considerable U.S. morbidity and mortality. While effective pharmacotherapy options are available to treat opioid and alcohol use disorders, for a variety of reasons, many patients lack access to treatment or may be reluctant to seek care due to concerns such as perceived stigma or a current lack of desire to completely curtail their substance use. Furthermore, treatment options are limited for patients with stimulant or polysubstance use disorders. Thus, there is considerable need to expand the substance use disorder harm reduction armamentarium. Kratom (Mitragyna speciosa Korth.) is an herbal substance that can produce both opioid and stimulant-like effects, and its use in the US is growing. Though there are concerns regarding adverse effects, dependence risk, and limited regulation of its manufacturing and sale, the pharmacology of kratom and early preclinical studies suggest a potential role as a harm reduction agent for various substance use disorders, and it has historically been used in Southeast Asia for such purposes. The goal of this review is to describe kratom's history of use, pharmacology, and early pre-clinical and observational research regarding its therapeutic potential in opioid use disorder, as well as alcohol, stimulant, and polysubstance use disorders, while also highlighting current concerns around its use, existing gaps in the literature, and directions for future research.

Explaining the high mortality among opioid-cocaine co-users compared to opioid-only users. A systematic review

RATIONALE

The opioid crisis in North America has recently seen a fourth wave, which is dominated by drug-related deaths due to the combined use of illicitly manufactured fentanyl [IMF] and stimulants such as cocaine and methamphetamine.

OBJECTIVES

A systematic review addressing the question why drug users combine opioids and stimulants and why the combination results in such a high overdose mortality: from specific and dangerous pharmacokinetic or pharmacodynamic interactions or from accidental poisoning?

RESULTS

Motives for the combined use include a more intensive high or rush when used at the same time, and some users have the unfounded and dangerous belief that co-use of stimulants will counteract opioid-induced respiratory depression. Overdose deaths due to combined (intravenous) use of opioids and stimulants are not likely to be caused by specific pharmacokinetic or pharmacodynamic interactions between the two drugs and it is unlikely that the main cause of overdose deaths is due to accidental poisoning.

CONCLUSION

The unexpectedly high overdose rates in this population could not be attributed to accidental overdosing or pharmacokinetic/pharmacodynamic interactions. The most likely explanation for the high rate of drug-related deaths in opioid-cocaine co-users is careless overdosing with either cocaine, opioid(s) or both, probably facilitated by the high level of preexisting impulsivity in these co-users and a further acute increase in impulsivity following cocaine use. The primary corollary is that cocaine users should avoid IMF use in the same time window. In addition, IMF users should refrain from cocaine use to avoid impulsive IMF overdosing.

Patterns of polydrug use among Black Americans who misuse opioids

In the United States, opioid-related deaths involving polydrug use are now more prevalent than those involving only opioids. What often goes unnoticed is that deaths involving more than one substance are increasing more rapidly among Black Americans than Whites. Unfortunately, little research attention is paid to understanding opioid-related polydrug use patterns among Black Americans. As a result, less is known regarding which drug combinations are most common among this population and their reasons for co-using certain drugs. Therefore, the objective of this mixed methods study was to identify which substances were most commonly co-used with opioids among Black Americans, while also capturing their motives for combining opioids with other drugs. This study used data from the Florida Minority Health Study, a mixed-methods project that included online surveys (n = 303) and qualitative in-depth interviews (n = 30) of Black Americans who misuse opioids. Data collection was conducted from August 2021 to February 2022 throughout Southwest Florida. Analyses revealed that opioids were most commonly combined with alcohol, cocaine, and methamphetamine, respectively. Opioids were co-used with alcohol in an attempt to enhance the desired effect (i.e., intoxication), while stimulants and opioids were combined to counteract the undesirable side effects of the other. This study begins to answer the question of which/why substances are combined with opioids among Black Americans and should inform behavioral health interventions targeted at this population. Data on this topic are especially timely as the United States goes through the current fourth wave of the opioid crisis that is characterized by deaths due to polydrug use. These findings invite further study using nationally representative data to determine the extent to which polydrug using patterns differ across racial/ethnic groups.

Stimulant Drugs and Stimulant Use Disorder

The authors aim to summarize several key points of stimulant drugs and stimulant use disorder, including their indications, short-term and long-term adverse effects, current treatment strategies, and association with opioid medications. The global prevalence of stimulant use has seen annual increase in the last decade. Multiple studies have shown that stimulant use and stimulant use disorder are associated with a range of individual and public health issues. Stimulant misuse has led to a significant increase of overdose deaths in the United States.

Changes in injecting versus smoking heroin, fentanyl, and methamphetamine among people who inject drugs in San Diego, California, 2020 to 2023

Background

Amidst a rapidly evolving drug supply in North America, people who inject drugs may be transitioning to smoking them. We aimed to assess changes in injecting and smoking heroin, fentanyl and methamphetamine among a cohort of people who injected drugs at baseline from San Diego, California.

Methods

Over five six-month periods spanning October 2020-April 2023, we assessed prevalence of injecting and smoking opioids or methamphetamine and whether participants used these drugs more frequently by smoking than injecting. Multivariable Poisson regression via Generalized Estimating Equations was used to examine time trends.

Results

Of 362 participants, median age was 40 years; most were male (72%), non-Hispanic (55%), and unhoused (67%). Among this cohort, of whom 100% injected (or injected and smoked) at baseline, by period five (two years later), 34% reported only smoking, while 59% injected and smoked, and 7% only injected. By period five, the adjusted relative risk (aRR) of injecting opioids was 0.41 (95% Confidence Interval [CI]: 0.33, 0.51) compared to period one, and the aRR for injecting methamphetamine was 0.50 (95% CI: 0.39, 0.63). Compared to period one, risks for smoking fentanyl rose significantly during period three (aRR=1.44, 95% CI: 1.06, 1.94), four (aRR=1.65, 95% CI: 1.24, 2.20) and five (aRR=1.90, 95% CI: 1.43, 2.53). Risks for smoking heroin and methamphetamine more frequently than injecting these drugs increased across all periods.

Conclusions

Opioid and methamphetamine injection declined precipitously, with notable increases in smoking these drugs. Research is urgently needed to understand the health consequences of these trends.

Synthesis of α3β4 Nicotinic Acetylcholine Receptor Modulators Derived from Aristoquinoline That Reduce Reinstatement of Cocaine-Seeking Behavior

Growing evidence suggests that inhibition of the α3β4 nicotinic acetylcholine receptor (nAChR) represents a promising therapeutic strategy to treat cocaine use disorder. Recently, aristoquinoline (1), an alkaloid from Aristotelia chilensis, was identified as an α3β4-selective nAChR inhibitor. Here, we prepared 22 derivatives of 1 and evaluated their ability to inhibit the α3β4 nAChR. These studies revealed structure-activity trends and several compounds with increased potency compared to 1 with few off-target liabilities. Additional mechanistic studies indicated that these compounds inhibit the α3β4 nAChR noncompetitively, but do not act as channel blockers, suggesting they are negative allosteric modulators. Finally, using a cocaine-primed reinstatement paradigm, we demonstrated that 1 significantly attenuates drug-seeking behavior in an animal model of cocaine relapse. The results from these studies further support a role for the α3β4 nAChR in the addictive properties of cocaine and highlight the possible utility of aristoquinoline derivatives in treating cocaine use disorder.

Polysubstance use and post-discharge mortality risk among hospitalized patients with opioid use disorder

Polysubstance use is becoming increasingly common and presents several harms. This study aimed to examine the association of comorbid cocaine, alcohol (binge drinking), and sedative use with mortality among hospitalized patients with opioid use disorder (OUD). A subsample of adult medical/surgical hospital patients with OUD who were seen by a hospital addiction consultation service in Baltimore City and enrolled in a randomized trial of a patient navigation intervention were included in this study (N = 314; 45 % female; 48 % White; mean age = 44). Death certificate data from the Maryland Division of Vital Records was used, covering 3.3-5.5 years post-discharge. Multivariable proportional hazards Cox regression and competing risks regression were used to estimate all-cause mortality and overdose mortality, respectively, as a function of concurrent use of cocaine, alcohol (binge drinking), and non-prescribed sedatives at baseline. In the 30 days prior to hospital admission, 230 (73 %) participants used cocaine, 64 (20 %) binge drank, and 45 (14 %) used non-prescribed sedatives. Nearly one-third (N = 98; 31 %) died during the observation period. Drug overdose caused 53 % (N = 52) of deaths. Older age (HR = 1.03 [1.01,1.05]; P = 0.001), less than high school education (HR = 0.36 [0.24,0.54]; P < 0.001), and past 30-day sedative use (HR = 2.05 [1.20,3.50]; P = 0.008) were significantly associated with all-cause mortality. The risk of overdose mortality was 62 % lower (HR = 0.38 [0.22,0.66]; P = 0.001) for those who completed high school. No other characteristics were significantly associated with overdose mortality. The concurrent use of opioids and sedatives increases the post-discharge mortality risk among hospitalized patients with OUD. Interventions are needed to prevent mortality among this high-risk population.

Impact of State Laws on Dispensing Opioid Prescriptions Following Posterior Lumbar Interbody Fusion Procedures: A Retrospective Large National Database Study

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVES

This study aimed to examine the effect of state legislation on prescribing behavior after a commonly performed spinal procedure, posterior lumbar interbody fusion (PLIF).

METHODS

Two cohorts of patients from the Pearl Diver Database were created based on patients who underwent PLIF surgery in 2014-15 and 2018-19. We compared opioid prescription rates and morphine-milli-equivalent (MME) between states with and without prescription legislation.

RESULTS

We analyzed 50 958 PLIF patients from 2014-15 and 46 751 patients from 2018-19. Among them, 38 states passed opioid prescription laws in 2016-2017, while 12 states did not. The percentage of patients receiving opioid prescriptions within 365 days post-surgery remained similar in both time periods (49% in 2014-15 and 48% in 2018-2019). This trend was consistent across states with and without prescription legislation (50% vs 48% in 2014-2015, and similar in 2018-19). Opioid prescription quantity significantly decreased in all states between 2014-15 and 2018-19. In states with legislation, average MME dropped from 9198 ± 21 002 to 4932 ± 13 213 (46.4% decrease), and in states without legislation, it decreased from 9175 ± 21 032 to 4994 ± 11 687 (45.6% decrease). However, these differences were not statistically significant (P = .7985).

CONCLUSION

From 2014 to 2018, there was a significant decrease in the number of opioids prescribed after PLIF. However, this decrease occurred irrespective of state legislation on prescribing practices being passed. We believe the reduction in opioids prescribed was due to increased awareness surrounding the dangers of opioids among physicians.

Postmortem toxicology findings from the Camden Opioid Research Initiative

The United States continues to be impacted by decades of an opioid misuse epidemic, worsened by the COVID-19 pandemic and by the growing prevalence of highly potent synthetic opioids (HPSO) such as fentanyl. In instances of a toxicity event, first-response administration of reversal medications such as naloxone can be insufficient to fully counteract the effects of HPSO, particularly when there is co-occurring substance use. In an effort to characterize and study this multi-faceted problem, the Camden Opioid Research Initiative (CORI) has been formed. The CORI study has collected and analyzed post-mortem toxicology data from 42 cases of decedents who expired from opioid-related toxicity in the South New Jersey region to characterize substance use profiles. Co-occurring substance use, whether by intent or through possible contamination of the illicit opioid supply, is pervasive among deaths due to opioid toxicity, and evidence of medication-assisted treatment is scarce. Nearly all (98%) of the toxicology cases show the presence of the HPSO, fentanyl, and very few (7%) results detected evidence of medication-assisted treatment for opioid use disorder, such as buprenorphine or methadone, at the time of death. The opioid toxicity reversal drug, naloxone, was detected in 19% of cases, but 100% of cases expressed one or more stimulants, and sedatives including xylazine were detected in 48% of cases. These results showing complex substance use profiles indicate that efforts at mitigating the opioid misuse epidemic must address the complications presented by co-occurring stimulant and other substance use, and reduce barriers to and stigmas of seeking effective medication-assisted treatments.

Presentation and Outcomes of Adults With Overdose-Related Out-of-Hospital Cardiac Arrest

Importance

Drug overdose (OD) is a public health challenge and an important cause of out-of-hospital cardiac arrest (OHCA). Existing studies evaluating OD-related OHCA (OD-OHCA) either aggregate all drugs or focus on opioids. The epidemiology, presentation, and outcomes of drug-specific OHCA are largely unknown.

Objective

To evaluate the temporal pattern, clinical presentation, care, and outcomes of adult patients with OHCA overall and according to the drug-specific profile.

Design, Setting, and Participants

This cohort study of adults with OHCA in King County Washington was conducted between January 1, 2015, and December 31, 2021. Etiology of OHCA was determined using emergency medical service, hospital, and medical examiner records. Etiology was classified as non-OD OHCA or OD-OHCA, with drug-specific profiles categorized as (1) opioid without stimulant, (2) stimulant without opioid, (3) opioid and stimulant, or (4) all other nonstimulant, nonopioid drugs. Statistical analysis was performed on July 1, 2023.

Exposure

Out-of-hospital cardiac arrest.

Main Outcomes and Measures

The primary outcome was survival to hospital discharge. The secondary outcome was survival with favorable functional status defined by Cerebral Performance Category 1 or 2 based on review of the hospital record.

Results

In this cohort study, there were 6790 adult patients with emergency medical services-treated OHCA from a US metropolitan system. During the 7-year study period, there were 702 patients with OD-OHCA (median age, 41 years [IQR, 29-53 years]; 64% male [n = 450] and 36% female [n = 252]) and 6088 patients with non-OD OHCA (median age, 66 years [IQR, 56-77 years]; 65% male [n = 3944] and 35% female [n = 2144]). The incidence of OD-OHCA increased from 5.2 (95% CI, 3.8-6.6) per 100 000 person-years in 2015 to 13.0 (95% CI, 10.9-15.1) per 100 000 person-years in 2021 (P < .001 for trend), whereas there was no significant temporal change in the incidence of non-OD OHCA (P = .30). OD-OHCA were more likely to be unwitnessed (66% [460 of 702] vs 41% [2515 of 6088]) and less likely to be shockable (8% [56 of 702] vs 25% [1529 of 6088]) compared with non-OD OHCA. Unadjusted survival was not different (20% [138 of 702] for OD vs 18% [1095 of 6088] for non-OD). When stratified by drug profile, combined opioid-stimulant OHCA demonstrated the greatest relative increase in incidence. Presentation and outcomes differed by drug profile. Patients with stimulant-only OHCA were more likely to have a shockable rhythm (24% [31 of 129]) compared with patients with opioid-only OHCA (4% [11 of 295]) or patients with combined stimulant-opioid OHCA 5% [10 of 205]), and they were more likely to have a witnessed arrest (50% [64 of 129]) compared with patients with OHCA due to other drugs (19% [14 of 73]) or patients with combined stimulant-opioid OHCA (23% [48 of 205]). Patients with a combined opioid-stimulant OHCA had the lowest survival to hospital discharge (10% [21 of 205]) compared with patients with stimulant-only OHCA (22% [29 of 129]) or patients with OHCA due to other drugs (26% [19 of 73]), a difference that persisted after multivariable adjustment.

Conclusions and Relevance

In a population-based cohort study, the incidence of OD-OHCA increased significantly from 2015 to 2021, with the greatest increase observed among patients with a combined stimulant-opioid OHCA. Presentation and outcome differed according to the drug-specific profile. The combination of increasing incidence and lower survival among among patients with a opioid-stimulant OHCA supports prevention and treatment initiatives that consider the drug-specific profile.

Navigating Evidence, Challenges, and Caution in the Treatment of Stimulant Use Disorders

Amidst the opioid epidemic, harm reduction-oriented approaches have gained traction, including interventions that focus on prescribing pharmaceutical-grade psychoactive substances, such as opioids, instead of illicit versions, intending to mitigate fatal overdose risks arising from the variability in potency and additives found in illicit drugs. Stimulants have increasingly been found in the victims of opioid overdoses, further prompting some to argue for the prescription of stimulant medications for individuals with stimulant use disorders. Yet, the evidence supporting this practice remains insufficient. In this communication, we critically examine the existing evidence, challenges, and cautions surrounding the treatment of stimulant use disorder.

The impact of opioid-stimulant co-use on tonic and cue-induced craving

The twin opioid-stimulant epidemics have led to increased overdose deaths and present unique challenges for individuals entering treatment with opioid-stimulant polysubstance use. This study examined tonic and cue-induced craving as a primary outcome among persons in substance use treatment who reported primary substances of opioids, methamphetamine, or cocaine. The sample consisted of 1974 individuals in 55 residential substance-use treatment centers in the United States in 2021. Weekly surveys were delivered via a third-party outcomes tracking system, including measures of tonic and cue-induced craving. Initial comparisons on tonic and cue-induced craving were made among those who primarily used opioids, cocaine, or methamphetamine. Further, the effect of opioid/stimulant polysubstance use on tonic and cue-induced craving was evaluated using marginal effect regression models. Primary methamphetamine use was associated with decreased tonic craving compared to primary opioid use (β = -5.63, p < 0.001) and primary cocaine use was also associate with decreased tonic craving compared to primary opioid use (β = -6.14, p < 0.001). Primary cocaine use was also associated with lower cue-induced cravings compared to primary opioid use (β = -0.53, p = 0.037). Opioid-methamphetamine polysubstance use was associated with higher tonic craving (β = 3.81, p = <0.001) and higher cue-induced craving (β = 1.55, p = 0.001); however, this was not the case for opioid-cocaine polysubstance use. The results of this study indicate that individuals who primarily use opioids and have secondary methamphetamine use experience higher cue-induced and tonic-induced craving, suggesting that these individuals may benefit from additional interventions that target craving and mitigate relapse risk and other negative sequelae.

Benzodiazepine Dose Intensity among Patients Concurrently Prescribed Buprenorphine in Rhode Island

Background: The concomitant use of buprenorphine and benzodiazepines has been linked to patient fatalities, with greater risk occurring with higher doses of benzodiazepines. We assessed benzodiazepine dose intensity among patients who were concurrently prescribed buprenorphine, as compared with patients prescribed benzodiazepines who were not receiving buprenorphine. Methods: We conducted a cross-sectional analysis of adult patients who received at least a 30-day supply of benzodiazepines during 2018, using data from the Rhode Island (RI) Prescription Drug Monitoring Program. Mean daily diazepam milligram equivalents (DME) were calculated overall and according to patient sex, age group, payment type, and RI county. Multivariable logistic regression analyses were conducted to assess the odds of higher-dose benzodiazepine utilization among patients with concurrent use of buprenorphine, as compared with patients not prescribed buprenorphine, adjusting for patient demographics. Results: Compared to patients prescribed benzodiazepines who were not receiving buprenorphine, those with concurrent buprenorphine utilization had a significantly higher mean DME/day (19.22, 95% CI: 18.70-19.74; vs 10.94, 95% CI: 10.93-10.95; p < 0.001). Patients who were prescribed benzodiazepines with concurrent utilization of buprenorphine also had a comparatively higher odds of a DME/day ≥15 (aOR: 2.86, 95% CI: 2.63-3.10), ≥20 DME/day (aOR: 2.98, 95% CI: 2.75-3.24), and ≥25 DME/day (aOR: 2.99, 95% CI: 2.65-3.18). Conclusion: Compared to patients prescribed benzodiazepines for at least 30 days who were not receiving buprenorphine, patients concurrently utilizing benzodiazepines and buprenorphine had more than twice the odds of higher dose benzodiazepine utilization. Future studies are needed to assess the relationship between benzodiazepine dose intensity, overdose outcomes, and treatment retention among patients receiving buprenorphine.