Circumstances of death of opioid users being treated with naltrexone

Attenuation of the Positive-Reinforcing Effects of Ultra-Potent Fentanyl Analogs, Along with Those of Fentanyl and Heroin, During Daily Treatment with Methocinnamox in Rhesus Monkeys

Without substantial intervention, the opioid crisis is projected to continue, underscoring the need to develop new treatments for opioid use disorder (OUD). One drug under development is the µ opioid receptor antagonist methocinnamox (MCAM), which appears to offer advantages over currently available medications; however, some questions remain about its potential utility, including its ability to block the effects of ultra-potent fentanyl analogs. The goal of this study was to examine its effectiveness in attenuating the abuse-related effects of the fentanyl analogs carfentanil and 3-methylfentanyl in monkeys responding for food or intravenous infusions under a choice procedure. These drugs were compared with fentanyl, heroin, methamphetamine, and cocaine. Food was preferred over saline, and there was a dose-dependent increase in responding for drug over food with no marked decrease in response rates or number of choice trials completed for any of the six drugs studied. Naltrexone (0.032 mg/kg) antagonized choice of µ opioid receptor agonists, producing rightward shifts in dose-effect curves ranging from 27-fold (carfentanil) to 71-fold (heroin). In contrast, naltrexone was less effective in attenuating choice of methamphetamine or cocaine with curves obtained in the presence of naltrexone shifted <3-fold. Daily treatment with 0.032 mg/kg MCAM also antagonized the effects of opioids, shifting curves 20-fold (fentanyl) to 72-fold (heroin) rightward; MCAM did not significantly change dose-effect curves for methamphetamine or cocaine. Thus, antagonism by MCAM is similar across a variety of µ opioid receptor agonists, including ultra-potent fentanyl analogs, further supporting its potential utility as a treatment for OUD. SIGNIFICANCE STATEMENT: Treatments for opioid use disorder (OUD) should attenuate the effects of a variety of opioids, including emerging threats like the ultra-potent fentanyl analogs. The novel µ opioid receptor antagonist MCAM is being developed to treat OUD because it provides long-lasting blockade of the reinforcing effects of heroin and fentanyl. The current study shows that MCAM attenuates the abuse-related effects of the fentanyl analogs carfentanil and 3-methylfentanyl, further supporting the utility of MCAM as a treatment for OUD.

Primary care management of Long-Term opioid therapy

The United States underwent massive expansion in opioid prescribing from 1990-2010, followed by opioid stewardship initiatives and reduced prescribing. Opioids are no longer considered first-line therapy for most chronic pain conditions and clinicians should first seek alternatives in most circumstances. Patients who have been treated with opioids long-term should be managed differently, sometimes even continued on opioids due to physiologic changes wrought by long-term opioid therapy and documented risks of discontinuation. When providing long-term opioid therapy, clinicians should document opioid stewardship measures, including assessments, consents, medication reconciliation, and offering naloxone, along with the rationale to continue opioid therapy. Clinicians should screen regularly for opioid use disorder and arrange for or directly provide treatment. In particular, buprenorphine can be highly useful for co-morbid pain and opioid use disorder. Addressing other substance use disorders, as well as preventive health related to substance use, should be a priority in patients with opioid use disorder. Patient-centered practices, such as shared decision-making and attending to related facets of a patient's life that influence health outcomes, should be implemented at all points of care.Key messagesAlthough opioids are no longer considered first-line therapy for most chronic pain, management of patients already taking long-term opioid therapy must be individualised.Documentation of opioid stewardship measures can help to organise opioid prescribing and protect clinicians from regulatory scrutiny.Management of resultant opioid use disorder should include provision of medications, most often buprenorphine, and several additional screening and preventive measures.

Opioid Use Disorder Diagnosis and Management

Opioid Use Disorder Diagnosis and ManagementThe last 20 years have seen a staggering increase in opioid-related morbidity and mortality. Although the consequences of untreated OUDs are significant, OUD is a treatable illness. This article reviews the epidemiology of OUD and its complications, screening, diagnosis, treatment, and harm reduction interventions.

Modifying naloxone to reverse fentanyl-induced overdose

Developing an effective antidote for fentanyl-induced overdose (OD) is an unmet medical need that requires both lipophilicity comparable to fentanyl and fast onset of overdose reversal. We synthesized and evaluated a bioreversible derivative of naloxone (NX-90) in silico, in vitro and in vivo to yield a robust reversal of fentanyl-induced OD in rats. All monitored reflexes along with the heart rate (HR) and respiratory rate (RR) were fully restored faster in the NX-90 groups than in naloxone groups on equimolar bases when given intranasally. In NX-90 treated rats RR over the time of observation (RR AUC) was significantly higher at all respective doses with no re-narcotization observed. Apart from the enhanced pharmacodynamics profile, NX-90 was found to have lower circulating levels of naloxone, clean profile in in vitro selectivity panels, as well as Ames and CYP450 counter screens. Finally, we demonstrated a robust release of the parent naloxone in brain matrix, as well as lower peripheral naloxone levels after NX-90 iv administration. With the demonstrated pharmacological profile superior yet congruent to naloxone we nominated NX-90 for preclinical development as an effective intranasal fentanyl antidote.