The Oxford Catalogue of Opioids: A systematic synthesis of opioid drug names and their pharmacology

Detection, chemical analysis, and pharmacological characterization of dipyanone and other new synthetic opioids related to prescription drugs

The emergence of structurally diverse new synthetic opioids (NSOs) has caused the opioid crisis to spiral to new depths. Little information is available about the pharmacology of most novel opioids when they first emerge. Here, using a β-arrestin 2 recruitment assay, we investigated the in vitro μ-opioid receptor (MOR) activation potential of dipyanone, desmethylmoramide, and acetoxymethylketobemidone (O-AMKD) - recent NSOs that are structurally related to the prescription opioids methadone and ketobemidone. Our findings indicate that dipyanone (EC₅₀=39.9 nM; E_max=155% vs. hydromorphone) is about equally active as methadone (EC₅₀=50.3 nM; E_max=152%), whereas desmethylmoramide (EC₅₀=1335 nM; E_max=126%) is considerably less active. A close structural analogue of ketobemidone (EC₅₀=134 nM; E_max=156%) and methylketobemidone (EC₅₀=335 nM; E_max=117%), O-AMKD showed a lower potency (EC₅₀=1262 nM) and efficacy (E_max=109%). Evaluation of the opioid substitution product buprenorphine and its metabolite norbuprenorphine confirmed the increased in vitro efficacy of the latter. In addition to in vitro characterization, this report details the first identification and full chemical analysis of dipyanone in a seized powder, as well as a postmortem toxicology case from the USA involving the drug. Dipyanone was quantified in blood (370 ng/mL), in which it was detected alongside other NSOs (e.g., 2-methyl AP-237) and novel benzodiazepines (e.g., flualprazolam). While dipyanone is currently not commonly encountered in forensic samples worldwide, its emergence is worrisome and representative of the dynamic NSO market. Graphical Abstract.

Potential inappropriate use of strong opioid analgesics in cancer outpatients during the last year of life in France and associated factors

AIMS

A better knowledge of opioid prescribing patterns would help to identify areas of potential improvement in cancer pain management. This study aimed to identify potential inappropriate use (PIU) of strong opioid analgesics in cancer outpatients in their last year of life.

METHODS

A retrospective cohort of cancer patients who died between 2011 and 2014 and were exposed as outpatient to a strong opioid analgesic in the last year of life was identified in the Echantillon Généraliste de Bénéficiaires (a 1/97th random sample of the French general population). Prescribing patterns of strong opioids were analysed and PIU was defined by at least 1 of these criteria: overlapping prescriptions; contraindicated prescriptions; lack of laxatives; potential drug interactions; prescription in patients hospitalized for opioid-related disorders. Factors associated with PIU were investigated through a multiple logistic regression model.

RESULTS

One third of the 2236 patients (median age 72 years [interquartile range: 61-82], 44.1% women) presented a PIU (insufficient laxative prescription [19.6% of patients], insufficient background treatment with transmucosal fentanyl [14.8%], overlapping prescriptions [2.6%]). The rate of PIU significantly decreased from 37.6% (2011) to 29.8% (2014). For patients with a duration of opioid use ≥3 months, factors associated with PIU were fentanyl prescription (adjusted odds ratio = 2.36; 95% confidence interval [1.86-3.00]) and previous use of strong opioid (adjusted odds ratio = 1.88; [1.50-2.36]).

CONCLUSION

In France, 1/3 of cancer patients exposed to strong opioids experienced PIU and this proportion tended to decrease over time. There is still room for progress in cancer pain management at the end of life.