Substance use disorder of equimolar oxygen-nitrous oxide mixture in French sickle-cell patients: results of the PHEDRE study

BACKGROUND

In many countries, nitrous oxide is used in a gas mixture (EMONO) for short-term analgesia. Cases of addiction, with significant misuse, have been reported in hospitalized patients. Patients suffering from sickle cell disease (SCD) could represent a high-risk population for substance use disorder (SUD) due to their significant pain crisis and repeated use of EMONO. The objective of the PHEDRE study was to assess the prevalence of SUD for EMONO in French SCD patients.

RESULTS

A total of 993 patients were included. Among 339 EMONO consumers, only 38 (11%) had a SUD, with very few criteria, corresponding mainly to a mild SUD due to a use higher than expected (in quantity or duration) and relational tensions with the care teams. Almost all patients (99.7%) were looking for an analgesic effect, but 68% of patients were also looking for other effects. The independent risks factors associated with at least one SUD criterion were: the feeling of effects different from the expected therapeutic effects of EMONO, at least one hospitalization for vaso occlusive crisis in the past 12 months and the presence of a SUD for at least one other analgesic drug.

CONCLUSIONS

The use of EMONO was not problematic for the majority of patients. Manifestations of SUD that led to tensions with healthcare teams should alert and lead to an evaluation, to distinguish a true addiction from a pseudoaddiction which may be linked to an insufficient analgesic treatment related to an underestimation of pain in SCD patients.

TRIAL REGISTRATION

Clinical Trials, NCT02580565. Registered 16 October 2015, https://clinicaltrials.gov/.

How to Measure Pain

PURPOSE OF REVIEW

Pain is a multi-faceted symptom. Effective pain assessment involves properly defining the pain syndrome, utilizing various assessment tools, and recognizing different conditions which may affect the expression and the management of pain.

RECENT FINDINGS

Pain results from multiple physical and psychosocial etiological interplay. It has traditionally been categorized as acute or chronic with chronic pain having been categorized further into 6 categories in ICD 11. At the same time, the opioid epidemic and the recent surge in cannabis popularity further complicates pain assessment and effective pain management. Adequate management of pain begins with proper assessment including conducting extensive medical and psychosocial history and physical examination, and utilizing various pain and substance risk assessment tools. An interdisciplinary team approach may be more effective in managing complex pain behaviors compared to a solo approach.

Pseudoaddiction: Fact or Fiction? An Investigation of the Medical Literature

Tremendous growth in opioid prescribing over two decades in the USA has correlated with proportional increases in diversion, addiction, and overdose deaths. Pseudoaddiction, a concept coined in 1989, has frequently been cited to indicate that under-treatment of pain, rather than addiction, is the more pressing and authentic clinical problem in opioid-seeking patients. This investigative review searched Medline articles containing the term "pseudoaddiction" to determine its footprint in the literature with a focus on how it has been characterized and empirically validated. By 2014, pseudoaddiction was discussed in 224 articles. Only 18 of these articles contributed to or questioned pseudoaddiction from an anecdotal or theoretical standpoint, and none empirically tested or confirmed its existence. Twelve of these articles, including all four that acknowledged pharmaceutical funding, were proponents of pseudoaddiction. These papers described pseudoaddiction as an iatrogenic disease resulting from withholding opioids for pain that can be diagnosed, prevented, and treated with more aggressive opioid treatment. In contrast, six articles, none with pharmaceutical support, questioned pseudoaddiction as a clinical construct. Empirical evidence supporting pseudoaddiction as a diagnosis distinct from addiction has not emerged. Nevertheless, the term has been accepted and proliferated in the literature as a justification for opioid therapy for non-terminal pain in patients who may appear to be addicted but should not, from the perspective of pseudoaddiction, be diagnosed with addiction. Future studies should examine whether acceptance of pseudoaddiction has complicated accurate pain assessment and treatment, and whether it has contributed to or reflected medical-cultural shifts that produced the iatrogenic opioid addiction epidemic.