What clinicians need to know about intranasal esketamine for treatment-resistant depression?

Major challenges in youth psychopathology: treatment-resistant depression. A narrative review

Major depressive disorder (MDD) represents a major health issue in adolescents and young adults, leading to high levels of disability and profoundly impacting overall functioning. The clinical presentation of MDD in this vulnerable age group may slightly differ from what can be observed in adult populations, and psychopharmacological strategies do not always lead to optimal response. Resistance to antidepressant treatment has a prevalence estimated around 40% in youths suffering from MDD and is associated with higher comorbidity rates and suicidality. Several factors, encompassing biological, environmental, and clinical features, may contribute to the emergence of treatment-resistant depression (TRD) in adolescents and young adults. Furthermore, TRD may underpin the presence of an unrecognized bipolar diathesis, increasing the overall complexity of the clinical picture and posing major differential diagnosis challenges in the clinical practice. After summarizing current evidence on epidemiological and clinical correlates of TRD in adolescents and young adults, the present review also provides an overview of possible treatment strategies, including novel fast-acting antidepressants. Despite these pharmacological agents are promising in this population, their usage is expected to rely on risk-benefit ratio and to be considered in the context of integrated models of care.

Combination of Acute and Maintenance Esketamine Treatment With Adjunctive Long-Term Vagus Nerve Stimulation in Difficult-to-Treat Depression

INTRODUCTION

The antidepressant effect of N-methyl-D-aspartate antagonists is often short lasting, raising the question of the best maintenance strategy, which has remained unanswered. Vagus nerve stimulation (VNS) as a treatment option for refractory and chronic major depression was shown to reduce the need for maintenance treatment sessions in patients receiving electroconvulsive therapy. To our knowledge, there are no published data on the combination of VNS and esketamine in the literature.

MATERIALS AND METHODS

This is a naturalistic prospective and retrospective observational study in patients treated with long-term VNS owing to difficult-to-treat depression. These patients also have received esketamine maintenance sessions in addition to short-term treatment. We have investigated the need for maintenance esketamine sessions per month after VNS implantation (number of sessions/number of months between visits), the change in depression severity (mean Montgomery-Asberg Depression Rating Scale [MADRS] score), and the number of hospitalizations per month (number of hospitalizations/number of postoperative observation months). Follow-up visits have been scheduled every three months after VNS implantation (follow-up period 12-24 months, mean 17).

RESULTS

All patients (n = 8, mean age 53.1 years) had severe difficult-to-treat depression (DTD) (mean MADRS at baseline 30.9). Mean number of hospitalizations per month decreased from 0.17 to 0.11 after VNS implantation (p = 0.041, T = 2.030, df = 7). Mean MADRS at 12 months was 18.3 (40.8% MADRS reduction, p = 0.008, T = 3.146, df = 7). Six of eight patients were offered maintenance esketamine treatment. Mean number of esketamine treatment sessions per month and case decreased from 2.3 at the six-month visit to 0.8 at 12 months (p = 0.076, T = 1,690, df = 5) after VNS implantation. Termination of maintenance esketamine was possible in four cases after a mean of 11.5 months.

CONCLUSIONS

Combination of esketamine and VNS was effective in patients with DTD to relieve disease severity and reduce hospitalizations. The need for esketamine treatment sessions decreased after 6 months of VNS. No safety concerns arose in this study regarding the combination treatment.

CLINICAL TRIAL REGISTRATION

The Clinicaltrials.gov registration number for the study is NCT03320304.

Efficacy and safety of esketamine for pediatric gastrointestinal endoscopy: a meta-analysis and trial sequential analysis

Objective

The role of esketamine in pediatric gastrointestinal endoscopy is still unclear. This study aims to evaluate the efficacy and safety of esketamine for pediatric gastrointestinal endoscopy.

Methods

Clinical trials of esketamine for pediatric gastrointestinal endoscopy were searched in eight common databases, up to October 2023. These clinical trials were included in the meta-analysis and trial sequential analysis (TSA). The risk ratio (RR) and weighted mean difference (WMD) were used as the effect sizes for dichotomous variables and continuity variables, respectively. When the heterogeneity test showed I2 < 50%, the fixed effects model was used for the meta-analysis and TSA; Otherwise, the random effects model was used for them.

Results

In terms of efficacy endpoints, the meta-analysis showed that compared with placebo or blank, esketamine significantly decreased recovery time by 2.34 min (WMD -2.34; 95% Confidence interval [CI] -3.65, -1.02; p = 0.0005) and propofol consumption by 0.70 mg/kg (WMD -0.70; 95% CI -0.98, -0.43; p < 0.00001), and increased mean heart rate by 4.77 beats/min (WMD 4.77; 95% CI 2.67, 6.87; p < 0.00001) and mean arterial pressure by 3.10 mmHg (WMD 3.10; 95% CI 1.52, 4.67; p = 0.0001), while induction time and mean blood oxygen remained comparable. TSA indicated conclusive evidence for these benefits. In terms of safety endpoints, the meta-analysis revealed that esketamine significantly reduced involuntary movements by 59% (RR 0.41; 95% CI 0.22, 0.76; p = 0.005) and choking by 51% (RR 0.49; 95% CI 0.26, 0.92; p = 0.03), while significantly increasing dizziness by 98% (RR 1.98; 95% CI 1.11, 3.56; p = 0.02) and there were no significant differences in total adverse events, respiratory depression, and vomiting. TSA demonstrated conclusive evidence for involuntary movements and dizziness. Low-dose analysis showed that esketamine at ≤0.3 mg/kg significantly reduced recovery time, propofol consumption and involuntary movements, and significantly increasing mean heart rate, with no increase in dizziness. The Begg's test (p = 0.327) and the Egger's test (p = 0.413) indicated no significant publication bias, yet the funnel plot suggested potential publication bias.

Conclusion

Esketamine is an effective adjuvant anesthesia for children undergoing gastrointestinal endoscopy. However, the general dose of esketamine may increase the risk of dizziness, which can be avoided by administering a low dose (≤0.3 mg/kg).

Novel rapid treatment options for adolescent depression

There is an urgent need for novel fast-acting antidepressants for adolescent treatment-resistant depression and/or suicidal risk, since the selective serotonin reuptake inhibitors that are clinically approved for that age (i.e., fluoxetine or escitalopram) take weeks to work. In this context, one of the main research lines of our group is to characterize at the preclinical level novel approaches for rapid-acting antidepressants for adolescence. The present review summarizes the potential use in adolescence of non-pharmacological options, such as neuromodulators (electroconvulsive therapy and other innovative types of brain stimulation), as well as pharmacological options, including consciousness-altering drugs (mainly ketamine but also classical psychedelics) and cannabinoids (i.e., cannabidiol), with promising fast-acting responses. Following a brief analytical explanation of adolescent depression, we present a general introduction for each therapeutical approach together with the clinical evidence supporting its potential beneficial use in adolescence (mainly extrapolated from prior successful examples for adults), to then report recent and/or ongoing preclinical studies that will aid in improving the inclusion of these therapies in the clinic, by considering potential sex-, age-, and dose-related differences, and/or other factors that might affect efficacy or long-term safety. Finally, we conclude the review by providing future avenues to maximize treatment response, including the need for more clinical studies and the importance of designing and/or testing novel treatment options that are safe and fast-acting for adolescent depression.

Research progress in brain-targeted nasal drug delivery

The unique anatomical and physiological connections between the nasal cavity and brain provide a pathway for bypassing the blood-brain barrier to allow for direct brain-targeted drug delivery through nasal administration. There are several advantages of nasal administration compared with other routes; for example, the first-pass effect that leads to the metabolism of orally administered drugs can be bypassed, and the poor compliance associated with injections can be minimized. Nasal administration can also help maximize brain-targeted drug delivery, allowing for high pharmacological activity at lower drug dosages, thereby minimizing the likelihood of adverse effects and providing a highly promising drug delivery pathway for the treatment of central nervous system diseases. The aim of this review article was to briefly describe the physiological structures of the nasal cavity and brain, the pathways through which drugs can enter the brain through the nose, the factors affecting brain-targeted nasal drug delivery, methods to improve brain-targeted nasal drug delivery systems through the application of related biomaterials, common experimental methods used in intranasal drug delivery research, and the current limitations of such approaches, providing a solid foundation for further in-depth research on intranasal brain-targeted drug delivery systems (see Graphical Abstract).