Tianeptine, an Antidepressant with Opioid Agonist Effects: Pharmacology and Abuse Potential, a Narrative Review

Tianeptine: enantiomeric separations, structural assignment, and biological interactions

Tianeptine is an atypical tricyclic antidepressant that has gained attention due to its unique mechanism of action, distinguishing it from other such medications. The drug has proliferated in recreational markets as "gas station heroin" since it produces opioid-like effects and euphoric highs as a result of binding to mu opioid receptors. The unrestricted availability of tianeptine has resulted in many irreversible adverse effects and fatal overdoses. Tianeptine is a chiral molecule and has not yet been widely investigated for the therapeutic/toxic effects of its single enantiomers. Such studies require reliable and fast chiral separation methods for separation and quantitation. In this study, the enantioselective HPLC methods in normal phase and polar ionic mode were developed for analytical and preparative separation and purification of tianeptine. Two chiral stationary phases were employed: one based on 1-(3,5-dinitrobenzamido)-1,2,3,4-tetrahydrophenanthrene and another based on a modified macrocyclic glycopeptide, both utilizing 2.7 μm core-shell bonded silica particles. These column chemistries are available under the commercial names of WhelkoShell and NicoShell, respectively. Both columns offer the same elution order, as confirmed by an optical circular dichroism detector. The absolute configurations of the purified single enantiomers were determined using vibrational circular dichroism spectroscopy with a 99 % confidence level. The total tianeptine and its enantiomeric ratio in recreational products were analyzed by HPLC-UV after developing a robust extraction procedure with ethanol for liquid and solid products. The assessment of the enantioselective binding of tianeptine to many essential proteins revealed higher affinity of human serum albumin for the S-tianeptine.

An Outbreak of Synthetic Cannabinoid-Adulterated Tianeptine Products in New Jersey - Case Series

BACKGROUND

Tianeptine, an atypical antidepressant not approved in the United States, is readily purchased from unregulated markets such as the internet and gas stations. We became aware of a cluster of 34 patients in New Jersey who became ill following ingestion of the tianeptine containing-product Neptune's Fix, the rate of which (4.6 cases per month) far exceeded the background rate for this substance of 0.5 cases per year.

METHODS

We retrospectively identified tianeptine exposures reported to the New Jersey Poison Information and Education System (NJPIES) prior to June 2023 to determine the background rate of tianeptine exposure. From June 2023- February 2024 we prospectively surveilled tianeptine exposures reported to NJPIES, recorded demographic and clinical information, and recruited samples for testing. Six samples of the ingested products were obtained and analyzed using gas chromatography mass spectrometry (GC-MS) and liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). Whole blood samples from two patients were tested for tianeptine and synthetic cannabinoids.

RESULTS

During the period of interest, NJPIES received 41 exposure calls, with 37 reporting acute toxicity in 34 unique patients, two reporting chronic tianeptine use, and two reporting withdrawal. Among the 37 exposures resulting in acute toxicity, commonly reported effects included altered mental status, tachycardia, hypotension, and seizures. 43% (n = 16) were intubated, and 65% (n = 24) were admitted to the ICU. Analytical testing of six samples identified variable product composition, containing various xenobiotics including tianeptine, kava alkaloids, natural cannabinoids, and the synthetic cannabinoids MDMB-4en-PINACA and ADB-4en-PINACA. MDMB-4en-PINACA was detected in one of the two patient blood specimens.

CONCLUSIONS

These cases represent a marked increase in tianeptine exposures compared with the poison center's historical average. Analytical testing revealed variable product composition, including the presence of synthetic cannabinoids. Clinicians should be aware that tianeptine containing products are widely available, unregulated, and can be adulterated.

Redefining Ketamine Pharmacology for Antidepressant Action: Synergistic NMDA and Opioid Receptor Interactions?

Ketamine is a racemic compound and medication comprised of (S)-ketamine and (R)-ketamine enantiomers and its metabolites. It has been used for decades as a dissociative anesthetic, analgesic, and recreational drug. More recently, ketamine, its enantiomers, and its metabolites have been used or are being investigated for the treatment of refractory depression, as well as for comorbid disorders such as anxiety, obsessive-compulsive, and opioid use disorders. Despite its complex pharmacology, ketamine is referred to as an N-methyl-d-aspartate (NMDA) receptor antagonist. In this review, the authors argue that ketamine's pharmacology should be redefined to include opioid receptors and the endogenous opioid system. They also highlight a potential mechanism of action of ketamine for depression that is attributed to bifunctional, synergistic interactions involving NMDA and opioid receptors.

Tianeptine Exposures Reported to United States Poison Centers, 2015-2023

INTRODUCTION

Tianeptine is an atypical tricyclic antidepressant not approved for medical use in the US but is found in dietary supplements. This study investigates single-substance tianeptine exposures reported to US poison centers.

METHODS

We analyzed cases involving tianeptine reported to the National Poison Data System from 2015 to 2023.

RESULTS

There were 892 single-substance tianeptine exposures reported to US poison centers from 2015 to 2023, and the rate of exposures increased 1,400% from 2015 to 2023, including a 525% increase from 2018 to 2023. Most exposures were associated with moderate (51.5%) or major (12.0%) effects, and 40.1% required medical admission, including 22.9% to a critical care unit. Individuals 50 years and older were more likely to experience major effects (RR: 1.70, 95% CI: 1.13-2.56) or require medical admission (RR: 1.43, 95% CI: 1.20-1.72) than younger individuals. Tianeptine abuse accounted for 40.1% of exposures and was more likely to be associated with moderate or major effects (RR: 1.18, 95% CI: 1.06-1.31) than exposures not attributed to abuse. Withdrawal accounted for 22.5% of tianeptine exposures. Tianeptine exposure rates were highest in the US South. Alabama enacted legislation to regulate tianeptine as a controlled substance in 2021. Alabama's tianeptine exposure rate increased by 1,413.7% from 2018 to 2021, followed by a 74.6% decrease from 2021 to 2023, while the rate in other southern states continued to increase.

CONCLUSIONS

This study demonstrates the toxicity and rapid increase of tianeptine exposures reported to US poison centers. Uniform regulation of tianeptine across all states may offer an important strategy to help mitigate this public health problem.

Classics in Chemical Neuroscience: Tianeptine

Tianeptine (1) is an unusual antidepressant in that its mechanism of action appears to be independent from any activity at serotonin receptors or monoamine transporters. In fact, tianeptine has been shown to be a moderately potent agonist for the mu opioid receptor (MOR) and to a lesser extent the delta opioid receptor (DOR). Additionally, tianeptine's efficacy may be related to its action on glutamate-mediated pathways of neuroplasticity. Regardless of which neurotransmitter system is primarily responsible for the observed efficacy, the MOR agonist activity is problematic with respect to abuse liability. Increasing numbers of case reports have demonstrated that tianeptine is indeed being used recreationally at doses far beyond what are considered therapeutically relevant or safe, and scheduling reclassifications or outright bans on tianeptine products are ongoing around the world. It is the aim of this review to discuss the medicinal chemistry and pharmacology of tianeptine and to summarize this intriguing discrepancy between tianeptine's historical use as a safe and effective antidepressant and its emerging potential for abuse.

The hormonal mechanism of the effects of meperidine, sertraline, tianeptine, and their combinations on reproductive functions in female rats

BACKGROUND

Infertility caused by drugs that inhibit serotonin reuptake has been attributed to serotonin toxicity. Serotonin has been linked to cause a rise in prolactin and cortisol. This study examined the effects of meperidine, sertraline, tianeptine and combinations on female rat reproductive function.

METHODS

Female rats were split into 8 groups (n=7): healthy control (HG), meperidine (MG), sertraline (SG), tianeptine (TG), meperidine+sertraline (MSG), meperidine+tianeptine (MTG), sertraline+tianeptine (STG), meperidine+sertraline+tianeptine (MSTG). Meperidine (20 mg/kg, 2×1) was injected intramuscularly. Sertraline (30 mg/kg, 1×1) and tianeptine (5 mg/kg, 1×1) were given orally. The HG received distilled water as solvent. Treatments continued for 20 days. Then, adult males were added to the rat groups and drug treatment continued for another five days. Blood samples were collected on day 26 for biochemical tests.

RESULTS

Total oxidant status (TOS) and total antioxidant status (TAS) were not statistically significant between groups (p>0.05). Meperidine (p<0.001) and sertraline (p<0.001) alone increased prolactin levels in comparison to HG and tianeptine inhibited the increase (p<0.001). While meperidine increased corticosterone levels versus HG (p<0.001), sertraline and tianeptine were close to HG (p>0.05). Number of infertile animals was 6 for meperidine, 3 for sertraline, and none for tianeptine. While the duration of pregnancy in MG (15 days) and SG (15 days) was longer compared to HG (2.86 days), no change was observed in TG (2.5 days).

CONCLUSION

Tianeptine and other serotonin re-uptake stimulants may be useful in the treatment of reproductive dysfunction and infertility due to serotonin re-uptake inhibitor treatment.

Examining the Gateway Hypothesis and Mapping Substance Use Pathways on Social Media: Machine Learning Approach

BACKGROUND

Substance misuse presents significant global public health challenges. Understanding transitions between substance types and the timing of shifts to polysubstance use is vital to developing effective prevention and recovery strategies. The gateway hypothesis suggests that high-risk substance use is preceded by lower-risk substance use. However, the source of this correlation is hotly contested. While some claim that low-risk substance use causes subsequent, riskier substance use, most people using low-risk substances also do not escalate to higher-risk substances. Social media data hold the potential to shed light on the factors contributing to substance use transitions.

OBJECTIVE

By leveraging social media data, our study aimed to gain a better understanding of substance use pathways. By identifying and analyzing the transitions of individuals between different risk levels of substance use, our goal was to find specific linguistic cues in individuals' social media posts that could indicate escalating or de-escalating patterns in substance use.

METHODS

We conducted a large-scale analysis using data from Reddit, collected between 2015 and 2019, consisting of over 2.29 million posts and approximately 29.37 million comments by around 1.4 million users from subreddits. These data, derived from substance use subreddits, facilitated the creation of a risk transition data set reflecting the substance use behaviors of over 1.4 million users. We deployed deep learning and machine learning techniques to predict the escalation or de-escalation transitions in risk levels, based on initial transition phases documented in posts and comments. We conducted a linguistic analysis to analyze the language patterns associated with transitions in substance use, emphasizing the role of n-gram features in predicting future risk trajectories.

RESULTS

Our results showed promise in predicting the escalation or de-escalation transition in risk levels, based on the historical data of Reddit users created on initial transition phases among drug-related subreddits, with an accuracy of 78.48% and an F1-score of 79.20%. We highlighted the vital predictive features, such as specific substance names and tools indicative of future risk escalations. Our linguistic analysis showed that terms linked with harm reduction strategies were instrumental in signaling de-escalation, whereas descriptors of frequent substance use were characteristic of escalating transitions.

CONCLUSIONS

This study sheds light on the complexities surrounding the gateway hypothesis of substance use through an examination of web-based behavior on Reddit. While certain findings validate the hypothesis, indicating a progression from lower-risk substances such as marijuana to higher-risk ones, a significant number of individuals did not show this transition. The research underscores the potential of using machine learning with social media analysis to predict substance use transitions. Our results point toward future directions for leveraging social media data in substance use research, underlining the importance of continued exploration before suggesting direct implications for interventions.

A Case of 'Neptune's Fix Elixir': The Dangerous Consequences of Unregulated Use of Tianeptine in Over-the-Counter Products

Tianeptine is an atypical tricyclic antidepressant approved for the treatment of major depressive disorder in some European, Asian, and Latin countries. Along with its serotonergic properties, tianeptine also acts as a full agonist at the mu-opioid receptor, creating sensations of euphoric highs and significant risks of addiction and withdrawal. For this reason, along with increased reports of adverse effects and fatalities, tianeptine has not been approved in the US. Despite this, tianeptine continues to be accessible through unregulated online stores and small retailers under street names such as Zaza, Tia, Tianna, 'gas-station dope', and a product not mentioned in the literature previously: Neptune's Fix Elixir. In this report, we discuss the case of a 34-year-old male who presented to the ED via EMS after being found unresponsive secondary to the ingestion of Neptune's Fix Elixir, whose main active ingredient is tianeptine.