Tianeptine (Stablon, Coaxil, Tatinol) is a neuroprotective antidepressant that reverses the neuronal damage and lasting misery caused by chronic, uncontrolled stress. Tianeptine acts both as a non-sedating anti-anxiety agent and a non-stimulating mood-brightener. Uniquely in clinical medicine, tianeptine acts as a selective serotonin reuptake enhancer. Its puzzling efficacy as an antidepressant illustrates how little modern psychiatric medicine really understands about mind, mood and depression.
A breakthrough in tianeptine research was announced in July 2014 with the unexpected discovery that tianeptine is a full agonist at the mu and delta opioid receptors with negligible effect at the kappa opioid receptors. Selective mu opioid agonists in the brain's "hedonic hotspots" typically induce euphoria. Selective kappa agonists typically induce dysphoria. The role of central delta opioid receptors is poorly understood. Dual activation of the mu and, less potently, delta opioid receptors may be critical to tianeptine's mood-brightening and anxiolytic effect - a therapeutic action seemingly unaccompanied by the physiological tolerance and dependence that have plagued traditional opioids. All previous research into tianeptine may need to be re-evaluated in this light. Neonatal Abstinence Syndrome following heavy use of tianeptine during pregnancy has been reported. The recently popular sulfate salt (tianeptine sulphate) is less readily absorbed and excreted from the body than the sodium salt, allowing one-per-day dosing, smoother plasma concentrations, and minimal risk of abuse. More research is urgently needed.
An inverse correlation exists between the suicide rate and dietary intake of the essential amino acid l-tryptophan, the rate-limiting precursor of serotonin synthesis. The widely prescribed selective serotonin reuptake inhibitors [i.e. the SSRIs fluoxetine (Prozac), sertraline (Zoloft), fluvoxamine (Luvox), paroxetine (Paxil) and citalopram (Celexa)] block the reuptake of the neurotransmitter serotonin into the presynaptic nerve cells by interfering with the serotonin transporter. They thereby increase the availability of serotonin in the synapse. SSRIs are marketed primarily as antidepressants. They are prescribed for a host of off-label indications too. In contrast to SSRIs, tianeptine facilitates the reuptake of serotonin into serotonergic terminals both in the cortex and hippocampus - confounding simplistic "low serotonin" theories of depression. Tianeptine lacks any significant activity at monoamine transporters or neurotransmitter receptors. How it actually accelerates serotonin reuptake, both acutely and chronically, is unclear. Like other contemporary antidepressants, its therapeutic action presumably depends on downstream adaptations both between and within neurons occurring over a period of several weeks.