Tianeptine: Paradoxical Mechanism and Pharmacokinetics
Tianeptinum stands out among psychotropic drugs due to its unique pharmacodynamic profile. Its specific action lies in the fact that it increases (stimulates) neuronal serotonin reuptake in the cerebral cortex and hippocampus. This mechanism is directly opposite to that of classic reuptake inhibitors. At the same time, the drug's effect on dopamine and norepinephrine metabolism remains weak.
Tianeptine's pharmacokinetic parameters provide high bioavailability (up to 99%) due to rapid and complete absorption from the gastrointestinal tract. In the blood, the drug binds extensively to plasma proteins (94%). Metabolism occurs via β-oxidation and N-demethylation. The elimination half-life is relatively short at 2.5 hours, though it extends to 3.5 hours in elderly patients. Excretion occurs via the kidneys: predominantly as metabolites, with only 8% excreted unchanged.
Clinical Effects and Safety of Tianeptine
The drug successfully combines antidepressant activity with a pronounced anxiolytic (anti-anxiety) effect. In clinical practice, it normalizes behavior and mood, restores physiological sleep, improves concentration, and effectively reduces somatic symptoms of depression.
Main indications for use include:
- Reactive and neurotic depressions.
- Anxious-depressive states accompanied by somatic complaints.
- Depressive disorders associated with chronic alcoholism.
The safety profile of tianeptine is considered highly favorable. The drug does not cause addiction, does not suppress libido, and has no negative impact on memory. Adverse effects occur relatively infrequently and are not life-threatening. These may include gastrointestinal disorders (dry mouth, epigastric pain, nausea, vomiting, constipation, flatulence, anorexia), central nervous system disturbances (insomnia or drowsiness, tremor, asthenia, dizziness, headache), and cardiovascular effects (tachycardia, extrasystoles, chest pain). In rare cases, patients report muscle pain, lower back pain, or dyspnea.
Mirtazapine: Receptor Profile and Mechanism of Action
Mirtazapinum is a tetracyclic antidepressant. Its primary pharmacological effect is based on the blockade of presynaptic α2-adrenergic receptors located in serotonergic and adrenergic synapses. By blocking these receptors, the drug causes a potent enhancement of neurotransmitter release—specifically serotonin and norepinephrine—from nerve terminals.
In addition to its main mechanism, mirtazapine exhibits several additional effects due to its affinity for other receptor types:
- Pronounced sedative action, resulting from the blockade of H1-histamine receptors.
- Weak blockade of peripheral α1-adrenergic receptors.
- Negligible anticholinergic activity.
Administration and Risks of Mirtazapine Therapy
In clinical practice, mirtazapine is used primarily to treat endogenous depressions, as well as conditions accompanied by pronounced psychomotor retardation. In therapeutic efficacy, it surpasses traditional tricyclic antidepressants. It is important to note that the clinical effect does not appear immediately, but rather after 1–2 weeks of regular intake.
Despite high efficacy, mirtazapine therapy carries specific adverse effects:
- Metabolic disturbances: increased appetite and weight gain are frequently observed.
- Neurological and psychiatric reactions: muscle twitches, apathy, and excessive sedation are possible.
- Cardiovascular reactions: orthostatic hypotension (explained by α2-adrenergic receptor blockade).
- Hematological complications: rare but clinically significant conditions, such as leukopenia and agranulocytosis.
Additionally, discontinuing the drug carries the risk of withdrawal syndrome.