Tetracyclic antidepressants (TeCAs) are a class of antidepressants that were first introduced in the 1970s. They are named after their chemical structure, which contains four rings of atoms, and are closely related to the tricyclic antidepressants (TCAs), which contain three rings of atoms.
The TeCAs include:
Marketed
Maprotiline (Deprilept, Ludiomil, Psymion)
Mianserin (Bolvidon, Norval, Tolvon)
Mirtazapine (Remeron, Avanza, Zispin)
Pirlindole (Pirazidol) — a tetracyclic reversible inhibitor of monoamine oxidase A (RIMA) used in Russia
Setiptiline (Tecipul)
Not marketed
Aptazapine (CGS-7525A)
Esmirtazapine (ORG-50,081)
Metralindole — a tetracyclic RIMA investigated as an antidepressant
Oxaprotiline (C 49-802 BDA)
Doubtful classification — the following agents contain four rings not fused together
Amoxapine (Asendin) — widely classified as a secondary amine tricyclic antidepressant
Ciclazindol (WY-23,409)
Losindole (BI-27,062)
Loxapine (Loxapac, Loxitane, Adasuve) — a tricyclic antipsychotic with antidepressant properties; produces amoxapine as an active metabolite
Mazindol (Mazanor, Sanorex)
The affinities (Kd (nM)) of a selection of TeCAs have been compared below at an assortment of binding sites:
The selected ligands act as antagonists (or inverse agonists depending on the site in question) at all receptors listed and as inhibitors of all transporters listed.
