Tricyclic antidepressant
Tricyclic antidepressants (TCAs) are heterocyclic chemical compound
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

s used primarily as antidepressant
An antidepressant is a psychiatric medication used to alleviate mood disorders, such as major depression and dysthymia and anxiety disorders such as social anxiety disorder. According to Gelder, Mayou &*Geddes people with a depressive illness will experience a therapeutic effect to their mood;...

s. The TCAs were first discovered in the early 1950s and were subsequently introduced later in the decade; they are named after their chemical structure
Chemical structure
A chemical structure includes molecular geometry, electronic structure and crystal structure of molecules. Molecular geometry refers to the spatial arrangement of atoms in a molecule and the chemical bonds that hold the atoms together. Molecular geometry can range from the very simple, such as...

, which contains three rings of atom
Cyclic compound
In chemistry, a cyclic compound is a compound in which a series of atoms is connected to form a loop or ring.While the vast majority of cyclic compounds are organic, a few inorganic substances form cyclic compounds as well, including sulfur, silanes, phosphanes, phosphoric acid, and triboric acid. ...

s. The tetracyclic antidepressant
Tetracyclic antidepressant
Tetracyclic antidepressants are a class of drugs used primarily as 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 which contain three rings of...

s (TeCAs), which contain four rings of atoms, are a closely related group of antidepressant compounds.

In recent times, the TCAs have been largely replaced in clinical use in most parts of the world by newer antidepressants such as the selective serotonin reuptake inhibitor
Selective serotonin reuptake inhibitor
Selective serotonin re-uptake inhibitors or serotonin-specific reuptake inhibitor are a class of compounds typically used as antidepressants in the treatment of depression, anxiety disorders, and some personality disorders. The efficacy of SSRIs is disputed...

s (SSRIs) and serotonin-norepinephrine reuptake inhibitor
Serotonin-norepinephrine reuptake inhibitor
Serotonin–norepinephrine reuptake inhibitors are a class of antidepressant drugs used in the treatment of major depression and other mood disorders...

s (SNRIs), which typically have more favorable side-effects profiles, though they are still sometimes prescribed
Medical prescription
A prescription is a health-care program implemented by a physician or other medical practitioner in the form of instructions that govern the plan of care for an individual patient. Prescriptions may include orders to be performed by a patient, caretaker, nurse, pharmacist or other therapist....

 for certain indication
Indication (medicine)
In medicine, an indication is a valid reason to use a certain test, medication, procedure, or surgery. The opposite of indication is contraindication.-Drugs:...

The TCAs include the following agents which are predominantly serotonin and/or norepinephrine reuptake inhibitor
Norepinephrine reuptake inhibitor
A norepinephrine reuptake inhibitor or adrenergic reuptake inhibitor , is a type of drug which acts as a reuptake inhibitor for the neurotransmitters norepinephrine and epinephrine by blocking the action of the norepinephrine transporter...

As well as the following atypical compounds:
  • Amineptine
    Amineptine was developed by the French Society of Medical research in the 1960s. Under the trade-names is used as an atypical tricyclic antidepressant that selectively inhibits the reuptake of dopamine and to a lesser extent norepinephrine, thus exerting a powerful and fast-acting...

     (Survector, Maneon, Directim) - Norepinephrine-dopamine reuptake inhibitor
    Norepinephrine-dopamine reuptake inhibitor
    A norepinephrine-dopamine reuptake inhibitor is a drug which acts as a reuptake inhibitor for the neurotransmitters norepinephrine and dopamine by blocking the action of the norepinephrine transporter and the dopamine transporter , respectively...

  • Iprindole
    Iprindole , formerly known as pramindole, is a tricyclic antidepressant used in Europe for the treatment of depression. It was introduced by Wyeth and has been used clinically since 1967...

     (Prondol, Galatur, Tetran) - 5-HT2 receptor
    5-HT2 receptor
    The 5-HT2 receptors are a subfamily of 5-HT receptors that bind the endogenous neurotransmitter serotonin . The 5-HT2 subfamily consists of three G protein-coupled receptors which are coupled to Gq/G11 and mediate excitatory neurotransmission, including 5-HT2A, 5-HT2B, and 5-HT2C...

    Receptor antagonist
    A receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses...

  • Opipramol
    Opipramol is an antidepressant and anxiolytic used in Germany and other European countries. Although it is a member of the tricyclic antidepressants, opipramol's primary mechanism of action is much different in comparison...

     (Insidon, Pramolan, Ensidon, Oprimol) - σ receptor
    Sigma receptor
    The sigma receptors σ1 and σ2 bind to ligands such as 4-PPBP, SA 4503, ditolylguanidine, dimethyltryptamine and siramesine.- Classification :...

  • Tianeptine
    Tianeptine was discovered by The French Society of Medical Research in the 1960s. Under the trade-names it is a drug used for treating major depressive episodes ....

     (Stablon, Coaxil, Tatinol) - Selective serotonin reuptake enhancer
    Selective serotonin reuptake enhancer
    A selective serotonin reuptake enhancer is a type of drug which enhances the plasmalemmal reuptake of the neurotransmitter serotonin, leading to a decrease in its synaptic concentrations and therefore a decrease in serotonergic neurotransmission....

  • Trimipramine
    Trimipramine is a tricyclic antidepressant . It has antidepressant, anxiolytic, antipsychotic, sedative, and analgesic effects.- Indications :...

     (Surmontil) - 5-HT2 receptor antagonist

The TCAs were developed amid the "explosive birth" of psychopharmacology in the early 1950s.