Tetracyclic antidepressant

Source: Wikipedia, the free encyclopedia.
Not to be confused with Tetracycline or Tricyclic antidepressant.
Chemical structure of the TeCA mirtazapine. Notice its four rings fused together.

Tetracyclic antidepressants (TeCAs) are a class of antidepressants that were first introduced in the 1970s. They are named after their tetracyclic chemical structure, containing four rings of atoms, and are closely related to the tricyclic antidepressants (TCAs), which contain three rings of atoms.

List of TeCAs

Marketed

Drugs that contain four rings not all fused together but are sometimes still classified as TeCAs include:

Miscellaneous

  • Benzoctamine (Tacitin) – a tetracyclic compound and is closely related to maprotiline, with the two compounds differing only in the length of their side chain, but benzoctamine is not used as an antidepressant and is instead used as an anxiolytic
  • Loxapine (Adasuve, Loxitane) – a typical antipsychotic that produces amoxapine as a major metabolite and is said to have antidepressant effects, but it is not usually regarded as a TeCA

Drugs that contain four rings not all fused together but could still be classified as tetracyclic include:

  • appetite suppressant
    and with potential antidepressant effects, but not classified as a TeCA

Never marketed

Drugs that contain four rings not all fused together but could still be classified as tetracyclic include:

  • Ciclazindol (WY-23,409) – a close analogue of mazindol

Pharmacology

See also: Pharmacology of antidepressants

TeCAs have diverse

overdose.[1][2]

Binding profiles

See also: Tricyclic antidepressant § Binding profiles

The binding profiles of various TeCAs in terms of their

affinities (Ki, nM) for various receptors and transporters are as follows:[3]

Compound SERTTooltip Serotonin transporter NETTooltip Norepinephrine transporter DATTooltip Dopamine transporter 5-HT1A 5-HT2A 5-HT2B 5-HT2C 5-HT3 5-HT6 5-HT7 α1 α2
D2
H1
H2
 mAChTooltip Muscarinic acetylcholine receptor
Amoxapine 58 16 4,310 ND 0.5 ND 2.0 ND 6.0–50 41 50 2,600 3.6–160 7.9–25 ND 1,000
Maprotiline 5,800 11–12 1,000 ND 51 ND 122 ND ND 50 90 9,400 350–665 0.79–2.0 776 570
Mianserin 4,000 71 9,400 400–2,600 1.6–20 1.6–55 0.63–6.5 5.8–300 55–81 48–56 34 3.8–73 ≥2,100 0.30–1.7 437 820
Mirtazapine >10,000 ≥4,600 >10,000 ≥3,330 6.3–69 200 8.9–39 7.9 ND 265 316–1,815 18–88 >5,454 0.14–1.6 >10,000 670
Setiptiline >10,000 220 >10,000 ND ND ND ND ND ND ND ND 24 ND ND ND ND
Values are Ki (nM). The smaller the value, the more strongly the drug binds to the site. For assay species and references, see the individual drug articles. Most but not all values are for human proteins.

The TeCAs act as

inhibitors
of the transporters.

See also

References

  1. ISSN 0300-7995
    .
  2. S2CID 28546654
    .
  3. ^ Roth, BL; Driscol, J. "PDSP Ki Database". Psychoactive Drug Screening Program (PDSP). University of North Carolina at Chapel Hill and the United States National Institute of Mental Health. Retrieved 14 August 2017.