chemistry

Tetracyclic antidepressant

Tetracyclic antidepressant is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Tetracyclic antidepressant rather than just read about it. In short: 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, as well as to benzodiazepines which are composed of hexagonal benzene and heptagonal diazepine rings.

Key takeaways

Tetracyclic antidepressant belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Tetracyclic antidepressant to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Tetracyclic antidepressant from memory before moving on to harder problems.

Reference excerpt

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, as well as to benzodiazepines which are composed of hexagonal benzene and heptagonal diazepine rings.

List of TeCAs

Marketed Maprotiline (Ludiomil) – can also be classified as a TCA and grouped with the secondary amines Mianserin (Tolvon) Mirtazapine (Remeron) Setiptiline (Tecipul) Drugs that contain four rings not all fused together but are sometimes still classified as TeCAs include:

Amoxapine (Asendin) – often classified as a TCA and grouped with the secondary amines Quetiapine (Seroquel) - an atypical antipsychotic sometimes used as an adjunct antidepressant

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:

Mazindol (Mazanor, Sanorex) – a monoamine reuptake inhibitor used as an appetite suppressant and with potential antidepressant effects, but not classified as a TeCA

Never marketed Aptazapine (CGS-7525A) – a close analogue of mirtazapine Esmirtazapine (ORG-50,081) – the (S)-(+) enantiomer of mirtazapine Oxaprotiline (C 49-802 BDA) – a close analogue of maprotiline 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

TeCAs have diverse pharmacology and differ from TCAs in a number of ways. With the exception of amoxapine, TeCAs do not inhibit the reuptake of serotonin. However, aside from mirtazapine, they do inhibit the reuptake of norepinephrine. TeCAs block the serotonin 5-HT2 receptors similarly to TCAs. Besides mirtazapine, they also block the α1-adrenergic receptor. Conversely, whereas TCAs have relatively low affinity for the α2-adrenergic receptor, mianserin and mirtazapine potently antagonize this receptor, and this action is thought to be involved in their antidepressant effects. TeCAs block the histamine H1 receptor similarly to the TCAs, but tend to be even stronger antihistamines than TCAs. On the other hand, in contrast to almost all TCAs, TeCAs have only low affinity for the muscarinic acetylcholine receptors, and for this reason, are associated with few or no anticholinergic side effects. Mianserin and mirtazapine are far less toxic than TCAs in overdose.

Binding profiles

The binding profiles of various TeCAs in terms of their affinities (Ki, nM) for various receptors and transporters are as follows:

The TeCAs act as antagonists or inverse agonists of the receptors and as inhibitors of the transporters.

See also List of antidepressants Noradrenergic and specific serotonergic antidepressant

References

Illustrations

Worked examples

Example 1 — a first encounter with Tetracyclic antidepressant

Start with the simplest possible case. Write down what Tetracyclic antidepressant claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Tetracyclic antidepressant before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Tetracyclic antidepressant ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Tetracyclic antidepressant

In research: Tetracyclic antidepressant appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Tetracyclic antidepressant in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Tetracyclic antidepressant is common in secondary-school and first-year university syllabi. It links to neighbouring topics Chemical classes of psychoactive drugs, Tetracyclic antidepressants, so understanding it makes those chapters shorter.
In everyday life: Look for Tetracyclic antidepressant outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Tetracyclic antidepressant in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Tetracyclic antidepressant means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Tetracyclic antidepressant out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Tetracyclic antidepressant in simple terms?

Why does Tetracyclic antidepressant matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Tetracyclic antidepressant?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Tetracyclic antidepressant.