Aptazapine is a 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...

 (TeCA) which was assayed in clinical trial

Clinical trial

Clinical trials are a set of procedures in medical research and drug development that are conducted to allow safety and efficacy data to be collected for health interventions...

s for the treatment of depression in the 1980s but was never marketed. It is a potent

Potency (pharmacology)

In the field of pharmacology, potency is a measure of drug activity expressed in terms of the amount required to produce an effect of given intensity. A highly potent drug evokes a larger response at low concentrations, while a drug of lower potency evokes a small response at low concentrations...

 α₂-adrenergic receptor

Alpha-2 adrenergic receptor

The alpha-2 adrenergic receptor is a G protein-coupled receptor associated with the Gi heterotrimeric G-protein. It consists of three highly homologous subtypes, including α2A-, α2B-, and α2C-adrenergic. Some species other than humans express a fourth α2D-adrenergic receptor as well...

 antagonist

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...

 with ~10x the strength of the related compound mianserin

Mianserin

Mianserin is a psychoactive drug of the tetracyclic antidepressant chemical class which is classified as a noradrenergic and specific serotonergic antidepressant and has antidepressant, anxiolytic, hypnotic, antiemetic, orexigenic, and antihistamine effects...

 and has also been shown to act as a 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...

 antagonist

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...

 and H₁ receptor

H1 receptor

The H1 receptor is a histamine receptor belonging to the family of Rhodopsin like G-protein-coupled receptors. This receptor, which is activated by the biogenic amine histamine, is expressed throughout the body, to be specific, in smooth muscles, on vascular endothelial cells, in the heart, and in...

 inverse agonist

Inverse agonist

In the field of pharmacology, an inverse agonist is an agent that binds to the same receptor as an agonist but induces a pharmacological response opposite to that agonist....

, while having no significant effects on the reuptake

Reuptake

Reuptake, or re-uptake, is the reabsorption of a neurotransmitter by a neurotransmitter transporter of a pre-synaptic neuron after it has performed its function of transmitting a neural impulse....

 of serotonin

Serotonin

Serotonin or 5-hydroxytryptamine is a monoamine neurotransmitter. Biochemically derived from tryptophan, serotonin is primarily found in the gastrointestinal tract, platelets, and in the central nervous system of animals including humans...

 or norepinephrine

Norepinephrine

Norepinephrine is the US name for noradrenaline , a catecholamine with multiple roles including as a hormone and a neurotransmitter...

. Based on its pharmacological profile, aptazapine may be classified as a noradrenergic and specific serotonergic antidepressant

Noradrenergic and specific serotonergic antidepressant

Noradrenergic and specific serotonergic antidepressants are a class of psychiatric drugs used primarily as antidepressants. They act by antagonizing various adrenergic and serotonin receptors, of which typically consist of α1-adrenergic and α2-adrenergic, and 5-HT2A, 5-HT2C, and 5-HT3, respectively...

(NaSSA).