tricyclic

American  

[trahy-sahy-klik, -sik-lik] / traɪˈsaɪ klɪk, -ˈsɪk lɪk /

adjective

1. pertaining to or embodying three cycles.

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noun

1. Also called tricyclic antidepressant.  Pharmacology. any of a group of pharmacologically active substances, as imipramine, that share a common three-ring structure, used to treat depression and cocaine abuse.

tricyclic British  

/ traɪˈsaɪklɪk /

adjective

1. (of a chemical compound) containing three rings in the molecular structure

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noun

1. an antidepressant drug having a tricyclic molecular structure

tricyclic Scientific  

/ trī-sī′klĭk,-sĭk′lĭk /

1. Relating to a chemical compound having three closed rings. Anthracene is a tricyclic hydrocarbon.

2. Relating to a class of drugs used to treat depression and having a tricyclic chemical structure consisting of two benzene rings fused to opposite sides of a seven-member ring. The seven-member ring consists of six carbon atoms and one nitrogen atom. Tricyclic antidepressants enhance the activity of monoamine neurotransmitters in the brain by inhibiting their reuptake by the cells that secrete them.

3. Composed of or arranged in three distinct whorls, as the petals of a flower.

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Etymology

Origin of tricyclic

First recorded in 1890–95; tri- + cyclic

Example Sentences

More pharmacological discoveries followed, including the first tricyclic antidepressants — drugs that reduce the absorption of neurotransmitters called catecholamines.

From Salon • May 23, 2025

First there were tricyclic antidepressants, then there were SSRIs like Prozac and SNRIs like Cymbalta, drugs that target neurotransmitters such as serotonin and norepinephrine.

From Los Angeles Times • Oct. 2, 2022

Dr Laurence Wainwright, a researcher at the University of Oxford's psychiatry department, told the BBC there is "evidence to suggest a link between tricyclic antidepressants, antipsychotics and heat-related illnesses".

From BBC • Aug. 12, 2022

I try anti-inflammatories, steroids, muscle relaxants, antihistamines, beta blockers, calcium-channel blockers, SSRIs, tricyclic antidepressants, antipsychotics, anticonvulsants, and a medication prescribed to slow the onset of Alzheimer’s.

From The Guardian • Nov. 17, 2016

He prescribed nortryptyline, a tricyclic antidepressant sometimes used to treat migraines, which Miller took for a year without noticing any improvement.

From Washington Post