Tricyclic antidepressants

Tricyclic antidepressants (TCAs) are a class of medications that are used primarily as antidepressants. TCAs were first discovered in the early 1950s and were marketed later in the decade. They are named after their chemical structure, which contains three rings of atoms.

History

The first TCA, imipramine, was discovered in the early 1950s. It was initially intended to treat schizophrenia, but was found to have significant antidepressant effects. This led to the development and marketing of other TCAs.

Mechanism of action

TCAs work by inhibiting the reuptake of certain neurotransmitters, such as norepinephrine and serotonin, thereby increasing their levels in the brain. Some TCAs also have affinity for muscarinic receptors, which can lead to certain side effects.

Uses

TCAs are used primarily to treat depression. They may also be used for other conditions, such as anxiety disorders, bipolar disorder, and certain types of chronic pain.

Side effects

Common side effects of TCAs include dry mouth, blurred vision, constipation, urinary retention, and dizziness. More serious side effects may include an increased risk of suicide in those under the age of 25, arrhythmias, and an increased risk of death in those with pre-existing cardiovascular disease.

See also

• List of tricyclic antidepressants
• Antidepressant
• Selective serotonin reuptake inhibitor
• Monoamine oxidase inhibitor

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