Overview of Tricyclic Antidepressants

Aug 27, 2025

Overview

This lecture introduces tricyclic antidepressants (TCAs), covering how to recognize their names, their clinical uses, key side effects, and risks.

Recognizing TCAs

  • TCAs are a class of drugs used for depression and nerve pain, often abbreviated as TCAs.
  • Common TCAs end in "tryptaline" (e.g., amitriptyline, nortriptyline) or "pramine" (e.g., imipramine, clomipramine, desipramine).
  • Doxepin is an exception and does not follow these typical endings.

Clinical Uses

  • TCAs are primarily used to treat depression by increasing brain serotonin and norepinephrine levels.
  • They are also used for nerve pain, especially in diabetic neuropathy and fibromyalgia.
  • TCAs are not first-line therapy for depression due to their side effects.

Side Effects and Risks

  • TCAs cause orthostatic (postural) hypotension, leading to dizziness and risk of falling.
  • They have anticholinergic effects (e.g., urinary retention, blurry vision, dry mouth, tachycardia) due to acetylcholine blockade.
  • TCAs are dangerous in overdose and can cause fatal cardiac arrhythmias.

Key Terms & Definitions

  • Tricyclic Antidepressants (TCAs) — A class of drugs used for depression and nerve pain, named for their three-ringed chemical structure.
  • Orthostatic Hypotension — A drop in blood pressure when standing up, causing dizziness/falls.
  • Anticholinergic Effects — Side effects from reduced acetylcholine activity, such as dry mouth, blurred vision, and urinary retention.

Action Items / Next Steps

  • Review the common TCA drug names and their endings ("tryptaline", "pramine", and doxepin).
  • Memorize the major uses and side effects for TCAs.
  • Study the warning about TCA overdose and its lethality, especially cardiac risks.