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.