Tricyclic Antidepressants

Tricyclic antidepressants preceded SSRIs and other antidepressants for treatment of depression.  TCAs are used for many clinical indications ranging from sleep disorder, neuropathic pain syndromes, and depression.  TCAs have a wide variety of side effects due to their interactions with many receptor types.  

Overdose of TCAs is serious and life-threatening.  Cardiovascular effects including arrhythmias and hypotension are life-threatening. TCA overdoses cause QRS widening that worsens to ventricular dysrhythmias does not typically respond to cardioversion and is treated with sodium bicarbonate.  CNS effects of TCA overdose include depressed mental status and seizures. Seizures are treated with benzodiazepines.  

Class Drugs

• Amitriptyline

• Amoxapine

• Clomipramine

• Desipramine

• Doxepin

• Imipramine

• Maprotiline

• Nortriptyline

• Protriptyline

• Trimipramine

Class Mechanism of Action

• NE and serotonin reuptake inhibition

• Serotonin, alpha, histamine, and muscarinic receptor blockers

Class Application

Depression

• Improves alertness, elevates mood, and increases physical activity.

• At least 2 weeks are needed to see therapeutic effect.

• Individuals respond differently to each medication.

Sleep disorder

Chronic pain syndromes such as neuropathic pain

Class Adverse Effects

Muscarinic receptor blockade effects

• Dry mouth, blurred vision, urinary retention, sinus tachycardia, constipation

Sodium channel blockade effects

• Life-threatening cardiac arrhythmias in overdose

Alpha blockade effects

• Orthostasis, dizziness

Histamine blockade effects

• Drowsiness

Discontinuation syndrome

• Occurs when TCA is stopped suddenly

• Headache, malaise, agitation, irritability, sleep change

Seizures

Weight gain

Sexual dysfunction

Suicidal Ideation in pediatric and young adult patients

Considerations in overdose

• Arrhythmias due to sodium channel blockade and inhibition of potassium channels (Sodium bicarbonate given for QRS widening)

• Hypotension secondary to alpha blockade effects (Give fluid bolus, then consider vasopressors)

• Seizures (Treat with benzodiazepines)

Drug Table

Drug Name	Application	Comments	Image
Amitriptyline			"Amy's Pizza" "Trip odometer" "Line"
Amoxapine		Movement disorders; Due to dopamine receptor antagonist properties	"An Ox" "Pine tree"
Clomipramine			"Pray" bear "Claw" is "Mine"
Desipramine			"Desk" "Pray" "Mine"
Doxepin			"Ox" and bowling "Pin"
Imipramine	Enuresis		"Emu" "Pray" "Mine"
Maprotiline			"Map" and "Rotini"
Nortriptyline			"North" "Trip" "Line"
Protriptyline			"Pro" "Trip" "Line"
Trimipramine			"Trimmer" "Pray" "Mine"