Tricyclic Antidepressant Poisoning
To view the entire topic, please log in or purchase a subscription.
Emergency Central is a collection of disease, drug, and test information including 5-Minute Emergency Medicine Consult, Davis’s Drug, McGraw-Hill Medical’s Diagnosaurus®, Pocket Guide to Diagnostic Tests, and MEDLINE Journals created for emergency medicine professionals. Explore these free sample topics:
-- The first section of this topic is shown below --
Basics
Description
- Class of medications sharing a similar tricyclic structure
- Mechanism of action in therapeutic dosing:
- Inhibition of serotonin reuptake
- Inhibition of norepinephrine reuptake
- Primarily developed as antidepressants
- Decreased use as antidepressant given alternative medications with safer profiles in overdose
- Increasingly used for chronic and neuropathic pain
- Also used for OCD, enuresis, and ADHD
Etiology
- Primary mechanism of tricyclic antidepressant (TCA) toxicity:
- Sodium channel blocking effect (quinidine-like effect)
- Inhibition of norepinephrine reuptake
- Peripheral α-blockade
- Anticholinergic effect
- TCAs:
- Amitriptyline
- Nortriptyline
- Imipramine
- Doxepin
- Newer-generation antidepressants (nontricyclic) have different toxic profile than TCAs:
- Selective serotonin reuptake inhibitors (SSRIs):
- Wider margin of safety than TCA
- Less CNS/cardiovascular toxicity
- Nonselective serotonin reuptake inhibitors:
- Serotonin and norepinephrine reuptake inhibitors TCA (SNRIs)
- Less CNS/cardiovascular toxicity
- Can cause cardiac dysrhythmias or seizures
- Venlafaxine (Effexor)
- See Antidepressants, Poisoning
- Selective serotonin reuptake inhibitors (SSRIs):
-- To view the remaining sections of this topic, please log in or purchase a subscription --
Basics
Description
- Class of medications sharing a similar tricyclic structure
- Mechanism of action in therapeutic dosing:
- Inhibition of serotonin reuptake
- Inhibition of norepinephrine reuptake
- Primarily developed as antidepressants
- Decreased use as antidepressant given alternative medications with safer profiles in overdose
- Increasingly used for chronic and neuropathic pain
- Also used for OCD, enuresis, and ADHD
Etiology
- Primary mechanism of tricyclic antidepressant (TCA) toxicity:
- Sodium channel blocking effect (quinidine-like effect)
- Inhibition of norepinephrine reuptake
- Peripheral α-blockade
- Anticholinergic effect
- TCAs:
- Amitriptyline
- Nortriptyline
- Imipramine
- Doxepin
- Newer-generation antidepressants (nontricyclic) have different toxic profile than TCAs:
- Selective serotonin reuptake inhibitors (SSRIs):
- Wider margin of safety than TCA
- Less CNS/cardiovascular toxicity
- Nonselective serotonin reuptake inhibitors:
- Serotonin and norepinephrine reuptake inhibitors TCA (SNRIs)
- Less CNS/cardiovascular toxicity
- Can cause cardiac dysrhythmias or seizures
- Venlafaxine (Effexor)
- See Antidepressants, Poisoning
- Selective serotonin reuptake inhibitors (SSRIs):
There's more to see -- the rest of this topic is available only to subscribers.