Podcast 98 – Cyclic (Tricyclic) Antidepressant Overdose - a podcast by Scott D. Weingart, MD FCCM

I had a crazy case of Tricyclic Overdose while on an overnight shift at Janus General.

Initial and Post-Treatment EKGs

Initial



Post-Treatment

List of Tricyclic Agents from Wikipedia.org



* Amitriptyline (Tryptomer, Elavil)

* Amitriptylinoxide (Amioxid, Ambivalon, Equilibrin)

* Butriptyline (Evadyne)

* Clomipramine (Anafranil)

* Demexiptiline (Deparon, Tinoran)

* Desipramine (Norpramin, Pertofrane)

* Dibenzepin (Noveril, Victoril)

* Dimetacrine (Istonil, Istonyl, Miroistonil)

* Dosulepin/Dothiepin (Prothiaden)

* Doxepin (Adapin, Sinequan)

* Imipramine (Tofranil, Janimine, Praminil)

* Imipraminoxide (Imiprex, Elepsin)

* Lofepramine (Lomont, Gamanil)

* Melitracen (Deanxit, Dixeran, Melixeran, Trausabun)

* Metapramine (Timaxel)

* Nitroxazepine (Sintamil)

* Nortriptyline (Pamelor, Aventyl, Norpress)

* Noxiptiline (Agedal, Elronon, Nogedal)

* Pipofezine (Azafen/Azaphen)

* Propizepine (Depressin, Vagran)

* Protriptyline (Vivactil)

* Quinupramine (Kevopril, Kinupril, Adeprim, Quinuprine)



Additionally...



* Amineptine (Survector, Maneon, Directim) Norepinephrine-dopamine reuptake inhibitor

* Iprindole (Prondol, Galatur, Tetran) 5-HT2 receptor antagonist

* Opipramol (Insidon, Pramolan, Ensidon, Oprimol) ? receptor agonist

* Tianeptine (Stablon, Coaxil, Tatinol) Selective serotonin reuptake enhancer

* Trimipramine (Surmontil) 5-HT2 receptor antagonist and moderate-potency norepinephrine reuptake inhibitor.



And of course, the non-TCA agents...







* Diphenhydramine

* Cocaine

* Cyclobenzaprine (I add this one to the list, b/c there can be TCA-like effects in toxicity, but it seems the potential for cardiac effects is markedly less though still possible. (J Emerg Med 1995;13(6):781-5) This one is from Bryan Hayes)



Pharmacologic Effects of TCAs







K+ Channel Blockade

QTC Prolongation





NE & Serotonin Reuptake Inhibition

Initial hypertension quickly followed by hypotension





Na+ Channel Blockade

QRS Prolongation

Hypotension — depresses myocardial contractility

Ventricular dysrhythmias

Brugada-like findings on EKG





Muscarinic Anticholinergic Receptor Antagonism

Anticholinergic Toxidrome





Antihistaminergic

CNS stimulation or sedation





Alpha1 Adrenergic Antagonism

Hypotension





GABA-A Receptor Blockade

Seizures







This chart was taken from the excellent Resus Review Blog by Charles Bruen

Sodium Bicarbonate

Increases amount of drug in non-ionized form and may decrease binding to Na-channels [cite]11482860[/cite]



May need many, many amps. For some reason the sodium and the bicarb don't rise significantly in severe toxicity



My goals are QRS duration <100, hemodynamically stable, Na ~150, pH ~7.5

Electrolyte Abnormalities

Beware of hypokalemia and hypocalcemia



Send VBG with lytes at least Q1 hour

Hyperventilation

To promote alkalosis

Hypertonic Saline

If the patient is too alkalotic or out of amps of Bicarb

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