Cite this post as:
Scott Weingart, MD FCCM. Podcast 98 – Cyclic (Tricyclic) Antidepressant Overdose. EMCrit Blog. Published on May 14, 2013. Accessed on December 7th 2021. Available at [https://emcrit.org/emcrit/tricyclic-antidepressant-overdose/ ].
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Unless otherwise noted at the top of the post, the speaker(s) and related parties have no relevant financial disclosures.
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R. Garrett Hanzel writes:
Hey Scott, I didn’t see cyclobenzaprine (Flexeril) on your list. I’ve heard that its 3-ringed structure can give you +TCA on a drug screen, but I can’t find much solid evidence of whether it causes sodium channel blockade and would be managed like any other TCA overdose. Thanks for any thoughts on this.?
The literature is scant, but at least 1 article: Am J Emerg Med. 2011 Jul;29(6):645-9, indicates no TCA-like effects despite the false + on urine drug testing.
Carbamazepine, Valproic acid and phenytoin also have sodium channel blocking properties.
absolutely
Although the cyclobenzaprine structure is similar to TCA and it has the potential to cause TCA-like toxicity, overdoses usually don’t cause TCA-like cardiovascular effects. Lethargy and anticholinergic toxicity predominate. Still check in ECG. J Emerg Med 1995;13(6):781-5.
fantastic. added it to the main post.
Good podcast Scoot, I’m EP from Colombia and everytime I share your Podcast with students, residents and collegues. Thank you!
relucho@gmail.com
thanks buddy!
Great stuff as always. If you pop in an ILMA after ketamine without a paralytic, is that truly RSA? I always thought RSA was defined as induction + paralysis + SGA (without any attempt at laryngoscopy).
That antidysrhythmic rap was pure gold. Reminded me of Schoolhouse Rock!
Yeah, Bill I suppose it is not classic RSA, but gosh do I not want another acronym so I’m going to stick with it. : )
sedation-only LMA = SOLMA…?
Ugggggh!
hehehe
What is the drip rate you usually use with the bicarb drip with a TCA OD?
Great podcast as always! Thanks!
Double maintenance or to make it easy 200 ml/hr
Excellent podcast. Say I responded to an altered patient, and did not see pill bottles indicative of a TCA-like OD laying around. And I obtained the initial ECG you posted above. I’m betting my first thought would be hyperkalemia. (Not that I’m correct and I understand the significant of the R in aVR, but to me at least it has a hyperkalemia-like QRS widening and one could convince oneself that (ie V1) the sine wave is coming.) By our EMS protocol I would give 1 G CaCl and 1 mEq/kg Sodium Bicarb, along with possibly some Albuterol; then more CaCl… Read more »
Hey Mike,
Hyperkalemia generally would not give the AMS or seizures, but if in doubt give CaCl and bicarb with no loss for either dx.
Hi Scott, Had a bad case of TCA overdose last month ( 400 tabs of 25mg nortriptylene, AND Ace inhibitor, B Blocker, Quitiapine on top of those. Walked to ambulance, on arrival to ED GCS 10ish. Was maximally aggressive, intubation, gut decontamination, Bicarb, Pressors, insulin-glucose, glucagon, Intra-lipids. Unfortunately ECMO not option. Despite all of this patient died after 9 hours of maximal therapy after transfer to ICU. All of my training suggested we should be able to win when we do everything right. Really frustrating. Apparently sometimes these overdoses are bigger than us. Noticed in all review articles except this… Read more »
Cheers Renee. At this stage the tox folks feel intra-lipids should be given a shot for any tox-induced cardiac arrest.
Your case sounds horrible and short of ECMO, probably not much else would work.
I’ve also read about phenytoin (good and bad). What’s your opinion on this?
The article on lidocaine above goes through the evidence for phenytoin as well. Lidocaine as edged it out as the preferred agent.
Thanks for the interesting review. I was surprised when you said you RSI-ed this pt with succs, given the wide QRS, which could lead to a sine wave rhythm cardiac arrest. Did you consider roc or another agent?
It is a great question. The EKG didn’t look like hyperK and there was no clinical context to suspect it. If you had doubt, sure give roc. Problem with a case like this is you lose the ability to know if the pt is seizing again (which she turned out to do soon afterwards).
Hi,
Was wondering where you found your evidence for hyperventilation these patients. I know this is still common place in many hospitals and EMS services but very little evidence exists to prove it’s worth – some studies even suggest it results in poorer outcomes. Current guidelines on up to date don’t mention it…
I know this is an old podcast, but I’m going through all of the content chronilogically while I work out.
Any thoughts on empiric administration of Calcium (either gluconate or chloride) with the initial couple amps of Bicarb?
Reason for asking is that I tend to give Bicarb and Calcium as soon as I see really WCT.
Thanks.