Intravenous Fat Emulsion (IFE) Improvement of Qt-Interval in Tricyclic Antidepressant Overdose.
In recent years, there have multiple well document case reports of IFE therapy used to successfully treat TCA overdose. We believe our study adds to this growing body of information. To our knowledge, this study is the first description of IFE therapy specifically in an overdose of nortriptyline, a metabolite of amitriptyline.
Initially, the mechanism of IFE was unknown, theoretic mechanisms such as “lipid sink” were proposed, but lacked much evidence. As interest in IFE grows, more research has been undertaken to elucidate its action. This case report provides an opportunity to review current research in this area.
Current research into the action of IFE therapy indicates it is likely multimodal, simultaneously affecting multiple physiologic processes. The 2015 Fettiplace et al study proposes three related mechanisms based on bench research. First, the lipid acts a shuttle, drawing the lipophilic toxin out of the cardiac tissue and transporting it to tissues where it can be safely metabolized.
As the intra-tissue toxicity decreases, the lipid is then able to directly support cardiac inotropic function. Finally, free fatty acids from the lipids provide a supportive energy source throughout detoxification. These mechanisms of action help us understand how IFE supports cardiac function. However, this proposal of mechanism has a few caveats when discussing its use specifically in TCA overdose.
Emerg Med Open J. 2016; 2(2): 23-26. doi: 10.17140/EMOJ-2-124
