Treatment of amitriptyline intoxications by extended high cut-off dialysis

[Extracorporeal treatment in poisoning]

In rare cases, intoxicated patients may require an extracorporeal procedure for enhanced toxin elimination. The Extracorporeal Treatments in Poisoning (EXTRIP) workgroup provides consensus- and evidence-based recommendations regarding the use of extracorporeal procedures in the management of critically ill, poisoned patients, with ongoing updates. Extracorporeal clearance is highest for low molecular weight substances with low volume of distribution, low plasma protein binding, and high water-solubility. To maximize the effect of extracorporeal clearance, blood and dialysate flow rates should be as high as possible, and the membrane with the largest surface area should be utilized. Intermittent hemodialysis is the most commonly employed extracorporeal procedure due to its highest effectiveness, while hemodynamically compromised patients can benefit from a continuous procedure.

Use of CytoSorb in cases of acute amitriptyline intoxication

WHAT IS KNOWN AND OBJECTIVE

Intoxications with the tricyclic antidepressant amitriptyline frequently occur in the clinical setting and require immediate treatment. Although various poisonings can be counteracted with specific remedies, treatment options for amitriptyline intoxication remain sparse. Besides conventional approaches, a new haemoadsorption device might represent an opportunity for therapeutic detoxification.

CASE SUMMARY

We report on two patients who were admitted as an emergency case with suspected amitriptyline overdose. Due to potentially life-threatening intoxication, the decision was made to initiate continuous renal replacement therapy (CRRT) together with CytoSorb haemoadsorption. As a result, drug-level measurements showed fast and efficient reduction of amitriptyline levels in the blood (case 1 from 186 µg/l to 54.7 µg/l, case 2 from 844 µg/l to 290 µg/l) and helped to stabilize a critical situation.

WHAT IS NEW AND CONCLUSION

We were able to quickly and efficiently reduce amitriptyline to non-toxic serum levels and to stabilize a critical situation using the CytoSorb adsorber. Therefore, in the absence of other proven beneficial treatment regimen, the use of CytoSorb haemoadsorption could represent a potential treatment modality for severe amitriptyline intoxication.

Molecular adsorbent recirculating system (MARS) and continuous veno-venous hemodiafiltration (CVVHDF) for diltiazem removal: An in vitro study

The objective of the present study was to evaluate the efficacy of the molecular adsorbent recirculating system (MARS) vs continuous veno-venous hemodiafiltration (CVVHDF). Diltiazem poisoning was simulated in a central compartment consisting in a 5L dialysis solute spiked with diltiazem at two different toxic concentrations: 750 and 5000 µg/L. For CVVHDF, mean extraction coefficients (EC = (in concentration - out concentration)/in concentration) were concentration-dependent with a decrease all along the dialysis. At the end of the sessions the mean amounts remaining in the central compartment were 8% and 7% of the initial dose at 750 and 5000 µg/L, respectively. The mean cumulative amounts found in the effluent were 60% and 75% of the initial dose, respectively. The missing amounts accounted for 32% and 18% of the initial dose, respectively, corresponding to an adsorption to the dialysis membrane. In contrast, the different compartments of the MARS resulted in undetectable output concentration earlier that the end of the session. The mean concentrations of diltiazem remaining in the central compartment were <1 µg/L at the end of the sessions. Global ECs were around 50% all along the experiment at both concentrations, and the average charcoal cartridge ECs was 80% throughout the experiments.CVVHDF system in the developed model was efficient for diltiazem removal, mainly by diffusion, convection and to a lesser extent by adsorption to the dialysis membrane. In MARS system, resin cartridge and hemodialysis components are ineffective, charcoal cartridge is responsible for almost all drug removal.

Physiologically based pharmacokinetic-quantitative systems toxicology and safety (PBPK-QSTS) modeling approach applied to predict the variability of amitriptyline pharmacokinetics and cardiac safety in populations and in individuals

The physiologically based pharmacokinetic (PBPK) models allow for predictive assessment of variability in population of interest. One of the future application of PBPK modeling is in the field of precision dosing and personalized medicine. The aim of the study was to develop PBPK model for amitriptyline given orally, predict the variability of cardiac concentrations of amitriptyline and its main metabolite-nortriptyline in populations as well as individuals, and simulate the influence of those xenobiotics in therapeutic and supratherapeutic concentrations on human electrophysiology. The cardiac effect with regard to QT and RR interval lengths was assessed. The Emax model to describe the relationship between amitriptyline concentration and heart rate (RR) length was proposed. The developed PBPK model was used to mimic 29 clinical trials and 19 cases of amitriptyline intoxication. Three clinical trials and 18 cases were simulated with the use of PBPK-QSTS approach, confirming lack of cardiotoxic effect of amitriptyline in therapeutic doses and the increase in heart rate along with potential for arrhythmia development in case of amitriptyline overdose. The results of our study support the validity and feasibility of the PBPK-QSTS modeling development for personalized medicine.

Amitriptyline-induced ventricular tachycardia: a case report

Background

In Bangladesh, each emergency physician faces amitriptyline overdose nearly a day. An acute cardiovascular complication, one of the worst complications is mainly responsible for the mortality in tricyclic overdose. Recently, we managed ventricular tachycardia in a young female presented with an impaired consciousness 10 h after intentionally ingesting 2500 mg amitriptyline. Here, we report it, discuss how the electrocardiography is vital to acknowledge and predict it and its’ complications and also the recent update of the management of it.

Case presentation

A young married Bangladeshi-Bengali girl, 25-year-old, having a history of disharmony with her husband, came with an impaired consciousness after intentionally ingesting 2500 mg amitriptyline about 10 h before arrival. There was blood pressure 140/80 mmHg, heart rate 140 beats-per-min, temperature 103 °F, Glasgow coma scale 10/15, wide complex tachycardia with QRS duration of 178 ms in electrocardiography, blood pH 7.36. Initially, treated with 100 ml 8.4% sodium bicarbonate. After that, QRS duration came to 100 ms in electrocardiography within 10 min of infusion. To maintain the pH 7.50–7.55 over the next 24 h, the infusion of 8.4% sodium bicarbonate consisting of 125 ml dissolved in 375 ml normal saline was started and titrated according to the arterial blood gas analysis. Hence, a total dose of 600 mmol sodium bicarbonate was given over next 24 h. In addition to this, gave a 500 ml intravenous lipid emulsion over 2 h after 24 h of admission as she did not regain her consciousness completely. Afterward, she became conscious, though, in electrocardiography, ST/T wave abnormality persisted. So that, we tapered sodium bicarbonate infusion slowly and stopped it later. At the time of discharge, she was by heart rate 124/min, QRS duration 90 ms in electrocardiogram along with other normal vital signs.

Conclusion

Diagnosis of amitriptyline-induced ventricular tachycardia is difficult when there is no history of an overdose obtained. Nevertheless, it should be performed in the clinical background and classic electrocardiographic changes and wise utilization of sodium bicarbonate, intravenous lipid emulsion, and anti-arrhythmic drugs may save a life.