The Management of Tricyclic Antidepressant Poisoning

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.

Amitriptyline accumulation in tissues after coated activated charcoal hemoperfusion-a randomized controlled animal poisoning model

Amitriptyline poisoning (AT) is a common poisoning, and AT possess the ability to promote life-threatening complications by its main action on the central nervous and cardiovascular systems. The pharmacokinetic properties might be altered at toxic levels compared to therapeutic levels. The effect of coated activated charcoal hemoperfusion (CAC-HP) on the accumulation of AT and its active metabolite nortriptyline (NT) in various tissues was studied in a non-blinded randomized controlled animal trial including 14 female Danish Land Race piglets. All piglets were poisoned with amitriptyline 7.5 mg/kg infused in 20 min, followed by orally instilled activated charcoal at 30 min after infusion cessation. The intervention group received 4 h of CAC-HP followed by a 1-h redistribution phase. At study cessation, the piglets were euthanized, and within 20 min, vitreous fluid, liver tissue, ventricle and septum of the heart, diaphragm and lipoic and brain tissues were collected. AT and NT tissue concentrations were quantified by UHPLC-MS/MS. A 4-h treatment with CAC-HP did not affect the tissue accumulation of AT in the selected organs when tested by Mann-Whitney U test (p values between 0.44 and 0.73). For NT concentrations, p values were between 0.13 and 1.00. Although not significant, an interesting finding was that data showed a tendency of increased tissue accumulation of AT and NT in the CAC-HP group compared with the control group. Coated activated charcoal hemoperfusion does not significantly alter the tissue concentration of AT and NT in the AT-poisoned piglet.

Activated Charcoal Haemoperfusion in the Treatment of Experimental Amitriptyline Poisoning in Pigs - The Effect on Amitriptyline Plasma Concentration and Haemodynamic Parameters

Coated activated charcoal haemoperfusion (CAC-HP) is a well-known treatment modality. Case reports have revealed conflicting results about the efficacy of CAC-HP in the treatment of amitriptyline (AT) poisoning, and no randomized clinical trials have been identified in the literature. This study aimed at quantifying the efficacy of modern CAC-HP as an adjunctive treatment of AT intoxication compared with standard care alone. Fourteen female Danish landrace pigs were randomized to either standard care or standard care plus 4 hr of CAC-HP. The pigs were anaesthetized, and vital parameters were continuously recorded. Amitriptyline infusion (7.5 mg/kg) was completed in 20 min. Thirty minutes after AT infusion, activated charcoal was instilled orally in both groups. In the intervention group, CAC-HP was initiated 60 min. after AT infusion. Blood and urine samples were collected as were vital parameters at specific time intervals. The protocol was approved by the Danish Experimental Animal Expectorate and complied with the NIH guide for care and use of laboratory animals. Data were managed according to the ARRIVE guidelines. No statistical significant differences between intervention and control groups were found when analysing for differences in AT levels in plasma at any time-point. Furthermore, significant differences between the control and intervention groups in regard to vital parameters could not be found either. In our animal model, the addition of CAC-HP did not improve the clearance of AT compared with standard treatment alone. We suggest that the effect of modern CAC-HP as a treatment modality in AT-poisoned human patients may be inadequate.

Analysis of Gastric Lavage Reported to a Statewide Poison Control System

BACKGROUND

As decontamination trends have evolved, gastric lavage (GL) has become a rare procedure. The current information regarding use, outcomes, and complications of GL could help refine indications for this invasive procedure.

OBJECTIVES

We sought to determine case type, location, and complications of GL cases reported to a statewide poison control system.

METHODS

This is a retrospective review of the California Poison Control System (CPCS) records from 2009 to 2012. Specific substances ingested, results and complications of GL, referring hospital ZIP codes, and outcomes were examined.

RESULTS

Nine hundred twenty-three patients who underwent GL were included in the final analysis, ranging in age from 9 months to 88 years. There were 381 single and 540 multiple substance ingestions, with pill fragment return in 27%. Five hundred thirty-six GLs were performed with CPCS recommendation, while 387 were performed without. Complications were reported for 20 cases. There were 5 deaths, all after multiple ingestions. Among survivors, 37% were released from the emergency department, 13% were admitted to hospital wards, and 48% were admitted to intensive care units. The most commonly ingested substances were nontricyclic antidepressant psychotropics (n = 313), benzodiazepines (n = 233), acetaminophen (n = 191), nonsteroidal anti-inflammatory drugs (n = 107), diphenhydramine (n = 70), tricyclic antidepressants (n = 45), aspirin (n = 45), lithium (n = 36), and antifreeze (n = 10). The geographic distribution was clustered near regions of high population density, with a few exceptions.

CONCLUSIONS

Toxic agents for which GL was performed reflected a broad spectrum of potential hazards, some of which are not life-threatening or have effective treatments. Continuing emergency physician and poison center staff education is required to assist in patient selection.

A Simple, Rapid and Reliable Method to Determine Imipramine and Desipramine in Mouse Serum Using Ultra-High-Performance Liquid Chromatography-Quadrupole-Time-of-Flight Mass Spectrometry

A rapid and sensitive ultra-high-performance liquid chromatography-quadrupole-time-of-flight mass spectrometric (UHPLC-Q-TOF-MS) method was developed for quantification of imipramine, one of the most widely used tricyclic antidepressants, and desipramine, an active metabolite of imipramine, in mouse serum. The developed method included a simple protein precipitation with acetonitrile in 50 μL of serum and analyte separation on an Acquity UPLC BEH C18 column using a gradient elution of acetonitrile with 0.1% formic acid and 20 mM ammonium formate. As a result, the entire analysis time was <20 min including the sample preparation and the LC-MS analysis. The limit of quantification was 5.0 ng mL(-1) for both imipramine and desipramine, and calibration curves were linear over the concentration range of 5.0-1,000.0 and 5.0-250.0 ng mL(-1) for imipramine and desipramine, respectively. Intraday precisions at three levels were 2.2-3.6 and 1.7-4.2% for imipramine and desipramine, respectively, whereas interday precisions were 2.6-5.0 and 2.0-8.4% for imipramine and desipramine, respectively. Accuracy ranged between 93.6 and 106.6% for imipramine and 94.1 and 106.4% for desipramine. Absolute recovery was 96.0-97.6% for imipramine and 87.0-99.5% for desipramine. Finally, the described method was applied to mice administered with imipramine, demonstrating the suitability for quantification of imipramine and desipramine for therapeutic drug monitoring or bioequivalence studies.

Treatment of amitriptyline intoxications by extended high cut-off dialysis

Antidepressants, especially amitriptyline, are among the most frequent drug classes involved in intoxications. Despite its small molecular weight, amitriptyline is not considered to be eliminated by extracorporeal treatment methods due to its high protein binding and large volume of distribution. New high cut-off dialysers have so far not been used for removal of amitriptyline. We report two cases of amitriptyline poisoning in which we measured the amitriptyline elimination using extended high cut-off (HCO) dialysis. Despite dialyser clearances of 33 and 58 mL/min, resulting in the reduction of initial serum concentrations by ∼30%, only 211 and 920 µg of amitryptilin, respectively, (<3% of the ingested amount) could be recovered in the total collected dialysate. Hence, due to the high volume of distribution of amitriptyline, even HCO dialysis does not contribute substantially to the extracorporeal removal of amitryptilin.

Extracorporeal treatment for tricyclic antidepressant poisoning: recommendations from the EXTRIP Workgroup

The Extracorporeal Treatments In Poisoning (EXTRIP) workgroup was formed to provide recommendations on the use of extracorporeal treatments (ECTR) in poisoning. Here, the workgroup presents its results for tricyclic antidepressants (TCAs). After an extensive literature search, using a predefined methodology, the subgroup responsible for this poison reviewed the articles, extracted the data, summarized findings, and proposed structured voting statements following a predetermined format. A two-round modified Delphi method was chosen to reach a consensus on voting statements and RAND/UCLA Appropriateness Method to quantify disagreement. Blinded votes were compiled, returned, and discussed in person at a meeting. A second vote determined the final recommendations. Seventy-seven articles met inclusion criteria. Only case reports, case series, and one poor-quality observational study were identified yielding a very low quality of evidence for all recommendations. Data on 108 patients, including 12 fatalities, were abstracted. The workgroup concluded that TCAs are not dialyzable and made the following recommendation: ECTR is not recommended in severe TCA poisoning (1D). The workgroup considers that poisoned patients with TCAs are not likely to have a clinical benefit from extracorporeal removal and recommends it NOT to be used in TCA poisoning.

Blood purification in toxicology: nephrology's ugly duckling

Contrary to popular opinion, application of extracorporeal therapies for poisonings predates their use for ESRD. Despite this observation, the science of blood purification in toxicology remains desperately stagnant today. In fact, much of our current knowledge is derived from George Schreiner's 1958 review. Original publications are almost exclusively composed of case reports and case series, from which good inference is impossible. Until randomized controlled trials become available, the medical community would be well served by a group mandated to systematically review available literature, extract relevant information, provide recommendations based on current evidence, and propose research initiatives. The EXtracorporeal TReatments In Poisoning workgroup, formed by several international experts in different medical fields and represented by over 20 societies, now has this mission.

Fatal toxicity of drugs used in psychiatry

Certified deaths from fatal poisoning (accidents, suicides and open verdicts) in England and Wales have declined steadily (from 3952 in 1979 to 2565 in 2004). There was also a small annual reduction in suicides in males and in females over this period. In 2004, self-poisoning accounted for 25% of suicides and open verdicts in males (n = 862) and 45% in females (n = 540). Poisoning death rates per million prescriptions were about 10 times higher for tricyclic antidepressants (TCAs) than for selective serotonin reuptake inhibitors (SSRIs), England and Wales, 1993-2004. However, despite the increased prescription of SSRIs and related compounds in recent years, there has been only a slight decrease (some 10%) in the annual number of antidepressant-related poisoning deaths, in line with the reduction in suicides (all methods) over this period. Citalopram appears to have higher overdose toxicity than other SSRIs. Of newer non-SSRI antidepressants, the overdose toxicity of venlafaxine, although lower than that of TCAs, appears to be higher than that of SSRIs, with seizures, serotonin syndrome, rhabdomyolysis, renal failure and hepatic failure having been reported. Poisoning deaths involving antipsychotics either alone, or with other drugs and/or alcohol are many fewer than those involving antidepressants (713 and 5602 deaths, respectively, England and Wales, 1993-2004). Following the restriction on thioridazine usage (2000), thioridazine-associated fatal poisoning fell to zero by 2002, but this was balanced by an increase in deaths associated with atypical antipsychotics, most notably clozapine, olanzapine and quetiapine. Antipsychotic-related poisoning deaths were higher in 2004 than at any time since 1993.

[Intoxication with a tricyclic antidepressant]

A 48-year-old woman with a major depression and treatment with doxepin was found comatose in her flat. Her son last saw her 48 h prior to being found. On arrival of the emergency physician, she presented a generalized seizure. The patient underwent endotracheal intubation and mechanical ventilation due to respiratory insufficiency and severe cyanosis. Empty packages of tablets (doxepin ca. 4000 mg and zolpidem 100 mg) were found in the flat. On hospital admission the doxepin blood concentration was 1.2 microg/ml. No life-threatening arrhythmia occurred at any time. On the advice of the poison information center, hemoperfusion was performed for extracorporeal elimination. Within several hours the doxepin blood concentration could be lowered to 0.8 microg/ml and although still above the therapeutic range the patient was extubated. However, the patient developed a generalized seizure which required re-intubation. As a consequence of the high distribution volume and re-distribution phenomena, the doxepin blood concentration had increased again to 1.2 microg/ml. Approximately 72 h later she was extubated again while the doxepin blood concentration was 0.9 microg/ml and 3 days later, the doxepin blood concentration was lowered to 0.3 microg/ml and the patient was transferred to the psychiatric ward the following day. This case report questions the efficacy of hemoperfusion during acute doxepin intoxication in the given constellation of a non-life-threatening arrhythmia.

Demands on scientific studies in clinical toxicology

Scientific case studies in clinical toxicology on single cases or series of similar cases should document sufficient information on the clinical methodology and observations, the medical laboratory methodology and results, the toxicological analyses methodology and results, the source of used reference values for drug/poison concentrations and kinetics with critical discussion of such values, a description and discussion of the toxicodynamic, the toxicological and the kinetic properties of the detected drugs and/or poisons. The data management, statistical analysis and finally the clinical and/or analytical outcomes must also be described and discussed in correlation to already published data. Statistical methods used for evaluation of clinical as well as for analytical data should be described in detail. When possible, quantitative findings should be presented with appropriate indicators of measurement error or uncertainty. Requirements for such studies are discussed.