[Diagnostics and treatment of selected clinically relevant, acute drug intoxications]

Acute drug poisoning due to accidental or self-damaging overdoses is responsible for 5-10% of emergency medical interventions in Germany. The treatment of asymptomatic to life-threatening courses requires extensive expertise. On the basis of a selective literature search, this article gives an overview of selected clinically relevant, acute drug poisonings with regard to epidemiology, symptomatology, diagnostics, and therapy.Intoxications with psychotropic drugs are the most common drug intoxications. Poisoning with tricyclic antidepressants causes anticholinergic, central nervous, and cardiovascular symptoms. Less toxic are selective serotonin reuptake inhibitors (SSRIs); the intoxication may be characterized by serotonin syndrome. Malignant neuroleptic syndrome is a severe complication of neuroleptic poisoning.Poisoning with analgesics is clinically relevant due to its high availability. For paracetamol poisoning, intravenous acetylcysteine is available as an antidote. Hemodialysis may be indicated for severe salicylate intoxication. Poisoning with nonsteroidal anti-inflammatory drugs is usually only associated with mild signs of intoxication.Poisoning with cardiac drugs (β-blockers and calcium antagonists) can cause life-threatening cardiovascular events. In addition to symptomatic therapy, insulin glucose therapy also plays an important role.The majority of acute drug poisonings can be treated adequately by symptomatic and partly intensive care therapy - if necessary with the application of primary and secondary toxin elimination. Depending on the severity of the intoxication, pharmacology-specific therapy must be initiated.

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.

Refractory Arrhythmias in a Young Patient Poisoned by Imipramine

Tricyclic antidepressants are used to treat a variety of mental disorders, and are considered a common cause of fatal drug poisoning. This study reports a young woman with no history of cardiac diseases who presented to the emergency department with heart palpitation, weakness, and lethargy. After a short period of time, she became unconscious and experienced hypotension and refractory arrhythmia, finally being diagnosed with imipramine poisoning. Accurate history taking and the possible causes of these complications including cardio-toxic drug poisoning should be considered in such patients.

Unusual complications from amitriptyline intoxication

Althoughtricyclic antidepressants(TCAs) are frequently prescribed to patients with depression, these drugs can also be misused. A 21-year-old comatose patient was referred to our hospital presenting with ventricular tachycardia. Despite initial treatment including intravascular lipid emulsion, ventricular fibrillation occurred soon after arrival. Venoarterial extracorporeal membrane oxygenation and therapeutic hypothermia were administered. Refractory arrhythmia disappeared on the next day. A high concentration of amitriptyline was identified in his blood samples on arrival. Mechanical bowel obstruction followed after abdominal compartment syndrome caused by anticholinergic effects, and refractory seizure occurred due to TCA intoxication. Although seizure was brought under control with anticonvulsant agents, his Glasgow Coma Scale did not recover to the full score. MRI presented irreversible damage to the bilateral frontal lobe and insula. Amitriptyline has the potential to cause unusual serious complications, such as abdominal compartment syndrome, irreversible central nervous system disability and lethal arrhythmia.

Comparison of High-Fidelity Medical Simulation to Short-Answer Written Examination in the Assessment of Emergency Medicine Residents in Medical Toxicology

We compared high-fidelity medical simulation to short-answer written examination in the assessment of emergency medicine residents (EMR) on a month-long medical toxicology rotation. Knowledge-based assessment tools using cases of an aspirin overdose and a tricyclic antidepressant overdose were used to assess all consecutive rotating EMR (n=53). Assessment by simulation had similar accuracy and precision but higher satisfaction rates when compared to written examination. Incorporating simulation into the ABEM certifying examination warrants further study.

[How I treat … a poisoning with tricyclic antidepressants : potential role of a treatment with lipid emulsion]

Poisoning with tricyclic antidepressants is common and can be life-threatening. The classic management is well known (chelating gastrointestinal, sodium bicarbonate, benzodiazepine, norepinephrine). A few years ago, a treatment with lipid emulsion, previously used in local anesthetics poisoning, has been successfully tested in tricyclic poisoning with cardiac arrest. We are currently unable to explain the exact mechanism of this treatment but it could have a place in the treatment of severe tricyclic poisoning with hemodynamic instability in addition to the conventional treatment.

A retrospective analysis of antidepressant poisonings in the emergency department: 11-year experience

Between 1993 and 2004, patients with antidepressant poisoning admitted to an emergency department (ED) were analysed retrospectively with regard to demographics, clinical findings and treatment attempts. Age, gender, suicide attempts, classification of antidepressants, Glasgow Coma Scale (GCS) score, ECG findings, need for endotracheal intubation, follow-up period and Antidepressant Overdose Risk Assessment (ADORA) criteria were analysed by SPSS software. A total of 356 antidepressant poisoning cases were evaluated. Tricyclic antidepressants (TCA), especially opipramol and amitriptyline, were the most common agents (58.4%). The most frequent ECG finding was sinus tachycardia (40.7%, n=145). Endotracheal intubation was required in 9.6% of cases. Patients with TCA ingestion had a longer observation time in the ED, abnormal ECG findings, abnormal physical examination findings and more ADORA criteria, than patients who ingested selective serotonin re-uptake inhibitors (SSRI) (P=0.008, P=0.008, P<0.001, P<0.001). It was found that the patients who ingested TCA (P=0.001), poisoned with amitriptyline (P=0.001), patients with GCS scores of 8 and less (P=0.001), patients with two or more ADORA criteria (P=0.001), with seizures (P=0.001), with abnormal ECG (P=0.012), and patients with a history of two or more suicide attempts were intubated more frequently. Suicide attempts, classification of the antidepressant, ECG findings, seizure, GCS score and number of detected ADORA criteria affect the need for intubation in patients with antidepressant poisoning.

Acute amitriptyline intoxication: an analysis of 44 children

The tricyclic antidepressant agents, particularly amitriptyline and dothiepin, are recognized for their potentially lethal cardiovascular and neurological effects in poisoned patients. In this article, the clinical and laboratory findings of 44 children with amitriptyline intoxication are reviewed. Our purpose was to investigate amitriptyline intoxication in childhood. Of 44 patients, 21 (47.7%) were boys, 23 (52.3%) were girls, and the ages ranged from 12 months to 14 years (mean9 / SD; 4.099 / 2.9 years). All children except one who took an overdose of amitriptyline to decrease his pain accidentally ingested an overdose of amitriptyline. The amount of amitriptyline ingested was between 2 mg/kg and 97.5 mg/kg (mean9 / SD; 13.69 / 17.7 mg/kg per dose) (the drug dosage was not known in 13 children). The most commonly observed clinical and laboratory findings were lethargy, tachycardia, convulsion, hyperglycemia and leukocytosis. In all patients except for two children who died the abnormal clinical and laboratory findings returned to normal within a few days after admission and they were discharged from the hospital in good health within the fourth day of admission. One of the children ingested 97.5 mg/kg amitriptyline and probably died due to status epilepticus and another child who died ingested 36 mg/ kg amitriptyline and died due to cardiopulmonary arrest. In conclusion, our findings showed that initial symptoms and signs of acute amitriptyline intoxication appeared severe, but they disappeared with only supportive care required in most children except for cases that ingested high doses of drug within a few days. In contrast to adults, we infrequently noted respiratory insufficiency, arrhythmia and hypotension in children with acute amitriptyline intoxication.

ECG Of the Month: Suicide

Apparently depression ran in this man's family, and when he took an overdose of his tricyclic antidepressant, he also took the tricyclics of his mother and his sister. Most patients who die of an overdose of a tricyclic antidepressant are pronounced dead without reaching a hospital, and those who die after arriving in the emergency room do so within a few hours.2 Central nervous system toxicity of tricyclic antidepressants may manifest as confusion, agitation, hallucinations, coma, myoclonus, or seizures. Generalized seizures often presage cardiopulmonary arrest,2 and within 20 seconds of the ECG with evidence of generalized seizure activity shown here, the QRS duration increased from 188 ms to 212 ms, and the patient died soon thereafter.

Amitriptyline overdose in emergency department of university hospital: evaluation of 250 patients

OBJECTIVE

The purpose of this study was to evaluate the patients with acute amitriptyline poisoning and investigate predictive factors for the development of life-threatening complications.

METHODS

Demographics, clinical, laboratory, and electrocardiographic (ECG) findings of 250 patients were evaluated retrospectively. Predictive parameters for the development of serious complications were studied.

RESULTS

Median age of patients was 14.6 years, of which, 70% of patients were female and 66% were in pediatric age group. The most common pathological clinical finding and laboratory abnormality were alteration of consciousness and hyponatremia. The rate of convulsive seizure, arrhythmia, and respiratory depression were 17 (6.8%), 16 (6.4%), and 11 (4.4%), respectively. These complications were more seen in pediatric patients than adults (15.8% and 1.2%). The incidence of hyponatremia was more in pediatric patients and severe poisoning groups (38.8 and 53.4%, respectively). The levels of amitriptyline and nortriptyline were significantly higher in the group with complications than the group without complications (p < 0.05). All adult patients were discharged with good prognosis. In pediatric age group, one patient was discharged with severe neurological sequelae and one patient died. QRS duration >100 ms, long corrected QT duration interval, and low Glasgow Coma Score (GCS) at admission were identified as independent risk factors for the development of life-threatening complications (odds ratio: 69.4, 1.9, and 1383, respectively; p < 0.05).

CONCLUSION

Amitriptyline poisoning may be associated with life-threatening complications, especially in pediatric age group and in patients with hyponatremia. Low GCS, presence of hyponatremia, high serum drug levels, and pathological ECG findings on admission may be helpful in predicting the development of complications and poor prognosis.

Severe childhood amitriptyline intoxication and plasmapheresis: a case report

Tricyclic antidepressant intoxication is one of the most frequently encountered and life-threatening causes of intoxication among referrals to emergency departments due to drug intoxication. There is no known antidote against any of the tricyclic antidepressants. The American Society for Apheresis (ASFA) recommends plasmapheresis to support primary treatment in this type of drug poisoning, which does not respond to certain and traditional treatments. We present a 15-year-old girl who ingested amitriptyline with suicidal intent. On admission, she was in a comatose state (Glasgow Coma Scale score: 5), with no spontaneous respiration and presence of pathological reflexes. Due to the intake history of lethal doses and the severe clinical picture, plasmapheresis was performed. She was discharged on her fifth day of hospitalization.Due to the high plasma protein binding property of amitriptyline, plasma exchange therapy should be considered in cases of severe amitriptyline intoxication as a life-saving therapeutic modality.

Cerebellitis developing after tricyclic antidepressant poisoning

Acute cerebellitis is a rare inflammatory disease involving the cerebellum and is characterized by acute compromise of cerebellar functions. It most frequently originates from infectious causes, although cases of cerebellitis associated with other causes have also been reported. This report discusses a case of cerebellitis developing in a 4-year-old girl who had to be intubated after accidental ingestion of tricyclic antidepressant. There are no previous reports of cerebellitis after tricyclic antidepressant. This case shows that cerebellitis can develop in patients with poisoning of this kind.

Rhabdomyolysis as a manifestation of clomipramine poisoning

CONTEXT

Tricyclic antidepressive agents are widely used in suicide attempts and present a variety of deleterious effects. Rhabdomyolysis is a rare complication of such poisoning.

CASE REPORT

A 55-year-old woman ingested 120 pills of 25 mg clomipramine in a suicide attempt two days before admission. After gastric lavage in another emergency department on the day of intake, 80 pills were removed. On admission to our department, she was disoriented, complaining of a dry mouth and tremors at the extremities. An electrocardiogram showed a sinus rhythm with narrow QRS complexes. Laboratory results showed high creatine phosphokinase (CK = 15,094 U/l on admission; normal range = 26 to 140 U/l), hypocalcemia, slightly increased serum transaminases and mild metabolic acidosis. The patient's medical history included depression with previous suicide attempts, obsessive-compulsive disorder, hypothyroidism and osteoporosis. She presented cardiac arrest with pulseless electric activity for seven minutes and afterwards, without sedation, showed continuous side-to-side eye movement. She developed refractory hypotension, with need for vasopressors. Ceftriaxone and clindamycin administration was started because of a hypothesis of bronchoaspiration. The patient remained unresponsive even without sedation, with continuous side-to-side eye movement and a decerebrate posture. She died two months later. Rhabdomyolysis is a very rare complication of poisoning due to tricyclic drugs. It had only previously been described after an overdose of cyclobenzaprine, which has a toxicity profile similar to tricyclic drugs.

CONCLUSIONS

Although arrhythmia is the most important complication, rhabdomyolysis should be investigated in cases of clomipramine poisoning.

[Prolonged toxic coma and anisocoria secondary to doxepin, lorazepam and phenobarbital poisoning--case study]

Doxepin is a tricyclic antidepressant from the group of dibenzoxepines. Apart from the antidepressant effect, it has also the sedative and anxiolytic effect, so it is used in the treatment of anxiety disorder in the course of psychosis, organic diseases and alcoholism. Doxepin increases concentration of norepinephrine and serotonin in the brain by preventing inactivation and blocking their reuptake. In addition, the drug has an antagonistic effect on receptors in CNS (muscarinic M1, histamine H1, alpha-1adrenergic, serotonergic 5-HT2) and also blocks sodium and potassium channels in cardiomyocytes. In this paper we present a case of severe poisoning by various drugs, including doxepin. The dominating symptom was prolonged toxic coma. Slow return of consciousness was observed from the fifth day after intoxication, logical verbal contact with the patient was possible on the seventh day. It seems that this symptom results from the pharmacokinetic properties of doxepin as well as the high drug dose and a synergistic effect of lorazepam and phenobarbital. Transient anisokoria was an unusual symptom that appeared in the course of intoxication. The patient was examined by a neurologist and underwent CT of the head twice - no organic causes were revealed. This phenomenon can be explained by physiological anisokoria, caused by asymmetry in the sympathetic innervation of pupil rectractor muscle, exacerbated by a complete parasympathetic conduction block as a result of anticholinergic action of doxepin. Tricyclic antidepressants are often used by patients for the purpose of suicide. Because of the serious cardiological and neurological symptoms the course of doxepin intoxication may be severe.

[Severe tricyclic antidepressants poisoning--a case study]

Long QT syndrome is a disease characterized by periodic or constant prolongation of QT interval and attacks of ventricular polymorphic tachycardia known as torsade de pointes. It may appear as a result of various medicines application, both anti-arrhythmic and non-cardiovascular. Currently, a list of medicines which may cause proarrhythmic action in consequence of QT prolongation is long and constantly updated. It contains tricyclic antidepressants, which are the most toxic antidepressants currently used and are often the cause of poisoning and hospitalization on toxicology wards. The paper presents the case of a 20-year-old man, treated in the clinical toxicology ward, after severe poisoning with tricyclic antidepressants. The patient, treated many times in our toxicology centre, had very high concentration of tricyclic antidepressants in the serum (2768 ng/ml). The concentration above 1000 ng/ml indicates serious life-threatening poisoning. Very severe symptoms of cardiotoxicity were observed: in ECG - wide QRS (160 ms) with heart rate 120-150 per minute, ventricular tachycardia, periodically polymorphic, prolongation of QT interval, hypotonia (80/60 mm Hg) and also recurrent attacks of seizures. Also metabolic/respiratory acidosis was stated (pH - 7.089; pCO2 - 56.9 mm Hg, HCO3 - 16.8 mmol/l). Gastric lavage, activated charcoal were administered, symptomatic and supportive treatment according to the intensive therapy rule was applied, including sodium bicarbonate, magnesium sulfate and vasopressors intravenous infusion. High concentration of the drug, unknown after ingestion and significantly developed symptoms of cardiotoxicity caused, that the treatment was ineffective. The case described shows that treatment of severe poisoning with tricyclic antidepressants and induced acquired long QT syndrome is still a challenge.

[Determination of doxepin in whole blood by SPE-LC-MS/MS]

OBJECTIVE

To develop a method of SPE-LC-MS/MS for the determination of doxepin in whole blood.

METHODS

After solid phase extraction, the samples were identified by LC-MS/MS. Positive ion electrospray ionization mode and multiple reaction monitoring (MRM) mode was selected. Amitriptyline was used as internal standard. The m/z of doxepin: 280-->107, 280-->235 and 280-->220. The m/z of amitriptyline: 278-->233. The retaining time of doxepin and amitriptyline were 15.15 and 16.94 min, respectively.

RESULTS

The calibration curve was linear among the concentration of doxepin range from 0.005 to 1.00 microg/mL. The linear correlation equation was y = 3.2047x + 0.0339, the correlation coefficient was 0.9996. The detection limit of doxepin was 0.001 microg/mL and average recovery rate was 78.0%-82.9%. The relative standard precision for within-day and between-day were less than 2.55% and 5.90%, respectively.

CONCLUSION

The method is effective, simple, reliable and can be used in the determination of doxepin in whole blood.

[Tricyclic antidepressant overdose rescued by percutanenous cardiopulmonary support: report of two cases]

We report the case of two patients tricyclic antidepressant (TCA) overdoses complicated with severe circulatory failure, successfully resuscitated using percutaneous cardiopulmonary support (PCPS). In case 1, a woman transferred to our emergency department, presented with severe circulatory failure and developed cardiopulmonary arrest. She received prolonged cardiopulmonary resuscitation, and initiated with PCPS. In case 2, a woman presented our emergency department on foot. 3 hours after admission, she falled into severe circulatory failure with polymorphic ventricular tachycardia, and PCPS was started. TCA remains widely used despite its dangerous cardiovascular and neurological effects in overdosed patients. The most common cause of death after TCA overdose is cardiovascular toxicities. In current guidelines, cardiopulmonary resuscitation with extracorporeal cardiopulmonary bypass may be particularly effective for these patients to have a reversible etiology without preceding multisystem organ failure. Cardiotoxicities in TCA overdose are reversible and extracorporeal cardiopulmonary support should be promptly considered in refractory arrhythmia and hypotension despite conventional advanced life support.

Small dose... big poison

BACKGROUND

It is not possible to identify all toxic substances in a single journal article. However, there are some exposures that in small doses are potentially fatal. Many of these exposures are particularly toxic to children. Using data from poison control centres, it is possible to recognise this group of exposures.

OBJECTIVE

This article provides information to assist the general practitioner to identify potential toxic substance exposures in children.

DISCUSSION

In this article the authors report the signs and symptoms of toxic exposures and identify the time of onset. Where clear recommendations on the period of observation and known fatal dose are available, these are provided. We do not discuss management or disposition, and advise readers to contact the Poison Information Service or a toxicologist for this advice.

Brugada like pattern in ECG with drug overdose

Tricyclic antidepressants (TCAs) may have dangerous cardiac effects in overdose. ECG is useful as both a screening tool for tricyclic antidepressant exposure and as a prognostic indicator. TCA overdose may produce various ECG changes. We report a case of Dothiepin overdose resulting in Brugada like pattern including RBBB which resolved spontaneously.

Clinical cases in acute intoxication

Over 2.5 million accidental and intentional drug-related poisonings are reported annually in the United States. Early diagnosis and management of patients who present with acute intoxication can significantly reduce both morbidity and mortality. The initial evaluation of patients with suspected or proven intoxications should focus on hemodynamic stability, mental status, and respiratory function. However, early recognition of toxic ingestion is paramount to implementing life-saving treatments. Important historical clues are often found in a social history that considers intravenous drug use, alcohol use, and any access or exposure to illicit substances. A patient's medication list should also be scrutinized for psychoactive or sedative medications, such as tricyclic antidepressants or opioids. In this article we present case-based discussions of the specific diagnosis and management of 5 commonly occurring acute intoxication syndromes.

Self-poisoning in older adults: patterns of drug ingestion and clinical outcomes

BACKGROUND AND AIMS

self-poisoning accounts for a substantial proportion of acute medical hospital presentations, but has been poorly characterised in older adults. This study sought to determine the agents ingested by older adults presenting to hospital after drug overdose, and to compare clinical outcomes to younger patients.

METHODS

a retrospective observational study of patients admitted via the emergency department due to drug overdose between 2004 and 2007.

RESULTS

during the study period, there were 8,059 admissions, including 4,632 women (57.5%). This included a subgroup of 361 patients (4.5%) who were >60 years of age. This subgroup was more likely to require hospital stay >1 night, odds ratio (95% confidence interval) = 4.3 (3.6-5.5, P < 0.0001), transfer to a critical care area = 3.8 (1.1-13.0, P = 0.0340) and had higher mortality = 4.8 (1.1-22.1, P = 0.0463). A higher proportion of older patients required transfer to a psychiatric unit (P < 0.0001) or to a general medical ward (P < 0.0001) than younger adults.

CONCLUSIONS

older adults that presented to hospital after drug overdose had ingested different drugs than younger patients, possibly due to different prescribing patterns, and had a poorer outcome. The use of drugs associated with significant toxicity should be avoided in older patients at risk of self-harm.

[Seizure triggered by benzodiazepine receptor antagonist]

Flumazenil is a benzodiazepine antagonist. It is widely used as an antidote in comatose patients suspected of having ingested a benzodiazepine overdose. Flumazenil is known to induce cardiac arythmias and seizures, in part because of drug interactions. We present a 75-year-old woman, who was brought to the Emergency Department with a drug overdose following a suicide attempt. She developed generalized seizures shortly after the administration of flumazenil.

Hemoperfusion with Amberlite resin in the treatment of self-poisoning

Ten patients with various intoxications were treated with resin hemoperfusion. Three of four patients with grade IV coma due to tricyclic antidepressant (TCA) poisoning could be extubated during or on termination of hemoperfusion. Clearance values of 135--185 and 190--200 ml/min were obtained for amitriptyline and nortriptyline, respectively. One patient with severe chloral hydrate poisoning could be extubated after less than one hour's hemoperfusion. A clearance of 140 ml/min was obtained in a uremic patient with AV block II due to digitoxin intoxication. Four patients with mushroom poisoning were treated with combined hemoperfusion-hemodialysis. A transient fall in platelet count was seen in all patients. Resin hemoperfusion is of definite value in selected, severe cases of self-poisoning with psychotropic drugs such as TCA and possibly in cases of mushroom poisoning where the prognosis with hemodialysis and supportive therapy is doubtful.

Clinical features in poisonings by tricyclic antidepressants with special reference to the ECG

Clinical variables, and especially their relation to the ECG, have been studied in 153 cases of poisonings by tricyclic antidepressants (TCA). The mean age of the patients was 34 years. Amitriptyline poisoning accounted for 112 (73%) of the cases and the mean dose ingested was about 1 000 mg. Coma was present in 87 patients (57%) and on admission 40 (26%) had a systolic blood pressure (BP) below 100 mmHg. The systolic BP on admission was significantly lower (p less than 0.001) and the heart rate (HR) higher (p less than 0.001) than when the patients left the ward. Apart from an increased HR (greater than or equal to 90 beats/min), which was present in 73% of the cases, the most characteristic ECG change was a QRS prolongation (greater than or equal to 0.11 sec), this being found in 42% of the cases. About the same proportion displayed a QT prolongation and 28% had a prolonged PQ time. The mean of the QRS times was 0.11 sec. Unlike the QT time, the QRS time was not correlated to HR. Statistical analysis of the material with regard to clinical variables (dose of TCA, BP, coma duration, etc.) showed that the QRS time was closely related to the severity of poisoning. Five patients (3) died, all of whom already on admission demonstrated advanced ECG changes with arrhythmias and a mean QRS time of 0.19 sec. Excluding dibenzepine poisonings (4 cases, all fatal), the mortality rate was 0.7%. The importance of high initial preparedness for cardiac complications is pointed out, as is the value of the QRS time as a guide to the severity of poisoning.

Self-poisoning treated in the ICU

This retrospective study compares number and type of self-poisonings admitted to the intensive care units (ICU) at Sahlgren's Hospital, Gothenburg, during 1972 and 1976. The total number of patients requiring intensive care was unchanged, but a change in the pattern of self-poisoning was seen. In 1976 the number of patients requiring intensive care following acute alcohol intoxication had increased, whereas the number of barbiturate and methaqualone poisonings decreased. Tricyclic antidepressants formed the largest group in both years. Fewer patients needed endotracheal intubation and IPPV in 1976 than in 1972. Also, fewer complications were seen, and the death rate among ICU-treated patients decreased. In the Gothenburg area barbiturates accounted for one half of all deaths due to self-poisoning and tricyclic antidepressants for one fifth. Any expected decrease in intensive care as a result of fewer barbiturate and methaqualone poisonings was obscured by an increase in severe alcohol intoxication.

Clinical aspects of tricyclic antidepressant poisoning

Self-poisoning with antidepressant drugs was studied retrospectively in 225 patients admitted to an intensive care unit. Amitriptyline accounted for the overwhelming majority of cases (70%); 106 patients (47%) had taken two or more drugs, in 81 patients (36%) ethanol was found in the blood. Four patients (2%) died. On admission, 111 patients (49%) were unconscious (grade III). A further 30 patients (13%) were in grade IV coma, and of these 27 had taken amitriptyline. Twenty-four hours after admission, 22 patients (10%) remained in coma. Thirty-six patients (16%) required assisted ventilation. Nineteen patients (8%) had convulsions and 6 (3%) aspired stomach contents. Sixty-one patients (27%) had a widened QRS interval exceeding 100 msec, 18 (30%) of them required assisted ventilation, 21 (34%) were in stage IV coma and 15 (25%) had convulsions. This relationship between a widened QRS interval and the severity of intoxication should be considered in the initial assessment of patients with tricyclic antidepressant poisoning.

Suicidal antidepressant overdoses: a comparative analysis by antidepressant type

INTRODUCTION

The safety of antidepressants following overdose is critical because of the high risk of suicide attempts in depressed patients. This study was conducted to decrease the fatality rate of antidepressant overdoses by providing data to shift prescribing toward safer antidepressants.

METHODS

US poison control data for 2000-2004 were analyzed by 25 antidepressant types. Medical outcome differences were quantified using a hazard index (number of major or fatal outcomes per 1000 reported antidepressant ingestions).

RESULTS

Of 82,802 suicidal single-agent ingestions of identifiable antidepressants approved for use in the US, cases occurred predominantly in females and peaked in teens. Fatal cases peaked at 40 to 49 years of age. Suicidal ingestions of the SSRIs, SNRIs, and other antidepressants peaked in teens, lithium in the twenties, tricyclics and tetracyclics in the thirties, and MAO inhibitors in the forties. There were 40 major or fatal outcomes per 1000 cases. Weighted by antidepressant type, the mean hazard index for the 25 antidepressants was 79 (range: 0 to 292). Amoxapine (292), maprotiline (211), and desipramine (187) had the highest hazard indices. The tricyclic antidepressants, MAO inhibitors, maprotiline, and bupropion were in the more severe half of antidepressants, ranked by hazard index. All SSRIs had low hazard indices. Hazard index and exposure frequency were inversely correlated (R = -0.423, p = 0.035), while hazard index and use of critical care were positively correlated for the 25 antidepressant types (R = 0.797, p < 0.001). Clinical effect profiles for each antidepressant type are presented.

CONCLUSION

Suicidal overdose severity varied considerably by antidepressant type. Prescribing decisions should be informed by regularly updated comparative overdose severity data.

Tricyclic antidepressant poisoning: an evidence-based consensus guideline for out-of-hospital management

A review of U.S. poison center data for 2004 showed over 12,000 exposures to tricyclic antidepressants (TCAs). A guideline that determines the conditions for emergency department referral and prehospital care could potentially optimize patient outcome, avoid unnecessary emergency department visits, reduce healthcare costs, and reduce life disruption for patients and caregivers. An evidence-based expert consensus process was used to create the guideline. Relevant articles were abstracted by a trained physician researcher. The first draft of the guideline was created by the lead author. The entire panel discussed and refined the guideline before distribution to secondary reviewers for comment. The panel then made changes based on the secondary review comments. The objective of this guideline is to assist poison center personnel in the appropriate prehospital triage and management of patients with suspected ingestions of TCAs by 1) describing the manner in which an ingestion of a TCA might be managed, 2) identifying the key decision elements in managing cases of TCA ingestion, 3) providing clear and practical recommendations that reflect the current state of knowledge, and 4) identifying needs for research. This guideline applies to ingestion of TCAs alone. Co-ingestion of additional substances could require different referral and management recommendations depending on their combined toxicities. This guideline is based on the assessment of current scientific and clinical information. The panel recognizes that specific patient care decisions may be at variance with this guideline and are the prerogative of the patient and the health professionals providing care, considering all the circumstances involved. This guideline does not substitute for clinical judgment. Recommendations are in chronological order of likely clinical use. The grade of recommendation is in parentheses. 1) Patients with suspected self-harm or who are the victims of malicious administration of a TCA should be referred to an emergency department immediately (Grade D). 2) Patients with acute TCA ingestions who are less than 6 years of age and other patients without evidence of self-harm should have further evaluation including standard history taking and determination of the presence of co-ingestants (especially other psychopharmaceutical agents) and underlying exacerbating conditions, such as convulsions or cardiac arrhythmias. Ingestion of a TCA in combination with other drugs might warrant referral to an emergency department. The ingestion of a TCA by a patient with significant underlying cardiovascular or neurological disease should cause referral to an emergency department at a lower dose than for other individuals. Because of the potential severity of TCA poisoning, transportation by EMS, with close monitoring of clinical status and vital signs en route, should be considered (Grade D). 3) Patients who are symptomatic (e.g., weak, drowsy, dizzy, tremulous, palpitations) after a TCA ingestion should be referred to an emergency department (Grade B). 4) Ingestion of either of the following amounts (whichever is lower) would warrant consideration of referral to an emergency department: an amount that exceeds the usual maximum single therapeutic dose or an amount equal to or greater than the lowest reported toxic dose. For all TCAs except desipramine, nortriptyline, trimipramine, and protriptyline, this dose is >5 mg/kg. For despiramine it is >2.5 mg/kg; for nortriptyline it is >2.5 mg/kg; for trimipramine it is >2.5 mg/kg; and for protriptyline it is >1 mg/kg. This recommendation applies to both patients who are naïve to the specific TCA and to patients currently taking cyclic antidepressants who take extra doses, in which case the extra doses should be added to the daily dose taken and then compared to the threshold dose for referral to an emergency department (Grades B/C). 5) Do not induce emesis (Grade D). 6) The risk-to-benefit ratio of prehospital activated charcoal for gastrointestinal decontamination in TCA poisoning is unknown. Prehospital activated charcoal administration, if available, should only be carried out by health professionals and only if no contraindications are present. Do not delay transportation in order to administer activated charcoal (Grades B/D). 7) For unintentional poisonings, asymptomatic patients are unlikely to develop symptoms if the interval between the ingestion and the initial call to a poison center is greater than 6 hours. These patients do not need referral to an emergency department facility (Grade C). 8) Follow-up calls to determine the outcome for a TCA ingestions ideally should be made within 4 hours of the initial call to a poison center and then at appropriate intervals thereafter based on the clinical judgment of the poison center staff (Grade D). 9) An ECG or rhythm strip, if available, should be checked during the prehospital assessment of a TCA overdose patient. A wide-complex arrhythmia with a QRS duration longer than 100 msec is an indicator that the patient should be immediately stabilized, given sodium bicarbonate if there is a protocol for its use, and transported to an emergency department (Grade B). 10) Symptomatic patients with TCA poisoning might require prehospital interventions, such as intravenous fluids, cardiovascular agents, and respiratory support, in accordance with standard ACLS guidelines (Grade D). 11) Administration of sodium bicarbonate might be beneficial for patients with severe or life-threatening TCA toxicity if there is a prehospital protocol for its use (Grades B/D). 12) For TCA-associated convulsions, benzodiazepines are recommended (Grade D). 13) Flumazenil is not recommended for patients with TCA poisoning (Grade D).

A Preliminary Study of Tricyclic Antidepressant (TCA) Ovine FAB for TCA Toxicity

BACKGROUND

Animal studies suggest that tricyclic antidepressant antibody fragments (TCA Fab) may be a useful therapy for tricyclic antidepressant poisoning. The objective of this study is to determine if TCA Fab increases total serum TCA levels without raising free serum TCA levels in human overdose patients, indicating that TCA Fab effectively binds TCA.

METHODS

This was a prospective, dose escalation study of patients with mild to moderate TCA poisoning. Patients were treated with an escalating intravenous infusion totaling 7 or 14 gm of TCA Fab. The outcomes of interest were serum TCA levels (total and free), worsening of TCA toxicity, and adverse effects.

RESULTS

Seven patients were treated with Fab. Infusion of TCA Fab was associated with a dramatic increase in total serum TCA levels, while free TCA levels fell in both dosing groups. There were no significant changes in QRS duration, heart rate or mean arterial pressure associated with the Fab Infusion. Worsening of TCA toxicity did not occur despite marked elevation of total serum TCA concentrations. The two patients with the greatest prolongation of QRS showed a prompt shortening in their QRS duration temporally associated with the Fab infusion. Mild wheezing was observed in one asthmatic patient.

CONCLUSIONS

1) TCA Fab raises total serum TCA levels while lowering free levels in TCA poisoned patients; 2) no toxic effects were associated with the increase in TCA levels and no severe adverse effects were observed during the hospital course following Fab infusion.

Massive intoxication involving unusual high concentration of amitriptyline

Amitriptyline is a tricyclic antidepressant widely used in the treatment of depression. Antidepressant drugs are among the most commonly encountered causes of self-poisoning, as illustrated by several published cases in the literature. This investigation reports a case of massive amitriptyline intoxication, involving a 44-year old female found dead in bed. The presence of this tricyclic antidepressant was revealed by a routine screening procedure. The concentration was calculated by gas chromatography/ electron ionization-mass spectrometry in the selected ion monitoring mode after solid-phase extraction using proadifen as internal standard and was in the post-mortem whole blood sample 85.9 mug/mL. This value was much higher than the reported toxic values ever found in the literature, and may therefore have caused the victim's death. Nortriptyline was also detected in the toxic concentration range, as well as therapeutic levels of diazepam and nor-diazepam. Taking into account both the available circumstantial information and toxicological results, it is very likely that death was caused by self-poisoning. Human & Experimental Toxicology (2007) 26, 667-670.

[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.

A Fatal Doxepin Poisoning Associated With a Defective CYP2D6 Genotype

It has been suggested that the polymorphism of the CYP2D6 gene can contribute to occurrence of fatal adverse effects. We therefore investigated postmortem toxicology cases of fatal drug poisonings related to CYP2D6 substrates, with the manner of death denoted as accidental or undetermined. CYP2D6 genotypes were determined in 11 consecutive cases with samples available for DNA analysis. A case of fatal doxepin poisoning with an undetermined manner of death was found to coincide with a completely nonfunctional CYP2D6 genotype (*3/*4), indicating a total absence of CYP2D6 enzyme and suggesting a poor metabolizer phenotype. The doxepin concentration was 2.4 mg/L, the concentration of nordoxepin 2.9 mg/L, and the doxepin/nordoxepin ratio 0.83, the lowest found among the 35 nordoxepin-positive postmortem cases analyzed during the same year. No alcohols or other drugs were detected in the case. The CYP2C19 genotype was determined as that of an extensive metabolizer. The high N-desmethylmetabolite concentration is not consistent with acute intoxication. It is therefore probable that the defective genotype has contributed to the death, possibly involving repeated high dosage of doxepin. Our case strongly emphasizes that a pharmacogenetic analysis in postmortem forensic setting may reveal new insight to the cause or manner of death.

Slow the ticking clock of toxicity

Time is a crucial element in preventing the most severe consequences of overdose.

Efficacy of magnesium sulfate for treatment of ventricular tachycardia in amitriptyline intoxication

In our country, tricyclic antidepressants are usually present in most of the homes. Myocardial depression and ventricular arrhythmia are the severe side effects in tricyclic antidepressant overdose. A 4-year-old boy was brought to our hospital after taking 70 mg/kg of amitriptyline. On arrival, the patient was comatose (Glasgow Coma Score was 3), had a shallow breathing pattern with bradycardia (HR <30/min), and hypotension. He was intubated and resuscitated with multiple doses of adrenaline and sodium bicarbonate. He was infused with a bolus of 20 mg/kg of normal saline for hypotension. After 30 minutes, ventricular fibrillation was detected. Lidocaine and bicarbonate were not effective in converting the rhythm to normal, therefore, synchronized cardioversion was used. After cardioversion, the rhythm converted to ventricular tachycardia. Because ventricular tachycardia did not resolve, we administered a load of less than 2 g of magnesium sulfate for 30 minutes followed by a continuous infusion of 3 mg/min. After magnesium sulfate infusion, a normal cardiac rhythm was achieved. Magnesium sulfate is a very effective treatment in intractable arrhythmias caused by high-dose amitriptyline intoxication.