Data collection in clinical toxicology: are there too many variables?

Developing the minimum data set of the corrosive ingestion registry system in Iran

Background

Corrosive ingestion is still a major health problem, and its outcomes are often unpredicted. The implementation of a registry system for poisoning with corrosive substances may improve the quality of patient care and might be useful to manage this type of poisoning and its complications. Therefore, our study aimed to establish a minimum data set (MDS) for corrosive ingestion.

Methods

This was an applied study performed in 2022. First, a literature review was conducted to identify the potential data items to be included in the corrosive ingestion MDS. Then, a two-round Delphi survey was performed to attain an agreement among experts regarding the MDS content, and an additional Delphi step was used for confirming the final MDS by calculating the individual item content validity index (CVI) and content validity ratio (CVR) and by using other statistical tests.

Results

After the literature review, 285 data items were collected and sent to a two-round Delphi survey in the form of a questionnaire. In total, 75 experts participated in the Delphi stage, CVI, kappa, and CVR calculation. Finally, the MDS of the corrosive ingestion registry system was identified in two administrative and clinical sections with 21 and 152 data items, respectively.

Conclusions

The development of an MDS, as the first and most important step towards developing the corrosive ingestion registry, can become a standard basis for data collection, reporting, and analysis of corrosive ingestion. We hope this MDS will facilitate epidemiological surveys and assist policymakers by providing higher quality data capture to guide clinical practice and improve patient-centered outcomes.

Minimum Data Set for a Poisoning Registry: A Systematic Review

Poisoning, as a well-known medical condition, puts everyone at risk. As a data management tool, a registry plays an important role in monitoring the poisoned patients. Having a poisoning minimum data set is a major requirement for creating a poisoning registry. Therefore, the present systematic review was conducted in 2019 to identify the minimum data set for a poisoning registry. Searches were performed in four scientific databases, i.e., PubMed, Scopus, Web of Science, and Embase. The keywords used in the searches included minimum data set, "poison", and "registry". Two researchers independently evaluated the titles, abstracts, and texts of the papers. The data were collected from the related papers. Ultimately, the minimum data set was identified for the poisoning registry. Data elements extracted from the sources were classified into two general categories: administrative data and clinical data. Ninety-eight data elements in the administrative data category were subdivided into three sections: general data, admission data, and discharge data. One-hundred and thirty-one data elements in the clinical data category were subdivided into five sections: clinical observation data, clinical assessment data, past medical history data, diagnosis data, and treatment plan data. The minimum data set is a prerequisite for creating and using a poisoning registry and data system. It is suggested to evaluate and use the poisoning minimum data set in accordance with the national laws, needs, and standards based on the opinion of the local experts.

Development a national minimum data set for poisoning registry in Iran

OBJECTIVES

In the developing countries with high mortality rates, poisoning is considered to be one of the most common causes of admission to emergency wards. Given the importance of registering data on poisoned patients, it is very important to have a complete poisoning Minimum Data Set (MDS). Therefore, the purpose of this study was to determine an MDS for poisoning registry in Iran.

METHODS

This applied and cross-sectional study was conducted through of Delphi technique in the poisoning ward of Imam Reza Hospital (northeastern Iran) in 2019. Literature reviews were initially carried out on such databases as PubMed, Web of Sciences, Scopus, and Embase. Then, Google search was done to retrieve poisoning forms and poisoning registry websites. Also, we considered International Classification of Diseases, 10th Revision coding guidelines of poisoning. Then, a questionnaire containing data elements of poisoning was developed.

RESULTS

In total, 558 data elements were developed during two rounds of Delphi technique. The MDS was divided into 10 categories including patient and communication data, encounter data, diagnostic data and medical history, exposure data, clinical data, treatment data, complications, paraclinical tests, biobank, and discharge data.

CONCLUSIONS

Establishing an MDS as the first and most important step towards implementing poisoning registry can be the standard basis for collecting poisoned patient data. The data registered in the poisoning registry can be used for planning, policy-making, prevention, and control purposes.

Minimum data set development for a drug poisoning registry system

Objective

Drug poisoning is the most prevalent type of poisoning throughout the world that can occur intentional or unintentional. Standard way for data gathering with uniform definitions is a requirement for preventing, controlling and managing of drug poisoning management. The purpose of this study was to develop a minimum data set, as an initial step, for a drug poisoning registry system in Iran.

Methods

This was descriptive and cross-sectional study that was performed in 2019. As the first step a comprehensive literature review was performed to retrieve related resources in Persian and English languages. For the second step the medical records of drug poisoning patients at Afzalipour hospital affiliated to Kerman University of Medical Sciences were assessed. Related data from these two steps were gathered by a checklist. Finally, a questionnaire that was created based on the checklist data elements and had three columns of ‘essential,' ‘useful, but not essential', and ‘not essential' was used to reach a consensus on the data elements. Then the content validity ratio and the mean of experts’ judgments were calculated for each data element. The Cronbach’s alpha value for the entire questionnaire was obtained 0.9.

Results

The minimum data set of a drug poisoning registry system was categorised into the administrative part with three sections including 32 data elements, and clinical parts with six sections including 81 data elements.

Conclusion

This study provides a minimum data set for development of a drug poisoning registry system. Collecting this minimum data set is critical for helping policy makers and healthcare providers to prevent, control and manage drug poisoning.

Use of a tablet-based application for clinical handover and data collection

Context: Inpatient toxicology services undertake remote as well as inpatient management of poisoned patients. The aim of this study is to describe the introduction of a tablet-based electronic data collection tool allowing data to be captured on inpatient and remote consultations.Methods: Retrospective review of all cases entered in the database from 1 March 2014 to 28 February 2016. Data collected included demographics (age, sex), clinical details (exposure category), presentation facility and disposition.Results: The database included 3616 cases: 59 (1.6%) were excluded due to inadequate details, 122 (3.4%) had no electronic medical record available, 1985 (54.9%) presented to the inpatient unit facility and 1450 (40.1%) were external consultations. Of these 1450, 223 (6.2%) were paediatric (aged less than 12 years), 395 (10.9%) adolescent (12-17 years) and 832 (23.0%) adults (18 years and over). The proportion of paediatric cases (median age 2 y; 45.7% females) with pharmaceutical ingestions was 122 (54.7%; 95% confidence intervals (CIs): 48.2-61.1) compared with 345 (87.3%; 95% CI: 83.7-90.3) in adolescents (median age 15 y; 79.5% females). Of the adult presentations, 659 (18.2%) were metropolitan/regional facility presentations and 173 (4.8%) rural facilities with 125 (3.4%) adults subsequently transferred to the inpatient facility. Median age was 38 years (interquartile range (IQR) 35-52) with 338 (51.4%) females in the metropolitan group and 37 years (IQR 26-48) with 51 (30.5%) females in the rural group. There were more bites and stings in the rural group, 41 (23.7%; 95% CI: 18.0-30.6) versus 54 (8.2%; 95% CI: 6.3-10.5), more recreational substance exposures 27 (15.6%; 95% CI: 11.0-21.8) versus 40 (6.1%; 95% CI: 4.5-8.2) and less pharmaceutical exposures 93 (53.8%; 95% CI: 46.3-61.0) versus 462 (70.1%; 95% CI: 66.5-73.5).Conclusions: The tablet based database provided useful information on populations of poisoned patients not accessible previously. It demonstrated important differences in the types of patients presenting to rural versus metropolitan hospitals.

The relative lethal toxicity of pharmaceutical and illicit substances: A 16-year study of the Greater Newcastle Hunter Area, Australia

AIMS

We aim to calculate 2 metrics of relative lethal toxicity; the fatal toxicity index (FTI; number of deaths per year of a daily dose) and the case fatality (CF; number of deaths per overdose) with a focus on opioids, antidepressants, antipsychotics, benzodiazepines and illicit drugs.

METHODS

This descriptive cohort study used the Australian National Coronial Information System (NCIS) to identify a population of individuals with drug-associated deaths in the Greater Newcastle Hunter Area between January 2002 and December 2016. This was combined with Australian medicine dispensing data and corresponding data from the Hunter Area Toxicology Service to calculate FTI and CF.

RESULTS

There were 444 drug-related deaths and 21,296 overdoses during the study period. FTI and CF were well correlated (Spearman's rho 0.64, P < .001). Of the classes of interest, opioids had the highest FTI (40.3 95% confidence interval [CI] 35.2-45.4 deaths per 100 years of use at the defined daily dose or deaths/DDD/100 years) and CF (12.4% 95%CI 11.0-13.9). Fentanyl, methadone and morphine had the highest relative fatal toxicity within this class. Tricyclic antidepressants had the highest relative fatal toxicity of all antidepressants (FTI 14.5 95%CI 9.7-19.3 deaths/DDD/100 years and CF 7.1% [95%CI 4.8-9.3]) and benzodiazepines appeared to be more associated with multiple agent deaths than single. Of the illicit drugs, heroin had the highest CF (26.4%, 95%CI 19.1-33.7).

CONCLUSION

Knowledge of relative lethal toxicity is useful to prescribers and medicines and public health policy makers in restricting access to more toxic drugs and may also assist coroners in determining cause of death.

Postcards from the EDge: 5-year outcomes of a randomised controlled trial for hospital-treated self-poisoning

BACKGROUND

Repetition of hospital-treated self-poisoning and admission to psychiatric hospital are both common in individuals who self-poison.

AIMS

To evaluate efficacy of postcard intervention after 5 years.

METHOD

A randomised controlled trial of individuals who have self-poisoned: postcard intervention (eight in 12 months) plus treatment as usual v. treatment as usual. Our primary outcomes were self-poisoning admissions and psychiatric admissions (proportions and event rates).

RESULTS

There was no difference between groups for any repeat-episode self-poisoning admission (intervention group: 24.9%, 95% CI 20.6-29.5; control group: 27.2%, 95% CI 22.8-31.8) but there was a significant reduction in event rates (incidence risk ratio (IRR) = 0.54, 95% CI 0.37-0.81), saving 306 bed days. There was no difference for any psychiatric admission (intervention group: 38.1%, 95% CI 33.1-43.2; control group: 35.5%, 95% CI 30.8-40.5) but there was a significant reduction in event rates (IRR = 0.66, 95% CI 0.47-0.91), saving 2565 bed days.

CONCLUSIONS

A postcard intervention halved self-poisoning events and reduced psychiatric admissions by a third after 5 years. Substantial savings occurred in general hospital and psychiatric hospital bed days.

Cognitive skills underlying driving in patients discharged following self-poisoning with central nervous system depressant drugs

BACKGROUND

Central nervous system-depressant (CNS-Ds) drugs can impair cognitive functions and driving. They are also the most common drugs taken in overdose in hospital-treated episodes of self-poisoning. In Australia most of these patients are discharged within 48 h, while they still have possible subclinical drug effects. We aimed to determine whether patients treated for self-poisoning with CNS-Ds are impaired in the Trail-Making Test (TMT, parts A and B), a neuropsychological test that is known to correlate with driving performance.

METHODS

This study was a conducted from November 2008 to April 2011 in a referral center for poisonings in New South Wales, Australia. One hundred seven patients discharged from the clinical toxicology unit following treatment for self-poisoning of CNS-Ds (benzodiazepines, atypical antipsychotics, or opioids) and a control group of 68 discharged following self-poisoning of non-CNS-depressant drugs (acetaminophen or nonsedating antidepressants) were tested with the TMT (parts A and B). Due to the known association of impaired TMT with driving impairment and increased risk of traffic accidents, performance less than the 10th percentile for age was defined as significant impairment in each part of the TMT. The odds ratio (OR) for impairment in each part was calculated in multivariate logistic regression (MLR) models adjusted for gender, education, IQ, and the presence of a major psychiatric illness. A secondary MLR analysis was conducted only for those patients (78 CNS-D and 54 control group participants) who were directly discharged home, after excluding those who were transferred for further psychiatric care.

RESULTS

The odds of impairment in the CNS-D group was 2.8 times that of the control group on the TMT-A (38 [35.5%] vs. 11 [16.2%]: adjusted OR = 2.76, 95% confidence interval [CI]: 1.28-5.97), and 4.6 times on the TMT-B (67 [62.6%] vs. 22 [32.4%]: adjusted OR = 4.63, 95% CI: 2.06-10.42). The results were similar in the subgroup of patients discharged home, and the odds of impairment in the CNS-D group was 3.3 times that of the control group on the TMT-A (25 [32.1%] vs. 7 [13.0%]: adjusted OR = 3.30, 95% CI: 1.28-8.52), and 3.6 times on the TMT-B (46 [59.0%] vs. 17 [31.5%]: adjusted OR = 3.64, 95% CI: 1.44-9.20). TMT-B impairment in the CNS-D group remained significant even after adjusting for TMT-A performance.

CONCLUSIONS

Patients with CNS-D overdose may have significant impairment in cognitive skills underlying driving at the time of discharge from hospitals. Clinicians should warn these patients that their driving skills might still be impaired, even if they are considered clinically recovered and advise them not to drive during the first 1 to 2 days following discharge.

The Toxicology Investigators Consortium (ToxIC) Registry

Many medical toxicologists are interested in participating in a practice-based, multicenter research and toxicosurveillance network. In 2009, the American College of Medical Toxicology established the Toxicology Investigators Consortium (ToxIC). One facet of ToxIC is a registry that can be used for surveillance of new or old agents, assessment of treatment decisions, and the creation of new research questions. This paper describes the development of and the initial experiences with this registry of toxicology patients. In November 2009, ACMT invited members to participate in a new registry of cases evaluated and cared for by practicing medical toxicologists who provide direct hands-on clinical care. A password-protected, encrypted, online registry data site was created to upload a newly developed electronic case report form (CRF) on registry patients. The CRF includes demographics; encounter circumstances; agent; syndrome, symptoms, and signs; and treatment. A test version at four sites began in January 2010, seven additional sites were added in March 2010 for the beta phase, and the registry was opened to all interested US medical toxicology practices in April 2010. The CRF underwent continuous modifications based upon frequent feedback from and discussion among the participants. Thirty-three toxicology practice sites, encompassing 56 hospitals and clinics, have entered data into the ToxIC Registry. During the first 14 months of data collection, 5,412 patients were entered. The experience thus far demonstrates that the creation of this registry is feasible and constitutes a potentially powerful toxicosurveillance and robust research tool.

Toxicologists in public health--Following the path of Louis Roche (based on the Louis Roche lecture "An accidental toxicologist in public health", Bordeaux, 2010)

BACKGROUND

The global burden of clinical toxicology suggests a natural partnership with public health. This article reflects the content of a Louis Roche lecture given in 2010. HISTORICAL CONTEXT: Our practice and research in clinical toxicology has evolved from clinical cases to toxico-epidemiology to public health. This evolution in practice was initially unplanned but gained momentum and impact as we placed it more formally in a public health framework. This perspective is implicit in Louis Roche's call to "examine all aspects of the poisoning problem" and still provides a valuable starting point for any clinical toxicologist.

DISCUSSION

Clinical toxicology has always had a patient centered focus but its greatest successes have been related to public health interventions. Our early failures and later success in pubic health toxicology correlated with our understanding of the importance of partnerships outside our field. The most rapid dissemination and implementation of information derived from research occur through apriori partnerships with other agencies and international partners.

CONCLUSION

Addressing both local and global need has a number of bilateral synergies. Repositioning clinical toxicology into a public health framework increases access to strategic partnerships, research funds, and policy implementation while still addressing questions that are important to clinical practice.

Randomized controlled trial comparing the effectiveness and safety of intranasal and intramuscular naloxone for the treatment of suspected heroin overdose

AIMS

Traditionally, the opiate antagonist naloxone has been administered parenterally; however, intranasal (i.n.) administration has the potential to reduce the risk of needlestick injury. This is important when working with populations known to have a high prevalence of blood-borne viruses. Preliminary research suggests that i.n. administration might be effective, but suboptimal naloxone solutions were used. This study compared the effectiveness of concentrated (2 mg/ml) i.n. naloxone to intramuscular (i.m.) naloxone for suspected opiate overdose.

METHODS

This randomized controlled trial included patients treated for suspected opiate overdose in the pre-hospital setting. Patients received 2 mg of either i.n. or i.m. naloxone. The primary outcome was the proportion of patients who responded within 10 minutes of naloxone treatment. Secondary outcomes included time to adequate response and requirement for supplementary naloxone. Data were analysed using multivariate statistical techniques.

RESULTS

A total of 172 patients were enrolled into the study. Median age was 29 years and 74% were male. Rates of response within 10 minutes were similar: i.n. naloxone (60/83, 72.3%) compared with i.m. naloxone (69/89, 77.5%) [difference: -5.2%, 95% confidence interval (CI) -18.2 to 7.7]. No difference was observed in mean response time (i.n.: 8.0, i.m.: 7.9 minutes; difference 0.1, 95% CI -1.3 to 1.5). Supplementary naloxone was administered to fewer patients who received i.m. naloxone (i.n.: 18.1%; i.m.: 4.5%) (difference: 13.6%, 95% CI 4.2-22.9).

CONCLUSIONS

Concentrated intranasal naloxone reversed heroin overdose successfully in 82% of patients. Time to adequate response was the same for both routes, suggesting that the i.n. route of administration is of similar effectiveness to the i.m. route as a first-line treatment for heroin overdose.

Promethazine overdose: clinical effects, predicting delirium and the effect of charcoal

OBJECTIVE

The aim of this study was to describe the clinical effects of promethazine in overdose and explore the relationship between delirium and possible predictor variables.

METHODS

A case series of promethazine poisonings was identified from a prospective database of poisoning admissions to a regional toxicology service. Data were extracted including demographics, details of ingestion, clinical features including delirium, complications and medical outcomes. In addition to descriptive statistics, a fully Bayesian approach using logistic regression was undertaken to investigate the relationship between predictor variables and delirium.

RESULTS

There were 199 patients with 237 presentations, including 57 patients with 78 promethazine alone overdoses. Of these 57 patients who ingested promethazine alone the median age was 22 years [interquartile range (IQR): 17-31] and 42 were female (74%). The median dose ingested was 625 mg (IQR: 350-1250 mg). Median length of stay was 19 h (IQR: 13-27 h), ten were admitted to the intensive care unit (ICU) and four were ventilated. Delirium occurred in 33 patients (42%), tachycardia (HR>100) occurred on 44 occasions (56%) and hypotension only twice. There were no seizures, dysrhythmias or deaths. Multivariate analysis of 215 presentations (in 181 patients) where dose of promethazine ingested was known demonstrated that dose, administration of charcoal within 2 h and co-ingestants predicted whether patients developed delirium. No relationship was shown for sex and age. A plot of probability that a patient will develop delirium vs. dose was constructed which showed the probability of delirium for 250 mg was 31%, 500 mg was 42% and for 1 g was 55% for promethazine alone overdoses.

CONCLUSION

The main feature of promethazine toxicity is delirium, the probability of which can be predicted from the dose ingested. The administration of charcoal and the presence of co-ingestants appears to reduce the probability of delirium in a predictable manner.

Comparison of crystalline methamphetamine ("ice") users and other patients with toxicology-related problems presenting to a hospital emergency department

OBJECTIVE

To compare demographic and clinical characteristics of methamphetamine users and patients with other toxicology-related problems requiring medical intervention in a hospital emergency department (ED).

DESIGN AND SETTING

Prospective observational study of toxicology-related presentations to the ED of St Vincent's Hospital (SVH), Sydney, an inner-city tertiary hospital, between 1 October and 31 December 2006.

MAIN OUTCOME MEASURES

Differences between methamphetamine-related and other toxicology-related presentations to the ED in relation to behaviour, mode of arrival, accompaniment, need for scheduling, location of drug use, intravenous drug use history, psychiatric history and demographic characteristics.

RESULTS

During the study period there were 10 305 patient presentations to SVH ED; 449 (4%) were toxicology-related presentations, of which 100 (1% of total) were methamphetamine-related. Methamphetamine users were significantly more agitated, violent and aggressive than patients with other toxicology-related presentations and significantly less alert, communicative and cooperative (P < 0.001); 24% of methamphetamine users (24/100) arrived with police accompaniment versus 9% of other toxicology patients (33/349) (P < 0.001). Methamphetamine users were more likely to have a history of intravenous drug use and mental health problems (P < 0.001); 39% of methamphetamine presentations (39/100) required scheduling under the Mental Health Act 1990 (NSW) compared with 19% of other toxicology-related presentations (67/349) (P < 0.001); 43% of methamphetamine-related presentations (43/100) involved drug use on the street compared with 24% of other toxicology-related presentations (83/349) (P < 0.001). Two-thirds of all methamphetamine users were male, and the most common age group for both male and female users was 26-30 years. The mean age and sex distribution of patients with other toxicology-related presentations were not significantly different. Among methamphetamine users, 27% of women (9/33) were in the 21-25-year age group compared with 10% (7/67) of men (P < 0.001).

CONCLUSION

There were significant differences between methamphetamine-related and other toxicology-related presentations to SVH ED. Methamphetamine users were more aggressive, violent and dangerous, and thus more likely to pose a risk to health personnel and others. Methamphetamine appeared to be used consistently, rather than as an episodic "party drug".

Postcards from the EDge: 24-month outcomes of a randomised controlled trial for hospital-treated self-poisoning

BACKGROUND

Repetition of self-poisoning is common.

AIMS

To report the 24-month outcomes of a non-obligatory postcard intervention (plus treatment as usual) compared with treatment as usual.

METHOD

In a randomised-controlled trial (Zelen design) conducted in Newcastle, Australia, eight postcards were sent to participants over a 12-month period. The principal outcomes were the proportion of participants with one or more repeat episodes of self-poisoning and the number of repeat episodes per person.

RESULTS

No significant reduction was observed in the proportion of people repeating self-poisoning in the intervention group (21.2%, 95% CI 17.0-25.3) compared with the control group (22.8%, 95% CI 18.7-27.0; chi(2)=0.32, d.f.=1, P=0.57); the difference between groups was -1.7% (95% CI -7.5 to 4.2). There was a significant reduction in the rate of repetition, with an incidence risk ratio of 0.49 (95% CI 0.33-0.73).

CONCLUSIONS

A postcard intervention maintained the halving of the rate of repetition of hospital-treated self-poisoning events over a 2-year period, although it did not significantly reduce the proportion of individuals who repeated self-poisoning.

Safety and efficacy of intravenous N-acetylcysteine for acetaminophen overdose: analysis of the Hunter Area Toxicology Service (HATS) database

BACKGROUND

Acetaminophen (N-acetyl-p-aminophenyl; APAP) is the leading drug used in self-poisoning and frequently causes hepatotoxicity, including acute liver failure.

OBJECTIVE

To provide descriptive data on the safety and efficacy of intravenous N-acetylcysteine (IV-NAC) in the treatment of APAP toxicity, based on information in the Hunter Area Toxicology Service (HATS) database involving residents of the Greater Newcastle Area of New South Wales, Australia.

METHODS

This was a retrospective analysis of all APAP overdoses from January 1987 to January 2003. Data were collected prospectively according to a published protocol and included patient characteristics, exposures to APAP and other potential toxins, treatments, and outcomes. Primary safety/tolerability endpoints included the mortality rate and incidence of adverse drug reactions, while efficacy endpoints included alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels.

RESULTS

Of 1749 patients, 399 (22.8%) were treated with IV-NAC. Of these, 37 (9.3%) had an adverse drug reaction to IV-NAC, of which seven (1.8% of total) were anaphylactoid. There were five deaths in hospital (mortality rate = 0.3%), including two attributed to APAP (0.1%) and none to IV-NAC. Of 64 patients who were treated with IV-NAC within 8 hours after APAP ingestion and had available ALT/AST data, two (3.1%) developed hepatotoxicity (AST/ALT > 1000 IU/L) compared with 32 (25%) of 128 patients receiving IV-NAC > 8 hours after APAP ingestion (p = 0.0002). A total of 26 patients (15.6%) receiving IV-NAC treatment within 8 hours after APAP ingestion had hospitalization stays > 48 hours compared with 70 (33.3%) receiving IV-NAC > 8 hours after ingestion (p < 0.0001).

CONCLUSIONS

For patients with APAP overdose seen in the HATS database of New South Wales, Australia, in-hospital death was infrequent (< 1%) and hepatotoxicity was significantly less likely when IV-NAC was administered within 8 hours after APAP ingestion compared with longer intervals (p < 0.01). As a descriptive retrospective database analysis, this study could not exclude certain sources of bias, including temporal changes over the 16-year course of data collection in the use of IV-NAC and low ascertainment of mild, self-limiting reactions to IV-NAC.

Clinical toxicology: clinical science to public health

1. The aims of the present paper are to: (i) review progress in clinical toxicology over the past 40 years and to place it in the context of modern health care by describing its development; and (ii) illustrate the use of clinical toxicology data from Scotland, in particular, as a tool for informing clinical care and public health policy with respect to drugs. 2. A historical literature review was conducted with amalgamation and comparison of a series of published and unpublished clinical toxicology datasets from NPIS Edinburgh and other sources. 3. Clinical databases within poisons treatment centres offer an important method of collecting data on the clinical effects of drugs in overdose. These data can be used to increase knowledge on drug toxicity mechanisms that inform licensing decisions, contribute to evidence-based care and clinical management. Combination of this material with national morbidity datasets provides another valuable approach that can inform public health prevention strategies. 4. In conclusion, clinical toxicology datasets offer clinical pharmacologists a new study area. Clinical toxicology treatment units and poisons information services offer an important health resource.

Postcards from the EDge project: randomised controlled trial of an intervention using postcards to reduce repetition of hospital treated deliberate self poisoning

OBJECTIVE

To determine whether an intervention using postcards (postcards from the EDge project) reduces repetitions of hospital treated deliberate self poisoning.

DESIGN

Randomised controlled trial.

SETTING

Regional referral service for general hospital treated deliberate self poisoning in Newcastle, Australia.

PARTICIPANTS

772 patients aged over 16 years with deliberate self poisoning.

INTERVENTION

Non-obligatory intervention using eight postcards over 12 months along with standard treatment compared with standard treatment alone.

MAIN OUTCOME MEASURES

Proportion of patients with one or more repeat episodes of deliberate self poisoning and the number of repeat episodes for deliberate self poisoning per person in 12 months.

RESULTS

The proportion of repeaters with deliberate self poisoning in the intervention group did not differ significantly from that in the control group (57/378, 15.1%, 95% confidence interval 11.5% to 18.7% v 68/394, 17.3%, 13.5% to 21.0%: difference between groups -2%, -7% to 3%). In unadjusted analysis the number of repetitions were significantly reduced (incidence risk ratio 0.55, 0.35 to 0.87).

CONCLUSION

A postcard intervention reduced repetitions of deliberate self poisoning, although it did not significantly reduce the proportion of individual repeaters.

Naloxone in opioid poisoning: walking the tightrope

Acute opioid intoxication and overdose are common causes of presentation to emergency departments. Although naloxone, a pure opioid antagonist, has been available for many years, there is still confusion over the appropriate dose and route of administration. This article looks at the reasons for this uncertainty and undertakes a literature review from which a treatment algorithm is presented.

QTc abnormalities in deliberate self-poisoning with moclobemide

BACKGROUND

Several medications have been found to prolong the QT interval in overdose. This can predispose to torsade de pointes-type ventricular tachycardia.

AIMS

To analyse the effects of moclobemide deliberate self-poisoning on the length of both QT and corrected QT (QTc) intervals.

METHODS

Electrocardiograms (ECG) of all patients presenting to a regional toxicology service with moclobemide ingestion were reviewed. Cases where a cardiotoxic agent was coingested were excluded. QT and QTc parameters were compared with a comparison group of patients ingesting paracetamol or benzodiazepines.

RESULTS

Of 75 patients where ECG were available, the median ingested dose was 4.5 g (interquartile range (IQR): 2.4-7.5; range: 0.6-18 g) and the median age was 34 years (IQR: 26-44). The mean QT interval was 415 ms (standard deviation (SD): 51 ms) with a mean QTc of 459 ms (SD: 44 ms), and were prolonged compared with the comparison group. Twelve female patients had a QTc > 500 ms and in seven of these causality was established based on a pre- or post-ECG with a QTc < 500 ms. Only 10% of the moclobemide cases had a heart rate (HR) > 100 beats per minute, making overcorrection of HR by Bazett's formula an unlikely cause of the findings. No cardiac arrythmias were observed other than one case of first-degree heart block.

CONCLUSIONS

Moclobemide prolongs the QT and QTc intervals in overdose and a 12-lead ECG should be done on all moclobemide deliberate self-poisonings. Continuous cardiac monitoring for what is otherwise a relatively benign overdose would appear to be an inappropriate use of resources but can be considered in patients with a QTc > 500 ms or with known risks for QT prolongation.

Clinical management for hospital-treated deliberate self-poisoning: comparisons between patients with major depression and borderline personality disorder

OBJECTIVE

To compare the initial clinical management of hospital-treated deliberate self-poisoning patients with major depressive disorder (MDD) or borderline personality disorder (BPD) after controlling for demographic factors and level of suicide ideation.

METHOD

This study compared sequential hospital treated deliberate self-poisoning patients (n = 570) with either MDD or BPD (but no major comorbid psychopathology) on four outcomes modelled using logistic regression: (i) length of stay in the general hospital; (ii) discharge to a psychiatric hospital; (iii) psychiatric follow-up; and (iv) general practitioner (GP) follow-up.

RESULTS

BPD and MDD patients were discharged to psychiatric inpatient care at very similar rates (33%-35%) and almost all subjects with high levels of suicidal ideation were discharged to psychiatric hospital. However, for mild to moderate levels of suicidal ideation BPD patients were more likely to be discharged to psychiatric hospital than MDD patients. After controlling for demographics and suicidal ideation, BPD patients were more likely to be referred for psychiatric hospitalization on discharge (adjusted OR = 1.79, 95% CI = 1.01-3.18) and less likely to be referred to GPs if discharged to home (adjusted OR = 0.44, 95% CI = 0.24-0.81). There were no differences in general hospital length of stay or arrangements made for psychiatric follow-up for those discharged to home.

CONCLUSIONS

This suggests that for mild to moderate suicidal ideation levels clinicians are more likely to choose to send BPD patients, after deliberate self-poisoning, to inpatient psychiatric care than MDD patients. Clinicians are also apparently more likely to choose to manage MDD patients in primary care settings, for those patients discharged to home. This has implications for service planning and clinical guidelines.

Non-suicidal deaths following hospital-treated self-poisoning

OBJECTIVE

To quantify the non-suicidal mortality subsequent to hospital treated self-poisoning, and to identify risk factors for non-suicidal death.

METHOD

A prospective longitudinal cohort design was used, with data-linkage between the Hunter Area Toxicology Service database and the National Death Index. All patients with deliberate self-poisoning for a 10-year period (1991-2000) were studied and the first episode in the period was used as the index episode. The outcomes were: accidental, 'natural' and non-suicidal death, with follow-up for the study duration.

RESULTS

There were 4044 patients studied, and 170 (4.2%) of these had non-suicidal death; 64 were accidental and 106 were 'natural' cause deaths. The standardized mortality ratio (95% CI) for non-suicidal death for males, females and combined were 4.98 (4.08-6.07), 3.78 (3.0-4.75) and 4.20 (3.62-4.88), respectively. The increased mortality was apparent for both males and females, and was more marked in the younger age groups. For non-suicidal death the adjusted hazard ratio (95% CI) for increased risk were: increasing age 1.07 (1.06-1.08), male gender 1.77 (1.24-2.52), psychiatric diagnosis of substance related disorder 1.49 (1.03-2.16), prescription of a respiratory drug 2.69 (1.31-5.55), and prescription of an anti-diabetic drug 1.95 (0.93-4.07), while psychiatric diagnosis of adjustment disorder 0.64 (0.38-1.053) was associated with decreased risk.

CONCLUSIONS

Patients who present with self-poisoning have increased mortality from accidental and 'natural' causes. Long-term treatment goals for these patients need to address non-suicide mortality in addition to suicide mortality.

Alprazolam is relatively more toxic than other benzodiazepines in overdose

AIMS

To describe alprazolam poisoning and the relative toxicity of alprazolam compared with other benzodiazepines.

METHODS

A database of consecutive poisoning admissions to a regional toxicology service was searched to identify consecutive benzodiazepine deliberate self poisonings, which were coded as alprazolam, diazepam or other benzodiazepine. Major outcomes used were length of stay (LOS), intensive care (ICU) admission, coma (GCS < 9), flumazenil administration and requirement for mechanical ventilation. Prescription data were obtained for benzodiazepines for the study period.

RESULTS

There were 2063 single benzodiazepine overdose admissions: 131 alprazolam overdoses, 823 diazepam overdoses and 1109 other benzodiazepine overdoses. The median LOS for alprazolam overdoses was 19 h which was 1.27 (95% CI 1.04, 1.54) times longer compared with other benzodiazepines by multiple linear regression. For patients with alprazolam overdoses, 22% were admitted to ICU which was 2.06 (95% CI 1.27, 3.33) times more likely compared with other benzodiazepines after multivariate analysis adjusting for age, dose, gender, time to ingestion and co-ingested drugs. Flumazenil was administered to 14% of alprazolam patients and 16% were ventilated, which was significantly more than for other benzodiazepine overdoses (8% and 11%, respectively). Twelve percent of alprazolam overdoses had a GCS < 9 compared with 10% for other benzodiazepines. From benzodiazepine prescription data, total alprazolam prescriptions in Australia increased from 0.13 million in 1992 to 0.41 million in 2001. Eighty five percent of prescriptions were for panic disorder, anxiety, depression or mixed anxiety/depression.

CONCLUSIONS

Alprazolam was significantly more toxic than other benzodiazepines. The increased prescription of alprazolam to groups with an increased risk of deliberate self poisoning is concerning and needs review.

Presumed Angel's trumpet (Brugmansia) poisoning: clinical effects and epidemiology

OBJECTIVE

To investigate the pattern and epidemiology of anticholinergic plant poisoning, and to characterize its time course and clinical features.

METHODS

We reviewed all anticholinergic plant poisonings using a prospective database of all poisonings admitted to a major toxicology unit in Australia. All patients that presented with anticholinergic plant poisoning between July 1990 and June 2000 were included. Patient demographics, details of poisoning, diagnostic clinical features, adverse effects (seizures, arrhythmias, hypotension, accidental injury), and treatments required were obtained. Important diagnostic features were analysed and compared to previous studies.

RESULTS

Thirty-three patients were presumed to have ingested Brugmansia spp. (Angel's trumpet) based on their description of the plant; median age 18 years (interquartile range 16-20); 82% males. Thirty-one ingested a brewed tea or parts of the plant (flower). Thirty-one used it recreationally. Common clinical features were: mydriasis (100%), mean duration 29 h (SD 13) and delirium (88%) with a mean duration of 18 h (SD 12). Tachycardia only occurred in 11 of the 33 patients (33%). In 24 patients where the time of ingestion was certain, 7 of 8 (88%) patients presenting within 5 h had tachycardia and only 5 out of 16 (31%) presenting after 5 h had tachycardia. There were no deaths, seizures or arrhythmias (excepting tachycardia). One patient had hypotension and two sustained accidental traumatic injuries. Nineteen patients required sedation, mainly with benzodiazepines. Physostigmine was used diagnostically in eight cases.

CONCLUSIONS

Anticholinergic plant abuse is sporadic in nature. Most cases were moderate in severity, requiring sedation only, and severe toxicity was rare. Mydriasis and delirium were the commonest features, the later having important implications for management.

Relative Toxicity of Selective Serotonin Reuptake Inhibitors (SSRIs) in Overdose

BACKGROUND

Selective serotonin reuptake inhibitors (SSRIs) have increasingly replaced tricyclic antidepressants (TCAs) in the treatment of depression. They appear to be safer in overdose, but there is little information on their spectrum of toxicity in overdose, or relative toxicity of each agent.

OBJECTIVE

To determine the effect of SSRIs in overdose, as a group, and the relative toxicity of five different SSRIs.

METHODS

A review of consecutive SSRI poisoning admissions to a single toxicology unit. Outcomes examined were length of stay [LOS], intensive care [ICU] admission rate, coma, seizures, electrocardiographic [ECG] abnormalities, and presence of serotonin syndrome [SS]. Logistic regression was used to model the outcome QTc >440 msec.

RESULTS

There were 469 SSRI poisoning admissions analyzed after exclusions. The median LOS for all SSRI overdose admissions was 15.3 h (IQR: 10.5-21.3) and 30 of 469 (6.4%; 95% CI 4.3-9.0%) cases were admitted to ICU. The incidence of seizures was 1.9% and coma was 2.4%. Serotonin syndrome occurred in 14% of overdoses. Comparison of median QTc intervals of the five SSRIs was significantly different (p=0.0002); citalopram (450 IQR: 436-484) was individually different to fluoxetine (p=0.045), fluvoxamine (p=0.022), paroxetine (p=0.0002), and sertraline (p=0.001). The proportion of citalopram overdoses with a QTc >440 msec was 68%, differing significantly from sertraline (adjusted OR: 5.11 95% CI 2.32-11.27). Comparison of median QT intervals of the five SSRIs was statistically different (p=0.026); citalopram (400 IQR: 380-440) was individually different from sertraline (p=0.023).

CONCLUSIONS

This study shows SSRIs are relatively safe in overdose despite serotonin syndrome being common. The exception was citalopram, which was significantly associated with QTc prolongation. We believe that cardiac monitoring should be considered in citalopram overdose, particularly with large ingestions and patients with associated cardiac disease.

Risk factors for suicide and other deaths following hospital treated self-poisoning in Australia

OBJECTIVE

To analyze the risk factors for suicide, premature death and all-cause death in a representative population of hospital-treated deliberate self-poisoning patients.

METHOD

A prospective cohort study using data-linkage between the Hunter Area Toxicology Service Database and the National Death Index of the Australian Institute of Health and Welfare, from January 1991 to December 2000.

RESULTS

There were 4105 subjects, of whom 228 (5.6%) died, 122 (2.9%) by premature death and 58 (1.4%) by suicide. The probability of suicide after 10 years follow-up was 2%. The adjusted hazard ratios (95% CI) for suicide were: 'disorders usually diagnosed in infancy, childhood and adolescence', 5.28 (95% CI = 2.04-13.65): male gender, 4.25 (95% CI = 2.21-8.14); discharge to involuntary psychiatric hospital admission, 3.20 (95% CI = 1.78-5.76); and increasing age, 1.02 (95% CI = 1.01-1.04). Men and women showed different patterns of multivariate risks, although increased risk with increasing age and discharge to an involuntary psychiatric admission was true for both. The standardized all-cause mortality ratio (95% CI) was: for men, 6.42 (95% CI = 5.44-7.57), and for women 4.39 (95% CI = 3.56-5.41). The standardized suicide mortality ratio (95% CI) was: for men, 20.55 (95% CI = 15.24-27.73), and for women 22.95 (95% CI = 13.82-38.11).

CONCLUSIONS

Men and women have different risk factors for subsequent suicide after self-poisoning. Hospital-treated self-poisoning patients have increased risk of subsequent suicide, premature and all-cause death. Psychiatric assessment, leading to discharge decisions, is worthwhile in identifying patients at long-term risk of suicide, premature and all-cause death.

Aspiration pneumonitis in an overdose population: frequency, predictors, and outcomes

OBJECTIVE

To characterize the frequency of aspiration pneumonitis in an unselected population of overdose patients and, further, to identify factors that predispose to aspiration pneumonitis and the outcomes of patients with aspiration pneumonitis compared with those without.

DESIGN

Retrospective cohort study.

SETTING

Toxicology unit of a tertiary referral hospital.

PATIENTS

All poisoning admissions.

MEASUREMENTS AND MAIN RESULTS

A total of 71 of 4,562 poisoning admissions to the Hunter Area Toxicology Service between January 1997 and October 2002 had definite aspiration pneumonitis (1.6%; 95% confidence interval, 1.2-2.0). Older age, Glasgow Coma Score of <15, spontaneous emesis, seizures, delayed presentation to hospital, and ingestion of tricyclic antidepressants were associated with an increased risk of aspiration pneumonitis. Paracetamol poisoning and female sex were associated with a decreased risk of aspiration pneumonitis with univariate analysis. Ingestion of alcohol, benzodiazepines, antipsychotics, and administration of activated charcoal were not associated with aspiration pneumonitis. A logistic regression model for predicting aspiration pneumonitis contained seven predictors: age, sex, Glasgow Coma Score of <15 (odds ratio, 3.14; 95% confidence interval, 1.87-5.27), emesis (odds ratio, 4.17; 95% confidence interval, 2.44-7.13), seizure, tricyclic antidepressant ingestion, and time from ingestion to presentation (delay of >24 hrs [odds ratio, 4.42; 95% confidence interval, 2.42-8.10]). The mortality for patients with aspiration pneumonitis was 8.5% compared with 0.4% for those without (odds ratio, 23; 95% confidence interval, 9-60; p <.0001), and they had a significantly higher intensive care unit admission rate. The median length of stay of patients with aspiration pneumonitis was 126 hrs (interquartile range, 62-210 hrs) compared with 14.7 hrs (interquartile range, 7-23 hrs) in patients without (p <.0001).

CONCLUSIONS

Our study has shown a number of risk factors in overdose patients that are associated with aspiration pneumonitis that may allow the early identification of these patients for appropriate observation and management. Patients with aspiration pneumonitis have a significantly increased mortality and length of stay in the hospital.

Quetiapine poisoning

STUDY OBJECTIVE

We describe the effects of quetiapine in overdose.

METHODS

Quetiapine poisonings were identified from a prospective database of poisoning admissions to a regional toxicology service. Data extracted included details of ingestion, clinical features, investigations (including ECG), and other outcomes (length of stay and ICU admission rate).

RESULTS

There were 45 cases of quetiapine overdose, of which 18 patients with quetiapine assay results were included. Median length of stay was 35 hours (interquartile range [IQR] 14 to 42 hours) for the 18 patients, and 9 were admitted to the ICU. The median ingested dose was 3.5 g (IQR 1.7 to 6.2 g), and reported ingested dose was highly correlated with estimated peak drug concentration (r(2)=0.84; P<.0001), confirming patient-provided history of ingestion. Seizures occurred in 2 patients, delirium occurred in 3 patients, and mechanical ventilation was required in 4 patients. No arrhythmias or deaths occurred. Six of the 18 patients ingested quetiapine alone, with a median length of stay of 35 hours, and 3 were admitted to the ICU. In 1 patient who ingested 24 g, hypotension and seizures occurred. For 10 patients for whom ECGs were available and who had ingested no cardiotoxic drugs, tachycardia occurred in 8 patients. For these 10 patients, the mean corrected QT (QTc) interval was increased at 487 ms, but the mean uncorrected QT interval was 349 ms. Reported dose and peak quetiapine concentrations were significantly associated with ICU admission and length of stay more than 24 hours. A reported dose less than 3 g and a Glasgow Coma Scale score not less than 15 predicted patients not requiring ICU admission or length of stay more than 24 hours.

CONCLUSION

Quetiapine overdose causes central nervous system depression and sinus tachycardia. In large overdoses, patients may require intubation and ventilation for associated respiratory depression. Although a prolonged QTc occurs, its clinical significance is unclear because it is most likely caused by an overcorrection caused by the tachycardia. In our experience, a reported dose of less than 3 g for patients who are not drowsy (with a Glasgow Coma Scale score of 15) at least 4 hours after ingestion and who did not coingest another toxic agent defined a group not requiring ICU admission or inpatient admission greater than 24 hours.

Intentional Warfarin Overdose

Warfarin toxicity is common and usually results from dose changes or drug interactions. There are few reported cases of intentional overdose. The management of warfarin overdose is usually complicated by the patient using warfarin therapeutically, often for a mechanical heart valve or pulmonary embolus prophylaxis. Untreated patients have a significant bleeding risk, but treatment carries a significant risk of complete reversal of anticoagulation and consequent risk of thrombosis. The objective of this study was to describe warfarin overdoses and complications of treatment and develop a safe approach to management. Three patients are described. Two patients received a single 10-mg dose of vitamin K. Both required anticoagulation, and in one, warfarin resistance persisted for 2 weeks. In a third patient serial INR, factor levels and warfarin concentrations were measured, and incremental doses of vitamin K (up to 7.5 mg) were given based on INR. This patient did not require anticoagulation, and regular warfarin therapy was recommenced after 4 days. Patients intentionally overdosing on warfarin can be classified into three groups based on preexisting indications for warfarin: nontherapeutic, moderate risk, and major risk for thromboembolic complications. All patients should have regular INR measurements (6-hourly) to catch rapid rises. Patients not on warfarin therapeutically can be given 10 mg of vitamin K1 and repeat INRs as an outpatient. Titrating intravenous vitamin K with doses of 0.5 to 2.0 mg when INR > 5 is appropriate to reduce INR without causing warfarin resistance. The high-risk group must be kept anticoagulated, and warfarin resistance avoided.

Moclobemide poisoning: toxicokinetics and occurrence of serotonin toxicity

AIMS

To investigate the spectrum of toxicity of moclobemide overdose, the occurrence of serotonin toxicity, and to estimate toxicokinetic parameters.

METHODS

All moclobemide overdoses presenting over a 10-year period to the Hunter Area Toxicology Service were reviewed. Clinical features, complications, length of stay (LOS) and intensive care (ICU) admission rate were extracted from a standardized, prospectively collected database. Comparisons were made between moclobemide alone and moclobemide with a serotonergic coingestant poisoning. Serotonin toxicity was defined by a combination of Sternbach's criteria and a clinical toxicologist's diagnosis. In five patients serial moclobemide concentrations were measured. Time to maximal plasma concentration (Tmax), peak plasma concentration (Cmax) and terminal elimination half-lives were estimated.

RESULTS

Of 106 included patients, 33 ingested moclobemide alone, 21 ingested moclobemide with another serotonergic agent (in some cases in therapeutic doses) and 52 ingested moclobemide with a nonserotonergic agent. Eleven (55%) of 21 patients coingesting a serotonergic drug developed serotonin toxicity, which was significantly more than one (3%) of 33 moclobemide-alone overdoses (odds ratio 35, 95% confidence interval 4, 307; P < 0.0001). In six of these 21 cases severe serotonin toxicity developed with temperature >38.5 degrees C and muscle rigidity requiring intubation and paralysis. The 21 patients had a significantly increased LOS (34 h) compared with moclobemide alone overdoses (12 h) (P < 0.0001) and a significantly increased ICU admission rate of 57% vs. 3% (P < 0.0001). Time to peak plasma concentration was delayed in two patients where prepeak samples were obtained. Cmax increased slightly with dose, but all three patients ingesting > or = 6 g vomited or had charcoal. The mean elimination half-life of moclobemide in the five patients in whom serial moclobemide concentrations were measured was 6.3 h and elimination was first order in all cases. There was no evidence of a dose-dependent increase in half-life.

CONCLUSIONS

The effects of moclobemide alone in overdose are minor, even with massive ingestions. However, moclobemide overdose in combination with a serotonergic agent (even in normal therapeutic doses) can cause severe serotonin toxicity. The elimination half-life is prolonged by two to four times in overdose, compared with that found in healthy volunteers given therapeutic doses. This may be a result of wide interindividual variation in overall elimination, also seen with therapeutic doses, but appears not to be due to saturation of normal elimination pathways.

The Hunter Serotonin Toxicity Criteria: simple and accurate diagnostic decision rules for serotonin toxicity

BACKGROUND

There are difficulties with the diagnosis of serotonin toxicity, particularly with the use of Sternbach's criteria.

AIM

To improve the criteria for diagnosing clinically significant serotonin toxicity.

DESIGN

Retrospective analysis of prospectively collected data

METHODS

We studied all patients admitted to the Hunter Area Toxicology Service (HATS) following an overdose of a serotonergic drug from January 1987 to November 2002 (n = 2222). Main outcomes were: diagnosis of serotonin toxicity by a clinical toxicologist, fulfillment of Sternbach's criteria and treatment with a serotonin receptor (5-HT(2A)) antagonist. A learning dataset of 473 selective serotonin reuptake inhibitor (SSRI)-alone overdoses was used to determine individual clinical features predictive of serotonin toxicity by univariate analysis. Decision rules using CART analysis were developed, and tested on the dataset of all serotonergic overdose admissions.

RESULTS

Numerous clinical features were associated with serotonin toxicity, but only clonus (inducible, spontaneous or ocular), agitation, diaphoresis, tremor and hyperreflexia were needed for accurate prediction of serotonin toxicity as diagnosed by a clinical toxicologist. Although the learning dataset did not include patients with life-threatening serotonin toxicity, hypertonicity and maximum temperature > 38 degrees C were universal in such patients; these features were therefore added. Using these seven clinical features, decision rules (the Hunter Serotonin Toxicity Criteria) were developed. These new criteria were simpler, more sensitive (84% vs. 75%) and more specific (97% vs. 96%) than Sternbach's criteria.

DISCUSSION

These redefined criteria for serotonin toxicity should be more sensitive to serotonin toxicity and less likely to yield false positives.

Bupropion overdose: QTc prolongation and its clinical significance

OBJECTIVE

To investigate the cardiotoxicity of bupropion hydrochloride in deliberate self-poisoning.

METHODS

A prospective study was conducted in a national poisons information center (PIC) of cases of adult deliberate self-poisoning with medical record follow-up of the patients. Fifty-nine cases of bupropion deliberate self-poisoning managed in the hospital, in which the New South Wales PIC was contacted for advice, were evaluated from November 2000 through July 2001. Clinical effects and electrocardiographic (ECG) parameters (QRS, QT, QTc) were the main outcome measures.

RESULTS

ECGs were available for 17 of the 59 patients for analysis, 9 patients (53%) were women, and median patient age was 28 years (interquartile range 22-37). The mean +/- SD ingested bupropion dose was 3.8 +/- 3.1 g. Tachycardia occurred in 13 patients (76%; 95% CI 50 to 93) and hypertension in 8 patients (47%). There were no reports of hypotension or arrhythmias. There was a significantly increased QTc of 461 +/- 34 msec in the patients with bupropion overdose compared with previously developed controls; 13 of the 17 cases had a QTc >440 msec (76%; 95% CI 50 to 93). The uncorrected QT interval did not differ from that of controls.

CONCLUSIONS

A moderately prolonged QTc (>440 msec) is common in bupropion overdose. However, this may not be a result of intrinsic cardiac toxicity, but overcorrection of the QTc due to the tachycardia that occurs. It is important that the QTc is interpreted with caution in overdoses of agents that cause significant tachycardia (>100 beats/min).

Feasibility of prehospital treatment with activated charcoal: Who could we treat, who should we treat?

OBJECTIVES

To investigate the feasibility and potential risk benefit of prehospital administration of activated charcoal.

METHODS

Review of deliberate self poisoning presentations to the emergency department (ED) of a toxicology unit by ambulance over six years. Data were extracted from a standardised prospective database of poisonings. Outcomes included: number of patients attended by ambulance and number arriving in emergency within one hour. Cases were stratified by ingestion type, based on toxicity and sedative activity.

RESULTS

2041 poisoning admissions were included. The median time to ambulance attendance was 1 h 23 min (IQR 37 min-3 h) and to hospital attendance was 2 h 15 min (IQR 1 h 25 min-4 h). In 774 cases (38%) ambulance attendance occurred within one hour, but in only 161 (8%) did ED attendance occur within one hour. Non-sedating, highly toxic substances were ingested in 55 cases, 24 (23 with GCS>14) with ambulance attendance, and five with ED attendance, within one hour. Conversely 439 patients ingested a less toxic, sedative agent, 160 with ambulance attendance, and 32 with ED attendance, within one hour. Limiting decontamination to patients ingesting highly toxic, non-sedating compounds (GCS<14) reduces the proportion requiring treatment to 23 of the 774 (3.0%), an additional 18 patients.

CONCLUSION

More patients could potentially be decontaminated if all patients attended by ambulance within one hour received charcoal. However, this would expose 128 patients with sedative, low risk poisonings to the risk of aspiration, and only treat 18 extra high risk poisonings. This small potential benefit of prehospital charcoal is unlikely to justify the expense in training and protocols required to implement it

Valproate overdose: a comparative cohort study of self poisonings

AIMS

Based on individual case reports of massive overdoses, valproate is often regarded as having significant toxicity. This study aimed to describe the epidemiology of valproate poisoning and the spectrum of its clinical effects.

METHODS

Consecutive valproate poisonings were identified and compared with other anticonvulsant overdoses and all other poisonings, from a prospective database of poisoning admissions presenting to a regional toxicology service. National prescription data for the same period were obtained.

RESULTS

There were 79 patients with valproate poisoning from January 1991 to November 2001, 15 cases with valproate alone. Of the 15 cases, drowsiness occurred in two patients (both taking> 200 mg kg-1), vomiting occurred in four and tachycardia in five. In patients co-ingesting other medications, moderate to severe effects were consistent with the co-ingestants. There was one death not directly related to valproate. One patient had metabolic acidosis and thrombocytopaenia consistent with severe valproate toxicity. Comparison of valproate, carbamazepine, phenytoin and control groups showed that length of stay for both phenytoin and carbamazepine was significantly longer than for valproate (P < 0.0001), and there was a significantly increased risk of intensive care unit admission for carbamazepine vs valproate (OR 2.73; 95% CI 1.22, 6.28; P = 0.015). Although valproate prescriptions increased over the 10 years, there was relatively greater increase in the incidence of valproate poisoning. The odds of a valproate overdose in 1992 compared with carbamazepine were 0.29 (95% CI 0.07, 1.28; P = 0.141), but in 2001 were 2.73 (95% CI 1.38, 5.39; P = 0.004).

CONCLUSIONS

Valproate causes mild toxicity in the majority of cases. Massive overdoses of greater than 400 mg kg-1 can cause severe toxicity, but these are uncommon. The older anticonvulsants phenytoin and carbamazepine remain a greater problem than valproate in overdose.

Repetition risk for adolescent self-poisoning: a multiple event survival analysis

OBJECTIVES

To examine risk factors associated with re-presentation (event rates) following an initial episode of hospital treated self-poisoning.

METHOD

A longitudinal cohort study using the Hunter Area Toxicology Service (HATS) database of all presentations to hospital of self-poisoned patients aged 10-19 in Newcastle and Lake Macquarie Regions of New South Wales from January 1991 to December 1995. The study factors were: age, gender, employment status, 'substance abuse' and psychiatric diagnosis at index (first documented episode during the study time-period) admission. The main outcome measure was re-presentations per unit time. Time-event analysis (multivariate) was used to compare re-presentation rates per person-year exposure to the study factors.

RESULTS

There were 450 patients who presented on a total of 551 occasions. The median and modal age at initial presentation was 17. Three hundred and nine (69%) were female and 141 (31%) were male. The probability (95% CI) of a patient re-presenting within one year of an index admission with self poisoning was 0.09 (0.07-0.12) and within 5 years was 0.16 (0.12-0.21). The adjusted rate ratios for episodes of re-presentation were: any 'substance abuse (ever)' 3.87 (2.08-7.21), 'alcohol abuse' 2.32 (1.15-4.68),'benzodiazepine abuse' 4.89 (1.63-14.62), schizophrenia and other psychotic disorders (DSM-IV) 2.85 (1.2-6.79), and any personality disorder (DSM-IV) 2.68 (1.73-4.16).

CONCLUSIONS

Interventions to decrease recurrence rates for adolescent self poisoning should be directed towards substance (particularly alcohol or benzodiazepine) abuse, non-affective psychoses and personality disorder.