Comparison of two commonly practiced atropinization regimens in acute organophosphorus and carbamate poisoning, doubling doses vs. ad hoc: a prospective observational study

Acute organophosphorus toxicity in a regional hospital in Johannesburg, South Africa: A retrospective chart review

Introduction

Intentional and accidental organophosphorus exposures pose a significant healthcare-related burden on South African communities. This study will review the demographics, characteristics and clinical course of patients presenting with features of acute organophosphorus toxicity to a regional Emergency Centre in Johannesburg, South Africa.

Methods

This was a retrospective chart review of all patients treated for possible acute organophosphorus toxicity from January 2020 to August 2021.

Results

A total of 205 patients were identified of which 134 patients were included in the study. The median age was 26 years with a male predominance (male= 56%, female=44%). 109 patients (81.3%) survived, 18 patients (13.4%) demised and the outcome of 7 patients (5.2%) was unknown. The median hospital length of stay was 8 days, (IQR= 5-13 days), and the longest hospital stay was 37 days in ICU. Atropinisation dose was significantly higher for intubated patients (median=140.0mg; IQR=90mg-219.5mg) compared to patients who were not intubated (median=60mg; IQR=20.5mg-120mg, p < 0.05). The length of stay was significantly higher for intubated patients (median=11 days; IQR=7-15 days) compared to patients who were not intubated (median=5 days; IQR=3-8 days, p < 0.00). There was a moderate positive correlation between atropinisation dose and length of stay (Correlation coefficient = 0.37, p < 0.00). There was a moderate negative correlation between atropinisation dose and cholinesterase level (Correlation coefficient= - 0.39, p < 0.00). Of those reported to have adverse effects 78.6%, were related to atropine toxicity.

Conclusion

Our study shows a high mortality rate secondary to organophosphorus toxicity. Significant exposures and thus higher doses of atropine were associated with increased length of stay and need for intubation. We found a high incidence of atropine-related adverse effects. More studies are needed to further establish the balance between the therapeutic and adverse effects of high-dose atropine as a treatment modality for organophosphorus toxicity.

A complete, evidence-based review on novichok poisoning based on epidemiological aspects and clinical management

Background: The whole world has learned about the existence of a highly toxic neuro-paralytic substance called Novichok. A wide range of neuro-paralytic toxins were used during the wars of decades ago, which also had harmful and irreversible effects. Fortunately, the establishment of conventions prohibiting the use of these weapons prevented the adverse clinical consequences of these compounds. What we did in the present study was to evaluate the clinical features of Novichok, how to manage exposure to it, and to evaluate the prognostic aspects associated with this poisoning agent. Methods: The manuscript especial databases including Medline, Web of knowledge, Google scholar, and Scopus were deeply searched by the two blinded investigators for all eligible studies based on the considered keywords. Initially 98 articles were initially collected by database searching that considering eligibility criteria, 83 articles were finally eligible for the final assessment. There is a lack of clinical trials and case-cohort studies on general population about treatment and side effects when it comes to human nerve agents and most of the data in our search is based on animal studies. Results: In evaluating various clinical, auto physiological and prognostic aspects of exposure to these substances, special attention was necessary to the following points. First, Novichok agents are considered more potent than other toxic agents. Pathophysiologically, these agents irreversibly bind acetylcholinesterase and produce a rapid cholinergic toxidrome which is responsible for the clinical manifestations as well as the potential dangerous and life threatening side effects caused by these agents. Uniquely, these agents are thought to also target every neuron in the central and peripheral nervous system. As a managerial and therapeutic approach, early and timely treatment of its related complication along with prevents massive exposure and decontamination in addition to rapid resuscitation can prohibit debilitating neuropathy and death due to facing it. Conclusion: The present review highlights the importance of recognizing the potential acute toxic effects of Novichok agents, diagnostic and therapeutic approaches (life-saving antidotal therapy) to complications and ultimately the application of guidelines to improve the prognosis of exposure to these agents for both victims and medical community.

Acute organophosphate and carbamate pesticide poisonings - a five-year survey from the National Poison Control Center Of Serbia

Pesticide poisonings, intentional as well as accidental, are common, especially in undeveloped and developing countries. The goal of this study was to analyze the clinical presentation of patients hospitalized due to acute organophosphate (OPP) or carbamate pesticide (CP) poisoning as well as to analyze the factors that potentially influenced the severity and outcome of the poisonings. A retrospective cross-sectional study was performed. The age and gender of each patient were recorded, the type of ingested pesticide, whether the poisoning was intentional or accidental, number of days of hospitalization, the severity of the poisoning, and the outcome of the treatment (i.e., whether the patient survived or not). Clinical aspects of poisonings were analyzed, as well as the therapeutic measures performed. 60 patients were hospitalized due to acute OPP or CP poisoning, out of 51 (85.00%) were cases of intentional self-poisoning. The majority of patients were poisoned by OPPs (76.67%), in one-third the causative agent was malathion, followed in frequency by chlorpyrifos and diazinon. Dimethoate poisonings were manifested with the most severe clinical picture. A 70% or lower activity of reference values of acetylcholinesterase and butyrylcholinesterase was found in 50% and 58% of patients, respectively. The most common symptom was miosis (58.33%), followed by nausea and vomiting. Pralidoxime reactivated acetylcholinesterase inhibited by chlorpyrifos or diazinon, but not with malathion or dimethoate. Impairment of consciousness and respiratory failure, as well as the degree of acetylcholinesterase and butyrylcholinesterase inhibition, were prognostic signs of the severity of poisoning. The lethal outcome was more often found in older patients (t = 2.41, p = 0.019). The type of ingested pesticide significantly affects the severity and outcome of poisoning as well as the effectiveness of antidotes.

Adrenaline is effective in reversing the inadequate heart rate response in atropine treated organophosphorus and carbamate poisoning

BACKGROUND

In acute organophosphorus (OP) or carbamate poisoning, some patients require high dose atropine to counteract the effects on heart rate (HR) and blood pressure (BP). This study describes the factors associated with high dose atropine therapy and the use of adrenaline to reverse the inadequate HR response to atropine.

METHODS

Consecutive patients admitted to the intensive care unit (ICU) were prospectively recruited. Demographic data, treatment and outcomes of patients who failed to achieve target HR (100/min) or systolic BP >90 mm Hg with either a cumulative atropine dose of 100-mg within 6-h following admission or an infusion of 30 mg/h for at least 3-h were compared with patients who achieved the targets. Factors associated with high dose atropine therapy were explored using logistic regression analysis and expressed as odds ratio (OR) with 95% confidence intervals (CIs).

RESULTS

Of the 181 patients admitted with OP or carbamate poisoning, 155 patients fulfilled inclusion criteria. The mean (SD) age was 35.7 (15.8) years; admission APACHE-II score was 14.6 (7.5). Heart rate and/or BP target was not achieved in 13.6%. In these patients, target HR was achieved after adding adrenaline infusion at 2-4 μg/min. Ventilation duration (11.6 ± 6.3 vs. 8.4 ± 6.9 days, p = 0.05) and ICU stay (12.3 ± 5.8 vs. 8.9 ± 5.8 days, p = 0.01) were longer in patients requiring high dose atropine when compared with others. On multivariate logistic regression analysis, shorter time to presentation to hospital (p = 0.04) was associated with need for high dose atropine. Overall mortality was 9% and similar in both groups (p = 0.41).

CONCLUSIONS

High dose atropine therapy is required in a subset of patients with OP and carbamate poisoning and was associated with longer ventilation duration and ICU stay. Adrenaline infusion improved hemodynamics in these patients.

COPD and asthma therapeutics for supportive treatment in organophosphate poisoning

Context: Nerve agents like sarin or VX have repeatedly been used in military conflicts or homicidal attacks, as seen in Syria or Malaysia 2017. Together with pesticides, nerve agents assort as organophosphorus compounds (OP), which inhibit the enzyme acetylcholinesterase. To counteract subsequent fatal symptoms due to acetylcholine (ACh) accumulation, oximes plus atropine are administered, a regimen that lacks efficacy in several cases of OP poisoning. New therapeutics are in development, but still need evaluation before clinical employment. Supportive treatment with already approved drugs presents an alternative, whereby compounds from COPD and asthma therapy are likely options. A recent pilot study by Chowdhury et al. included β2-agonist salbutamol in the treatment of OP-pesticide poisoned patients, yielding ambiguous results concerning the addition. Here, we provide experimental data for further investigations regarding the value of these drugs in OP poisoning. Methods: By video-microscopy, changes in airway area were analyzed in VX-poisoned rat precision cut lung slices (PCLS) after ACh-induced airway contraction and subsequent application of selected anticholinergics/β2-agonists. Results: Glycopyrrolate and ipratropium efficiently antagonized an ACh-induced airway contraction in VX-poisoned PCLS (EC₅₀ glycopyrrolate 15.8 nmol/L, EC₅₀ ipratropium 2.3 nmol/L). β2-agonists formoterol and salbutamol had only negligible effects when solely applied in the same setting. However, combination of formoterol or salbutamol with low dosed glycopyrrolate or atropine led to an additive effect compared to the sole application [50.6 ± 8.8% airway area increase after 10 nmol/L formoterol +1 nmol/L atropine versus 11.7 ± 9.2% (10 nmol/L formoterol) or 8.6 ± 5.9% (1 nmol/L atropine)]. Discussion: We showed antagonizing effects of anticholinergics and β2-agonists on ACh-induced airway contractions in VX-poisoned PCLS, thus providing experimental data to support a prospective comprehensive clinical study. Conclusions: Our results indicate that COPD and asthma therapeutics could be a valuable addition to the treatment of OP poisoning.

Novel Clinical Toxicology and Pharmacology of Organophosphorus Insecticide Self-Poisoning

Organophosphorus insecticide self-poisoning is a major global health problem, killing over 100,000 people annually. It is a complex multi-organ condition, involving the inhibition of cholinesterases, and perhaps other enzymes, and the effects of large doses of ingested solvents. Variability between organophosphorus insecticides—in lipophilicity, speed of activation, speed and potency of acetylcholinesterase inhibition, and in the chemical groups attached to the phosphorus—results in variable speed of poisoning onset, severity, clinical toxidrome, and case fatality. Current treatment is modestly effective, aiming only to reactivate acetylcholinesterase and counter the effects of excess acetylcholine at muscarinic receptors. Rapid titration of atropine during resuscitation is lifesaving and can be performed in the absence of oxygen. The role of oximes in therapy remains unclear. Novel antidotes have been tested in small trials, but the great variability in poisoning makes interpretation of such trials difficult. More effort is required to test treatments in adequately powered studies.

Comparison of current recommended regimens of atropinization in organophosphate poisoning

Atropine is the mainstay of therapy in organophosphate (OP) toxicity, though research and consensus on dosing is lacking. In 2004, as reported by Eddleston et al. (J Toxicol Clin Toxicol 42(6):865-75, 2004), they noted variation in recommended regimens. We assessed revisions of original references, additional citations, and electronic sources to determine the current variability in atropine dosing recommendations. Updated editions of references from Eddleston et al.'s work, texts of Internal and Emergency Medicine, and electronic resources were reviewed for atropine dosing recommendations. For comparison, recommendations were assessed using the same mean dose (23.4 mg) and the highest dose (75 mg) of atropine as used in the original paper. Recommendations were also compared with the dosing regimen from the World Health Organization (WHO). Thirteen of the original recommendations were updated and 15 additional references were added giving a convenience sample of 28. Sufficient information to calculate time to targeted dose was provided by 24 of these samples. Compared to 2004, current recommendations have greatly increased the speed of atropinization with 13/24 able to reach the mean and high atropine dose within 30 min compared to 1/36 in 2004. In 2004, there were 13 regimens where the maximum time to reach 75 mg was over 18 h, whereas now, there are 2. While only one recommendation called for doubling the dose for faster escalation in 2004, 15 of the 24 current works include dose doubling. In 2004, Eddleston et al. called for an evidence-based guideline for the treatment of OP poisoning that could be disseminated worldwide. Many current recommendations can adequately treat patients within 1 h. While the WHO recommendations remain slow to treat patients with OP poisoning, other authorities are close to a consensus on rapid atropinization.

Can anisodamine be a potential substitute for high-dose atropine in cases of organophosphate poisoning?

A case of organophosphate (OP) poisoning was admitted to the emergency room. The patient accepted treatment with pralidoxime (PAM), atropine, and supporting therapy. It was observed that even after 22 h after treatment, 960 mg of atropine was not enough for the patient to be atropinized. However, a 160-mg follow-up treatment of anisodamine was quite enough for atropinization after 4 h. As a case report, more studies are required before any definite conclusion can be reached regarding the use of anisodamine as a potential substitute for high-dose atropine in cases of OP poisoning.

Efficiency of anisodamine for organophosphorus-poisoned patients when atropinization cannot be achieved with high doses of atropine

Poisoning by organophosphorus insecticides is a major global public health problem. Although atropine has been widely used to treat organophosphate (OP) poisoning, sometimes atropinization cannot be achieved, even with high doses of atropine. Hence, we aimed to assess the effect of anisodamine for organophosphorus poisoned patients for whom atropinization could not be achieved through high doses of atropine. In this study, sixty-four OP-poisoning patients, all of whom accepted routine treatments but who did not attain atropinization after high doses of atropine for 12 h, were enrolled. The result showed that the time to atropinization was 24.3±4.3 h in the anisodamine group, significantly shorter than in the atropine group (29.2±7.0 h, p<0.05); the hospital stay in the anisodamine group was 5.3±2.5 days, significantly shorter than the 6.9±2.3 days needed by the atropine group (p<0.05). We draw a conclusion that anisodamine can shorten the process of atropinization and hospital stay in organophosphorus poisoned patients for whom atropinization cannot be achieved with high doses of atropine.

Open-label randomized clinical trial of atropine bolus injection versus incremental boluses plus infusion for organophosphate poisoning in Bangladesh

Severe organophosphate compound (OPC) poisoning is an important clinical problem in many countries of the world. Unfortunately, little clinical research has been performed and little evidence exists with which to determine the best therapy. A study was therefore undertaken to determine the optimal dosing regimen for atropine in the treatment of OPC poisoning. An open-label randomized clinical trial was conducted in Chittagong Medical College Hospital, Chittagong, Bangladesh, on 156 hospitalized individuals with OPC poisoning from June to September 2006. The aim was to compare the efficacy and safety of conventional bolus doses with individualized incremental doses of atropine for atropinization followed by continuous atropine infusion for management of OPC poisoning. Inclusion criteria were patients with a clear history of OPC poisoning with clear clinical signs of toxicity, i.e. features of cholinergic crisis. The patients were observed for at least 96 h. Immediate outcome and complications were recorded. Out of 156 patients, 81 patients received conventional bolus dose atropine (group A) and 75 patients received rapidly incremental doses of atropine followed by infusion (group B). The mortality in group 'A' was 22.5% (18/80) and in group 'B' 8% (6/75) (p < 0.05). The mean duration of atropinization in group 'A' was 151.74 min compared to 23.90 min for group 'B' (p < 0.001). More patients in group A experienced atropine toxicity than in group 'B' (28.4% versus 12.0%, p < 0.05); intermediate syndrome was more common in group 'A' than in group 'B' (13.6% versus 4%, p < 0.05), and respiratory support was required more often for patients in group 'A' than in group 'B' (24.7% versus 8%, p < 0.05). Rapid incremental dose atropinization followed by atropine infusion reduces mortality and morbidity from OPC poisoning and shortens the length of hospital stay and recovery. Incremental atropine and infusion should become the treatment of choice for OPC poisoning. Given the paucity of existing evidence, further clinical studies should be performed to determine the optimal dosing regimen of atropine that most rapidly and safely achieves atropinization in these patients.

Organophosphorus poisoning (acute)

INTRODUCTION

Acetylcholinesterase inhibition by organophosphorus pesticides or organophosphate nerve agents can cause acute parasympathetic system dysfunction, muscle weakness, seizures, coma, and respiratory failure. Prognosis depends on the dose and relative toxicity of the specific compound, as well as pharmacokinetic factors.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical question: What are the effects of treatments for acute organophosphorus poisoning? We searched: Medline, Embase, The Cochrane Library, and other important databases up to April 2010 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

RESULTS

We found 62 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

CONCLUSIONS

In this systematic review we present information relating to the effectiveness and safety of the following interventions: activated charcoal (single or multiple doses), alpha(2) adrenergic receptor agonists, atropine, benzodiazepines, butyrylcholinesterase replacement therapy, cathartics, extracorporeal clearance, gastric lavage, glycopyrronium bromide (glycopyrrolate), ipecacuanha (ipecac), magnesium sulphate, milk or other home remedy immediately after ingestion, N-methyl-D-aspartate receptor antagonists, organophosphorus hydrolases, oximes, removing contaminated clothes and washing the poisoned person, and sodium bicarbonate.