A phase II clinical trial to assess the safety of clonidine in acute organophosphorus pesticide poisoning

The advantages of penehyclidine hydrochloride over atropine in acute organophosphorus pesticide poisoning: A meta-analysis

Background

Penehyclidine hydrochloride (PHC) has been used for many years as an anticholinergic drug for the treatment of acute organophosphorus pesticide poisoning (AOPP). The purpose of this meta-analysis was to explore whether PHC has advantages over atropine in the use of anticholinergic drugs in AOPP.

Methods

We searched Scopus, Embase, Cochrane, PubMed, ProQuest, Ovid, Web of Science, China Science and Technology Journal Database (VIP), Duxiu, Chinese Biomedical literature (CBM), WanFang, and Chinese National Knowledge Infrastructure (CNKI), from inception to March 2022. After all qualified randomized controlled trials (RCTs) were included, we conducted quality evaluation, data extraction, and statistical analysis. Statistics using risk ratios (RR), weighted mean difference (WMD), and standard mean difference (SMD).

Results

Our meta-analysis included 20,797 subjects from 240 studies across 242 different hospitals in China. Compared with the atropine group, the PHC group showed decreased mortality rate (RR=0.20, 95% confidence intervals [CI]: 0.16-0.25, P <0.001), hospitalization time (WMD=-3.89, 95% CI: -4.37 to -3.41, P <0.001), overall incidence rate of complications (RR=0.35, 95% CI: 0.28-0.43, P <0.001), overall incidence of adverse reactions (RR=0.19, 95% CI: 0.17-0.22, P <0.001), total symptom disappearance time (SMD=-2.13, 95% CI: -2.35 to -1.90, P <0.001), time for cholinesterase activity to return to normal value 50-60% (SMD=-1.87, 95% CI: -2.03 to -1.70, P <0.001), coma time (WMD=-5.57, 95% CI: -7.20 to -3.95, P <0.001), and mechanical ventilation time (WMD=-2.16, 95% CI: -2.79 to -1.53, P <0.001).

Conclusion

PHC has several advantages over atropine as an anticholinergic drug in AOPP.

Management of Organophosphorus Poisoning: Standard Treatment and Beyond

Organophosphorus (OP) compounds remain a leading cause of self-poisoning and mortality, especially in South East Asia, China, and Africa. Organophosphorus causes an acute cholinergic syndrome by inhibiting acetylcholinesterase. Atropine remains the mainstay of treatment, but recently some promising therapies are in the pipeline. Oximes are used widely in the management of organophosphorus poisoning, however clinical efficacy remains to be established. Magnesium sulfate, calcium channel blockers (nimodipine), plasma alkalinizing agents, β-2 agonists, nicotinic receptor antagonists, clonidine, and lipid emulsions are promising treatment alternatives. However, large phase III trials are required to establish their efficacy.

Role of penehyclidine in acute organophosphorus pesticide poisoning

BACKGROUND

Penehyclidine is a newly developed anticholinergic agent. We aimed to investigate the role of penehyclidine in acute organophosphorus pesticide poisoning (OP) patients.

METHODS

We searched the Pubmed, Cochrane library, EMBASE, Chinese National Knowledge Infrastructure (CNKI), Chinese Biomedical literature (CBM) and Wanfang databases. Randomized controlled trials (RCTs) recruiting acute OP patients were identified for meta-analysis. Main outcomes included cure rate, mortality rate, time to atropinization, time to 60% normal acetylcholinesterase (AchE) level, rate of intermediate syndrome (IMS) and rate of adverse drug reactions (ADR).

RESULTS

Sixteen RCTs involving 1,334 patients were identified. Compared with the atropine- or penehyclidine-alone groups, atropine combined with penehyclidine significantly increased the cure rate (penehyclidine+atropine vs. atropine, 0.97 vs. 0.86, RR 1.13, 95% CI [1.07-1.19]; penehyclidine+atropine vs. penehyclidine, 0.93 vs. 0.80, RR 1.08, 95% CI [1.01-1.15]) and reduced the mortality rate (penehyclidine+atropine vs. atropine, 0.015 vs. 0.11, RR 0.17, 95% CI [0.06-0.49]; penehyclidine+atropine vs. penehyclidine, 0.13 vs. 0.08, RR 0.23, 95% CI [0.04-1.28]). Atropine combined with penehyclidine in OP patients also helped reduce the time to atropinization and AchE recovery, the rate of IMS and the rate of ADR. Compared with a single dose of atropine, a single dose of penehyclidine also significantly elevated the cure rate, reduced times to atropinization, AchE recovery, and rate of IMS.

CONCLUSION

Atropine combined with penehyclidine benefits OP patients by enhancing the cure rate, mortality rate, time to atropinization, AchE recovery, IMS rate, total ADR and duration of hospitalization. Penehyclidine combined with atropine is likely a better initial therapy for OP patients than atropine alone.

Pharmacological treatment of organophosphorus insecticide poisoning: the old and the (possible) new

Despite being a major clinical and public health problem across the developing world, responsible for at least 5 million deaths over the last three decades, the clinical care of patients with organophosphorus (OP) insecticide poisoning has little improved over the last six decades. We are still using the same two antidotes - atropine and oximes - that first came into clinical use in the late 1950s. Clinical research in South Asia has shown how improved regimens of atropine can prevent deaths. However, we are still unsure about which patients are most likely to benefit from the use of oximes. Supplemental antidotes, such as magnesium, clonidine and sodium bicarbonate, have all been proposed and studied in small trials without production of definitive answers. Novel antidotes such as nicotinic receptor antagonists, beta-adrenergic agonists and lipid emulsions are being studied in large animal models and in pilot clinical trials. Hopefully, one or more of these affordable and already licensed antidotes will find their place in routine clinical care. However, the large number of chemically diverse OP insecticides, the varied poisoning they produce and their varied response to treatment might ultimately make it difficult to determine definitively whether these antidotes are truly effective. In addition, the toxicity of the varied solvents and surfactants formulated with the OP active ingredients complicates both treatment and studies. It is possible that the only effective way to reduce deaths from OP insecticide poisoning will be a steady reduction in their agricultural use worldwide.

Clonidine as an adjuvant in the management of acute poisoning by anticholinesterase pesticides

Introduction:

Anticholinesterase pesticides are widely used in agriculture and domestic settings throughout the world, and they are responsible for great morbidity and mortality. In Egypt and other developing countries, there is a pressing need for new affordable antidotes to treat anticholinesterase pesticide poisoning. Hence, this study was conducted to evaluate the safety and effectiveness of moderate doses of clonidine in the management of adult patients with acute anticholinesterase pesticide poisoning.

Methodology:

This study was an open-label, phase II pilot clinical trial. Sixty patients with acute anticholinesterase pesticide poisoning gave consent to participate in the study. They were divided into 2 equal groups, with 30 patients in each group. Group I received clonidine plus the routine treatment, while group II received only the routine treatment. Patients were subjected to full history taking, and their vital and clinical data were recorded. Serum cholinesterase levels and routine laboratory investigations were measured. The different outcomes of the patients were assessed.

Results:

The baseline characteristics of both groups were similar. Thirteen (43.3%) patients developed significant hypotension during clonidine treatment. The clinical outcomes (including mortality, need for assisted ventilation, length of hospital stay, and total doses of atropine) showed no significant differences between the two groups.

Conclusion:

The use of clonidine in acute anticholinesterase pesticide poisoning may be associated with a high incidence of hypotension requiring intervention. The clinical outcomes may not significantly improve in clonidine-treated patients.

Effect of monocrotophos, an organophosphorus insecticide, on the striatal dopaminergic system in a mouse model of Parkinson’s disease

Our earlier study had shown that low concentrations of monocrotophos (MCP) elicited dopaminergic features of Parkinson’s disease (PD) in the nematode Caenorhabditis elegans. In the present study, the effect of low doses of MCP on the striatal dopaminergic neurons was investigated using the mouse model system. MCP was initially screened for its ability to cause any neurobehavioral deficits and alterations in the dopaminergic system in Swiss albino mice, aged 8 weeks and weighing 25–30 g, with repeated doses at 0.3 and 0.6 mg/kg body weight (b.w.)/day for 7 days and 30 days. Mice were treated with four intraperitoneal injections for every 2 h with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) at the dosage of 14 mg/kg b.w. MCP was administered to these mice at the above-mentioned doses for 7 days. Mice administered with MCP alone revealed a significant ( p < 0.05) reduction in the dopamine (DA) content at both 7 and 30 days and showed a significant ( p < 0.05) increase in neurobehavioral deficits. Interestingly, when MCP was administered for 7 days to MPTP-treated mice, further significant decrease in both DA content and increase in neurobehavioral deficits were apparent. The extent of reactive oxygen species and lipid peroxidation were markedly increased, while the ratio of reduced to oxidized glutathione levels were significantly decreased ( p < 0.05) in the treated mice as compared to the control. Significant histopathological alterations and a marked reduction in the number of tyrosine hydroxylase positive cells were evident in striatum of mice treated with higher doses of MCP. These changes were comparable to that seen in mice treated with MPTP and post-administered lower doses of MCP. Our findings suggest that MCP per se has the propensity to induce pathological changes in the dopaminergic neurons as well as augment the degeneration in a compromised nigrostriatal system such as that in PD.

Applied clinical pharmacology and public health in rural Asia--preventing deaths from organophosphorus pesticide and yellow oleander poisoning

Self-poisoning with pesticides or plants is a major clinical problem in rural Asia, killing several hundred thousand people every year. Over the last 17 years, our clinical toxicology and pharmacology group has carried out clinical studies in the North Central Province of Sri Lanka to improve treatment and reduce deaths. Studies have looked at the effectiveness of anti-digoxin Fab in cardiac glycoside plant poisoning, multiple dose activated charcoal in all poisoning, and pralidoxime in moderate toxicity organophosphorus insecticide poisoning. More recently, using a Haddon matrix as a guide, we have started conducting public health and animal studies to find strategies that may work outside of the hospital. Based on the 2009 GSK Research in Clinical Pharmacology prize lecture, this review shows the evolution of the group's research from a clinical pharmacology approach to one that studies possible interventions at multiple levels, including the patient, the community and government legislation.

Potential therapeutic approaches for modulating expression and accumulation of defective lamin A in laminopathies and age-related diseases

Scientific understanding of the genetic components of aging has increased in recent years, with several genes being identified as playing roles in the aging process and, potentially, longevity. In particular, genes encoding components of the nuclear lamina in eukaryotes have been increasingly well characterized, owing in part to their clinical significance in age-related diseases. This review focuses on one such gene, which encodes lamin A, a key component of the nuclear lamina. Genetic variation in this gene can give rise to lethal, early-onset diseases known as laminopathies. Here, we analyze the literature and conduct computational analyses of lamin A signaling and intracellular interactions in order to examine potential mechanisms for altering or slowing down aberrant Lamin A expression and/or for restoring the ratio of normal to aberrant lamin A. The ultimate goal of such studies is to ameliorate or combat laminopathies and related diseases of aging, and we provide a discussion of current approaches in this review.

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.

Monocrotophos induced apoptosis in PC12 cells: role of xenobiotic metabolizing cytochrome P450s

Monocrotophos (MCP) is a widely used organophosphate (OP) pesticide. We studied apoptotic changes and their correlation with expression of selected cytochrome P450s (CYPs) in PC12 cells exposed to MCP. A significant induction in reactive oxygen species (ROS) and decrease in glutathione (GSH) levels were observed in cells exposed to MCP. Following the exposure of PC12 cells to MCP (10⁻⁵ M), the levels of protein and mRNA expressions of caspase-3/9, Bax, Bcl₂, P⁵³, P²¹, GSTP1-1 were significantly upregulated, whereas the levels of Bclw, Mcl1 were downregulated. A significant induction in the expression of CYP1A1/1A2, 2B1/2B2, 2E1 was also observed in PC12 cells exposed to MCP (10⁻⁵ M), whereas induction of CYPs was insignificant in cells exposed to 10⁻⁶ M concentration of MCP. We believe that this is the first report showing altered expressions of selected CYPs in MCP-induced apoptosis in PC12 cells. These apoptotic changes were mitochondria mediated and regulated by caspase cascade. Our data confirm the involvement of specific CYPs in MCP-induced apoptosis in PC12 cells and also identifies possible cellular and molecular mechanisms of organophosphate pesticide-induced apoptosis in neuronal cells.