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Herbicides
Published in Frank A. Barile, Barile’s Clinical Toxicology, 2019
Paraquat (PQ) and diquat are nonselective bipyridyl herbicides used widely in agricultural and commercial residential applications (lawn maintenance) to eradicate broad-leaf plants and shrubs. The chemicals inhibit plant photosynthesis by interfering with NADPH/NADP+ redox cycling. Their usefulness as contact herbicides resides in their ability to promote the reseeding of lawns and gardens within 24 hours after application. The two structurally similar compounds are often combined in commercial products. The acute toxicity of diquat, however, is lower than that of than PQ in humans (Figure 29.2). Structures of the bipyridal herbicides—paraquat and diquat.
Miscellaneous pesticides*
Published in Bev-Lorraine True, Robert H. Dreisbach, Dreisbach’s HANDBOOK of POISONING, 2001
Bev-Lorraine True, Robert H. Dreisbach
Paraquat or methyl viologen (1,1′-dimethyl-4,4′-dipyridylium dichloride), diquat, chlormequat (Cycocel), mepiquat (Pix), morfamquat, and difenzoquat (Avenge) are water-soluble quaternary ammonium herbicides supplied in concentrations of 20–50%. They are inactivated by contact with soil, presumably as a result of combination with clay particles in the soil, and are also subject to rapid photodecomposition.
Acute diquat poisoning resulting in toxic encephalopathy: a report of three cases
Published in Clinical Toxicology, 2022
Guangcai Yu, Tianzi Jian, Siqi Cui, Longke Shi, Baotian Kan, Xiangdong Jian
Diquat is a nonselective contact bipyridyl herbicide and a preharvest desiccant. As paraquat is banned in China, the use of diquat has gradually increased because of its effective herbicidal activity [1], resulting in an increase in the incidence of diquat poisoning. Diquat mainly affects cell membranes through lipid peroxidation via the production of oxygen free-radicals, leading to cell death and multiple-organ failure [2]. The target organs include the kidneys, liver, lungs, gastrointestinal tract, cardiovascular system, and central nervous system [3,4]. Acute kidney injury is common, leading to renal tubule damage. In severe cases, neurological disorders are a common clinical feature, often accompanied by a poor prognosis [5]. Herein, we report three cases of acute diquat poisoning resulting in acute renal failure, neurological disorders, and respiratory failure. This report highlights the imaging features and hypothesis mechanisms of diquat-related toxic encephalopathy.
Identification of differentially expressed genes and pathways in diquat and paraquat poisoning using bioinformatics analysis
Published in Toxicology Mechanisms and Methods, 2022
Diquat (DQ) (Magalhães et al. 2018) and paraquat (PQ) (Mitra et al. 2011) are nonselective and widely used herbicides. DQ (1,1′-ethylene-2,2′-bipyridinium ion) (Magalhães et al. 2018; Jones and Vale 2000) is an analog of PQ (1,1′-Dimethyl-4,4′-bipyridinium dichloride) (Mitra et al. 2011). The 50% of lethal dose (LD50) of PQ in humans is 20–40 mg ion/kg of body weight (Vale et al. 1987); In rats, the LD50 of oral PQ is 150 mg/kg (World Health and International Programme on Chemical 2004), whereas, that of oral DQ is 215-235 mg/kg (Magalhães et al. 2018). Therefore, DQ is considered less toxic than PQ (Fortenberry et al. 2016). PQ and DQ poisoning remain fairly common in developing countries (Xing et al. 2020; Lu et al. 2021).
Pesticide use, agricultural outputs, and pesticide poisoning deaths in Japan
Published in Clinical Toxicology, 2022
Michael Eddleston, Hiroshi Nagami, Chien-Yu Lin, Mark L. Davis, Shu-Sen Chang
Japan is one of the few countries that uses a 4.3% paraquat ion/4.1% diquat ion combination product. We previously studied the case fatality of this product and noted a modestly lower case fatality than paraquat SL20 products (65% vs 75%) [7,17]. Ingestion of ≥50 mL of 4.3% paraquat ion/4.1% diquat ion usually resulted in a fatal outcome. The minimal lethal dose in humans is believed to be around 50 mg/kg, or 1–2 g (10–20 mL of the 20% product) [34]; the lethal dose of a 5% product would therefore be about 40–80 mL if the diquat did not contribute to toxicity. Since diquat is toxic [35], the lethal dose is likely to lie somewhere between these ranges, consistent with a dose of 50 mL being frequently lethal.