Increased severity associated with tallowamine in acute glyphosate poisoning

Context: During the re-approval process of glyphosate in Europe, it was mentioned that glyphosate-based products (GBF) were more toxic than glyphosate alone. This phenomenon was attributed to the surfactants and among them, polyethoxylated tallowamine (POEA) has been suspected to significantly contribute to the toxicity of glyphosate products. In animal data acute oral toxicity of POEA has been suggested to be greater than glyphosate toxicity in animal studies. There are no data, however, comparing the clinical signs and severity of acute human poisoning with tallowamine-containing GBF (TA) and non-tallowamine-containing GBF (NTA). The aim of this study was to compare the severity of oral poisoning between TA and NTA cases, reported to the French Poison Control Centres (PCC) over 7 years.Methods: This is a retrospective study of cases of oral exposure to GBF reported to French PCCs between January 1st, 2008 and December 12th, 2014. The formulation of every GBF was reviewed using the PCC national database of products and compositions, to identify cases involving TA, NTA, or GBF with unknown co-formulants.Results: Between 2008 and 2014, 1362 cases of GBF ingestion were registered in the PCC national database of poisoning cases. Among them, 429 were symptomatic acute cases of ingestion of GBF. There were 235 exposures to TA, 105 to NTA, and 89 to unknown GBF. There were more severe cases in the TA group than in the NTA group (p = 0.037).Discussion: The present study shows that POEA rather than other co-formulants leads to more severe symptoms in those patients ingesting GBF. The acute toxicity of POEA might be explained by its irritating properties; in experimental studies, it caused skin irritation and severe eye and mucous membranes irritation.Conclusion: In this study, severe respiratory symptoms were also more frequently reported in the TA group. The surfactant properties of POEA are likely to cause aspiration pneumonitis which is a plausible explanation for the respiratory failure complicating severe GBF poisoning cases.