Paraquat Poisoning

Used as an herbicide; sale is controlled

Concentrated solutions are highly corrosive to oropharynx, esophagus, and stomach

After absorption, fatal dose may be as small as 4 mg/kg

If ingestion of paraquat is not rapidly fatal because of its corrosive effects, the herbicide may cause progressive pulmonary fibrosis, with death ensuing after 2–3 weeks

Clinical

Patients with plasma paraquat levels above 2 mg/L at 6 hours or 0.2 mg/L at 24 hours are likely to die

Administer 60 g of activated charcoal by gastric tube every 2 hours for at least three or four doses

Anecdotal reports of benefit with cyclophosphamide and dexamethasone

Supplemental oxygen should be withheld unless the PO₂ is < 70 mm Hg because oxygen may contribute to the pulmonary damage