What is the treatment for paraquat poisoning?

Treatment of Paraquat Poisoning

Paraquat poisoning requires immediate decontamination with multiple-dose activated charcoal after airway protection, strict oxygen restriction targeting saturations of 85-88%, and consideration of hemoperfusion for significant ingestions, with antioxidant therapy as an adjunctive measure. 1, 2

Immediate Safety and Initial Actions

• Ensure rescuer safety by wearing protective clothing and gloves when handling the victim's clothes or body fluids, as paraquat can cause toxicity through skin contact and inhalation 1
• Contact poison information centers immediately for expert guidance on specific treatment protocols 1
• Remove all contaminated clothing and thoroughly wash exposed skin areas to prevent continued dermal absorption 1, 2

Airway and Hemodynamic Stabilization - First Priority

• Secure the airway and achieve hemodynamic stability before attempting any gastrointestinal decontamination, as aspiration risk is significant 1, 2
• Provide supportive care focused on airway management, hemodynamic support, and correction of metabolic derangements 1

Gastrointestinal Decontamination

• Administer multiple-dose activated charcoal (15-20g every 6 hours) only after airway protection and hemodynamic stabilization 1, 2
• Do not perform routine gastric lavage, as activated charcoal is the evidence-based decontamination method 2
• Fuller's earth is an acceptable alternative to activated charcoal for adsorption of paraquat 2

Critical Oxygen Management - Unique to Paraquat

• Avoid supplemental oxygen unless oxygen saturation falls below 85%, and reduce or stop oxygen therapy if saturation rises above 88% 1, 2
• Target oxygen saturation of 85-88% because paraquat toxicity is dramatically worsened by high oxygen concentrations through increased free radical production 1, 2
• This restrictive oxygen strategy is counterintuitive but essential, as oxygen accelerates paraquat-induced lung injury 1, 2

Enhanced Elimination

• Hemoperfusion with coated activated charcoal should be performed for significant ingestions (>20-40 mg/kg), ideally as "continuous hemoperfusion" for approximately 8 hours daily over 2-3 weeks 3, 4
• Hemodialysis is an acceptable alternative when hemoperfusion is unavailable 5
• Enhanced elimination should be initiated as early as possible to remove paraquat from blood and tissues 4

Antioxidant Therapy - Adjunctive Treatment

• Consider early administration of antioxidant therapy including deferoxamine (100 mg/kg in 24 hours) and continuous infusion of acetylcysteine (300 mg/kg/day for 3 weeks) 6
• Vitamin E may be added as part of the antioxidant regimen 5
• While evidence is limited to case reports, early antioxidant therapy may limit systemic toxicity when combined with decontamination and enhanced elimination measures 6, 5

Immunosuppressive Therapy - Controversial

• Immunosuppressive therapy with steroids and cyclophosphamide may be considered to prevent late-onset irreversible pulmonary fibrosis caused by inflammatory cell recruitment 3
• This remains controversial with limited high-quality evidence supporting its routine use 3

Monitoring Parameters

• Perform intermittent assessment of pulmonary function throughout treatment 3
• Monitor plasma and urinary concentrations of paraquat when available 3
• Track renal and hepatic function, as paraquat causes multi-organ failure 5

Common Pitfalls to Avoid

• Never delay airway protection to perform gastrointestinal decontamination 2
• Never provide supplemental oxygen liberally, as this is uniquely harmful in paraquat toxicity 1, 2
• Do not use gastric lavage routinely when activated charcoal is superior 2
• Do not underestimate the lethality of paraquat—oral poisoning has a mortality rate up to 95% despite aggressive treatment 7

Bold: The most critical and unique aspect of paraquat poisoning management is restrictive oxygen therapy, targeting saturations of 85-88%, as liberal oxygen administration accelerates lung injury and worsens outcomes. 1, 2