What is the treatment for paraquat poisoning?

Management of Paraquat Poisoning

The immediate management of paraquat poisoning requires aggressive gastrointestinal decontamination, early hemoperfusion within 2-4 hours of ingestion, restricted oxygen therapy, and supportive care with immunosuppressive and antioxidant therapies to reduce mortality. 1

Initial Management and Decontamination

• Remove contaminated clothing and perform thorough skin decontamination with soap and water
• Use appropriate PPE (gloves) to prevent secondary exposure to healthcare providers 1
• Gastrointestinal decontamination:
  • Gastric lavage if within 1-2 hours of ingestion 1
  • Administer activated charcoal (30g) and Fuller's earth or bentonite as adsorbents 2, 3
  • Consider sequential gastrointestinal lavage with montmorillonite powder (60g) followed by 2.5% bicarbonate solution 4

Extracorporeal Elimination

• Initiate hemoperfusion with activated charcoal within 2-4 hours of ingestion for best outcomes 1, 5
  • Early hemoperfusion (≤6 hours) significantly improves survival rates compared to late hemoperfusion (>6 hours) 5
  • If hemoperfusion is unavailable, conventional hemodialysis may be used as an alternative 6
• Continue extracorporeal treatment until clinical improvement is observed

Oxygen Management (Critical)

• Restrict supplemental oxygen to target saturation of 85-88% 1
• Provide oxygen only when saturation falls below 85% to minimize free radical production and further lung damage
• Avoid mechanical ventilation with high oxygen concentrations when possible 1

Medication Therapy

• Immunosuppressive therapy:

  • Cyclophosphamide combined with methylprednisolone pulse therapy 1, 6
  • Dexamethasone may be added to the regimen 6

• Antioxidant therapy:

  • N-acetylcysteine (300 mg/kg/day for up to 3 weeks) 1, 6
  • Consider salicylates for their anti-inflammatory and NF-κB inhibitory actions 2

Organ Support and Monitoring

• Renal support:

  • Monitor for non-oliguric renal failure
  • Provide appropriate fluid management
  • Initiate dialysis if needed for acute kidney injury 1

• Respiratory management:

  • Early intubation may be necessary for airway protection
  • Use caution with oxygen settings (keep FiO2 as low as possible) 1

• Hepatic monitoring:

  • Monitor liver function tests regularly
  • Treat hepatic dysfunction as needed 1

Prognostic Indicators

• Plasma paraquat concentrations
• Urine and plasma dithionite tests
• Severity of clinical symptoms 1, 2

Common Pitfalls to Avoid

1. Excessive oxygen administration - can worsen lung injury through enhanced free radical production
2. Delayed hemoperfusion - effectiveness decreases significantly after 6 hours post-ingestion
3. Performing gastric lavage without proper adsorbents - reduces effectiveness of decontamination
4. Failing to consult with toxicology experts - immediate consultation with poison control centers is recommended (1-800-222-1222 in the US) 1
5. Overlooking complications - monitor for anemia, bacteremia, and deep vein thrombosis 6

The mortality rate for paraquat poisoning remains high despite treatment interventions, making early recognition and aggressive management crucial for improving survival chances 2.