What is the recommended dose of vitamin C (Vit C) for aluminum phosphide poisoning?

Vitamin C Dosing for Aluminum Phosphide Poisoning

For aluminum phosphide poisoning, vitamin C should be administered at a dose of 2-3 g per day intravenously as part of the supportive management protocol. 1

Pathophysiology and Treatment Approach

Aluminum phosphide (ALP) poisoning is a life-threatening condition with mortality rates of 70-100%, even with ingestion of small amounts (150-500 mg). The toxicity occurs when ALP releases phosphine gas upon contact with gastric acid, leading to:

• Refractory shock and circulatory failure 1, 2
• Severe metabolic acidosis 1
• Cardiac arrhythmias and cardiotoxicity 2
• Acute renal failure 1
• Hepatobiliary impairment 1

Vitamin C Dosing Recommendations

The recommended vitamin C dosing for ALP poisoning should follow these guidelines:

• Dose: 2-3 g per day intravenously 1, 3
• Route: Intravenous administration is crucial as enteral absorption may be unpredictable due to impaired gut function 4
• Duration: Throughout the acute phase of poisoning 4

Rationale for High-Dose Vitamin C

Vitamin C is recommended in ALP poisoning because:

1. It acts as a powerful water-soluble antioxidant that directly scavenges free radicals and mitigates oxidative stress 4
2. It helps protect the endothelium by promoting collagen synthesis and maintaining endothelial vasodilation 4
3. It can limit inflammatory response and ischemia-reperfusion injury 4
4. It improves host defense mechanisms compromised during severe poisoning 4

Comprehensive Management Protocol

Vitamin C should be administered as part of a comprehensive management protocol:

• Early decontamination: Gastric lavage with diluted potassium permanganate 5
• Cardiovascular support: Inotropes and vasopressors for refractory shock 5
• Additional antioxidants: Combine vitamin C with:
  • N-acetylcysteine 1, 3
  • Magnesium sulfate (for cardiac arrhythmias) 1, 2, 5
  • Thiamine 1
  • Hydrocortisone 1
  • Trimetazidine (for cardioprotection) 1, 3

Special Considerations

• Monitoring: Close hemodynamic monitoring is essential during vitamin C administration 5
• Renal function: Monitor renal function as ALP poisoning commonly causes acute renal failure 1
• Acid-base status: Regular arterial blood gas analysis to monitor metabolic acidosis 6

Potential Pitfalls

• Delayed treatment: Early initiation of vitamin C is crucial; delays significantly reduce effectiveness 1
• Inadequate dosing: Lower doses may be insufficient to combat the severe oxidative stress 4
• Oral administration: Avoid oral administration as gut absorption is compromised 4
• Reliance on vitamin C alone: Vitamin C should be part of a multimodal approach, not used in isolation 1, 3

Despite aggressive supportive care including vitamin C, mortality remains high in ALP poisoning. However, early intervention with appropriate dosing of vitamin C as part of a comprehensive protocol may improve outcomes 1, 5.