What is the appropriate deferoxamine dosing for a 92‑kg female who needs two 3‑gram intravenous infusions?

Deferoxamine 3G IV × 2 Dosing Assessment

The ordered dose of 3 grams IV twice (total 6 grams in 24 hours) for this 92-kg patient is appropriate and within FDA-approved maximum limits for acute iron intoxication, but the infusion rate must not exceed 15 mg/kg/hr for the first 1000 mg, followed by a maximum of 125 mg/hr for subsequent doses. 1

FDA-Approved Dosing for Acute Iron Intoxication

Maximum Daily Dose

• The total amount administered should not exceed 6000 mg (6 grams) in 24 hours 1
• For this 92-kg patient, the ordered 3 grams × 2 doses = 6 grams total, which meets but does not exceed this limit 1

Critical Infusion Rate Restrictions

• First 1000 mg: Maximum rate of 15 mg/kg/hr 1
  • For 92 kg: 15 × 92 = 1380 mg/hr maximum for first gram
  • Minimum infusion time for first 1000 mg: approximately 45 minutes
• Subsequent doses: Maximum rate of 125 mg/hr 1
  • For the remaining 2000 mg of each 3-gram dose: minimum 16 hours per 2 grams
  • Each 3-gram infusion requires approximately 17+ hours when following rate restrictions

Route Selection

• IV route should be used ONLY for patients in cardiovascular collapse 1
• Intramuscular route is preferred for all patients not in shock 1
• If patient is hemodynamically stable, consider switching to IM administration (1000 mg initially, then 500 mg every 4 hours) 1

Dosing Schedule Considerations

Timing Between Doses

• Standard dosing for acute iron toxicity: 1000 mg initially, followed by 500 mg every 4 hours for two doses, then 500 mg every 4-12 hours as needed 1
• The ordered "× 2" dosing of 3-gram infusions cannot be administered simultaneously or in rapid succession due to rate limitations 1
• Each 3-gram infusion requires minimum 17 hours to complete safely 1

Practical Administration

• First dose: 3 grams over approximately 17-20 hours
• Second dose: Can begin after first dose completes, requiring another 17-20 hours
• Total treatment duration: 34-40 hours minimum for both doses 1

Monitoring for Toxicity

Respiratory Complications

• High-dose IV deferoxamine has been linked to acute respiratory distress syndrome (ARDS), particularly when infusion rates exceed recommended limits 2
• Monitor respiratory status closely throughout infusion, especially with cumulative doses approaching 6 grams 2

Cardiovascular Monitoring

• Rapid IV bolus causes hypotension; slow infusion rate is essential 2
• Continuous hemodynamic monitoring recommended for IV administration 1

Infectious Risk

• Increased susceptibility to Yersinia and Klebsiella infections during deferoxamine therapy 2
• Monitor for signs of opportunistic infection throughout treatment course 2

Visual and Auditory Toxicity

• Monitor for visual disturbances and auditory changes during high-dose therapy 2

Clinical Context Assessment

When IV Route is Appropriate

• Patient must be in cardiovascular collapse/shock to justify IV route 1
• If patient stabilizes during treatment, switch to IM administration as soon as clinically feasible 1

Alternative Dosing if Not in Shock

• IM route: 1000 mg initially, then 500 mg every 4 hours × 2 doses, then 500 mg every 4-12 hours (maximum 6 grams/24 hours) 1
• IM route is safer and preferred for hemodynamically stable patients 1

Key Pitfalls to Avoid

• Rapid infusion: Never exceed 15 mg/kg/hr for first 1000 mg or 125 mg/hr thereafter—this causes hypotension and increases ARDS risk 1, 2
• Concurrent blood transfusion: Do not administer deferoxamine during blood transfusion due to difficulty interpreting adverse effects (rash, anaphylaxis, hypotension) 1
• Inadequate monitoring: Failure to monitor respiratory status with high cumulative doses risks missing early ARDS 2
• Wrong route selection: Using IV route in stable patients unnecessarily increases toxicity risk 1