What is the recommended deferiprone (oral iron chelator) protocol, including dosing, common adverse effects, and monitoring schedule for patients with iron overload?

Deferiprone Protocol, Side Effects, and Monitoring

Deferiprone should be administered orally at 75-100 mg/kg/day divided into three doses daily, with mandatory weekly absolute neutrophil count monitoring to detect the life-threatening risk of agranulocytosis. 1

Dosing Protocol

Standard Dosing:

• 75-100 mg/kg/day divided into three daily doses (every 8 hours) 1
• Rapid absorption occurs 45-60 minutes after oral ingestion when fasted, or up to 2 hours when fed 1
• The short plasma half-life of 1.5-2.5 hours necessitates the three-times-daily schedule 1
• A twice-daily formulation is now available with comparable efficacy and improved adherence 2, 3

Dose Adjustments:

• Higher doses (up to 100-113 mg/kg/day) demonstrate dose-dependent improvements in liver iron reduction (2.8 mg/g dry weight reduction per 10 mg/kg/day increase) 4
• For maintenance of normal iron stores after achieving target ferritin <350 μg/L, doses of 50-100 mg/kg/day may be sufficient, with some patients requiring intermittent withdrawal to prevent iron deficiency 5
• Lower maintenance doses are appropriate once iron burden is controlled 1

Side Effects

Critical Life-Threatening Adverse Effects:

• Agranulocytosis (absolute neutrophil count <0.5×10⁹/L): Occurs in approximately 1% of patients (0.6 cases per 100 patient-years) 1

  • This is the most serious complication requiring immediate drug discontinuation 1
  • Recent real-world data shows 0.6% incidence with full recovery in all cases 2

• Neutropenia (absolute neutrophil count 0.5-1.5×10⁹/L): Occurs in approximately 5% of patients 1

  • More common in non-splenectomized patients and during viral infections 1
  • May require temporary discontinuation or dose adjustment 1

Common Adverse Effects:

• Gastrointestinal disturbances: Most frequent side effects 1

  • Nausea, vomiting, abdominal pain (17.1% abdominal pain, 14.5% vomiting in recent trials) 6
  • Usually mild to moderate and manageable 1

• Arthropathy: Occurs in approximately 20% of patients 7

  • Ranges from mild joint pain (typically knee) to severe arthritis 1
  • May require dose adjustment or discontinuation

• Hepatic effects: Transient elevation of liver enzymes 1

  • Increased ALT (9.2%) and AST (9.2%) 6

• Zinc deficiency: Reported in a minority of patients 1

Monitoring Protocol

Mandatory Weekly Monitoring:

Weekly absolute neutrophil count (ANC) is non-negotiable to detect early agranulocytosis 1. This is the single most critical monitoring parameter given the life-threatening nature of this complication.

Additional Monitoring Parameters:

• Serum ferritin: Monitor regularly to assess treatment efficacy and guide dosing 1

  • Target: <350 μg/L for normal iron stores 5

• Liver function tests: Periodic monitoring for transaminase elevations 6

• Cardiac T2 MRI*: For patients with cardiac iron overload

  • Target: >20 ms 5
  • Improvements occur over months with treatment 1

• Liver iron concentration (LIC): Via R2* MRI

  • Target: >6.3 ms 5
  • Assess response to therapy 6

• Zinc levels: Periodic monitoring given risk of deficiency 1

Critical Management Principles

Immediate Actions Required:

1. Stop deferiprone immediately if agranulocytosis or severe neutropenia develops 1
2. Patient must contact physician immediately for any signs of infection: fever, sore throat, flu-like symptoms 1
3. Temporary discontinuation may be appropriate for common adverse effects, but agranulocytosis requires permanent cessation 1

Special Considerations:

• 75-90% of the drug is excreted renally 1, requiring caution in renal impairment
• The drug is primarily metabolized to an inactive glucuronide conjugate 1
• Combination therapy with deferoxamine may be used for intensive chelation in patients with cardiac involvement or inadequate response to monotherapy 1, 5

Common Pitfall: Failing to maintain weekly ANC monitoring is the most dangerous error in deferiprone management, as agranulocytosis can develop rapidly and is potentially fatal if not detected early. Patient education about infection symptoms is equally critical for safety.