What are the indications, dosing regimen, monitoring requirements, and contraindications for using deferiprone in patients aged three years or older with transfusional iron overload such as thalassemia or sickle‑cell disease?

Use of Deferiprone in Transfusional Iron Overload

Deferiprone is an FDA-approved oral iron chelator indicated for patients aged 3 years and older with transfusional iron overload from thalassemia syndromes or sickle cell disease, dosed at 75-100 mg/kg/day divided three times daily, with mandatory weekly absolute neutrophil count monitoring due to the risk of agranulocytosis. 1, 2

Indications

Deferiprone is specifically approved for:

• Transfusional iron overload in patients with thalassemia syndromes (including β-thalassemia major) 1, 3
• Sickle cell disease with chronic transfusion requirements 3, 4
• Age ≥3 years (pediatric formulations available for young children) 2, 5

The drug demonstrates superior cardiac iron removal compared to deferoxamine monotherapy, making it particularly valuable for patients with cardiac siderosis or reduced left ventricular ejection fraction 1, 6. Retrospective data suggest deferiprone offers better cardiac protection and improved survival compared to routine deferoxamine therapy, a benefit recognized by the European Medicines Agency 1.

Dosing Regimen

Standard Dosing

• 75-100 mg/kg/day divided into three daily doses 1
• Administered orally, with peak serum concentration at 45-60 minutes (fasted) or up to 2 hours (fed) 1
• Plasma half-life of 1.5-2.5 hours necessitates the three-times-daily schedule 1

Practical Administration

• Available as tablets (500 mg, 1000 mg) and liquid formulation for young children 2, 5
• The liquid formulation has demonstrated favorable safety in children ages 1-10 years 5
• 75-90% excreted renally as free deferiprone, glucuronide metabolite, and iron-deferiprone complex 1

Combination Therapy

For severe cardiac siderosis or inadequate response to monotherapy:

• Deferiprone + deferoxamine: Produces synergistic iron clearance, removing cardiac iron at 3.3-4.2% per month versus 2.2% with deferoxamine alone 1
• Deferiprone + deferasirox (DOIC): Recent real-world data show 80% of patients achieve ferritin <2000 ng/mL with adherence >85% 7

Monitoring Requirements

Mandatory Weekly Monitoring

Absolute neutrophil count (ANC) must be checked every week to detect early agranulocytosis 1. This is non-negotiable given the 1% incidence of agranulocytosis (0.6 cases per 100 patient-years) 1, 6.

ANC-Based Action Algorithm

• ANC <0.5 × 10⁹/L (agranulocytosis): Immediately discontinue deferiprone; patient must contact physician urgently 1
• ANC 0.5-1.5 × 10⁹/L (mild neutropenia): Occurs in ~5-6% of patients, particularly non-splenectomized patients and during viral infections; may resolve with continued therapy but requires close monitoring 1, 5
• All documented cases of agranulocytosis resolved without complications upon drug discontinuation 5, 4

Additional Monitoring

• Serum ferritin: Monitor to assess efficacy; target reductions of 25-45% are typical 7
• Liver enzymes (ALT): Check periodically; transient elevations occur in ~12% of patients but are usually self-limited 1, 5
• Zinc levels: Low plasma zinc reported in minority of patients 1
• MRI T2 (cardiac and hepatic)*: For organ-specific iron assessment; meaningful changes require >24 months of therapy 7, 8

Patient Education on Infection Symptoms

Patients must immediately report fever, sore throat, or flu-like symptoms, as these may indicate agranulocytosis 1.

Contraindications and Precautions

Absolute Contraindications

• Known hypersensitivity to deferiprone 2
• Pregnancy: Embryo-fetal toxicity documented; contraindicated 2

Serious Adverse Effects Requiring Caution

1. Agranulocytosis (~1% incidence): Most serious adverse reaction; requires immediate discontinuation 1, 6
2. Neutropenia (~5-6% incidence): More common in non-splenectomized patients 1, 5
3. Arthropathy: Ranges from mild joint pain (usually knee) to severe arthritis 1
4. Hepatotoxicity: Transient ALT elevations in ~12%; rarely requires discontinuation 1, 5

Common but Less Serious Effects

• Gastrointestinal symptoms: Nausea, vomiting, abdominal pain (most common adverse effects) 1
• Zinc deficiency: Monitor and supplement as needed 1, 6

Drug Interactions

Avoid concurrent use with drugs associated with neutropenia or agranulocytosis 2. The evidence does not specify aluminum-containing antacids as problematic (unlike with deferasirox), but timing with food affects absorption 1.

Clinical Efficacy Benchmarks

Cardiac Iron Removal

• Deferiprone monotherapy: Clears cardiac iron at 2.2% per month, nearly double the rate of standard deferoxamine 1
• Combination therapy: Achieves 3.3-4.2% per month cardiac iron clearance 1
• Improves left ventricular ejection fraction in patients with cardiac dysfunction 1, 9

Systemic Iron Control

• Mean serum ferritin reductions from baseline: 14-25% over 6-12 months 5, 7
• Real-world pediatric data: >80% achieve ferritin <2000 ng/mL 7

Special Populations

Pediatric Use

• Ages 3-10 years: Liquid formulation demonstrates favorable benefit/risk ratio 5
• Safety profile in children similar to or better than in adults 5
• No unexpected adverse reactions in children ages 1-10 years 5

Reproductive Considerations

• Females of reproductive potential: Must use effective contraception; embryo-fetal toxicity documented 2
• Lactation: Unknown if excreted in breast milk; consider risk-benefit 2

Common Pitfalls to Avoid

1. Failing to monitor ANC weekly: This is the single most critical safety measure and cannot be deferred 1
2. Continuing therapy during agranulocytosis: Must stop immediately when ANC <0.5 × 10⁹/L 1
3. Inadequate patient education: Patients must understand to report infection symptoms immediately 1
4. Expecting rapid organ iron changes: Meaningful MRI improvements require >24 months 7, 8
5. Assuming "plateaus" mean treatment failure: May reflect iron balance rather than biological ceiling; verify adherence and transfusion iron input before abandoning therapy 8