Eltrombopag Dosing for Adult Chronic Immune Thrombocytopenia (ITP)
The recommended initial dose of eltrombopag for adults with chronic ITP is 50 mg once daily, with subsequent dose adjustments based on platelet response to maintain platelet counts ≥50 × 10^9/L. 1
Initial Dosing Protocol
- Start with eltrombopag 50 mg orally once daily 1
- Take eltrombopag on an empty stomach (1 hour before or 2 hours after meals) as food significantly reduces absorption 1
- Avoid calcium-rich foods or supplements within 4 hours of taking eltrombopag 1
- Monitor platelet counts weekly until a stable count is achieved 1
- If platelet count remains <50 × 10^9/L after 2-3 weeks, increase dose to 75 mg once daily 1
- Maximum dose should not exceed 75 mg daily 1
Dose Adjustment and Maintenance
- If platelet count exceeds 200 × 10^9/L, reduce the dose by 25 mg 1
- If platelet count exceeds 400 × 10^9/L, temporarily discontinue eltrombopag and resume at a reduced dose when platelet count falls below 150 × 10^9/L 1
- The lowest effective dose to maintain platelet counts ≥50 × 10^9/L should be used 1
- Response to eltrombopag typically occurs within 1-2 weeks of initiating therapy 1, 2
- By day 15, more than 80% of patients receiving 50 or 75 mg of eltrombopag daily show increased platelet counts 1, 2
Monitoring Requirements
- Check platelet counts weekly until stable, then monthly 1
- Monitor liver function tests at baseline and regularly during treatment, as 13% of patients may develop liver function abnormalities 1
- Assess for signs of bone marrow reticulin formation if treatment failure or new cytopenia develops 1, 3
- Evaluate for thromboembolic events, particularly in patients with risk factors 1
Tapering and Discontinuation
- For patients with stable responses for at least 6 months, consider tapering by reducing eltrombopag by 25 mg every 2 weeks 1
- After reaching 25 mg daily, consider switching to 25 mg every other day for 2 weeks, then every 4 days before discontinuation 1
- Monitor closely for rebound thrombocytopenia upon discontinuation 1, 4
- Be aware that 83.3% of patients may relapse after discontinuation, with a median relapse-free survival of 15 days 3
Alternative Dosing Considerations
- Some patients may respond to lower maintenance doses such as 25 mg twice per week or 25 mg/day 3
- An alternative intermittent dosing protocol with 2-4 weekly doses has shown efficacy in maintaining platelet counts ≥50 × 10^9/L in 84% of measurements 5
- Patients with longer ITP duration or heavily pretreated cases may require higher doses or more frequent administration 3
Common Side Effects and Precautions
- Headache is the most common adverse event (occurring in >20% of patients) 1
- Monitor for hepatotoxicity, particularly in patients with pre-existing liver disease 1, 3
- Bone marrow fibrosis has been reported in some patients after prolonged treatment 3
- Grade 3-4 adverse events are rare (approximately 3% of patients) 2