Dosing of eltrombopag
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Eltrombopag is a thrombopoietin receptor agonist used for thrombocytopenia in ITP, aplastic anemia, and chronic hepatitis C. Dosing varies by indication and patient factors including ethnicity (East Asian patients require dose reduction).
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eltrombopag dosing
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Eltrombopag (Promacta/Revolade) - Dosing
Eltrombopag is an oral, small-molecule thrombopoietin (TPO) receptor agonist. It interacts with the transmembrane domain of the MPL receptor, producing a dose-dependent increase in platelet count. Peak levels occur in 2-6 hours; half-life is 26-35 hours. It is excreted primarily in feces.
Indication-Based Dosing
| Indication | Standard Starting Dose | Dose in East Asian Patients / Hepatic Impairment | Max Dose | Goal |
|---|---|---|---|---|
| Chronic ITP (inadequate response to prior therapy) | 50 mg orally once daily | 25 mg once daily | 75 mg/day | Maintain platelets >50,000/µL |
| Aplastic Anemia (with ATG + cyclosporine "triple therapy") | 150 mg once daily (standard); 75 mg once daily (East Asian) | 75 mg/day | - | 6 months duration |
| Hepatitis C-related thrombocytopenia | 25 mg once daily | 25 mg once daily | 100 mg/day | Allow initiation of interferon |
Chronic ITP
- Starting dose: 50 mg orally once daily
- Dose reduction (East Asian patients or hepatic impairment): 25 mg once daily
- Titration: Adjust dose every 2 weeks by 25 mg increments based on platelet response
- Maximum dose: 75 mg/day
- Target: Use the minimum dose required to maintain platelets >50,000/µL
- The drug is used in patients who have had inadequate response to corticosteroids, immunoglobulins, or splenectomy
(Goldman-Cecil Medicine; Goodman & Gilman's)
Aplastic Anemia (Triple Therapy)
- Combined with horse ATG + cyclosporine as standard first-line immunosuppression
- Eltrombopag is administered once daily for 6 months
- This triple regimen achieves overall response in ~70-80% and complete response in ~50% of patients
- FDA approved as standard-of-care since 2018
- Children benefit less from adding eltrombopag compared to adults
- Relapse may occur on tapering; some patients become dependent on continued therapy
(Harrison's Principles of Internal Medicine 22e)
Hepatitis C-Associated Thrombocytopenia
- Used to raise platelet counts sufficiently to allow initiation of interferon-based therapy
- Monitor liver function closely due to hepatotoxicity risk (hepatitis C adds to baseline risk)
(Katzung's Basic and Clinical Pharmacology 16e)
Special Populations and Key Adjustments
| Population | Adjustment |
|---|---|
| East Asian ethnicity | Start at 25 mg/day (ITP); 75 mg/day (aplastic anemia) - lower exposure due to pharmacogenomic differences |
| Hepatic impairment | Start at 25 mg/day; monitor LFTs regularly |
| Pediatric patients | Used in aplastic anemia (less additional benefit vs adults) |
Administration Notes
- Take on an empty stomach - food (especially polyvalent cations: dairy, calcium, antacids, iron) significantly reduces absorption
- Separate from polyvalent cation-containing products by at least 4 hours
- Monitor LFTs before, during, and after treatment
- Monitor platelet count regularly; adjust dose to avoid thrombocytosis (>400,000/µL - reduce dose; >600,000/µL - discontinue)
Important Adverse Effects
- Hepatotoxicity - most important, monitor LFTs (especially in hepatitis C patients)
- Portal vein thrombosis - reported in chronic liver disease setting
- Marrow fibrosis - generally reversible on discontinuation
- Rebound thrombocytopenia - on abrupt discontinuation
- Avoid in patients with myelodysplastic syndrome (theoretical risk of blast progression)
Sources: Goodman & Gilman's Pharmacological Basis of Therapeutics; Goldman-Cecil Medicine International Edition; Katzung's Basic and Clinical Pharmacology 16e; Harrison's Principles of Internal Medicine 22e (2025)
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