Eltrombopag

Generic Name: Eltrombopag

Brand Names: Promacta

Eltrombopag is an oral thrombopoietin receptor agonist that stimulates platelet production.

Hematology

Drug Class

Thrombopoietin Receptor Agonist (TPO-RA)

Pregnancy

Category C (animal studies showed adverse effects; no adequate human studies)

Available Forms

Tablet 12.5 mg, Tablet 25 mg, Tablet 50 mg, Tablet 75 mg, Oral suspension packet 12.5 mg, Oral suspension packet 25 mg

What It's Used For

Dosage Quick Reference

These are general dosage guidelines. Your doctor will determine the appropriate dose for your specific situation.

Condition	Starting Dose	Maintenance Dose
Chronic immune thrombocytopenia (ITP) — adults	50 mg once daily	Adjust to maintain platelets ≥50,000/µL; max 75 mg/day
Chronic ITP — East Asian ancestry	25 mg once daily	Adjust to maintain platelets ≥50,000/µL; max 75 mg/day
Chronic hepatitis C-associated thrombocytopenia	25 mg once daily	Titrate to target platelet count needed for interferon therapy; max 100 mg/day
Severe aplastic anemia (refractory)	50 mg once daily	Increase by 50 mg every 2 weeks; max 150 mg/day

Side Effects

Common Side Effects:

Nausea
Diarrhea
Upper respiratory tract infection
Vomiting
Increased ALT
Myalgia
Fatigue
Paresthesia
Cataract

Serious Side Effects:

Hepatotoxicity (boxed warning)
Thrombotic/thromboembolic events
Bone marrow reticulin fibrosis
Cataracts
Progression of existing MDS to AML
Rebound thrombocytopenia after discontinuation

Drug Interactions

Polyvalent cations (calcium, iron, magnesium, aluminum, zinc, selenium): Chelation with eltrombopag significantly reduces its absorption. Take eltrombopag at least 2 hours before or 4 hours after foods, supplements, or antacids containing these minerals.

Rosuvastatin and other OATP1B1/BCRP substrates: Eltrombopag inhibits the OATP1B1 and BCRP transporters, increasing rosuvastatin exposure by approximately 55%. Monitor for statin-related adverse effects and consider dose reduction of rosuvastatin.

Lopinavir/ritonavir: Decreases eltrombopag concentrations by approximately 17%. Monitor platelet counts and adjust eltrombopag dose as needed.

Cyclosporine: When used together for aplastic anemia, monitor closely for hepatotoxicity. Both agents carry hepatotoxic potential.

Additional Information

Eltrombopag is a thrombopoietin receptor agonist used to increase platelet production in various conditions including chronic immune thrombocytopenia (ITP), chronic hepatitis C-associated thrombocytopenia, and severe aplastic anemia. This oral medication stimulates megakaryocyte growth and differentiation.

Mechanism of Action

Eltrombopag is a small molecule, non-peptide thrombopoietin receptor (TpoR/c-MPL) agonist. It binds to the transmembrane domain of the TpoR, distinct from the binding site of endogenous thrombopoietin (TPO), and activates intracellular signaling pathways (JAK/STAT, MAPK) that promote megakaryocyte proliferation and differentiation from bone marrow progenitor cells. This leads to increased platelet production. Unlike recombinant TPO, eltrombopag does not compete with endogenous TPO and may have additive effects. In aplastic anemia, eltrombopag may also stimulate hematopoietic stem cells through direct and indirect mechanisms.

Available Formulations

Eltrombopag is available as film-coated tablets (12.5 mg, 25 mg, 50 mg, 75 mg) and as a powder for oral suspension (12.5 mg and 25 mg packets). The medication should be taken on an empty stomach (1 hour before or 2 hours after a meal). Food, especially dairy products and calcium-fortified foods, significantly reduces absorption. Metal cation-containing products should be separated by at least 4 hours.

Medical Uses

Eltrombopag is FDA-approved for chronic immune thrombocytopenia (ITP) in adults and pediatric patients 1 year and older with insufficient response to corticosteroids, immunoglobulins, or splenectomy; thrombocytopenia in patients with chronic hepatitis C to allow initiation and maintenance of interferon-based therapy; and severe aplastic anemia in patients with insufficient response to immunosuppressive therapy. It is also approved as first-line treatment for severe aplastic anemia in combination with standard immunosuppressive therapy.

Dosing Guidelines

For ITP in adults, start at 50 mg once daily (25 mg for East Asian patients), adjusting dose to achieve target platelet count (≥50,000/µL); maximum dose is 75 mg daily. For hepatitis C-associated thrombocytopenia, start at 25 mg daily, titrating to target platelet count needed for antiviral therapy. For severe aplastic anemia, doses up to 150 mg daily are used. Dose adjustments are based on platelet response. East Asian patients may have higher drug exposure and should start at reduced doses.

Important Safety Information

Eltrombopag carries a boxed warning for hepatotoxicity, including severe and potentially life-threatening cases. Liver function tests should be monitored before and during therapy; dose reduction or discontinuation may be required. The medication may increase thrombotic/thromboembolic risk in patients with chronic liver disease. Eltrombopag is only available through a restricted distribution program (PROMACTA CARES) for hepatitis C patients. Cataracts have developed in rodent studies; regular ophthalmologic monitoring is recommended.

Drug Interactions

Polyvalent cation-containing products (antacids, calcium, iron, magnesium, aluminum, zinc, selenium) significantly reduce eltrombopag absorption; administer 4 hours apart. Eltrombopag inhibits OATP1B1 and BCRP transporters, potentially increasing levels of substrates (rosuvastatin, methotrexate, topotecan). CYP2C8 and CYP1A2 metabolize eltrombopag; lopinavir/ritonavir may reduce levels. Monitor closely when used with other drugs affecting hepatic transporters.

Special Populations

Eltrombopag may cause fetal harm based on animal data; women should use effective contraception during treatment. It is unknown whether eltrombopag is excreted in human breast milk; breastfeeding is not recommended. Safety and efficacy have been established in pediatric patients 1 year and older for ITP. Elderly patients do not require dose adjustment but may be at increased thromboembolic risk. Dose reduction is not required for renal impairment. Reduce initial dose to 25 mg daily in patients with hepatic impairment (ITP) and avoid use in hepatitis C patients with hepatic decompensation.

Frequently Asked Questions

Eltrombopag binds to minerals (calcium, iron, magnesium, zinc) in food and supplements, which dramatically reduces its absorption. Take it at least 2 hours before or 4 hours after eating, or after consuming dairy products, mineral supplements, or antacids. Many patients find it easiest to take at bedtime, at least 2 hours after dinner.

Most patients see an increase in platelet counts within 1–2 weeks of starting eltrombopag, with peak effect often occurring by 2–4 weeks. Your doctor will check your platelet count weekly during dose titration. If there is no response after 4 weeks at maximum dose, the medication may be discontinued.

Yes. Eltrombopag can cause hepatotoxicity (liver damage). Liver function tests (ALT, AST, bilirubin) should be checked before starting therapy, every 2 weeks during dose adjustment, and monthly once on a stable dose. Report any symptoms of liver injury such as yellowing of eyes/skin, dark urine, or right upper abdominal pain.

Yes. Excessive platelet counts increase the risk of blood clots (thrombosis). Your doctor will regularly monitor your platelets and adjust the dose to maintain a safe level (typically ≥50,000/µL to reduce bleeding risk but not excessively elevated). Do not adjust the dose on your own.

Platelet counts typically drop within 1–2 weeks after discontinuation and may fall below pre-treatment levels temporarily. This rebound thrombocytopenia increases bleeding risk. Your doctor will monitor your platelets closely for at least 4 weeks after stopping the medication.

Questions to Ask Your Doctor

Consider discussing these topics at your next appointment:

✓How often will my platelet count and liver function be monitored?
✓Are there specific dietary restrictions I need to follow while on eltrombopag?
✓What signs of blood clotting should I watch for?
✓Is eltrombopag a long-term treatment for my condition, or is it temporary?
✓What are the alternatives if eltrombopag does not adequately raise my platelet count?

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Related Health Conditions

This medication is commonly used to treat or manage the following conditions:

Thrombocytopenia

Thrombocytopenia, a condition of low platelet count (below 150,000/microliter), can cause easy bruising and bleeding due to impaired clotting from decreased production, increased destruction, or splenic sequestration.

Learn More

Anemia

Anemia, characterized by a low red blood cell count, leads to fatigue and weakness due to reduced oxygen delivery; causes include blood loss, decreased production, and chronic diseases.

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Chronic Hepatitis

Chronic hepatitis, a long-term liver inflammation often caused by viral infections, autoimmune disorders, or metabolic issues, can lead to serious complications if undiagnosed.

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Medical Disclaimer: This information is for educational purposes only and should not be considered medical advice. Always consult with your healthcare provider before starting, stopping, or changing any medication. Your doctor can provide personalized recommendations based on your specific health condition and medical history.