eltrombopag

(el-trom-bo-pag) eltrombopag,

Promacta

(trade name),

Revolade

(trade name)

Classification

Therapeutic: antithrombocytopenics
Pharmacologic: thrombopoietin receptor agonists
Pregnancy Category: C

Indications

Treatment of chronic immune (idiopathic) thrombocytopenic purpura in patients who have had an inadequate response to corticosteroids, immunoglobulins or splenectomy (should only be used in patients with an ↑ risk of bleeding).Treatment of thrombocytopenia in patients with chronic hepatitis C to allow the initiation and maintenance of interferon-based therapy

Action

Increases platelet production by initiating proliferation and differentiation of megakaryocytes from bone marrow progenitor cells.

Therapeutic effects

Increased platelet count with reduced risk of bleeding.

Pharmacokinetics

Absorption: 52% absorbed following oral administration.Distribution: Unknown.Protein Binding: >99%.Metabolism and Excretion: Extensively metabolized; 59% eliminated in feces, 20% as unchanged drug; 31% excreted in urine as metabolites.Half-life: 21–35 hr.

Time/action profile (effect on platelet count)

ROUTE	ONSET	PEAK	DURATION
PO	1 wk	2 wk	1 wk

Contraindications/Precautions

Contraindicated in: Lactation: Lactation.Use Cautiously in: Myelodysplastic syndromes (may ↑ risk of hematologic malignancy); Hepatic impairment (lower initial dose required); genetic implication Patients of East Asian ancestry (may require lower doses); Geriatric: May be more sensitive to drug effects; ↑ dose cautiously, consider age-related ↓ in renal and hepatic function, concurrent disease states and drug therapy; Obstetric: Use only when potential maternal benefit outweighs potential risk to fetus.

Adverse Reactions/Side Effects

Ear, Eye, Nose, Throat

development/worsening of cataracts

Cardiovascular

thromboembolism (life-threatening)

Gastrointestinal

hepatotoxicity (life-threatening)

Hematologic

bone marrow changes

Interactions

Drug-Drug interaction

↓ availability and absorption of iron, calcium, aluminum, magnesium, selenium and zinc by chelation; do not administer within 4 hr of medications containing these and other polyvalent cations.↓ availability and absorption of iron, calcium, aluminum, magnesium, selenium, and zinc by chelation; do not administer within 4 hr of foods containing these and other polyvalent cations.

Route/Dosage

Chronic Immune (Idiopathic) Thrombocytopenia

Oral (Adults) 50 mg once daily, may be ↑ to achieve a platelet count of ≥50 x 10⁹/L (not to exceed 75 mg/day); genetic implication Patients of East Asian ancestry— 25 mg once daily initially, may be ↑ to achieve a platelet count of ≥50 x 10⁹/L (not to exceed 75 mg/day);.

Hepatic Impairment

(Adults) Mild, moderate, or severe hepatic impairment (Child Pugh Class A, B, C)—25 mg once daily initially, may be ↑ to achieve a platelet count of ≥50 x 10⁹/L (not to exceed 75 mg/day);genetic implication Patients of East Asian ancestry with mild, moderate, or severe hepatic impairment (Child Pugh Class A, B, C)— 12.5 mg once daily initially, may be ↑ to achieve a platelet count of ≥50 x 10⁹/L (not to exceed 75 mg/day)

Chronic Hepatitis C-Associated Thrombocytopenia

Oral (Adults) 25 mg once daily; may be ↑ by 25 mg every 2 wk to achieve the target platelet count required to initiate antiviral therapy; during antiviral therapy, adjust dose to avoid dose ↓ of peginterferon (not to exceed 100 mg/day)

Availability

Tablets: 12.5 mg, 25 mg, 50 mg, 75 mg

Nursing implications

Nursing assessment

Monitor for unusual bleeding and bruising and signs of hepatotoxicity during therapy.
Monitor for signs and symptoms of cataracts. Perform baseline ocular examination prior to administration and periodically during therapy.
Lab Test Considerations: Modify dose based on platelet count. If platelet count <50 x 10⁹/L following at least 2 wk of therapy, increase daily dose by 25 mg. If platelet count is ≥200 x 10⁹/L to ≤400 x 10⁹/L, decrease dose by 25 mg. Wait 2 wk to assess effects of dose adjustment. If platelet count >400 x 10⁹/L, stop eltrombopag, increase monitoring of platelet monitoring to 2x/wk. Once platelet count is <150 x 10⁹/L, reinititate therapy at dose reduced by 25 mg/day. If platelet count >400 x 10⁹/L after 2 wk of therapy at lowest dose, permanently discontinue eltrombopag. Discontinue eltrombopag if platelet count does not ↑ to a level sufficient to avoid clinically important bleeding after 4 wk of therapy at maximum daily dose of 75 mg.
- Monitor liver tests and CBC, including platelet counts and peripheral blood smears, prior to and throughout therapy. Monitor AST, ALT, and serum bilirubin prior to therapy, every 2 wk during dose adjustment, and monthly following stable dose. If bilirubin is ↑, perform fractionation. Evaluate abnormal liver tests with repeat testing in 3–5 days. If abnormalities are confirmed, monitor serum liver tests weekly until resolved, stabilize, or return to baseline. Discontinue eltrombopag if ALT levels ↑ to ≥3 x upper limit of normal and are progressive, persistent for ≥4 wk, or accompanied by ↑ direct bilirubin, or accompanied by clinical symptoms of liver injury or evidence of hepatic decompensation. Monitor CBC including platelet count, for at least 4 wk following discontinuation of therapy; may cause worsening thrombocytopenia.

Potential Nursing Diagnoses

Risk for injury (Adverse Reactions)

Implementation

Oral: Administer on an empty stomach, 1 hr before or 2 hr after a meal. Allow at least 4 hr between eltrombopag and other medications (antacids), calcium-rich foods (dairy and calcium-fortified juices), and supplements containing iron, calcium, aluminum, magnesium, zinc, and selenium.

Patient/Family Teaching

Explain purpose, risks and benefits of therapy to patient. Risks or long term therapy are unknown.
Instruct patient to avoid taking eltrombopag within 4 hr of foods, mineral supplements, and antacids containing iron, calcium, aluminum, magnesium, zinc, and selenium.
Advise patients to avoid activities that may increase risk of bleeding.
Instruct patient to notify health care professional if symptoms of liver problems (yellowing of skin or whites of eyes, unusual darkening of urine, unusual tiredness, pain in right upper stomach) occur.
Advise female patients to notify health care professional promptly if pregnancy is planned or suspected or if breastfeeding. A pregnancy registry has been established to collect information about eltrombopag effects during pregnancy. Enrollment is by calling 1-888-825-5249.
Emphasize the importance of routine lab tests to determine effectiveness and monitor for side effects.

Evaluation/Desired Outcomes

Increased platelet counts and decreased risk of bleeding. Platelet counts usually increase within 1–2 wk of starting and decrease within 1–2 wk of discontinuing therapy.