Eflornithine is an oral medication used to reduce the risk of recurrence in high-risk neuroblastoma. To ensure therapeutic efficacy and minimize adverse reactions, its clinical use requires precise dose calculation based on individual patient conditions, standardized administration, and timely dose adjustments when toxic reactions occur.
1. Recommended Pre-Treatment Tests
Before initiating treatment with eflornithine tablets, three key tests must be completed: a complete blood count (CBC), liver function tests (LFTs), and a baseline hearing test. These provide foundational data for subsequent treatment monitoring.
2. Recommended Dosage
The recommended dosage of eflornithine tablets is determined based on the patient’s body surface area (BSA), with specific dosage breakdowns as follows:
When BSA > 1.5 m²: 768 mg (4 tablets) orally, twice daily.
When BSA is between 0.75–1.5 m²: 576 mg (3 tablets) orally, twice daily.
When BSA ranges from 0.5–<0.75 m²: 384 mg (2 tablets) orally, twice daily.
When BSA is 0.25–<0.5 m²: 192 mg (1 tablet) orally, twice daily.
During treatment, the patient’s BSA must be recalculated every 3 months, and the dosage adjusted accordingly based on the results.
3. Dosage Adjustments for Adverse Reactions
Dosage Reduction Gradient
If the current dosage is 768 mg (4 tablets) twice daily, the first dose reduction is to 576 mg (3 tablets) twice daily.
If the current dosage is 576 mg (3 tablets) twice daily, reduce to 384 mg (2 tablets) twice daily.
If the current dosage is 384 mg (2 tablets) twice daily, adjust to 192 mg (1 tablet) twice daily.
If the current dosage is 192 mg (1 tablet) twice daily, further reduce to 192 mg (1 tablet) once daily.
If adverse reactions persist after subsequent adjustments, continue reducing the dosage until reaching the minimum dose of 192 mg (1 tablet) once daily. If the patient cannot tolerate this minimum dose, permanent discontinuation of eflornithine tablets is required.
Dosage Adjustments for Specific Adverse Reactions
Myelosuppression
Neutropenia: If the neutrophil count < 500/mm³, suspend treatment until the count recovers to ≥ 500/mm³. If recovery occurs within 7 days, resume treatment at the original dose; if recovery takes more than 7 days, treat at the next lower dose level.
Thrombocytopenia: If the platelet count < 25,000/mm³, suspend treatment until the count recovers to ≥ 25,000/mm³. If recovery occurs within 7 days, resume at the original dose; if recovery takes 7–14 days, use the next lower dose; if no recovery occurs within 14 days, discontinue permanently.
Anemia: If hemoglobin < 8 g/dL, suspend treatment until hemoglobin ≥ 8 g/dL, then resume at the original dose. If anemia recurs (hemoglobin < 8 g/dL again), suspend treatment until indicators return to normal, then treat at the next lower dose.
Hepatotoxicity
If aspartate aminotransferase (AST) or alanine aminotransferase (ALT) ≥ 10 times the upper limit of normal (ULN), suspend treatment until indicators decrease to < 10 × ULN. If recovery occurs within 7 days, resume at the original dose; if recovery takes more than 7 days, use the next lower dose.
Hearing Loss
If clinically significant new-onset or worsening hearing loss occurs (compared to baseline hearing tests), continue treatment and recheck hearing after 3 weeks. If hearing improves, maintain the original dose; if clinically significant hearing changes persist, suspend treatment for up to 30 days and recheck. Once hearing stabilizes or improves, treat at the next lower dose.
Other Adverse Reactions
For grade 3 nausea, vomiting, or diarrhea: If symptoms resolve with supportive care (e.g., antiemetics, antidiarrheals), maintain the original dose. If symptoms do not improve, suspend treatment until symptoms decrease to ≤ grade 2, then use the next lower dose.
For other grade 3 or 4 adverse reactions: Suspend treatment until symptoms decrease to ≤ grade 2, then use the next lower dose. If grade 4 adverse reactions recur, discontinue permanently.
4. Administration Method, Crushed Formulations, and Missed Dose Instructions
Administration Method
Eflornithine tablets are taken orally twice daily, either with food or on an empty stomach. The duration of treatment is 2 years, or until disease recurrence or unacceptable toxicity occurs. Tablets may be swallowed whole, chewed, or crushed before administration.
Crushed Formulations
For patients with swallowing difficulties, tablets may be chewed or crushed and mixed with 2 tablespoons of soft food or liquid. Visually confirm that the entire mixture is consumed. If crushed tablet particles remain in the container, add a small amount (no more than 1 ounce, or 30 mL) of additional soft food or liquid, mix, and administer. Crushed formulations must be taken within 1 hour of preparation; discard any unused portion after 1 hour.
