Eflornithine
Eflornithine is an enzyme-blocking medicine used to lower the risk of relapse in high-risk neuroblastoma (as an oral tablet) and to reduce unwanted facial hair in women (as a topical cream).
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 1 clinical label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
Eflornithine, on the U.S. market since about 2005, blocks ornithine decarboxylase (an enzyme cells need to grow). It comes as two unrelated products, Iwilfin tablets, a specialist medicine that lowers relapse risk in high-risk neuroblastoma (a childhood nerve-cell cancer) after immunotherapy, and Florexa cream, which reduces unwanted facial hair in women. The Iwilfin side effects people notice most are diarrhea, vomiting, fever and ear infections, while the cream’s main label concern is an allergic reaction. On Iwilfin, watch hearing above all, since it can also cause low blood counts and liver injury, so keep every scheduled hearing test, blood count and liver check.
Clinical pearls
- Iwilfin tablets can be swallowed whole, chewed, or crushed into soft food or liquid, which helps younger children.
- Iwilfin can harm an unborn baby, so women and men both need effective birth control until a week after the last dose.
- Mention any kidney problems to the care team, because Iwilfin clears more slowly and may need a lower dose.
- Florexa is meant only for the face and under the chin, and children under 12 should not use it.
Patient information guide A plain-language walkthrough of Eflornithine, written from its FDA label.
What Eflornithine is used for
▾
Eflornithine is used for two unrelated purposes, depending on the product.
- Iwilfin (oral tablet): lowers the risk of relapse in adults and children with high-risk neuroblastoma who responded at least partly to earlier multi-step treatment, including anti-GD2 immunotherapy.
- Florexa (topical cream): reduces unwanted facial hair in women, on the face and under the chin only.
How Eflornithine works
▾
Eflornithine permanently blocks an enzyme called ornithine decarboxylase (ODC). This enzyme is the first step in making polyamines, which help cells grow and multiply.
In neuroblastoma, blocking ODC lowered the activity of cancer-driving genes (MYCN and LIN28B). In lab studies it slowed the growth of neuroblastoma cells rather than killing them outright.
Eflornithine dosage
▾
Iwilfin and Florexa are used differently, so follow the directions for your product.
- Iwilfin tablets are taken by mouth twice daily, with or without food.
- They can be swallowed whole, chewed, or crushed and mixed with soft food or liquid.
- The dose depends on body surface area and is rechecked every 3 months.
- Treatment runs up to two years, or until the disease progresses or side effects become unacceptable.
- Florexa cream is used only on the face and under the chin.
Always follow your prescriber's instructions and the product label.
Dosing details from the FDA-approved label
From the Eflornithine prescribing information (“Dosage and Administration”). Doses are set by your prescriber for your product, condition, kidney function and age — never change a dose on your own.
- Body surface area >1.5 m2
- 768 mg (four tablets) orally twice a day
- Administer for two years or until recurrence of disease or unacceptable toxicity; recalculate BSA dosage every 3 months; may be taken with or without food
- Body surface area 0.75 to 1.5 m2
- 576 mg (three tablets) orally twice a day
- Administer for two years or until recurrence of disease or unacceptable toxicity; recalculate BSA dosage every 3 months; may be taken with or without food
- Body surface area 0.5 to < 0.75 m2
- 384 mg (two tablets) orally twice a day
- Administer for two years or until recurrence of disease or unacceptable toxicity; recalculate BSA dosage every 3 months; may be taken with or without food
- Body surface area 0.25 to < 0.5 m2
- 192 mg (one tablet) orally twice a day
- Administer for two years or until recurrence of disease or unacceptable toxicity; recalculate BSA dosage every 3 months; may be taken with or without food
Read the label’s full dosing text
2 DOSAGE AND ADMINISTRATION Prior to initiation of IWILFIN, perform baseline audiogram, complete blood count, and liver function tests. ( 2.1 , 5.3 ) Recommended dosage of IWILFIN is based on body surface area (see Table 1 ). ( 2.2 ) IWILFIN is taken orally twice daily with or without food until disease progression, unacceptable toxicity, or for a maximum of two years. ( 2.2 ) IWILFIN tablets may be swallowed whole, chewed, or crushed and mixed with soft food or liquid. ( 2.5 ) 2.1 Recommended Testing Before Initiating IWILFIN Prior to initiating IWILFIN, perform complete blood count, liver function tests, and baseline audiogram [see Warnings and Precautions (5.1 - 5.3) ]. 2.2 Recommended Dosage of IWILFIN The recommended IWILFIN dosage, based on body surface area (BSA), is provided in Table 1. Administer IWILFIN orally twice daily for two years or until recurrence of disease or unacceptable toxicity. Recalculate the BSA dosage every 3 months during treatment with IWILFIN. Table 1: Recommended Dose Body Surface Area (m 2 ) Dosage >1.5 768 mg (four tablets) orally twice a day 0.75 to 1.5 576 mg (three tablets) orally twice a day 0.5 to < 0.75 384 mg (two tablets) orally twice a day 0.25 to < 0.5 192 mg (one tablet) orally twice a day 2.3 Dosage Recommendations for Renal Impairment For the treatment of patients with severe renal impairment (eGFR <30 mL/min), reduce the recommended dose of IWILFIN by 50% as described in Table 2 [ see Use in Specific Populations (8.5) , Clinical Pharmacology (12.3) ]. Table 2: IWILFIN Dose Recommendations for Severely Renally Impaired Patients Body Surface Area (m 2 ) Recommended Dosage for Patients with Severe Renal Impairment (eGFR <30 mL/min) >1.5 384 mg (two tablets) orally twice a day 0.75 to 1.5 384 mg (two tablets) in the morning and 192 mg (one tablet) in the evening 0.5 to < 0.75 192 mg (one tablet) orally twice a day 0.25 to < 0.5 192 mg (one tablet) once a day 2.4 Dosage Modifications for Adverse Reactions The recommended dose reductions for adverse reactions are provided in Table 3.
Excerpted — the section continues on the label. Read the full Dosage and Administration section on DailyMed →
Eflornithine side effects
▾
In the Iwilfin safety studies, the most common side effects were:
Common side effects
- Hearing loss
- Ear infection (otitis media)
- Fever
- Pneumonia
- Diarrhea
- Cough, sinus infection and upper respiratory infections (seen in children in one study)
- Vomiting
- Abnormal blood or liver test results
When to get medical help
- Tell your doctor about any new or worsening hearing problems or ringing in the ears while taking Iwilfin.
- Call your doctor about fever, signs of infection, unusual bruising or bleeding, or unusual tiredness, which can signal low blood counts.
- Report symptoms of liver problems, since Iwilfin can raise liver enzymes.
- Stop using the product and get help if you have an allergic reaction (hypersensitivity).
- Tell your doctor right away if you become pregnant or think you might be.
Lab tests commonly showed higher liver enzymes (ALT, AST) and lower neutrophil and hemoglobin levels. Report any hearing changes, signs of infection, or signs of liver trouble to your doctor promptly.
Eflornithine warnings and precautions
▾
- Hearing loss: Iwilfin can cause new or worse hearing loss. A hearing test is done before starting and about every 6 months.
- Low blood counts: Iwilfin can lower white cells, platelets and red cells. Blood counts are checked before and during treatment.
- Liver injury: Liver tests are done before starting, monthly for the first six months, then about every 3 months.
- Pregnancy: Iwilfin can harm an unborn baby. Use effective contraception.
- Allergy: Stop use if hypersensitivity occurs.
Eflornithine interactions
▾
Interaction information is limited for this medicine.
- Florexa: it is not known whether it interacts with other products applied to the skin.
Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.
Before taking Eflornithine
▾
- Tell your doctor if you have ever reacted to any ingredient in these products.
- Florexa should not be used by children under 12.
- Iwilfin can harm a fetus. Women who could become pregnant, and men with partners who could, should use effective contraception during treatment and for 1 week after the last dose.
- Do not breastfeed while taking Iwilfin.
- Tell your doctor about any kidney problems. Iwilfin dose reductions are needed for some kidney impairment.
- Expect a hearing test, blood counts and liver tests before starting Iwilfin.
What Eflornithine does in the body
▾
How eflornithine's effects relate to dose and timing is not known. At the recommended dose, Iwilfin did not cause a large increase in the QTc interval, a measure of the heart's electrical cycle.
How your body processes Eflornithine
▾
After an Iwilfin tablet is swallowed, blood levels peak at about 3.5 hours. Food, even a high-fat meal, does not change how much is absorbed, and crushing tablets into pudding did not change it either. The half-life is about 3.5 hours.
People with moderate or severe kidney impairment had 2-fold and 4-fold higher exposure, respectively. Age, sex, body size and mild liver impairment did not meaningfully change exposure.
How to store Eflornithine
▾
Store at room temperature, 20°C to 25°C (68°F to77°F), excursions permitted between 15°C to 30°C (59°F to 86°F) .
Written from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
Supplements & herbs that interact with Eflornithine
9 supplements and herbal products have documented interactions with Eflornithine in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
- Moderate · 8
- Minor · 1
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
Eflornithine: pharmacist answers to common questions
Quick, plain-English answers to the questions patients ask most about Eflornithine — the kind of thing our pharmacy team would talk through with you at the counter.
What is eflornithine used for?
▾
How do I take Iwilfin?
▾
What side effects should I expect with Iwilfin?
▾
Why do I need so many tests?
▾
Is it safe in pregnancy?
▾
Can children use Florexa?
▾
Is Eflornithine available over the counter?
▾
When was Eflornithine first available?
▾
Answers drafted from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
More about Eflornithine on HelloPharmacist
Eflornithine forms and strengths (how it comes)
Eflornithine is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Need a version that does not list lactose, a gluten source, a dye or gelatin? Inactive ingredients differ by manufacturer: see Eflornithine inactive ingredients by manufacturer.
Tablet
How this form is used
- Iwilfin is used to reduce the risk of relapse in adults and children with high-risk neuroblastoma who responded at least partly to earlier therapy including anti-GD2 immunotherapy.
- Iwilfin is taken by mouth twice daily, with or without food.
- Iwilfin tablets may be swallowed whole, chewed, or crushed and mixed with soft food or liquid.
- Iwilfin dosing is based on body surface area and is recalculated every 3 months.
- Iwilfin treatment lasts up to two years, or until the disease progresses or side effects are unacceptable.
Eflornithine on the U.S. market: products, makers and brands
How Eflornithine appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
1 company lists 1 Eflornithine product record with the FDA, mostly as tablet; the earliest marketing or approval year on record is 1990. Brand names on the directory include Vaniqa, iwilfin; the rest are generics.
Also listed with the FDA, not a patient dose form: Powder (7) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.
How widely Eflornithine is used (Medicaid data)
A general measure of how commonly Eflornithine is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely Eflornithine is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is Eflornithine prescribed? Of the 1,601 medications we measure, Eflornithine ranks #1,363 by Medicaid prescriptions — more than 15% of them.
Utilization by Eflornithine product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
eflornithine 192 MG Oral Tablet
Summed across the 1 of 1 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2673199
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Eflornithine, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 1 of 1 listed Eflornithine NDCs with Medicaid activity.
Compare Eflornithine products
A representative set of FDA-listed product records for Eflornithine — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Tablet | ||||
| 250 mg | Oral | Uswm, Llc | NDA | View NDC → |
Showing 1 of 1 products — FDA National Drug Code Directory. See every product, package size and price: browse all 1 Eflornithine NDCs →
Eflornithine side effects reported to the FDA (FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Eflornithine — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Eflornithine in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
Eflornithine FDA approval history
How Eflornithine went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
Eflornithine recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
The FDA’s enforcement reports list no Eflornithine recalls since July 2021.
✅No Eflornithine recalls on record since July 2021Source: FDA enforcement (recall) reports, via openFDA; our copy was last updated Sep 24, 2026.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 569 3 dose forms · 4 strengths
-
Dose form (SCDF) Injectable Solution RxCUI 377245No current FDA listingClinical drug / strength (SCD) 200 MG/MLRxCUI 310054 -
Dose form (SCDF) Oral Tablet RxCUI 2673198In current FDA listingsClinical drug / strength (SCD) 192 MGRxCUI 2673199 -
Dose form (SCDF) Topical Cream RxCUI 377696No current FDA listingClinical drug / strength (SCD) 115 MG/MLRxCUI 484161139 MG/MLRxCUI 313975
Look up RxCUI 569 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
Eflornithine supply and shortage status
Whether Eflornithine is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
Eflornithine brand names
Eflornithine is sold under 2 brand names in the FDA directory — Vaniqa, iwilfin. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.
Who makes Eflornithine: manufacturers and labelers
One company lists Eflornithine products with the FDA. By number of product records, the largest are Uswm, Llc. Labelers include manufacturers and repackagers; the product in your bottle depends on which one your pharmacy stocks.
Eflornithine drug class (RxNorm)
Eflornithine belongs to the Antiprotozoal class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
Sources for this Eflornithine page
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How this page is built
HelloPharmacist combines public FDA and NLM records and does not author the underlying clinical facts. The plain-language sections are written with AI from the FDA-approved label text and reviewed by our pharmacy team before publication. Uswm, Llc is the representative DailyMed label linked for verification and dates. This is general education, not medical advice: always talk to your doctor or pharmacist about your own medicines. How we build and review drug pages →