Eflornithine (Iwilfin™)

Author: Allyson Distel, MPH
Content Contributor: Christine Cambareri, PharmD, BCPS, BCOP
Last Reviewed: December 22, 2023

Pronounce: ee-FLOR-ni-theen

Classification: Kinase Inhibitor

About: Eflornithine (Iwilfin™)

Eflornithine is a type of targeted therapy called a kinase inhibitor. A kinase is an enzyme that promotes cell growth. There are many types of kinases, which control different phases of cell growth. By blocking a particular enzyme from working, this medication can slow the growth of cancer cells. This medication is an ornithine decarboxylase inhibitor. This means that it blocks polyamines which allow cells to grow.

How to Take Eflornithine

This medication comes in a tablet form. It is often taken twice a day and your dose will depend on the size of your body. It can be taken with or without food and can be taken whole, chewed, or crushed. If you crush the medication, you should add it to 2 tablespoons of soft food or liquid. Any tablets that are crushed should be taken or thrown away after one hour. You may need to rinse your mouth with water and swallow to make sure you take all of the medication.

It is important to make sure you are taking the correct amount of medication every time. Before every dose, check that what you are taking matches what you have been prescribed.

If you miss a dose of this medication, you should take it again as soon as possible. If your next dose is 7 hours away or less, skip the missed dose and take your next dose as scheduled. If you vomit after taking Eflornithine, you should not take an additional dose.

Before starting this medication, your provider will ask you to complete a baseline audiogram (hearing test) and blood tests to check your liver and blood count. This will help to monitor if you are having side effects from the medication.

Storage and Handling of Eflornithine

Store your medication in the original, labeled container at room temperature and in a dry location (unless otherwise directed by your healthcare provider or pharmacist). Keep containers out of reach of children and pets.

Where do I get this medication?

Eflornithine is available through select specialty and retail pharmacies. Your oncology team will work with your prescription drug plan to identify an in-network pharmacy for the distribution of this medication.

Insurance Information

This medication may be covered under your prescription drug plan. Patient assistance may be available to qualifying individuals without prescription drug coverage. Co-pay cards, which reduce the patient co-pay responsibility for eligible commercially (non-government sponsored) insured patients, may also be available. Your care team can help you find these resources if they are available.

Possible Side Effects

There are a number of things you can do to manage the side effects of eflornithine. Talk to your care team about these recommendations. They can help you decide what will work best for you. These are some of the most common or important side effects:

Hearing and Ear Problems

Eflornithine can cause ear issues like infections and inflammation. Ear infections and inflammation can lead to hearing loss. Your provider will check your hearing before, during, and after taking this medication. Let your provider know if you have pain in your ears or notice any hearing changes.

Less common, but important side effects are:

  • Liver Toxicity: This medication can cause liver toxicity, which your doctor may monitor for using blood tests called liver function tests. Let your healthcare provider know if you notice yellowing of the skin or eyes, your urine appears dark or brown or pain in your abdomen, as these can be signs of liver toxicity.
  • Low White Blood Cell Count (Leukopenia or Neutropenia):White blood cells (WBC) are important for fighting infection. While receiving treatment, your WBC count can drop, putting you at a higher risk of getting an infection. You should let your doctor or nurse know right away if you have a fever (temperature greater than 100.4°F or 38°C), sore throat or cold, shortness of breath, cough, burning with urination, or a sore that doesn't heal.
    • Tips to preventing infection:
      • Washing hands, both yours and your visitors, is the best way to prevent the spread of infection.
      • Avoid large crowds and people who are sick (i.e.: those who have a cold, fever or cough or live with someone with these symptoms).
      • When working in your yard, wear protective clothing including long pants and gloves.
      • Do not handle pet waste.
      • Keep all cuts or scratches clean.
      • Shower or bathe daily and perform frequent mouth care.
      • Do not cut cuticles or ingrown nails. You may wear nail polish, but not fake nails.
      • Ask your oncology care team before scheduling dental appointments or procedures.
      • Ask your oncology care team before you, or someone you live with has any vaccinations.
      • Do not use a razor (an electric razor is fine).
      • Avoid contact sports and activities that can result in injury or bleeding.
      • Do not take aspirin (salicylic acid), non-steroidal, anti-inflammatory medications (NSAIDs) such as Motrin/Advil (ibuprofen), Aleve (naproxen), Celebrex (celecoxib), etc. as these can all increase the risk of bleeding. Please consult with your healthcare team regarding the use of these agents and all over-the-counter medications/supplements while on therapy.
      • Do not floss or use toothpicks and use a soft-bristle toothbrush to brush your teeth.
  • Low Red Blood Cell Count (Anemia): Your red blood cells are responsible for carrying oxygen to the tissues in your body. When the red cell count is low, you may feel tired or weak. You should let your oncology care team know if you experience any shortness of breath, difficulty breathing, or pain in your chest. If the count gets too low, you may receive a blood transfusion.
  • Low Platelet Count (Thrombocytopenia):Platelets help your blood clot, so when the count is low you are at a higher risk of bleeding. Let your oncology care team know if you have any excess bruising or bleeding, including nose bleeds, bleeding gums, or blood in your urine or stool. If the platelet count becomes too low, you may receive a transfusion of platelets.

Reproductive Concerns

Exposure of an unborn child to this medication could cause birth defects, so you should not become pregnant or father a child while on this medication. Effective birth control is necessary while taking this medication and for at least one week after the last dose. Even if your menstrual cycle stops or you believe you are not producing sperm, you could still be fertile and conceive. You should not breastfeed while taking this medication and for at least one week after the last dose.