Fluorouracil (topical)

Sold under the name Efudex as a cream, this drug slows the growth of abnormal cells so they can be eliminated.


Fluorouracil must be prescribed by your doctor for you to begin treatment. If you are suffering from a skin condition such as skin cancer, your doctor may suggest this medication. This drug works by interfering with the development of abnormal (cancerous) cells.

Drugs of this class are called anti-metabolites. They are commonly used in cancer treatment and are a form of chemotherapy. Topical Fluorouracil is mild, however, and should not cause as many side effects as its intravenous counterparts.

Side effects of this drug can include skin sensitivity and irritation, but these are mild and should not affect your day to day life. Do not use tanning beds while using this drug, and you should not expose yourself to sunlight any more than necessary. Wear sunscreen often, and try to limit your activities outside.

This drug may interact with some of your existing medications. Be sure to let your doctor know if you are taking any additional drugs, including over the counter medications and herbal remedies. If any of these medications conflict with Fluorouracil, your doctor may ask you to lower your dose or stop taking them entirely.

This drug should not be ingested under any circumstances. It should be kept out of the reach of children and pets, and if accidental ingestion occurs, call poison control. This drug can be affected by how you store it, so make sure to follow all the storage requirements.

Only use this drug as directed. Overdose is uncommon when this drug is used properly and only applied to the skin. Always wash your hands before and after administering this medication. Dosage for this medication can vary from patient to patient. If you need to know how much of this medication you need to take, discuss it with your doctor upon prescription.

Conditions Treated

  • Other cancerous growths

Type Of Medication

  • Anti-metabolite

Side Effects

This drug may cause effects beyond its intended use. These side effects can range from mild to troublesome, and they may be unpleasant. Most of the common side effects do not require medical attention and may disappear or lessen over time. If your side effects persist or begin to affect your daily life, contact your doctor to ask about possible solutions.

Side effects can be treated with lifestyle changes, additional medications, or the switch to a new treatment. If you have questions or concerns about how this drug might affect you, speak to your doctor before applying it for the first time.

Here are some of the most frequently reported side effects. If your experience is not listed, mention it to your doctor during your next visit or schedule an appointment to discuss it.

  • Mild burning or irritation at application site
  • Itching
  • Skin wetness/oozing, especially when accompanied by itching
  • Tenderness of skin
  • Skin sensitivity to heat/sunlight

These side effects are normal and may occur as your body adjusts to the medication. If they persist and spread into aggravated rashes/sore areas, talk to your doctor. Some serious side effects may occur, as not everyone is able to take this drug safely. Contact your doctor as soon as possible if you experience:

  • Stomach upset
  • Signs of infection (cough, chills, fever)

Allergies may occur on this drug. If you have had previous allergic reactions to other drugs/creams of this nature, be sure to mention this to your doctor. Allergy symptoms can include

  • Swelling of the application site
  • Closing of the airways
  • Unexplained fever
  • Trouble breathing
  • Severe skin rash
  • Itching
  • Hives

Be sure to monitor your side effects thoroughly while using this drug. If you encounter anything strange/painful because of the drug, make sure to tell your doctor. Some side effects are mild and do not require medical attention, while others can be a sign that Fluorouracil is not right for you. If you believe your life is in danger at any point while using this drug, contact medical help immediately.


The dosage of this drug can vary from person to person. Dosing is determined by their condition, how they react to the first dose, and how much is necessary to cover the afflicted area. Your doctor or pharmacist should give you insight on how much you need. If you have further questions, make sure to bring them up before your next dose.

Because this drug comes as a cream, it may be hard to quantify how much is necessary. Here are the recommended doses for those using the topical form of the drug:

For use in skin cancer treatment:

Adults should use the 5% skin cream two times a day, applied to the afflicted areas.

For use in pre-cancerous skin diseases:

It is recommended that adults use 0.5% or 1% cream, applied topically. Stronger concentrations of the drug may be prescribed for use on the hands.

Children and their parents should consult heavily with their doctor before using this drug, as the dosages may be very different. Children may require a stricter regime, so be sure to discuss your child's treatment with your doctor before using.

When applying this medication, you may do so with q-tips, gloves, cotton balls, or other applicators. If you are applying this drug with your bare fingers, make sure to wash your hands both before and after application. Do not take this medication orally, and avoid getting this drug anywhere near your mouth.

Apply a thin layer to the affected area, and do not touch it until your skin absorbs the cream/solution. Do this two times a day, and avoid applying more unless instructed to do so. This drug may rub off onto clothes or furniture, so cover the area if necessary. Try to apply this drug after showers, and cover the areas with bandages before bed.


This drug may interact with other medications in your prescription list. Make sure to run all of your current medications past your doctor upon being prescribed this drug. Notify your physician before beginning any new medications, and avoid taking any drugs you think might interact with Fluorouracil.

Interactions can vary from mild to extreme. If you think a drug may interact with Fluorouracil, be sure to let your doctor know before beginning your next dose. Do not use any additional topical creams on the areas that you are using this medication. Doing so may limit the efficacy of this drug.

Keep a detailed list of your medications on hand for your doctor. Your doctor may ask that you lower the doses of your existing medications or stop them altogether. This is normal. If this is an issue, speak to your doctor about the matter to find a solution. Your doctor may be able to switch you to a similar medication or find an alternative for Fluorouracil.

Keep in mind that your doctor is recommending this drug for your benefit. The benefits of a treatment plan usually far outweigh those of an untreated lifestyle, and this drug can successfully prevent a serious case of skin cancer if used properly. If you have further questions or concerns about this drug and its use, make sure to mention them to your doctor.


This drug comes with warnings and precautions for all users. While some patients may be more affected by these risks than others, all people using this drug should be aware of its effects. Your doctor may provide you with a pamphlet or additional information on this drug. Make sure to read and understand it before using Fluorouracil. If you have questions or don't understand the content, ask your doctor for insight.

While using this drug, you should avoid direct contact with sunlight. Wear hats, sunglasses, and covered clothing. Avoid trips to the beach or other sunlit areas. If you have a job that requires you to remain in the sun, make sure to cover your problem areas with opaque bandages, and try to stay in the shade. Avoid the outdoors during peak sunlight hours, which can range from 1pm to 3pm.

Use sunscreen to avoid further issues. SPF 15 or higher is recommended for everyone, although paler patients may require higher concentrations. Even if you have dark or tanned skin, you should not neglect to put n sunscreen. Make sure to apply it every time you go for a walk or outdoor activity. Re-apply it often, especially if you are in water.

Do not use tanning booths or tanning beds while using this medication. This can aggravate your condition and cause additional side effects and complications. Do not tan normally, either. Limit your contact with sunlight or other forms of UV rays. If you have family members that tan often, try to encourage them to adopt healthier habits.


Any form of topical Fluorouracil will probably come in a tube. Cream and solution forms of this medication should be kept between the temperatures of 68 and 77 degrees Fahrenheit. Do not put this medication in the fridge or freezer. Keep it in a dry, cool location, and do not allow it to become heated or frozen. Doing so may affect the efficacy of this medication, making it work less effectively.

Avoid storing this drug anywhere within reach of children. Keep it in a locked cabinet or drawer if necessary. Do not allow any children or pets to consume this drug. If accidental ingestion occurs, call poison control right away. Be sure to keep the prescription information so they know what the drug is upon arrival. Be ready to inform them on how much was taken, when it was taken, and what the drug does.

Disposal of this drug should be done carefully. Seal the tube in a plastic bag and throw it away with the rest of your garbage. Do not flush this drug or pour it down the sink. If you have excess medication, do not keep it around. It may expire in the meantime. Unless your doctor advises you to do so, do not keep this drug around any longer than necessary. Chances are, you will not need to use it after your treatment is over.

Do not give this drug to anyone else, no matter their symptoms. They may react badly, have a misdiagnosis, or want the drug for other reasons. If they need a prescription, they should be able to get one from their doctor. If you end up with excess medication, look for secure take-back programs in your area. They should be hosted/sponsored by hospitals or pharmacies, not independent people or groups.

If you need to travel with this drug in your possession, keep it in the original packaging. Show the drug to your TSA agent while passing through security, and make sure all the necessary information is on-hand. Do not put this drug in other containers, especially unmarked bottles.


This drug is used by many people to treat skin cancer and pre-cancerous growths. Its topical nature makes it easy to use, and the side effects of this drug are usually milder than its other, oral counterparts. If you react badly to this drug, have an allergic reaction, or experience a worsening condition while using this medication, stop using it and talk to your doctor.

This drug is only meant to be used topically. If you are being prescribed an injection of Fluorouracil, you need to look up the specifics of that route. Do not take this drug orally, rectally, or intravenously. It is only meant to be used on the skin's surface, so avoid applying it to sensitive areas like the genitals, eyes, or mouth.

Talk to your doctor before using this drug. They should be able to answer all of your questions and help you with this process. This drug is only available via prescription, so make sure to talk to your doctor if you are experiencing symptoms of skin cancer.