Efudix 5%

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Efudix 5%

Method of action: Antitumour, Cytostatic

Treatment option: Cancer

Medically reviewed

Laura Arias

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Efudix 5%

What is Efudix 5%?

Efudix 5% is a topical medicated cream used primarily for the treatment of specific types of skin conditions caused by sun damage or certain abnormal cell growth. The active ingredient in the formulation is fluorouracil, which belongs to a class of medications known as antimetabolites.

Mechanism of Action

Fluorouracil works by interfering with the synthesis of DNA and RNA within cells. Because abnormal or precancerous cells typically divide more rapidly than healthy skin cells, they take up the medication more readily. Once absorbed, the active ingredient disrupts the metabolic processes of these cells, preventing them from multiplying and eventually leading to their destruction.

Primary Uses

Efudix 5% is commonly prescribed for the following conditions:

  • Actinic Keratosis: Also known as solar keratosis, these are rough, scaly patches on the skin caused by years of sun exposure. They are considered precancerous because, if left untreated, they may develop into a type of skin cancer.
  • Bowen's Disease: A localized form of skin cancer where the abnormal cells are contained within the outer layer of the skin (in situ squamous cell carcinoma).
  • Superficial Basal Cell Carcinoma: A common form of skin cancer that grows slowly and is located on the surface of the skin.

Characteristics of the Medication

The treatment is designed to target damaged areas while sparing as much healthy surrounding tissue as possible. During the course of application, it is characteristic for the treated area to become red, inflamed, or crusty. This reaction is generally an indication that the medication is working to eliminate the abnormal cells. The skin typically heals after the course of treatment is completed, often resulting in a smoother appearance than before the therapy began.

Regulatory References

  1. antineoplastic antimetabolite
  2. NCI Dictionary of Cancer Terms - fluorouracil

What side effects are possible with Efudix 5%?

Possible Side Effects and Safety Information

Official regulatory documents classify the safety profile of topical fluorouracil (Efudix 5%) primarily based on the expected local response at the application site and specific risks of systemic exposure.

Adverse Reactions and Frequency

The most commonly documented effects are local cutaneous reactions, classified as Very Common in official labeling. These effects, which include erythema (redness), skin burning sensation, pain, swelling, exfoliation, and skin ulceration, are considered part of the expected pharmacological activity on the skin. Reactions such as dermatitis, eczema, and pruritus are also documented.

Systemic adverse reactions are classified as Very Rare and involve other System-Organ Classes, including haematological disorders and gastrointestinal effects like haemorrhagic diarrhoea and vomiting. Effects such as dysgeusia, headache, and conjunctival irritation are listed with a Frequency Not Known.


Serious Safety Considerations and Restrictions

The most serious safety risk documented in regulatory sources is life-threatening systemic toxicity. This is a Very Rare event, primarily associated with significant systemic absorption, particularly in individuals with a known complete Dihydropyrimidine Dehydrogenase (DPD) enzyme deficiency. For this reason, the medication is officially contraindicated in DPD-deficient patients.

Regarding specific populations, the cream is contraindicated in women who are or may become pregnant due to the potential for fetal harm. Safety and effectiveness have not been established in pediatric patients.

Time-related safety patterns indicate that the maximum inflammatory reaction and skin erosion typically occur during the second week of treatment. Furthermore, official regulatory documents state that application site irritation may persist for two or more weeks after treatment is stopped.

Safety constraints also include the avoidance of UV radiation exposure, which may increase the intensity of the inflammatory reaction, and a contraindication against concurrent use with certain antiviral nucleoside drugs.

Overdose and Emergency Response

Overdose Map: Overdose and when to seek help — Official Regulatory Information for Efudix 5%

Feature Official Regulatory Statement
Documented overdose presentations Systemic toxicity following excessive absorption or accidental ingestion may present with nausea, vomiting, diarrhea, stomatitis (mouth sores), and signs of blood dyscrasias
Physiological systems affected (as stated in label) Gastrointestinal system (severe toxicity) and Haematological system (myelosuppression, leukopenia, thrombocytopenia)
Dose-related or exposure-related factors (if applicable) Accidental ingestion or excessive topical absorption through ulcerated or inflamed skin are the circumstances associated with systemic overdose risk.
Population-specific overdose notes (if applicable) Patients with an undiagnosed Dihydropyrimidine Dehydrogenase (DPD) enzyme deficiency are at a significantly increased risk for acute, early-onset, and potentially life-threatening systemic toxicity.
Emergency-response statements (as written in official documents) If the cream is accidentally ingested, induce emesis and perform gastric lavage. If contact with eyes occurs, flush immediately with water or normal saline.
When immediate medical help is required (label-derived phrasing only) Seek immediate medical attention upon suspicion or occurrence of systemic toxicity, or if the local inflammatory reaction advances to the erosion, ulceration, and necrosis stages.

Overdose classifications (high-level)

Feature Official Regulatory Statement
Severity classification (as defined in official documents) Overdose can lead to life-threatening systemic toxicity and fatal complications from myelosuppression.
Regulatory basis (EMA / FDA / etc.) The overdose profile is documented in the FDA Prescribing Information and the EMA Summary of Product Characteristics (SmPC).
Overdose-context constraints (as defined in official documents) No specific antidote is known; management requires symptomatic and supportive care, though Uridine triacetate is approved for the emergency treatment of systemic fluorouracil overdose.

Resulting overdose structure

Official overdose statements:

  • Signs of systemic toxicity may include nausea, vomiting, diarrhea, stomatitis, and haematological disorders.
  • The most severe outcomes are life-threatening systemic toxicity, severe gastrointestinal complications, and myelosuppression.
  • Patients with DPD deficiency have a significantly increased risk of developing severe, early-onset systemic toxicity.
  • In the case of accidental ingestion, immediate actions include inducing emesis and performing gastric lavage, and immediate medical attention must be sought.

Connection to the overall overdose profile (3 sentences): Regulatory documents define the overdose profile based on the potential for systemic absorption or accidental ingestion to cause severe and potentially life-threatening systemic toxicity. This risk is primarily manifested through severe gastrointestinal and haematological disorders, requiring immediate medical attention and the discontinuation of treatment. The mandated emergency actions and supportive management procedures described in the regulatory labels ensure a structured response to mitigate these documented systemic risks.

Therapeutic Uses of Efudix 5%

What Efudix 5% Treats: Main Uses and Benefits

Efudix 5% is a specialized topical treatment commonly used for managing conditions characterized by abnormal cellular growth on the skin. It is applied when symptomatic assistance is needed for manifestations such as Actinic Keratoses (AKs), Superficial Basal Cell Carcinoma (sBCC), and Bowen's Disease (a form of in situ Squamous Cell Carcinoma). A key therapeutic benefit is supporting the removal of these abnormal cells. This may assist patients by offering a non-surgical option for addressing these concerning skin growths.

This cream is considered relevant in scenarios involving Field Cancerization, a widespread state where sun damage leads to numerous visible and subclinical precancerous cells. By treating the entire affected field, the medication is considered relevant for managing the overall risk of these pre-malignant changes progressing into more invasive skin cancer. For patients seeking a focused approach, “it is commonly used to address groups of symptoms that appear suddenly or fluctuate across sun-damaged skin.” The treatment may contribute to easing the overall symptom load during periods of heightened symptoms and may assist with maintaining functional stability.


Quick Fact: Relief for Scaly, Precancerous Patches The medication is relevant for managing conditions that present with disruptive symptom manifestations like rough or scaly lesions, contributing to improved comfort and helping to maintain a sense of stability when symptoms are more noticeable.

Regulatory References

  1. MedlinePlus Drug Information

Eligibility and Restrictions for Use

Who Can and Cannot Use Efudix 5%

The eligibility profile for Efudix 5% topical cream is strictly defined by regulatory authorities and centers on absolute contraindications and specific population restrictions.

Absolute Contraindications

Efudix 5% must not be used in certain patient populations as defined in regulatory labeling:

  • Pregnancy and Lactation: Use is formally contraindicated in women who are or may become pregnant, and in breastfeeding mothers.
  • Metabolic Deficiency: The medicine is contraindicated in patients with a known deficiency of the Dihydropyrimidine Dehydrogenase (DPD) enzyme, due to the risk of severe systemic toxicity.
  • Hypersensitivity: Patients with a known allergy or hypersensitivity to Fluorouracil or any other ingredient in the cream are excluded from use.
  • Drug Interaction: Concomitant use with certain antiviral nucleoside drugs (such as brivudine and its analogues) is contraindicated.

Age and Conditional Restrictions

  • Age: The product is not recommended for use in children (pediatric population) because its safety and effectiveness in this age group have not been established by regulators. Use in older adults (geriatric patients) is generally permitted.
  • Application Site: Application to mucous membranes (e.g., eyes, nostrils, mouth) must be avoided. Use on ulcerated or inflamed skin requires caution, as this condition may increase the amount of medicine absorbed into the body.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Official regulatory documentation identifies specific, highly significant interactions concerning the metabolism of Efudix 5% (Fluorouracil). These interactions define the restrictions and use limitations for the product.

Contraindicated Combinations and Metabolic Restrictions

The co-administration of Efudix 5% with antiviral nucleoside drugs, specifically brivudine and sorivudine, is formally contraindicated in regulatory labeling. This mandatory restriction is based on the documented mechanism where these antivirals act as potent inhibitors of the Dihydropyrimidine Dehydrogenase (DPD) enzyme.

Inhibition of the DPD enzyme, which is responsible for breaking down fluorouracil, leads to a substantial, documented increase in the systemic plasma concentration of fluorouracil and subsequent heightened toxicity risk. Consequently, a mandatory timing separation requirement of at least four weeks must be observed between the use of these contraindicated agents and the administration of the cream.

Population-Specific Interaction Caution

Systemic exposure risk is a primary regulatory concern for specific populations. The product is contraindicated in individuals with a known complete absence of DPD enzyme activity. This genetic deficiency mimics a severe drug interaction by preventing the drug’s metabolic clearance, and its complete absence represents a heightened risk of acute, life-threatening systemic toxicity.

Other Interactions

The official labeling for topical Efudix 5% does not document clinically significant interaction patterns with common medicinal products, food, alcohol, or herbal supplements.

Mechanism of Action

Molecular Targets and Mechanistic Cascades

The action of Fluorouracil (5-FU), the active ingredient in Efudix 5%, is focused on disrupting nucleic acid synthesis in rapidly dividing cells. The drug is an antimetabolite and a pyrimidine analog that requires intracellular bioactivation into its cytotoxic form, FdUMP. This metabolite functions as a mechanism-based inhibitor that forms a stable, irreversible complex with the enzyme Thymidylate Synthase (TS). This enzyme blockade critically halts the conversion of dUMP to dTMP, leading to a deficiency of the vital DNA precursor.

Simultaneously, other active metabolites are misincorporated into both RNA and DNA, inducing structural and functional errors in genetic material. This combined damage—DNA replication stress and RNA dysfunction—triggers a final cascade of apoptosis (programmed cell death) in the targeted, metabolically active cells. The physiological consequence of this sustained, localized cytotoxicity is the physical disintegration and subsequent clearance of the affected cell population at the site of application.

Dosage and Administration Information

Official Administration Guidelines

Efudix 5% (Fluorouracil 5% cream) is a medication for topical (dermal) use only. The standard administration involves applying the 5% w/w cream in an amount sufficient to cover the designated lesions or the entire affected field.

Instruction Entity Detail
Route of administration Topical (dermal) application only.
Frequency and timing Applied once or twice daily, depending on the specific condition being treated.
Age-group administration rules Use in children is not recommended due to insufficient clinical data.
Special procedural conditions The total treated area should not exceed 500 cm² (approximately 23 cm x 23 cm) at one time.

The use protocol requires careful handling. The cream should be applied using a non-metal applicator or a suitable glove, and hands must be washed thoroughly immediately after application. Application to sensitive areas, such as mucous membranes, should be avoided.

The treatment duration is dependent on the condition and clinical response. For Actinic Keratoses, the course typically runs from 3 to 4 weeks. For Superficial Basal Cell Carcinoma, the course is often longer, ranging from 3 to 6 weeks, with administration continuing until a marked inflammatory response or erosion is achieved. These timeframes establish the required commitment to the therapy.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Efudix 5%

The body of research for Efudix 5% (Fluorouracil 5% cream) has been developed through various clinical trials that focused on skin conditions characterized by abnormal cellular activity. These studies monitored patterns and outcomes in treated populations to contribute to the broader evidence landscape. This overview summarizes the structure of the existing research.


Evidence for Use in Actinic Keratosis (AK)

The research on Actinic Keratosis (AKs) primarily consists of Randomized Controlled Trials (RCTs) and Systematic Reviews. Studies explored outcomes related to physical discomfort and patient-reported experiences. The main outcome measurements involved assessing lesion change measurements of visible lesions. In studies where the cream was compared to a non-active vehicle, trials examined measurements of lesion changes.

Systematic reviews described patterns where the cream was studied for lesion change measurements compared to the vehicle used in the research. Studies tracking long-term outcomes reported patterns related to the need for continued treatment. The overall consistency of evidence across this research area is described by a coarse evidence level grading of High.


Evidence for Use in Superficial Basal Cell Carcinoma (sBCC)

Research for Superficial Basal Cell Carcinoma (sBCC) includes initial Non-comparative studies and subsequent Randomized Controlled Trials (RCTs). A key high-level outcome measured in this research was histological change determined by biopsy and tracking the long-term recurrence rate. Initial regulatory studies reported measured rates of histological change determined by biopsy shortly after the designated treatment period.

Comparative trials and reviews described patterns where the cream’s long-term tumor-free survival rates were monitored; comparative evidence is lacking or evidence quality varies across studies. The combination of initial change measurements and variable long-term comparative data is described by a coarse evidence level grading of Moderate.


Research Gaps and What Remains Uncertain

The existing research findings describe group patterns, not personal outcomes. What remains uncertain includes the absolute long-term effects related to the continued change of precancerous lesions (AKs) into invasive skin cancers; these outcomes are not fully established. For Basal Cell Carcinoma, the cream was studied for only the superficial subtype, and its use in treating deeper or nodular tumors data remain insufficient in the existing research. Additionally, results apply only to the populations studied; for key subgroups like children, subgroup findings are uncertain.

Key Studies & References

  1. Long-term Efficacy of Topical Fluorouracil Cream, 5%, for Treating Actinic Keratosis: A Randomized Clinical Trial (VAKCC trial)
  2. Surgical excision versus topical 5% 5-fluorouracil and photodynamic therapy in treatment of Bowen's disease: A multicenter randomized controlled trial
  3. Fluorouracil (topical route) - Drug information and Regulatory Approval Status (StatPearls)
  4. Fluorouracil (Topical) - Uses and Approved Indications (NCI)

Frequently Asked Questions (FAQ)

Common questions about Efudix 5% (FAQ)


Q: How soon after starting Efudix 5% will I see a reaction on my skin?

The skin reaction, involving redness and inflammation, is an expected part of the treatment process as described in official product information. Fluorouracil also treats abnormalities that were not previously visible, and these may become red and inflamed during the course of therapy.

Q: Is Efudix 5% safe for use on the face?

Use of the cream on the face is generally permitted for designated lesions, and regulatory documents note that facial lesions may respond more quickly than those on the limbs or trunk. However, official instructions advise avoiding application near mucous membranes, such as the eyes, nostrils, and mouth.

Q: What does 'actinic keratosis' mean in simple terms?

Actinic keratosis is described by medical authorities as a precancerous skin condition that results from long-term exposure to sunlight. These growths of the skin are the primary condition for which Efudix 5% cream is commonly used in topical therapy.

Q: How long does it take for the skin to fully heal after stopping Efudix 5%?

According to the official product information, the healing phase can be lengthy and may not be complete immediately after stopping treatment. Complete healing may take up to one or two months following the final application.

Q: Can I use moisturizers or makeup on the treated area while using Efudix?

Official guidance advises that the cream should be applied in a thin film only to the affected skin. Regulatory information generally advises against the use of other topical products or medications on the treated areas unless specifically instructed by a prescribing doctor.

Q: Is Efudix 5% known to cause long-term skin discoloration?

Regulatory documentation indicates that adverse reactions can include hyper- or hypopigmentation (skin darkening or lightening). Scarring is also listed as a potential adverse reaction associated with the use of the cream.

Q: Can I use other topical medications on the same area as Efudix 5%?

Official guidance advises avoiding the use of other medications on the areas being treated with fluorouracil. This is to prevent potential unknown interactions or interference with the primary therapy.

Q: What happens if I accidentally use Efudix on healthy skin?

Because the medicine is designed to affect rapidly dividing cells, it can also cause reactions like irritation, burning, or a rash on healthy skin. Regulatory guidance emphasizes applying the cream only to the affected area and avoiding surrounding normal skin.

Q: Does the cream cause scarring after the reaction subsides?

Official regulatory documents list scarring as one of the documented adverse reactions associated with the use of the cream. This is considered a potential outcome of the skin erosion and healing process.

Q: Why is the percentage '5%' important in the drug name?

The product contains a 5% weight-per-weight concentration of the active ingredient, fluorouracil. Clinical trials have sometimes compared this 5% strength with lower concentrations, indicating the specific concentration may be associated with varying rates of clearance and adverse events.

Q: Is Efudix 5% used to prevent future skin issues?

While the primary use of the cream is for existing lesions, clinical trials have explored the use of fluorouracil in combination with other treatments. These studies have investigated the use of the medicine to potentially reduce the occurrence of future non-melanoma skin cancers.

Q: Are there specific instructions for washing the treated area with Efudix?

Guidance derived from regulatory documentation advises patients to wash and thoroughly dry the affected areas of the skin before applying the cream. Administration instructions also stress the importance of washing your hands thoroughly immediately after applying the cream.

Q: What are the ingredients listed in the cream besides fluorouracil?

The active ingredient is fluorouracil. Official product information lists excipients (inactive ingredients) that may include substances such as Stearyl alcohol, Propylene glycol, Methyl parahydroxybenzoate, and Propyl parahydroxybenzoate.

Q: Is it normal to feel flu-like symptoms during Efudix treatment?

Severe systemic effects such as fever, chills, vomiting, or severe diarrhea are not typically expected with topical use, but have been documented as risks related to systemic exposure. This is especially relevant in patients with an enzyme deficiency. Systemic exposure risks include these potential effects.

Q: Does Efudix have any warnings related to accidental exposure to others?

Official warnings state that the cream must be kept safely out of the reach of children and pets. Ingesting the medicine, even in small amounts, may be fatal, highlighting the need for careful handling and storage.

Q: Is it necessary to avoid sunlight completely during the treatment period?

Official guidance emphasizes avoiding exposure to sunlight and sun lamps (UV radiation), as this may increase the intensity of the inflammatory reaction. When outdoors, using protective clothing and high-factor sunscreen (SPF 30 or higher) is generally advised.

Q: Is Efudix 5% a brand name for fluorouracil?

Yes, the name Efudix is a brand name for the active drug substance, which is fluorouracil. This substance is an antimetabolite and is often referred to in medical literature simply as 5-FU.

Q: What are the safety classifications for people with kidney or liver problems?

Official general safety information indicates that patients with a history of liver or kidney problems should have these considered prior to treatment. These conditions are considered relevant medical conditions requiring professional consideration.

Q: Is it known if Efudix 5% is suitable for individuals with a history of heart conditions?

The drug's active ingredient, fluorouracil, is associated with the potential for cardiotoxicity, although this risk is primarily seen with the intravenous form. Official patient guidance indicates that a history of heart problems is a relevant condition for professional discussion.

How should Efudix 5% be stored and disposed of?

Storage and Disposal Requirements for Efudix 5% Cream (Fluorouracil)

Efudix 5% Cream must be stored in a manner that protects its stability, as defined in regulatory labeling.

Storage Conditions

Temperature and Environment: The cream must be stored at room temperature, generally defined as not above 25 C or 30 C, depending on the region. It is strictly stated that the product must not be refrigerated or frozen. The container must be kept tightly closed and protected from excessive heat, moisture, and direct light.

Shelf-Life and Safety: Once the tube is first opened, the product has a limited shelf life of 90 days, after which any remaining cream must be discarded. The medicine must always be kept out of the reach of children and pets.

️ Disposal Instructions

Any unused or expired Efudix 5% Cream and contaminated materials must be disposed of in accordance with local requirements. The official procedure is to consult a pharmacist or healthcare professional for guidance on proper disposal. The product should not be disposed of into wastewater or household trash.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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