Fluorouracil cream, also called topical 5-FU, is used for actinic keratoses and selected superficial skin cancers. NCI topical identity. Injectable fluorouracil has a separate treatment scope.
Confidence is high in documented instructions. This review does not establish independent comparative efficacy; the trial’s commercial author interests remain despite public funding.
- Confirm cream and lesion.
- Severe blistering or ulceration needs action.
- Systemic symptoms require immediate medical advice.
- Keep fluorouracil away from pets.
Table of contents
- Evidence summary
- Cream names and uses
- How it works
- Reactions and follow-up
- Skin care
- Dispensing and research
- Urgent symptoms
- DPD and antivirals
- Pregnancy and allergy
- Using the cream
- Animals and ownership
- Funding and source roles
- Frequently asked questions
- Sources and funding notes
Evidence summary
Clinical descriptions, care guidance and independently established treatment outcomes have different evidentiary roles. The table identifies what the reviewed sources can support and which financial or clinical questions remain unresolved.
| Question / approach | Evidence reviewed | Funding / conflicts | Interpretation / limits |
|---|---|---|---|
| Identity and route | NCI | Reviewer chain unclosed | Dated topical context; no stock claim. |
| UK products | 4%; 5% | Sellers | Different licensed lesions; no conversion. |
| Patient precautions | Tolak; 5% leaflet | Sellers | Immediate warnings and handling. |
| US Tolak | 2022 label | Hill seller | Separate dated instructions, not availability. |
| Field-treatment trial | 2019 original | ZonMw; author commercial ties | Methods only; independent outcomes unestablished. |
| England items | Original Tables 7–8 | Agency route below | Topical presentations; not cancer diagnoses. |
Cream names and uses
Fluorouracil is an antimetabolite; 5-FU and 5-fluorouracil are synonyms. Class and names. The concentration and formulation are part of the prescription.
UK Tolak 4% covers non-hyperkeratotic, non-hypertrophic actinic keratoses on adults’ face, ears and scalp. Current Tolak indication.
UK 5% includes actinic keratoses, Bowen’s disease and superficial basal-cell carcinoma; deep, penetrating or nodular cancers require different care. 5% licence.
The dated US NCI page lists Carac, Efudex, Fluoroplex and Tolak; only Efudex’s entry includes selected superficial basal-cell cancer when conventional treatment cannot be used. August 2019 US context. This does not verify current local availability.
US Tolak: actinic keratoses on face, ears and scalp. US product.
Actikerall combines fluorouracil and salicylic acid. Separate presentation. This guide covers single-ingredient creams.
How it works
Fluorouracil metabolites interfere with DNA synthesis and RNA processing. Mechanism. This is not an independent clinical-benefit estimate.
Ask the prescriber to identify your product and treatment area. This guide supplies no conversion or injection regimen.
Reactions and follow-up
Actinic keratoses are sun-damaged rough patches. Seek assessment if a patch grows, bleeds, changes colour, becomes tender or forms a lump; such changes can indicate cancer. Lesion assessment.
US reactions: redness, scaling, crusting, itching, burning and swelling. Reactions. Report difficult reactions promptly.
Avoid further 5% application for severe inflammation, including ulceration or blistering. Warning.
Ask who will review the lesion, when to contact them, and how to report unexpected changes.
Skin care
Avoid UV exposure during 5% treatment. UV precaution.
Avoid UV exposure during Tolak treatment. UV warning.
NHS prevention advice includes shade, protective clothing and sunscreen. Sun protection. Ask how these fit your prescribed skin-care instructions.
Discuss creams, cosmetics, herbs and supplements with the team. NCCIH warns that complementary products may interfere with cancer care and should not replace or delay it. Disclosure and care boundary. No independent cream-specific supplement benefit is established here.
Before adding a product to a treated area, ask the pharmacist to check its exact ingredients. This review gives no do-it-yourself steroid, moisturiser, peeling-product or supplement regimen.
Dispensing and research
FY2025/26 England PCA Table 7 records 94,478 items for “Fluorouracil (Antimetabolites)”, BNF 0801030H0. Its Table 8 presentations are topical creams, predominantly Tolak. Original rows. This is not an injection count or cancer-only patient count.
The separate Skin code includes 5% cream and a fluorouracil/salicylic-acid solution; those items are not pooled here. Separate BNF grouping.
PCA covers community dispensing. Official publication. Hospital-issued prescriptions dispensed in the community are included; hospital dispensary supplies are excluded. Proprietary-name mappings are approximate. Actual methodology. Items are not unique people, diagnoses, treatment success or worldwide popularity.
Jansen’s 2019 Dutch randomised study compared four field treatments for multiple head/neck actinic keratoses, with a lesion-reduction endpoint. Its public grant and declared author interests are documented below. Original study design. This review uses its design, not its efficacy ranking; it does not establish interchangeability between cream strengths.
Urgent symptoms
With Tolak, stop and call a doctor immediately for mouth/throat sores, abdominal pain, diarrhoea with or without blood, vomiting, fever or chills. Immediate toxicity warning.
Call 999 or your local emergency number for sudden throat/tongue swelling, severe breathing difficulty or collapse suggesting anaphylaxis. Emergency allergy recognition.
Swallowed 5% cream: get medical advice straight away. Eye, nose or mouth contact: wash with water; contact a doctor, pharmacist or hospital straight away. Exposure.
For suspected harmful ingestion, seek emergency help. Do not induce vomiting, give food/drink or drive yourself to emergency care. Poisoning precautions.
Fluorouracil can kill pets that chew a tube or lick treated skin. Suspected exposure needs an immediate vet call; bring the pack. Store and dispose of it beyond animals’ reach. FDA pet warning. Ask the prescriber about safe skin protection rather than adding an occlusive dressing yourself.
DPD and antivirals
Damaged skin, occlusion and DPD deficiency increase systemic-toxicity risk; suspected systemic toxicity requires stopping treatment. Toxicity.
DPD breaks down fluorouracil. The MHRA’s October 2020 advice distinguishes systemic treatment testing from topical use: routine pre-treatment DPD testing is not required for topical fluorouracil, but activity assessment may be considered if toxicity is suspected. Route-specific advice. This is not reassurance for a person with known deficiency.
US Tolak is contraindicated in DPD deficiency. Its studies were not designed to evaluate drug interactions. US restrictions and uncertainty.
Brivudine, sorivudine and related antivirals are incompatible. DPD-inhibitor warning. Report recent medicines; do not arrange a washout.
Pregnancy and allergy
UK Tolak must not be used during pregnancy or breastfeeding; if pregnancy occurs, stop and inform the doctor immediately. Peanut or soya allergy also prohibits this product. Product exclusions.
UK 5% excludes pregnancy/breastfeeding. Discuss fertility and contraception with the prescriber. Precautions.
Tolak is not recommended when trying to conceive. Ask about fertility and effective contraception. UK precaution.
US professional guidance calls for a nursing-versus-medicine decision based on maternal need; patient instructions say do not breastfeed while using Tolak. US feeding instructions. Coordinate feeding and treatment with the prescriber.
Ask the pharmacist to read the ingredient list on your own pack and record your allergies.
Using the cream
Tolak instructions include washing hands afterwards, avoiding eyes/mucosa/open wounds and avoiding occlusion. Application safety.
Missed application: consult pack; never double. Check opening and expiry instructions; store safely. Pack-specific instructions.
5% residue makes clothing, bedding and dressings burn more easily: no smoking or naked flames. Washing may not remove all residue. Fire hazard.
Correctly used 5% cream is unlikely to affect driving. Driving.
This guide cannot assess your driving fitness or prescribe routine changes. Follow the urgent instructions above.
Animals and ownership
Tolak’s reproductive animal findings concern high-dose systemic experiments. Preclinical scope. They do not establish topical benefit or pregnancy safety.
Pierre Fabre’s current ownership page identifies Foundation control through a holding company; own ownership disclosure. Its April 2026 page describes commercial medicine/dermocosmetic revenue and dividends supporting the Foundation. Own revenue route. Charitable ownership does not remove a medicine seller’s incentives.
Viatris reports commercial sales/financing and its UK subsidiary. Selected 2025 filing.
5% batch release: ICN Polfa Rzeszów. Manufacturer.
The Bausch exhibit lists that subsidiary. Group listing. These records do not close every contract, lot or beneficial-investor chain.
Funding and source roles
Research funding at a glance
36 disclosure entries. The counts below summarize independence tiers explicitly assigned in this article. They count disclosures, not studies, funding amounts or evidence quality.
Consult this article’s source and funding notes for named funders, countries, relationships and exceptions where available. Institutional backing, researcher interests and trial sponsorship are separate questions. Public funding alone does not establish independence; commercial ties alone do not prove a claim false. This overview is not a new financial audit.
The source-specific map separates documented institutional funding from disease-page payments and trial sponsorship. Unknown allocations remain unknown. A public agency, charity or academic address does not by itself establish independent treatment efficacy.
| Source | Funding / backers | Country / jurisdiction | Independence | Credibility / incentives / gaps |
|---|---|---|---|---|
| NCI: topical fluorouracil | Public/gift routes below; reviewer chain unclosed. | US; Bethesda. | Tier 2 education, provisional. | C — August 2019. No current availability or independent efficacy. |
| NCI: fluorouracil dictionary | Public/gift routes below; reviewer chain unclosed. | US; Bethesda. | Tier 2 education, provisional. | C — date unexposed; mechanisms are not patient outcomes. |
| UK Tolak SmPC | Pierre Fabre; parent/hosting routes below. | UK; Reading holder. | Tier 4 seller. | D — 29 October 2025 text. Regulated instructions; efficacy excluded. |
| UK Tolak leaflet | Pierre Fabre; parent/hosting routes below. | Reading holder; Castres manufacturer, France. | Tier 4 seller. | D — October 2025. Product-specific safety, not outcomes. |
| UK 5% SmPC | Viatris; parent/hosting routes below. | UK; Potters Bar holder. | Tier 4 seller. | D — September 2025. Efficacy excluded. |
| UK 5% leaflet | Viatris holder; ICN Polfa batch release; corporate/hosting routes below. | UK; Rzeszów batch release, Poland. | Tier 4 seller. | D — September 2025. Instructions; efficacy excluded. |
| US Tolak label | Hill seller; NLM host; routes below. | US; Sanford, Florida manufacturer. | Tier 4 seller. | D — August 2022 text; September 2022 SPL. Availability not verified. |
| NHS: actinic keratoses | National-site policy below; personal receipts unclosed. | United Kingdom. | Tier 2 context, provisional. | C — June 2023; June 2026 review deadline passed. |
| MHRA: route-specific DPD advice | Public/industry-fee route below. | United Kingdom. | Tier 3 regulator. | B — October 2020. Safety duties, not independent treatment outcomes. |
| FDA: fluorouracil and pets | Budget/user-fee route below. | United States. | Tier 3 regulator. | B — clinical revision unexposed. Actual safety body; not incidence. |
| NHS: anaphylaxis | National-site policy below; personal receipts unclosed. | United Kingdom. | Tier 2 safety, provisional. | C — June 2023; June 2026 deadline passed. |
| NHS: poisoning | National-site policy below; personal receipts unclosed. | United Kingdom. | Tier 2 safety, provisional. | B — June 2025; no home antidote. |
| NCCIH: complementary cancer care | Public/gift routes below; named NCI/NCCIH reviewer interests unclosed. | US; Bethesda. | Tier 2 context, provisional. | C — October 2021; no cream-adjunct efficacy adopted. |
| Jansen 2019 original trial | ZonMw grant 80-83600-98-3054; no commercial trial support reported. Authors disclose Galderma conference costs, LEO advisory fees and Mosterd’s Meda trial supplies. | Four Dutch hospitals. | Tier 3 connected authors. | C — primary PDF methods/footer read. Separate disclosure forms unclosed; outcomes excluded. |
| ZonMw: funding and identity | VWS/NWO and other ministries; health-fund, Health~Holland and European programme co-funding. | The Hague, Netherlands. | Tier 3 institutional self-report. | B — actual body; not the complete 2019 grant ledger. |
| Pierre Fabre: ownership | Foundation 86% via Pierre Fabre Participations; employees 9.5%; treasury 4.5%. | France; separate legal identity below. | Tier 4 corporate self-report. | D — current ownership, not evidence independence; private allocations unclosed. |
| Pierre Fabre: 2025 revenue | Medicine/dermocosmetic sales; dividends fund shareholder Foundation. | France; legal identity below. | Tier 4 seller self-report. | D — April 2026 update; not full audited accounts or cream receipts. |
| Pierre Fabre: legal notice | Commercial group; sales/ownership above. | Pierre Fabre SA, Castres, France. | Tier 4 corporate identity. | D — actual legal body; not every UK manufacturing contract. |
| Viatris 2025 Form 10-K | Product sales, debt/equity; Viatris Products Ltd listed. | Delaware corporation; Canonsburg executive offices, US. | Tier 4 commercial filing. | D — selected revenue/finance/subsidiary sections; investors and cream receipts unclosed. |
| Bausch Health 2025 report | Product/alliance sales; debt/equity financing. | British Columbia corporation; Laval executive offices, Canada. | Tier 4 commercial filing. | D — selected original financial sections; contracts/investors unclosed. |
| Bausch: subsidiary exhibit | Commercial parent report above; ICN Polfa listed. | ICN Polfa: Poland. | Tier 4 corporate filing. | D — 18 February 2026; group listing, not lot receipts. |
| Hill Dermaceuticals: company | Privately owned drug developer/manufacturer; full accounts/backers unclosed. | Sanford, Florida, US. | Tier 4 seller. | D — actual indexed own body; direct homepage failed. No independent efficacy. |
| eMC: publisher model | Datapharm; pharmaceutical subscriptions pay for publication. | Leatherhead registered office, England. | Tier 4 industry-paid host. | D — company-origin regulated texts; shareholder/product fees unclosed. |
| NCI: appropriations | Congressional HHS/NIH appropriations. | United States. | Tier 3 fiscal self-report. | B — May 2026; enacted/request distinguished; page allocation unknown. |
| NCI: Gift Fund | Voluntary gifts and research designations. | Bethesda, US. | Tier 3 self-report. | B — August 2025; no named page receipt inferred. |
| NHS: content policy | DHSC funds site; no advertising/corporate sponsorship under policy. | United Kingdom. | Tier 3 self-report. | B — October 2022; October 2025 deadline passed. Not provider/trial money. |
| NCCIH: appropriations | Congressional funding; table ends FY2024. | Bethesda, US. | Tier 3 fiscal self-report. | B — no current total or page allocation inferred. |
| NCCIH: gifts | Conditional/unconditional donations and bequests. | Bethesda, US. | Tier 3 self-report. | B — authority, not a named receipt. |
| FDA: FY2026 operating plan | Budget authority and statutory user fees. | United States. | Tier 3 fiscal report. | B — selected human/veterinary rows; no pet-page allocation inferred. |
| MHRA 2025/26 accounts | DHSC support; industry fees, service charges and research income. | United Kingdom. | Tier 3 financial report. | B — selected pages 76–77/145/164–165; underlying evidence unclosed. |
| NLM FY2027 budget justification | Congressional appropriation; enacted/request columns separate. | United States. | Tier 3 fiscal report. | B — selected original budget tables; DailyMed allocation unclosed. |
| NIH: gift-administration policy | Conditional/unconditional gifts; FNIH transfer authority separately described. | US federal institutions. | Tier 3 official policy. | B — selected actual provisions; no NLM receipt inferred. |
| NHSBSA: PCA 2025/26 | Agency finance below. | England. | Tier 2 statistics, provisional. | B — 4 June 2026; dispensing, not benefit. |
| PCA original Tables 7–8 | NHSBSA compilation; finance below. | England. | Tier 2 administrative data. | B — FY2025/26; distinct Cancer/Skin codes, not diagnoses. |
| PCA June 2026 methods | Agency finance below. | England. | Tier 2 statistics context. | B — actual selected methods; proprietary mapping is approximate. |
| NHSBSA 2025/26 accounts | DHSC parliamentary funding; external service charges. | Newcastle upon Tyne, UK. | Tier 3 financial report. | B — selected pages 132–133/143 reread; PCA allocation unclosed. |
Frequently asked questions
Is fluorouracil cream the same as injected 5-FU? The route is different. The NCI separates topical treatment from injection. Route distinction. Never substitute one for the other.
Does redness prove clearance? No; seek clinical reassessment.
Does everyone need a DPD test before cream? The MHRA’s topical advice does not require routine testing. Route-specific testing.
What if my pet licks the treated skin? Contact a vet immediately and provide the pack details. Urgent animal-exposure advice. Do not wait for visible illness.
Sources and funding notes
The legitimate university-hosted publisher PDF supplied the trial’s actual methods and published financial footer. Individual disclosure forms and historical receipts remain unclosed.
Corporate and agency financial reports were read in selected sections. Pierre Fabre’s full annual-report download and Hill’s direct homepage failed; actual own indexed company text was read. No complete accounts/private-contract or independent comparative-efficacy claim is made.
- NCI: topical fluorouracil — Dated US identity.
- NCI: fluorouracil dictionary — Class, synonyms and mechanism.
- UK Tolak SmPC — Licence, mechanism, precautions.
- UK Tolak leaflet — Urgent warnings and handling.
- UK 5% SmPC — Separate licence and warnings.
- UK 5% leaflet — Patient safety and manufacture.
- US Tolak label — Separate US precautions.
- NHS: actinic keratoses — Symptoms and assessment.
- MHRA: route-specific DPD advice — Testing distinction.
- FDA: fluorouracil and pets — Fatal-exposure prevention.
- NHS: anaphylaxis — Emergency recognition.
- NHS: poisoning — Harmful-ingestion precautions.
- NCCIH: complementary cancer care — Disclosure and treatment boundaries.
- Jansen 2019 original trial — Methods and financial provenance.
- ZonMw: funding and identity — Current funder route.
- Pierre Fabre: ownership — Documented controlling route.
- Pierre Fabre: 2025 revenue — Commercial funding route.
- Pierre Fabre: legal notice — Separate legal identity.
- Viatris 2025 Form 10-K — Revenue, financing and UK subsidiary.
- Bausch Health 2025 report — Manufacturer-group finances.
- Bausch: subsidiary exhibit — ICN Polfa group identity.
- Hill Dermaceuticals: company — US seller/manufacturer route.
- eMC: publisher model — Hosting and payment route.
- NCI: appropriations — Public finance.
- NCI: Gift Fund — Separate gift authority.
- NHS: content policy — National-site funding.
- NCCIH: appropriations — Historical public route.
- NCCIH: gifts — Separate gift authority.
- FDA: FY2026 operating plan — Regulator finances.
- MHRA 2025/26 accounts — Regulator finances.
- NLM FY2027 budget justification — Host public funding.
- NIH: gift-administration policy — Separate host funding authority.
- NHSBSA: PCA 2025/26 — Publication setting.
- PCA original Tables 7–8 — Exact rows and topical route.
- PCA June 2026 methods — Coverage and item limitations.
- NHSBSA 2025/26 accounts — Agency money and address.
Educational research reviewed 5 October 2026. Diagnosis and treatment require a qualified clinician; this article does not provide an individual prescription or replace urgent assessment.
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