Fluorouracil
- Medical Review: Adrienne Gropper Waks, MD
Fluorouracil is an antimetabolite chemotherapy medicine used to treat breast cancer. It is one of the most commonly used medicines to treat cancer. Fluorouracil is also known as 5-fluorouracil and 5-FU.
How fluorouracil works
Fluorouracil interferes with the normal growth process of cancer cells. It stops them from making and fixing DNA, the directions that cells use to grow. Fluorouracil causes the cells to die when they try to divide. It works at specific times in the growth of the cell.
Who gets fluorouracil
Fluorouracil may be used in chemotherapy treatment regimens for invasive breast cancer, including triple-negative breast cancer.
It can be used to treat any stage of breast cancer, including metastatic disease.
How fluorouracil is given
Fluorouracil is given with other chemotherapy medicines in breast cancer. Some common combinations in breast cancer include:
- CAF (Cytoxan, Adriamycin and Fluorouracil) or FAC (Fluorouracil, Adriamycin, and Cyclophosphamide)
- CEF (Cytoxan, Epirubicin and Fluorouracil) or FEC
- CMF (Cytoxan, Methotrexate and Fluorouracil)
Fluorouracil is given by vein. It is usually given in several cycles, with a day (or days) of treatment followed by a period of “off” days. The exact schedule depends on the medicines used. Most chemotherapy regimens consist of between four and six cycles of treatment given over 3 to 6 months.
Side effects and things to remember
Side effects may include:
- Anemia
- Loss of appetite
- Diarrhea
- Fatigue
- Hand and foot syndrome
- Menopausal symptoms
- Mouth sores
- Nausea and vomiting
- Drop in white blood cells
- Taste changes
- Vision or eye problems
Before starting fluorouracil, tell your doctor about any medicines you are taking, including vitamins, herbal supplements and over-the-counter medicines. You should not take fluorouracil during the first trimester of pregnancy.
Your doctor will test your blood before and during treatment to check your white and red blood cell levels. Your liver and kidneys will also be checked.
Be sure to call your doctor right away if:
- You have chest pain, as this may be a sign of heart problems
- You have pain at the injection site, as this can be a sign of an allergic reaction
- You have a high fever, as this can be a sign of a serious infection
Your doctor, pharmacist or nurse can help you manage your side effects. You can also go to our section on Side effects for more information.
Stay connected
Sign up to receive emotional support, medical insight, personal stories, and more, delivered to your inbox weekly.
- 3-dimensional radiation therapy
- 4-hydroxytamoxifen
- ablation
- abnormal
- Abraxane
- absolute risk
- AC regimen
- AC-T regimen
- AC-T-T regimen
- AC-Taxol regimen
- AC-TH regimen
- accelerated partial-breast irradiation
- action study
- acupoint
- acupressure
- acupuncture
- acupuncture needle
- acupuncture point
- acupuncture point injection
- acupuncturist
- acustimulation
- acute
- acute pain
- adenocarcinoma
- adenopathy
- adenosis
- adjunct agent
- adjunct therapy
- adjunctive therapy
- adjuvant therapy
- advance directive
- advanced practice nurse
- adverse effect
- aerobic exercise
- agent study
- aggravating factor
- aggressive
- AJCC staging system
- Alkeran
- alkylating agent
- Allegra
- allopathic medicine
- alopecia
- amifostine
- aminoglutethimide
- amitriptyline
- anabolic steroid
- analgesic
- anaplastic
- anastrozole
- ancillary test
- anemia
- anesthesia
- anesthesiologist
- angiogenesis
- angiogenesis inhibitor
- antagonist
- anthracycline
- anti-anxiety medicine
- anti-idiotype vaccine
- anti-inflammatory
- antibody-dependent cellular cytotoxicity
- antibody therapy
- anticachexia
- anticancer antibiotic
- anticancer therapy
- anticonvulsant
- antidepressant
- antiemetic
- antiestrogen
- antifolate
- antigen-presenting cell vaccine
- antihormone therapy
- antimetabolite
- antimitotic agent
- antineoplastic
- antitumor
- anxiety
- anxiolytic
- Anzemet
- APN
- apocrine gland
- apoptosis
- aprepitant
- areola
- Aromasin
- aromatase inhibitor
- aromatherapy
- arthralgia
- ascites
- aspirate
- aspiration
- assay
- asthenia
- asymptomatic
- atypia
- atypical ductal hyperplasia
- atypical hyperplasia
- atypical lobular hyperplasia
- avoidance
- axillary lymph node
- axillary lymph node dissection
- BAK gel
- balloon catheter radiation
- baseline
- behavior modification
- best practice
- BI-RADS
- Biafine cream
- bias
- bilateral
- bilateral breast cancer
- bilateral prophylactic mastectomy
- bilateral salpingo-oophorectomy
- biofeedback
- biologic
- biopsy
- biopsy specimen
- biotherapy
- bisphosphonate
- bisphosphonate-associated osteonecrosis
- blinded study
- blood-brain barrier
- blood-brain barrier disruption
- blood cell count
- blood chemistry study
- board certified oncology pharmacy specialist
- body image
- body mass index
- bolus dose
- bone density
- bone metastasis
- bone mineral density scan
- bone scan
- bone-seeking radioisotope
- brachytherapy
- brain metastasis
- BRCA1
- BRCA2
- BRCAPro
- breast carcinoma in situ
- breast-conserving surgery
- breast density
- breast duct
- breast duct endoscopy
- breast lobe
- breast lobule
- breast reconstruction
- breast self-exam
- Brief Pain Inventory
- cachexia
- CAF regimen
- calcification
- cancer vaccine
- candidiasis
- capecitabine
- carboplatin
- carcinogen
- carcinoma
- carcinoma in situ
- carcinomatous meningitis
- carcinosis
- carcinostatic
- cardiotoxicity
- caregiver
- carmustine
- case-control study
- case report
- case series
- CAT scan
- CBC
- cell
- cell-cycle regulation
- cell proliferation
- central nervous system
- central nervous system metastasis
- central nervous system prophylaxis
- central venous access catheter
- cetuximab
- cevimeline
- chaplain
- charged-particle radiation therapy
- chemoembolization
- chemoimmunotherapy
- chemoprevention
- chemoprevention study
- chemoprotective
- chemoradiation
- chemosensitivity
- chemosensitivity assay
- chemosensitizer
- chemotherapeutic agent
- chemotherapy
- chest wall
- chest X-ray
- Chinese meridian theory
- chronic
- chronic pain
- cisplatin
- Claus model
- clergy
- clinical
- clinical breast exam
- clinical practice guidelines
- clinical researcher
- clinical resistance
- clinical series
- clinical stage
- clinical staging
- clinical study
- clinical trial
- clinician
- clodronate
- CMF regimen
- cognition
- cognitive behavior therapy
- cognitive therapy
- cohort
- cohort study
- coinsurance
- combination chemotherapy
- comedo carcinoma
- comfort care
- Coming Out
- Community Advisory Board
- comorbidity
- compassionate use trial
- complementary and alternative medicine
- complementary medicine
- complete metastasectomy
- complete remission
- complete response
- complex decongestive therapy
- compliance
- complication
- compression garment
- computed tomography scan
- concomitant
- concurrent therapy
- condition
- consolidation therapy
- constitutional acupuncture
- continuum of care
- contract research organization
- contraindication
- contralateral
- contrast material
- control group
- controlled clinical trial
- controlled study
- conventional medicine
- conventional therapy
- copayments
- cope
- coping skills
- core biopsy
- core needle biopsy
- corticosteroid
- counseling
- COX inhibitor
- cryoablation
- cryopreservation
- cryosurgery
- CT scan
- cultural competency
- cumulative dose
- cumulative exposure
- cure
- cutaneous
- cutaneous breast cancer
- cyclophosphamide
- cyclosporine
- CYP2D6 inhibitor
- cystosarcoma phyllodes
- cytopenia
- cytotoxic
- cytotoxic chemotherapy
- Cytoxan
- Data and Safety Monitoring Board
- DCIS
- de novo
- debulking
- deductible
- definitive surgery
- definitive treatment
- dehydration
- denosumab
- depression
- diagnosis
- diagnostic mammogram
- diagnostic procedure
- diagnostic technique
- diagnostic trial
- diameter
- diarrhea
- diaziquone
- DIEP flap
- dietary counseling
- dietary supplement
- dietitian
- differentiation
- diffuse
- digital mammography
- diphenhydramine
- discharge
- disease progression
- disease-specific survival rate
- distant cancer
- distant metastasis
- Distant recurrence
- distress
- DNR order
- docetaxel
- dolasetron
- dose
- dose-dense chemotherapy
- dose-dependent
- dose-limiting
- dose-rate
- double-blinded
- doxorubicin
- drain
- dronabinol
- droperidol
- drug interaction
- drug resistance
- drug therapy
- drug tolerance
- duct
- ductal carcinoma
- ductal carcinoma in situ
- ductal lavage
- duloxetine
- durable power of attorney
- dysfunction
- dysgeusia
- dyspepsia
- dyspnea
- early menopause
- early-stage breast cancer
- edema
- EEG biofeedback
- efficacy
- Eklund displacement views
- electroacupuncture
- electron beam
- eligibility criteria
- Ellence
- emesis
- emetic
- endocrine
- endocrine therapy
- endpoint
- energy healing
- enteral nutrition
- epidemiology
- epirubicin
- ER+
- ER-
- ER
- ER-PR-HER2/neu-
- eribulin mesylate
- erythema
- estradiol
- estrogen
- estrogen blocker
- estrogen receptor
- estrogen receptor-negative
- estrogen receptor-positive
- estrogen receptor test
- estrogen replacement therapy
- etanidazole
- etidronate
- everolimus
- Evista
- excision
- excisional biopsy
- exemestane
- expanded access trial
- experimental
- extranodal
- false-negative test result
- false-positive test result
- familial cancer
- family medical history
- Faslodex
- fast-neutron beam radiation
- fatigue
- FDA
- febrile neutropenia
- FEC regimen
- Femara
- fertility
- fexofenadine
- fibroadenoma
- fibrocystic breast changes
- fiducial marker
- film mammography
- fine-needle aspiration biopsy
- first-degree relative
- first-line therapy
- five-year survival rate
- fluorouracil
- fluoxetine
- FNA biopsy
- focal
- Food and Drug Administration
- Fosamax
- fractionation
- fulvestrant
- functional magnetic resonance imaging
- gadolinium
- Gail model
- gallium scan
- gamma irradiation
- Gamma Knife therapy
- gamma ray
- Gelclair
- gemcitabine
- gene
- gene expression profile
- gene therapy
- general anesthesia
- generalized anxiety disorder
- generic
- genetic
- genetic counseling
- genetic marker
- genetic marker of susceptibility
- genetic predisposition
- genetic profile
- genetic susceptibility
- genetic testing
- genetic testing
- genetics
- genome
- genome-wide association study
- genomic profile
- genomic test
- genomics
- gland
- Good Clinical Practice
- goserelin
- grade
- grading
- granisetron
- gross description
- Halaven
- hazard ratio
- healing touch
- Health Insurance Portability and Accountability Act
- healthcare provider
- healthcare proxy
- healthy control
- helical computed tomography
- HER2/neu
- Herceptin
- hereditary
- hereditary mutation
- heteronormative
- high-dose chemotherapy
- high-dose radiation
- high-energy proton therapy
- high grade
- high-risk cancer
- HIPPA
- histologic examination
- histology
- historic cohort study
- historical control subject
- homeopathic medicine
- hormonal therapy
- hormone
- hormone receptor
- hormone receptor test
- hormone replacement therapy
- hormone responsive
- hormone therapy
- hospice
- hot flash
- human epidermal growth factor receptor 2
- human participant protection regulations
- hydroxydaunorubicin
- hyperalimentation
- hypercalcemia
- hyperfractionated radiation therapy
- hyperfractionation
- hyperplasia
- hypersensitivity
- hypofractionated radiation therapy
- hypofractionation
- hypoxia
- ibandronate
- ibuprofen
- idiopathic
- image-guided radiation therapy
- imaging
- imaging procedure
- immune adjuvant
- immune function
- immune response
- immune system
- immune system tolerance
- immunization
- immunoassay
- immunocompromised
- immunodeficiency
- immunohistochemistry
- immunology
- immunomodulation
- immunosuppression
- immunotherapy
- implant
- implant displacement views
- implant radiation therapy
- implantable pump
- in network
- in situ
- incidence
- incision
- incisional biopsy
- indication
- indolent
- induction therapy
- infection
- infertile
- infertility
- infiltrating breast cancer
- infiltrating ductal carcinoma
- inflammation
- inflammatory breast cancer
- informed consent
- infusion
- ingestion
- inherited
- iniparib
- injection
- inoperable
- insomnia
- Institutional Review Board
- intensification therapy
- intensity-modulated radiation therapy
- interfering thought
- internal mammary lymph nodes
- internal radiation therapy
- International Unit
- internist
- interstitial radiation therapy
- intervention
- intervention group
- intra-arterial
- intracarotid infusion
- intradermal
- intraductal breast papilloma
- intraductal carcinoma
- intrahepatic
- intrahepatic infusion
- intramuscular
- intramuscular injection
- intraoperative radiation therapy
- intraoperative ultrasound
- intratumoral
- intravasation
- intravenous
- intravenous infusion
- intravenous injection
- intrusive thought
- intrusive thoughts
- invasive breast cancer
- invasive cancer
- invasive procedure
- investigational
- investigator
- ionizing radiation
- ipsilateral
- IRB
- irradiated
- irradiation
- irreversible toxicity
- ixabepilone
- joint pain
- Karnofsky Performance Status
- laboratory test
- lapatinib
- laser
- laser surgery
- laser therapy
- lassitude
- late effects
- late-stage cancer
- latent
- laxative
- LEEP
- legal aid organization
- lesion
- lethargy
- letrozole
- leukopenia
- levels of evidence
- Lexapro
- libido
- lidocaine
- ligation
- linac
- linear accelerator
- lipoma
- lisofylline
- liver metastasis
- liver scan
- living will
- lobaplatin
- lobe
- lobectomy
- lobular carcinoma
- lobular carcinoma in situ
- lobule
- local anesthesia
- local cancer
- local therapy
- localization
- localized
- locally advanced cancer
- locally recurrent cancer
- lomustine
- loop electrosurgical excision procedure
- loop excision
- lorazepam
- low grade
- lubricant
- lumbar puncture
- lumpectomy
- lung metastasis
- luteinizing hormone-releasing hormone agonist
- lymph
- lymph gland
- lymph node
- lymph node dissection
- lymph node drainage
- lymph node mapping
- lymph vessel
- lymphadenectomy
- lymphadenopathy
- lymphangiogram
- lymphangiography
- lymphatic basin
- lymphatic fluid
- lymphatic mapping
- lymphatic system
- lymphatic vessel
- lymphedema
- lymphography
- lymphoscintigraphy
- Lyrica
- lytic lesion
- macrocalcification
- magnetic resonance imaging
- magnetic resonance perfusion imaging
- magnetic resonance spectroscopic imaging
- mainstream medicine
- maintenance therapy
- male breast cancer
- malignancy
- malignant
- malignant pleural effusion
- malnutrition
- mammary
- mammary dysplasia
- mammary gland
- mammogram
- mammography
- MammoSite
- Mammotome
- mantle field
- MAO inhibitor
- margin
- marker
- mass
- massage therapy
- mastectomy
- mastitis
- maternal
- maximum tolerated dose
- mean survival time
- measurable disease
- medial supraclavicular lymph node
- median
- median survival time
- Medicaid
- medical castration
- medical device
- medical nutrition therapy
- medical oncologist
- Medicare
- medicine
- medullary breast carcinoma
- mega-voltage linear accelerator
- megestrol
- melphalan
- meningeal metastasis
- menopause
- menorrhagia
- menstrual cycle
- menstrual period
- menstruation
- mental health
- mental health counselor
- meridian
- mesna
- meta-analysis
- metallic
- metastasectomy
- metastasis
- metastasize
- metastatic
- methotrexate
- metoclopramide
- metronomic therapy
- microcalcification
- micrometastasis
- microscopic
- milk duct
- mind/body exercise
- mindfulness relaxation
- Miraluma test
- mitigate
- modified radical mastectomy
- molecular marker
- molecular medicine
- molecular risk assessment
- molecularly targeted therapy
- monoamine oxidase inhibitor
- monoclonal antibody
- morbidity
- mortality
- MRI
- MRSI
- MTD
- mTOR
- mucositis
- multicenter study
- multicentric breast cancer
- multidisciplinary
- multidisciplinary opinion
- multidrug resistance
- multidrug resistance inhibition
- multifocal breast cancer
- music therapy
- mutation
- mutation carrier
- myalgia
- myelosuppression
- nanoparticle paclitaxel
- narcotic
- National Cancer Institute
- National Center for Complementary and Alternative Medicine
- National Institutes of Health
- natural history study
- naturopathy
- nausea
- NCCAM
- NCI
- NCI clinical trials cooperative group
- needle biopsy
- needle localization
- needle-localized biopsy
- negative axillary lymph node
- negative test result
- neoadjuvant therapy
- neoplasm
- nerve
- nerve block
- neurocognitive
- neurologic
- neuropathy
- neurotoxicity
- neurotoxin
- neutropenia
- NIH
- nipple
- nipple discharge
- nitrosourea
- NMRI
- node-negative
- node-positive
- nodule
- nonblinded
- nonconsecutive case series
- noninvasive
- nonmalignant
- nonmetastatic
- nonprescription
- nonrandomized clinical trial
- nonsteroidal anti-inflammatory drug
- nonsteroidal aromatase inhibitor
- nontoxic
- normal range
- normative
- NP
- NPO
- NSAID
- nuclear grade
- nuclear magnetic resonance imaging
- nuclear medicine scan
- nurse
- nurse practitioner
- nutrition
- nutrition therapy
- nutritional counseling
- nutritional status
- nutritional supplement
- nutritionist
- obese
- objective improvement
- objective response
- observation
- observational study
- obstruction
- off-label
- olaparib
- oncologist
- oncology
- oncology nurse
- oncology pharmacy specialist
- oncolysis
- ondansetron
- onset of action
- oophorectomy
- open biopsy
- open label study
- open resection
- operable
- opiate
- opioid
- opportunistic infection
- oral
- organ
- orthodox medicine
- osteolytic
- osteonecrosis of the jaw
- osteopenia
- osteoporosis
- OTC
- out of network
- outcome
- outpatient
- ovarian
- ovarian ablation
- ovarian cancer
- ovarian suppression
- ovary
- over-the-counter
- overall survival rate
- overdose
- overexpress
- overweight
- ovulation
- PA
- paclitaxel
- paclitaxel albumin-stabilized nanoparticle formulation
- paclitaxel-loaded polymeric micelle
- Paget disease of the nipple
- pain threshold
- palliation
- palliative care
- palliative therapy
- palmar-plantar erythrodysesthesia
- palonosetron hydrochloride
- palpable disease
- palpation
- palpitation
- pamidronate
- panic
- papillary tumor
- Paraplatin
- parenteral nutrition
- paroxetine hydrochloride
- PARP
- PARP inhibitor
- partial-breast irradiation
- partial mastectomy
- partial oophorectomy
- partial remission or partial response
- pastoral counselor
- paternal
- pathologic fracture
- pathological stage
- pathological staging
- pathologist
- pathology report
- patient advocate
- Paxil
- peau d'orange
- pedigree
- peer-review process
- peer-reviewed scientific journal
- perfusion magnetic resonance imaging
- perimenopausal
- periodic neutropenia
- perioperative
- peripheral neuropathy
- peripheral venous catheter
- personal health record
- personal medical history
- personalized medicine
- Pertuzumab
- PET scan
- pharmacist
- phase I/II trial
- phase I trial
- phase II/III trial
- phase II trial
- phase III trial
- phase IV trial
- phlebotomy
- photon beam radiation therapy
- phyllodes tumor
- physical examination
- physical therapist
- physical therapy
- physician
- physician assistant
- physiologic
- PI3 kinase inhibitor
- pilocarpine
- pilot study
- placebo
- placebo-controlled
- plastic surgeon
- plastic surgery
- population study
- positive axillary lymph node
- positive test result
- positron emission tomography scan
- post-traumatic stress disorder
- postmenopausal
- postoperative
- postremission therapy
- potentiation
- power of attorney
- PR
- PR+
- PR-
- practitioner
- preauthorization
- precancerous
- preclinical study
- predictive factor
- pregabalin
- premalignant
- premature menopause
- premenopausal
- premium
- prescription
- prevention
- preventive
- preventive mastectomy
- primary care
- primary care doctor
- primary endpoint
- primary therapy
- primary treatment
- primary tumor
- Principal investigator
- prochlorperazine
- progesterone
- progesterone receptor
- progesterone receptor-negative
- progesterone receptor-positive
- progesterone receptor test
- progestin
- prognosis
- prognostic factor
- progression
- progression-free survival
- progressive disease
- Prolia
- proliferative index
- promegapoietin
- prophylactic
- prophylactic mastectomy
- prophylactic oophorectomy
- prophylactic surgery
- prophylaxis
- prospective
- prospective cohort study
- prosthesis
- protective factor
- protein
- protein-bound paclitaxel
- protein expression
- protein expression profile
- protocol
- proton
- proton magnetic resonance spectroscopic imaging
- pruritus
- psychiatrist
- psychological
- psychologist
- psychosocial
- psychotherapy
- PTSD
- pump
- punch biopsy
- qi
- qigong
- quadrantectomy
- quality assurance
- quality of life
- radiation
- radiation brachytherapy
- radiation dermatitis
- radiation fibrosis
- radiation necrosis
- radiation nurse
- radiation oncologist
- radiation physicist
- radiation surgery
- radiation therapist
- radiation therapy
- radical lymph node dissection
- radical mastectomy
- radioactive
- radioactive drug
- radioactive seed
- radioisotope
- radiologic exam
- radiologist
- radiology
- radionuclide
- radionuclide scanning
- radiopharmaceutical
- radiosensitization
- radiosensitizer
- radiosurgery
- radiotherapy
- raloxifene
- raloxifene hydrochloride
- randomization
- randomized clinical trial
- receptor
- RECIST
- reconstructive surgeon
- reconstructive surgery
- recreational therapy
- recurrence
- recurrent cancer
- referral
- reflexology
- refractory
- refractory cancer
- regimen
- regional
- regional anesthesia
- regional cancer
- regional chemotherapy
- regional lymph node
- regional lymph node dissection
- registered dietician
- regression
- rehabilitation
- rehabilitation specialist
- relapse
- relative survival rate
- relaxation technique
- remission
- remission induction therapy
- remote brachytherapy
- research nurse
- research study
- resectable
- resected
- resection
- residual disease
- resistant cancer
- resorption