Flucytosine

Flucytosine

Clinical data
Trade names	Ancobon, Ancotil, others
AHFS/Drugs.com	Monograph
MedlinePlus	a601132
Pregnancy category	AU: B3 US: C (Risk not ruled out)
Routes of administration	by mouth, intravenous
ATC code	D01AE21 (WHO) J02AX01 (WHO)
Legal status
Legal status	UK: POM (Prescription only) US: ℞-only
Pharmacokinetic data
Bioavailability	75 to 90% (by mouth)
Protein binding	2.9 to 4%
Metabolism	minimal, in the GI tract
Biological half-life	2.4 to 4.8 hours
Excretion	kidney (90%)
Identifiers
IUPAC name 4-amino-5-fluoro-1,2-dihydropyrimidin-2-one
CAS Number	2022-85-7 Y
PubChem (CID)	3366
DrugBank	DB01099 Y
ChemSpider	3249 Y
UNII	D83282DT06 Y
KEGG	D00323 Y
ChEBI	CHEBI:5100 Y
ChEMBL	CHEMBL1463 Y
ECHA InfoCard	100.016.336
Chemical and physical data
Formula	C4H4FN3O
Molar mass	129.093 g/mol
3D model (Jmol)	Interactive image
SMILES FC=1\C=N/C(=O)NC=1N
InChI InChI=1S/C4H4FN3O/c5-2-1-7-4(9)8-3(2)6/h1H,(H3,6,7,8,9) Y Key:XRECTZIEBJDKEO-UHFFFAOYSA-N Y

Flucytosine, also known as 5-fluorocytosine (5-FC), is an antifungal medication. It is specifically used, together with amphotericin B, for serious Candida infections and . It may be used by itself or with other antifungals for chromomycosis. Flucytosine is used by mouth and by injection into a vein.

Common side effects include bone marrow suppression, loss of appetite, diarrhea, vomiting, and psychosis. anaphylaxis and other allergic reactions occasionally occur. It is unclear if use in pregnancy is safe for the baby. Flucytosine is in the fluorinated pyrimidine analogue family of medications. It works by being converted into fluorouracil inside the fungal which then blocks its ability to make protein.

Flucytosine was first made in 1957. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. As of 2016, in the United States the medication cost about 2,000 USD per day will in the United Kingdom it is about 22 USD per day. It is not available in much of the developing world.

Flucytosine by mouth is used for the treatment of serious infections caused by susceptible strains of Candida or . It can also be used for the treatment of chromomycosis (chromoblastomycosis), if susceptible strains cause the infection. Flucytosine must not be used as a sole agent in life-threatening fungal infections due to relatively weak antifungal effects and fast development of resistance, but rather in combination with amphotericin B and/or azole antifungals such as fluconazole or itraconazole. Minor infections such as candidal cystitis may be treated with flucytosine alone. In some countries, treatment with slow intravenous infusions for no more than a week is also a therapeutic option, particular if the disease is life-threatening.