Nitrofurantoin

Nitrofurantoin
Clinical data
Trade names	Macrobid, others
AHFS/Drugs.com	Monograph
MedlinePlus	a682291
License data	US DailyMed: Nitrofurantoin;
Pregnancy; category	AU: A; ;
Routes of; administration	By mouth
Drug class	Antibiotic
ATC code	J01XE01 (WHO) ;
Legal status
Legal status	AU: S4 (Prescription only); CA: ℞-only; UK: POM (Prescription only); US: ℞-only; EU: Rx-only;
Pharmacokinetic data
Bioavailability	~20–94%
Protein binding	60–77% (primarily albumin)
Elimination half-life	0.33–1.7 hours
Excretion	Almost exclusively urine (4–59% over 3–30 hours; ~20–25% unchanged) and bile
Identifiers
	IUPAC name (E)-1-[(5-nitro-2-furyl)methylideneamino]imidazolidine-2,4-dione;
CAS Number	67-20-9 ;
PubChem CID	6604200;
DrugBank	DB00698 ;
ChemSpider	5036498 ;
UNII	927AH8112L;
KEGG	D00439 ;
ChEBI	CHEBI:71415 ;
ChEMBL	ChEMBL572 ;
CompTox Dashboard (EPA)	DTXSID7020972 ;
ECHA InfoCard	100.000.587
Chemical and physical data
Formula	C8H6N4O5
Molar mass	238.159 g·mol−1
3D model (JSmol)	Interactive image;
Melting point	270 to 272 °C (518 to 522 °F) (decomp.)
	SMILES O=[N+]([O-])c2oc(/C=N/N1C(=O)NC(=O)C1)cc2;
	InChI InChI=1S/C8H6N4O5/c13-6-4-11(8(14)10-6)9-3-5-1-2-7(17-5)12(15)16/h1-3H,4H2,(H,10,13,14)/b9-3+ ; Key:NXFQHRVNIOXGAQ-YCRREMRBSA-N ;
	(verify)

Nitrofurantoin, sold under the brand name Macrobid among others, is an antibacterial medication of the nitrofuran class. It is used primarily to treat lower urinary tract infections (UTIs) but it is also used in bladder infections. It is not indicated for kidney infections nor is it as effective for them. It is taken by mouth.

Common side effects include nausea, loss of appetite, diarrhea, and headaches. Rarely numbness, lung problems, or liver problems may occur. While it appears to be generally safe during pregnancy its use is not recommended near time of delivery. While it usually works by slowing bacterial growth, it may result in bacterial death at the high concentrations found in urine, provided forced fluid dilution of urine is avoided.

As the name or branding suggests, nitrofurantoin (due to the brand name macrobid) should be taken twice per day, or bis in die (B.I.D.). Nitrofurantoin was first sold in 1953. It is on the World Health Organization's List of Essential Medicines. It is available as a generic medication. In 2023, it was the 143rd most commonly prescribed medication in the United States, with more than 3 million prescriptions.