Title: Florfenicol
CAS Registry Number: 73231-34-2
CAS Name: 2,2-Dichloro-N-[(1S,2R)-1-(fluoromethyl)-2-hydroxy-2-[4-(methylsulfonyl)phenyl]ethyl]acetamide
Additional Names: D-(threo)-1-p-methylsulfonylphenyl-2-amino-3-fluoro-1-propanol; fluorothiamphenicol
Manufacturers' Codes: Sch-25298
Trademarks: Aquafen (Schering-Plough); Aquaflor (Schering-Plough); Florocol (Schering-Plough); Nuflor (Schering-Plough)
Molecular Formula: C12H14Cl2FNO4S
Molecular Weight: 358.21
Percent Composition: C 40.24%, H 3.94%, Cl 19.79%, F 5.30%, N 3.91%, O 17.87%, S 8.95%
Literature References: Fluorinated derivative of thiamphenicol, q.v. Inhibits bacterial protein synthesis by binding to ribosome 50S and 70S subunits. Prepn: T. Nagabhushan, EP 14437; US 4235892 (both 1980 to Schering); D. P. Schumacher et al., J. Org. Chem. 55, 5291 (1990). Improved prepn: G. Wu et al., ibid. 62, 2996 (1997). HPLC determn in fish plasma: C. Vue et al., J. Chromatogr. B 780, 111 (2002). In vitro antibacterial activity: H. C. Neu, K. P. Fu, Antimicrob. Agents Chemother. 18, 311 (1980); V. P. Syriopoulou et al., ibid. 19, 294 (1981); vs bovine and porcine respiratory disease isolates: S. J. Shin et al., Vet. Microbiol. 106, 73 (2005). Pharmacokinetics in veal calves: K. J. Varma et al., J. Vet. Pharmacol. Ther. 9, 412 (1986); in sheep: J. Shen et al., ibid. 27, 163 (2004). Therapeutic effect on pseudotuberculosis in yellowtail tuna: N. Yasunaga, S. Yasumoto, Fish Pathol. 23, 1 (1988).
Properties: Crystals from 2-propanol/H2O, mp 152-154°. [a]26 +17.9° (DMF). Sol in water.
Melting point: mp 152-154°
Optical Rotation: [a]26 +17.9° (DMF)
Therap-Cat-Vet: Antibacterial.
Flosequinan Floxacillin Floxuridine Fluacizine Fluanisone

Systematic (IUPAC) name
Clinical data
AHFS/Drugs.com International Drug Names
Legal status veterinary prescription only
Routes intramuscular, subcutaneous
CAS number 73231-34-2 N
ATCvet code QJ01BA90 QJ51BA90
PubChem CID 114811
ChemSpider 102776 YesY
UNII 9J97307Y1H YesY
KEGG D04194 YesY
Synonyms 2,2-dichloro-N-((1R,2S)-3-fluoro-1-hydroxy-1-(4-(methylsulfonyl)phenyl)propan-2-yl)ethanamide
Chemical data
Formula C12H14Cl2FNO4S 
Mol. mass 358.21 g/mol
 N (what is this?)  (verify)

Florfenicol (marketed by Schering-Plough Animal Health under the trade name Nuflor) is a fluorinated synthetic analog of thiamphenicol.[1]

In the United States, florfenicol is currently indicated for the treatment of bovine respiratory disease (BRD) associated with Mannheimia (Pasteurella) haemolytica, Pasteurella multocida, and Haemophilus somnus, for treatment of bovine interdigital phlegmon (foot rot, acute interdigital necrobacillosis, infectious pododermatitis) associated with Fusobacterium necrophorum and Bacteroides melaninogenicus.

The use of florfenicol in horses, and likely in other equids, typically causes diarrhea. This has been anecdotally reported to progress to lethal cases of acute colitis. Therefore, use of this antimicrobial in the equine patient should be limited to cases in which other, safer, options are not available. [2]