Nitrofurazone (INN, trade name Furacin) is an antimicrobial organic compound belonging to the nitrofuran class. It is most commonly used as a topical antibiotic ointment. Its use in medicine has become less frequent, as safer and more effective products have become available. Nitrofurazone is listed under California Prop 65, and has demonstrated clear evidence to be mutagenic and carcinogenic during animal studies, and has been discontinued for human use in the USA. The substance is pale yellow and crystalline. It was once widely used as an antibiotic for livestock.
Medical uses
thumb|left|Drugstore-made ~400 mL aqueous solution of Furacilin (, nitrofural), 1 : 5000 (0.2 mg/mL or 0.02%), ready for topical use.
Human use
Nitrofurazone was previously available as a prescription in the U.S., and was indicated as a topical solution, topical cream, or topical ointment for the treatment of bacterial skin infections, wounds, burns, and ulcers. Nitrofurazone is still very popular as a topical solution for the treatment of tonsillitis in Russia.
Animal use
Nitrofurazone is indicated for topical use in dogs, cats, and horses, for the treatment or prophylactic treatment of superficial bacterial infections, burns, and cutaneous ulcers. The use of nitrofurazone, or related compounds, in animals raised for human consumption has been strictly banned.
Pharmacokinetics
The metabolism of topically applied nitrofurazone is thought to be by 5-nitro reduction and cleavage of the -CH=N- linkage to generate a reactive species which can covalently bond to cellular macromolecules, none of the end products are thought to be antimicrobial.
Mechanism of action
The mechanism of action is not fully understood, but nitrofurazone's antimicrobial properties are suspected to be due to the interference of DNA synthesis in the microorganism by inhibiting certain enzymes that are involved with glycolysis. Symptoms are similar to ethylene glycol poisoning, in that increased serum calcium levels occur concurrently with decreased ionized calcium. Studies demonstrate that nitrofurazone induces mammary tumors (fibroadenoma and adenocarcinoma) in rats and ovarian tumors in mice. Proper personal protective equipment should be utilized when handling nitrofurazone.