Chemotherapeutic properties of prominent nitrofurans

Nitrofurazone, nitrofurantoin and furazolidone are rather broad spectrum antimicrobial agents effective against both Gram-positive and Gram-negative bacteria. Nitrofurazone has been found to be effective also against certain trypanosomes and furazolidone against trichomonads and Giardia. Resistance to these nitrofurans develops rather slowly and is seldom complete. In practice, resistance development has not been a significant problem over the many years that these compounds have been in use. Cross-resistance with antibiotics and sulphonamides has not been observed and transferable resistance is at most a very rare phenomenon. The precise mode of action of the nitrofurans has not been elucidated, however, they are known to inhibit the actions of a number of bacterial enzymes. Adverse reactions to these compounds have been observed but the incidence of severe reactions is relatively low. At present nitrofurazone is used primarily as a topical agent, furazolidone as a gastrointestinal agent and nitrofurantoin for infections of the urinary tract. Of the three, nitrofurantoin is currently the one most extensively used in human medicine.