|This article does not cite any references or sources. (December 2009)|
Empiric therapy is a medical term referring to the initiation of treatment prior to determination of a firm diagnosis. It may be thought of as taking the initiative against an anticipated and likely cause of infectious disease. It is most often used when antibiotics are given to a person before the specific bacterium causing an infection is known. Examples of this include antibiotics given for pneumonia, urinary tract infections, and suspected bacterial meningitis in newborns aged 0 to 6 months.
Empiric antibiotics are typically broad-spectrum, in that they treat both Gram-positive and Gram-negative bacteria. When more information is known (as from a blood culture), treatment may be changed to a narrow-spectrum antibiotic which more specifically targets the bacterium known to be causing disease.
The advantage of indicating antibiotics empirically exists where a causative pathogen is likely albeit unknown and where diagnostic tests will not be influential to treatment. In this case, there may be little if any perceived benefit of using what may be costly and inconclusive tests that will only delay treatment of the same antibiotics.
The empirical use of broad-spectrum antibiotics increases, by selection, the prevalence of bacteria resistant to several antibiotics.