Rating an antibiotic's importance to humans
How does FDA determine which antibiotics are medically important to humans?
Basically, the agency asks five questions about each antibiotic:
- Is it used to treat enteric pathogens that cause foodborne disease?
- Is it the sole therapy or one of few alternatives to treat serious human disease or a drug that is an essential component among many antimicrobials in treatment of human disease?
- Is it used to treat enteric pathogens in non-foodborne disease?
- Is there cross-resistance within the drug class or linked resistance with other drug classes?
- How easily does resistance to a drug cross over to other genera and species of organisms?
* List of medically important drugs will be reviewed periodically and updated by FDA as needed.2
Source: Zoetis, based on GFI #152, Appendix A3
MAKING THE GRADE
If the answer to questions 1 and 2 is yes, the antimicrobial is considered "critically important." If either question draws a nod, the antimicrobial is considered "highly important."
If the answer to questions 1 and 2 is no, but yes to questions 3, 4 or 5, the antimicrobial is rated "important" to human health. All other antimicrobials are considered non-medically important.
Under the new guidelines, producers will be advised to obtain a VFD order before any medically important antibiotics are used in poultry, and then these antimicrobials should only be used to prevent, control or treat a disease indicated on the product label.
Table 1 lists FDA's current rankings of commonly used poultry antimicrobials. FDA insists the list is "not static," however, and that it will periodically be updated as necessary, taking into consideration such factors as the development of new antimicrobials for human therapy, the emergence of diseases in humans or changes in US prescribing practices.