All but one of the affected companies have committed in writing to comply with the U.S. Food and Drug Administration’s (FDA) voluntary guidance released last December.

Guidance for Industry 213 directs companies to seek withdrawal of approvals for production use of antimicrobial drugs determined to be important in human medicine, according to Drovers CattleNetwork.

FDA also is working with animal health companies to change the use of their products from over-the-counter to use by Veterinary Feed Directive (VFD) or prescription.

An updated list of products affected by the guidance is available on the FDA’s website.