List of Approved Medically Important Antimicrobial Drugs Administered in the Feed of Food-Producing Animals that Lack a Defined Duration of Use
Since January 2017, as a result of the implementation of Guidance for Industry (GFI) #213, medically important antimicrobials administered in the feed or water of food-producing animals are only available for use through a licensed veterinarian. However, a limited number of currently approved medically important antimicrobials administered through animal feed include indications that lack a defined duration of use. All new animal drug applications on the list below have been identified as medically important antimicrobial drug products approved for use in feed that have one or more indications without a defined duration of use. There are currently no such products approved for use in water with an undefined duration of use.
The FDA’s Guidance for Industry #273: Defining Durations of Use for Approved Medically Important Antimicrobial Drugs Fed to Food-Producing Animals, finalized in February 2026, provides recommendations for how animal drug sponsors may voluntarily establish defined durations of use for the list of affected products below.
Establishing durations of use for these applications is a continuation of the FDA’s antimicrobial stewardship efforts. Our primary objective is to update product dosage regimens to better target when and for how long the drug may be used. Defining more targeted durations of use for the affected applications supports the FDA's ongoing efforts to slow the development of antimicrobial resistance by fostering the judicious use of medically important antimicrobial drugs in animals. This important work helps to preserve the effectiveness of these antimicrobials in both veterinary and human medicine and is one of the actions highlighted in CVM’s five-year plan for supporting antimicrobial stewardship in veterinary settings.
| Type of Application | Application Number | Sponsor | Ingredient(s) | Action(s) |
|---|---|---|---|---|
| Pioneer Type A medicated article | 006-391 | Huvepharma EOOD | Sulfaquinoxaline | |
| Pioneer Type A medicated article | 008-804 | Phibro Animal Health Corp. | Oxytetracycline | |
| Pioneer Type A medicated article | 010-918 | Elanco US, Inc. | Hygromycin B | |
| Pioneer Type A medicated article | 012-491 | Elanco US, Inc. | Tylosin | |
| Pioneer Type A medicated article | 035-688 | Zoetis Inc. | Chlortetracycline, Sulfamethazine | |
| Pioneer Type A medicated article | 040-209 | Zoetis Inc. | Ormetoprim, Sulfadimethoxine | |
| Pioneer Type A medicated article | 041-275 | Elanco US, Inc. | Tylosin, Sulfamethazine | |
| Pioneer Type A medicated article | 046-415 | Zoetis Inc. | Tylosin | |
| Pioneer Type A medicated article | 046-699 | Zoetis Inc. | Chlortetracycline | |
| Pioneer Type A medicated article | 048-480 | Pharmgate LLC | Chlortetracycline | |
| Pioneer Type A medicated article | 048-761 | Zoetis Inc. | Chlortetracycline | |
| Pioneer Type A medicated article | 049-287 | Zoetis Inc. | Chlortetracycline | |
| Pioneer Type A medicated article | 065-410 | Zoetis Inc. | Tetracycline | |
| Pioneer Type A medicated article | 091-467 | Phibro Animal Health Corp. | Virginiamycin | |
| Pioneer Type A medicated article | 091-749 | Zoetis Inc. | Sulfamethazine, Tylosin | |
| Pioneer Type A medicated article | 092-286 | Phibro Animal Health Corp. | Chlortetracycline | |
| Pioneer Type A medicated article | 094-975 | Phibro Animal Health Corp. | Neomycin, Oxytetracycline | |
| Pioneer Type A medicated article | 095-143 | Phibro Animal Health Corp. | Oxytetracycline | |
| Pioneer Type A medicated article | 097-505 | Zoetis Inc. | Lincomycin | |
| Pioneer Type A medicated article | 098-431 | Phibro Animal Health Corp. | Tylosin | |
| Pioneer Type A medicated article | 138-934 | Pharmgate LLC | Chlortetracycline, Sulfamethazine | |
| Pioneer Type A medicated article | 138-935 | Pharmgate LLC | Chlortetracycline | |
| Pioneer Type A medicated article | 138-938 | Pharmgate LLC | Oxytetracycline | |
| Pioneer Type A medicated article | 138-939 | Pharmgate LLC | Neomycin, Oxytetracycline | |
| Pioneer Type A medicated article | 140-998 | Phibro Animal Health Corp. | Virginiamycin | |
| Generic Type A medicated article | 200-484 | Huvepharma EOOD | Tylosin | |
| Generic Type A medicated article | 200-510 | Pharmgate LLC | Chlortetracycline | |
| Pioneer combination medicated feed | 045-444 | Zoetis Inc. | Chlortetracycline, Decoquinate | |
| Pioneer combination medicated feed | 046-718 | Zoetis Inc. | Oxytetracycline, Melengestrol | |
| Pioneer combination medicated feed | 046-719 | Zoetis Inc. | Oxytetracycline, Melengestrol | |
| Pioneer combination medicated feed | 092-507 | Zoetis Inc. | Chlortetracycline, Robenidine | |
| Pioneer combination medicated feed | 099-006 | Phibro Animal Health Corp. | Oxytetracycline, Monensin | |
| Pioneer combination medicated feed | 104-646 | Elanco US, Inc. | Tylosin, Monensin | |
| Pioneer combination medicated feed | 110-047 | Phibro Animal Health Corp. | Tylosin, Pyrantel | |
| Pioneer combination medicated feed | 116-044 | Phibro Animal Health Corp. | Lincomycin, Pyrantel | |
| Pioneer combination medicated feed | 138-870 | Zoetis Inc. | Tylosin, Melengestrol, Monensin | |
| Pioneer combination medicated feed | 138-992 | Zoetis Inc. | Tylosin, Lasalocid, Melengestrol | |
| Pioneer combination medicated feed | 138-995 | Zoetis Inc. | Tylosin, Melengestrol | |
| Pioneer combination medicated feed | 139-192 | Zoetis Inc. | Tylosin, Melengestrol | |
| Pioneer combination medicated feed | 140-579 | Zoetis Inc. | Oxytetracycline, Lasalocid | |
| Pioneer combination medicated feed | 141-114 | Phibro Animal Health Corp. | Virginiamycin, Semduramicin | |
| Pioneer combination medicated feed | 141-149 | Zoetis Inc. | Tylosin, Monensin, Decoquinate | |
| Pioneer combination medicated feed | 141-1721 | Elanco US, Inc. | Tylosin, Ractopamine | |
| Pioneer combination medicated feed | 141-1851 | Zoetis Inc. | Chlortetracycline, Decoquinate | |
| Pioneer combination medicated feed | 141-201 | Zoetis Inc. | Chlortetracycline, Laidlomycin | |
| Pioneer combination medicated feed | 141-2241 | Elanco US, Inc. | Tylosin, Monensin, Ractopamine | |
| Pioneer combination medicated feed | 141-2331 | Elanco US, Inc. | Tylosin, Monensin, Ractopamine, Melengestrol | |
| Pioneer combination medicated feed | 141-250 | Zoetis Inc. | Chlortetracycline, Lasalocid | |
| Pioneer combination medicated feed | 141-289 | Phibro Animal Health Corp. | Virginiamycin, Semduramicin | |
| Pioneer combination medicated feed | 141-4292 | Phibro Animal Health Corp. | Narasin, Nicarbazin Virginiamycin | |
| Pioneer combination medicated feed | 141-430 | Phibro Animal Health Corp. | Virginiamycin, Monensin | |
| Pioneer combination medicated feed | 141-4622 | Phibro Animal Health Corp. | Narasin, Virginiamycin | |
| Pioneer combination medicated feed | 141-5642 | Pharmgate Inc. | Chlortetracycline, Monensin | |
| Pioneer combination medicated feed | 141-468 | Phibro Animal Health Corp. | Virginiamycin, Salinomycin | |
| Pioneer combination medicated feed | 141-469 | Phibro Animal Health Corp. | Virginiamycin, Amprolium | |
| Pioneer combination medicated feed | 141-470 | Phibro Animal Health Corp. | Virginiamycin, Lasalocid | |
| Pioneer combination medicated feed | 141-472 | Huvepharma EOOD | Virginiamycin, Diclazuril | |
| Pioneer combination medicated feed | 141-473 | Huvepharma EOOD | Lincomycin, Halifuginone | |
| Pioneer combination medicated feed | 141-482 | Zoetis Inc. | Lincomycin, Robenidine | |
| Pioneer combination medicated feed | 141-483 | Zoetis Inc. | Lincomycin, Decoquinate | |
| Pioneer combination medicated feed | 141-484 | Zoetis Inc. | Lincomycin, Salinomycin | |
| Pioneer combination medicated feed | 141-485 | Zoetis Inc. | Lincomycin, Clopidol | |
| Pioneer combination medicated feed | 141-488 | Zoetis Inc. | Lincomycin, Lasalocid | |
| Pioneer combination medicated feed | 141-489 | Zoetis Inc. | Lincomycin, Zoalene | |
| Pioneer combination medicated feed | 141-491 | Zoetis Inc. | Lincomycin, Monensin | |
| Pioneer combination medicated feed | 141-5122 | Elanco US, Inc. | Monensin, Tylosin, Lubabegron | |
| Pioneer combination medicated feed | 141-5302 | Zoetis Inc. | Chlortetracycline, Melengestrol Acetate | |
| Pioneer combination medicated feed | 141-5312 | Zoetis Inc. | Chlortetracycline, Lasalocid, Melengestrol Acetate | |
| Pioneer combination medicated feed | 141-5642 | Pharmgate | Chlortetracycline and Monensin | |
| Pioneer combination medicated feed | 141-5862 | Phibro | Virginiamycin, Monensin, Lubabegron | |
| Pioneer combination medicated feed | 141-5881 | Phibro | Virginiamycin, Monensin | |
| Pioneer combination medicated feed | 141-5911 | Elanco US, Inc. | Tylosin, Monensin, Melengestrol, Lubabegron | |
| Generic combination medicated feed | 200-375 | Elanco US, Inc. | Tylosin, Melengestrol, Monensin | |
| Generic combination medicated feed | 200-4241 | Elanco US, Inc. | Tylosin, Monensin, Ractopamine, Melengestrol | |
| Generic combination medicated feed | 200-427 | Elanco US, Inc. | Tylosin, Melengestrol | |
| Generic combination medicated feed | 200-430 | Elanco US, Inc. | Tylosin, Lasalocid, Melengestrol | |
| Generic combination medicated feed | 200-4801 | Elanco US, Inc. | Tylosin, Melengestrol, Monensin, Zilpaterol | |
| Generic combination medicated feed | 200-5301 | Huvepharma EOOD | Tylosin, Ractopamine | |
| Generic combination medicated feed | 200-531 | Huvepharma EOOD | Tylosin, Monensin | |
| Generic combination medicated feed | 200-532 | Huvepharma EOOD | Tylosin, Melengestrol | |
| Generic combination medicated feed | 200-533 | Huvepharma EOOD | Tylosin, Decoquinate, Monensin | |
| Generic combination medicated feed | 200-534 | Huvepharma EOOD | Tylosin, Melengestrol, Monensin | |
| Generic combination medicated feed | 200-535 | Huvepharma EOOD | Tylosin, Melengestrol, Lasalocid | |
| Generic combination medicated feed | 200-5581 | Zoetis Inc. | Tylosin, Ractopamine | |
| Generic combination medicated feed | 200-5611 | Zoetis Inc. | Tylosin, Monensin, Ractopamine | |
| Generic combination medicated feed | 200-5621 | Zoetis Inc. | Tylosin, Monensin, Ractopamine, Melengestrol | |
| Generic combination medicated feed | 200-5661 | Huvepharma EOOD | Tylosin, Monensin, Ractopamine | |
| Generic combination medicated feed | 200-5671 | Huvepharma EOOD | Tylosin, Monensin, Ractopamine, Melengestrol | |
| Generic combination medicated feed | 200-5841 | Zoetis Inc. | Ractopamine, Tylosin | |
| Generic combination medicated feed | 200-617 | Pharmgate LLC | Chlortetracycline, Lasalocid | |
| Generic combination medicated feed | 200-622 | Pharmgate LLC | Chlortetracycline, Decoquinate | |
| Generic combination medicated feed | 200-6422 | Huvepharma EOOD | Monensin, Tylosin Phosphate | |
| Generic combination medicated feed | 200-6432 | Huvepharma EOOD | Monensin, Tylosin Phosphate | |
| Generic combination medicated feed | 200-6532 | Huvepharma EOOD | Decoquinate, Monensin, Tylosin Phosphate | |
| Generic combination medicated feed | 200-6562 | Huvepharma EOOD | Decoquinate, Monensin, Tylosin Phosphate | |
| Generic combination medicated feed | 200-6602 | Huvepharma EOOD | Melengestrol Acetate, Monensin, Tylosin Phosphate | |
| Generic combination medicated feed | 200-6612 | Huvepharma EOOD | Melengestrol Acetate, Monensin, Tylosin Phosphate | |
| Generic combination medicated feed | 200-6852 | Huvepharma EOOD | Melengestrol Acetate, Monensin, Tylosin Phosphate | |
| Generic combination medicated feed | 200-7482 | Huvepharma EOOD | Chlortetracycline and Monensin | |
| Generic combination medicated feed | 200-7701 | Huvepharma EOOD | Chlortetracycline, Melengestrol | |
| Generic combination medicated feed | 200-8081 | Huvepharma EOOD | Tylosin, Monensin, Melengestrol, Lubabegron | |
| Generic combination medicated feed | 200-7242 | Huvepharma EOOD | Tylosin, Monensin, Melengestrol, Lubabegron |
1 The regimens for these combination medicated feeds are appropriately defined as currently approved. These applications will require only administrative revisions to one or more labeling components that contain language referencing other undefined regimen(s) that are associated with the reference listed antimicrobial Type A medicated articles.
2 Application approved after April 2019 when this list was initially published.