The U.S. Food & Drug Administration has alerted veterinary medical professionals as well as those who work with horses and pigs that a synthetic progesterone product commonly used in these animals may cause reproductive system disorders and other adverse effects in people who become exposed to the drug.
FDA said it provided this alert because of the nature of the adverse events, some of which have occurred in teenage girls.
Altrenogest belongs to the class of drugs called progestins and is used to suppress estrus in mares and to synchronize estrus in gilts. FDA said altrenogest is marketed under several brand names, including the equine products Regumate, Ovamed and Altren and the swine products Matrix, Chronomate and Swinemate. The equine products are available via a veterinarian’s prescription and can be administered directly to the base of the mare’s tongue or on the mare’s feed. The swine products are available over the counter and are administered on a portion of the gilt’s feed. These liquid products may be administered to the animals on a daily basis for prolonged periods of time.
FDA said it has received 130 reports of accidental human exposure to altrenogest products between Oct. 6, 1987, and May 30, 2018, and of those, 121 reports were for Regumate, approved in 1983, and nine reports were for Matrix, approved in 2003. Although FDA has not received any reports for the other (generic) products, the agency’s alert includes these products because they are used in the same manner as Regumate and Matrix and on the same animal populations and, therefore, have the same risk for adverse events.
Some reports described exposures in more than one person. Adverse effects were reported in 137 people, including 115 women and 22 men. Eighteen of the women affected were teenage girls, FDA said, noting that some reports have described adverse effects in girls as young as 14 years of age.
Most people became exposed when the drug contacted their skin. Some of these exposures have occurred when people who did not administer the drug touched product residue on barn surfaces, equipment or treated animals.
FDA said it is aware that adverse events may be under-reported, particularly if the effects are mild or the person is not aware they were exposed. Therefore, the true number of adverse events may be greater than reported.
The labeling for all altrenogest products includes extensive warnings against human exposure, as the hormone is readily absorbed through intact skin, the agency said. Altrenogest is not approved for use in people; the list of exposure precautions is based upon the known effects of other progestins used in people on a chronic (long-term) basis.
FDA emphasized that it is essential for people administering altrenogest products to take appropriate precautions to prevent exposing themselves or other people to the medication. Product labeling directs the use of impermeable, non-porous protective gloves when handling these drug products. These gloves should be nitrile, butyl, vinyl, polyethylene or neoprene. Disposable latex gloves may not provide adequate protection when handling these drug products, FDA said. If accidental exposure does occur, it is important to wash away any drug product on the skin, eyes, mouth or clothing. If adverse effects become apparent, seek medical care.
FDA said it has been in contact with Merck, the sponsor of the pioneer products Regumate and Matrix, to discuss ways that the labeling and packaging of these products could be modified to enhance safety to the user. Any changes to the labeling of these pioneer products must, by law, be applied to any generic products.
The agency has issued a warning letter to Bimeda, the sponsor of Ovamed, a generic altrenogest equine product, because an advertisement for the product did not include important risk information associated with use of this product. FDA said omission of this information in promotional materials created a misleading impression about the safety of Ovamed for people handling and administering the product.
FDA continues to monitor reports of adverse drug events in people exposed to altrenogest products. Veterinary professionals, horse owners and operators and employees of swine and equine facilities are encouraged to report adverse drug events to product manufacturers, who, in turn, are required to report this information to FDA.
For additional information about adverse drug experience reporting for animal drugs, contact FDA at 1-888-FDA-VETS or https://www.fda.gov/AnimalVeterinary/SafetyHealth.