FDA Approves Emergency Use of Generic Ivermectin to Prevent New World Screwworm in Cattle

The FDA has issued an emergency use authorization for Bimectin, a generic injectable ivermectin, to help prevent New World screwworm infestations in cattle. The over-the-counter drug can be administered within 24 hours of birth, during castration, or when a wound appears.

Bimectin is the FDA’s 14th emergency authorization related to New World screwworm as confirmed U.S. animal cases continue increasing, particularly in Texas. The USDA has confirmed 47 domestic cases, including three dogs. The authorization applies only to the injectable product and excludes lactating dairy cows and calves intended for veal. Producers must observe a 35-day slaughter withdrawal period.

Bimectin is a generic version of Ivomec, which received emergency authorization in February 2026. The FDA relied on established bioequivalence and previous ivermectin research rather than requiring new safety and efficacy studies. Officials said authorizing generic and pioneer products gives cattle producers additional options during the ongoing screwworm threat.