FDA: Bimectin EUA for New World Screwworm in Cattle

• The FDA issued an Emergency Use Authorization for Bimectin (ivermectin) injection to prevent New World screwworm infestations in cattle.
• Bimectin, a generic version of Ivomec, is authorized for use within 24 hours of birth, at castration, or upon wound appearance, but not for lactating dairy cows or veal calves.
• A critical 35-day slaughter withdrawal time must be strictly observed to prevent drug residues and ensure food safety.
• This authorization expands generic drug options, aiming to reduce producer dependence on a single manufacturer for NWS prevention.
• Cattle producers are responsible for adhering to product labeling and fact sheet guidelines for this over-the-counter veterinary drug.

A critical requirement is the careful observance of a 35-day slaughter withdrawal time for cattle treated with Bimectin injection.

The U.S. Food and Drug Administration (FDA) has issued an Emergency Use Authorization (EUA) for Bimectin (ivermectin) injection, a significant step aimed at preventing New World screwworm (NWS) infestations, also known as myiasis, in cattle. This authorization specifically permits the use of the veterinary drug under certain conditions: it must be administered within 24 hours of an animal's birth, at the time of castration, or upon the appearance of a wound. This targeted approach underscores the agency's focus on proactive measures against the parasitic threat.

It is crucial for cattle producers to note the specific limitations accompanying this FDA ivermectin Emergency Use Authorization. Bimectin injection is explicitly not authorized for use in lactating dairy cows, nor is it permitted for calves destined to be processed for veal. These restrictions are paramount for maintaining the integrity of the food supply chain. Bimeda Animal Health Ltd., based in Ireland, sponsors this particular formulation.

This Bimectin cattle NWS prevention measure introduces a generic alternative to the market. Bimectin injection is recognized as a generic version of Ivomec, a product that received its own authorization for NWS myiasis prevention in cattle in February 2026. Notably, the FDA had previously approved Bimectin injection for the broader treatment and control of various parasites in cattle, but this EUA is confined solely to the injection form and does not extend to other dosage forms of Bimectin. The product is readily available over the counter, without requiring a prescription.

The FDA's decision to grant this Emergency Use Authorization for Bimectin reflects a strategic commitment to broadening the availability of veterinary drug options, particularly in the face of public health emergencies. Timothy Schell, Ph.D., who serves as the director of the FDA's Center for Veterinary Medicine, emphasized that this authorization demonstrates the agency's dedication to expanding generic drug choices for combating New World screwworm. This move aligns with the Trump Administration's broader objective of safeguarding American agriculture from the NWS threat.

Dr. Schell further articulated the rationale behind authorizing both pioneer and generic products, stating that it ensures producers are not reliant on a single manufacturer or product to protect their herds. This approach fosters competition and resilience within the veterinary pharmaceutical market, providing cattle producers with more diverse tools for disease management. The FDA concluded, based on the totality of available scientific evidence, that it is reasonable to believe Bimectin injection may be effective for NWS myiasis prevention in specific cattle populations when used as authorized, and that its known and potential benefits outweigh its known and potential risks.

For veterinary pharmaceutical companies, this expanded authorization for generic drugs under EUA signals a potential shift in market dynamics, impacting product development strategies and competitive landscapes. Compliance officers within these organizations should closely monitor such regulatory developments, as they can influence market entry for generic alternatives and the overall competitive environment for animal health products.

Adherence to strict guidelines is paramount for cattle producers utilizing the FDA Bimectin EUA New World Screwworm authorization, particularly concerning food safety. A critical requirement is the careful observance of a 35-day slaughter withdrawal time for cattle treated with Bimectin injection. This mandatory waiting period is essential to prevent drug residues from entering the food supply, thereby maintaining public health standards and avoiding potential regulatory violations.

Producers and their legal advisors must ensure meticulous compliance with all usage restrictions, which include not administering the drug to lactating dairy cows or to calves intended for veal processing. The U.S. Food and Drug Administration veterinary drug approval process places a high emphasis on these controls to protect consumers. Cattle producers bear the sole responsibility for ensuring that Bimectin injection is used strictly in accordance with its product labeling and accompanying fact sheet.

The Emergency Use Authorization for Bimectin is not permanent; its effectiveness is contingent upon specific conditions. It will remain in effect until it is formally revoked by the FDA or until the Secretary of Health and Human Services terminates the declaration that the potential public health emergency posed by NWS justifies the emergency use authorization of animal drugs for NWS. This temporary nature underscores the importance of ongoing vigilance and compliance within the industry. The careful management of the 35-day slaughter withdrawal time cattle is a non-negotiable aspect of this authorization.

Compliance officers in veterinary pharmaceutical companies should note the FDA's expanded authorization for generic drugs under EUA, which impacts market competition and product development. Cattle producers and their legal advisors must ensure strict adherence to the 35-day slaughter withdrawal period and specific usage restrictions to avoid drug residues and potential regulatory violations related to food safety.

Source: Original reporting via FDA statement