By Shelby Shank
Field Editor

The U.S. Food and Drug Administration (FDA) issued an emergency use authorization  for Ivomec (Ivermectin) 1% injectable solution against New World screwworm (NWS) in cattle.

Ivomec is authorized for use in preventing infestations caused by NWS larvae when administered within 24 hours of birth, at the time of castration or when a wound appears.

Ivomec is not for use in female dairy cattle producing milk for human consumption or in calves that will be processed for veal. The slaughter withdrawal period for cattle is 35 days.

“An over-the-counter injectable option allows ranchers to act immediately when facing a New World screwworm threat,” said Tracy Tomascik, Texas Farm Bureau associate director of Commodity and Regulatory Activities. “Quick access to treatment is essential to stopping the spread and protecting the livestock industry.”

Ivomec is a brand name for the drug ivermectin, a product widely used as an anti-parasitic in cattle, sheep, goats and pets for controlling both internal and external parasites. While ivermectin is not new to the market, the emergency use authorization makes it the first over-the-counter option available to ranchers to preventively treat for NWS in cattle.

The authorization allows Ivomec to be sold without a veterinary prescription, but ranchers remain responsible for using the product in accordance with FDA approved labeling and fact sheet.

To help reduce the risk of antiparasitic resistance and preserve the long-term effectiveness of ivermectin, the FDA encourages ranchers to use products like Ivomec only when medically necessary and as part of comprehensive parasite management strategy. This includes good animal husbandry practices, monitoring livestock closely for wounds and working with veterinarians.

The emergency use authorization will remain in effect until it is revoked or until the U.S. Department of Health and Human Services secretary terminates the declaration that the potential public health emergency presented by NWS justifies the emergency use of animal drugs for NWS.

Ivermectin is one of three drugs approved by the FDA for emergency use treatment of NWS in livestock. The others include Dectomax-CA1 and Exzolt Cattle-CA1.