LENEXA, Kan. (April 7, 2026) — Norbrook® has announced the launch of Defendazole™ (fenbendazole), the first generic white drench dewormer to receive FDA approval. Defendazole™ (fenbendazole) is bioequivalent to and delivers the same safety and efficacy as Safe-Guard® (fenbendazole) oral suspension, providing a reliable, efficacious and cost-effective solution for treating and controlling multiple species of internal parasites that reduce feed efficiency, health and performance in beef and dairy cattle and goats. This addition significantly bolsters Norbrook’s comprehensive portfolio of animal health products for U.S. producers and veterinarians.
Defendazole™ (fenbendazole) treats and controls many of the lungworms, stomach worms and intestinal worms most commonly associated with economic loss in beef and dairy cattle. Defendazole™ (fenbendazole) is also approved for the treatment and control of adult Haemonchus contortus and Teladorsagia circumcincta in goats.
Internal parasites negatively impact overall cattle health, causing impaired immune response, decreased weaning weights, reduced fertility and decreased milk production. In addition to Defendazole™ (fenbendazole), Norbrook’s parasiticide portfolio includes Noromectin® (ivermectin) Injection for Cattle and Swine, Noromectin® Plus (ivermectin and clorsulon) Injection for Cattle, Noromectin® Pour-On (ivermectin topical solution) for Cattle, Eprizero® (eprinomectin) Pour-On for Beef and Dairy Cattle and Tauramox® (moxidectin) Injectable Solution.
“With Defendazole™ (fenbendazole), you can expect the same parasite control and animal performance advantages as Safe-Guard® (fenbendazole) oral suspension. It’s a valuable addition to deworming protocols,” says Megan Bollin, DVM, Technical Service Veterinarian, Norbrook.
Supporting Norbrook’s commitment to maximizing producer gains, Defendazole™ (fenbendazole) is available in a standard 1 liter container and a convenient, gravity-fed 5 liter container that can be hung on the chute, minimizing product waste. Defendazole™ (fenbendazole) 5 liter treats 32% more head of equivalent weight cattle per container, or 52,000 more pounds of body weight, than Safe-Guard® (fenbendazole) oral suspension 1 gallon. Norbrook is a market leader in cattle parasite control, providing bioequivalent deworming solutions essential to preserving the health and productivity of herds for generations.
Defendazole™ (fenbendazole) is now available where you purchase animal health products. For more information on Defendazole™ (fenbendazole) from Norbrook, contact your veterinarian, animal health supplier or visit Norbrook.com/us/.
IMPORTANT SAFETY INFORMATION:
Do not use in beef calves less than 2 months old, dairy calves and veal calves. A withdrawal period has not been established for this product in pre-ruminating calves. Additionally, the following meat withdrawal and milk discard times apply: Cattle must not be slaughtered for human consumption for 8 days following last treatment with this drug product. Goats must not be slaughtered for human consumption within 6 days following last treatment with this drug product. For dairy cattle, the milk discard time is 48 hours following last treatment with this drug product. Do not use in lactating goats as no milk discard time has been established.
About Norbrook
Norbrook Holdings Ltd. is the ultimate holding company for all Norbrook’s trading businesses. Norbrook is a leading global provider of veterinary pharmaceuticals enhancing the health of animals. Norbrook, headquartered in Newry, Northern Ireland, distributes products to over 100 countries, with operations in the UK and Ireland, Europe, US, Africa, Australia and New Zealand.
© 2026 Norbrook Laboratories Limited. Defendazole is a trademark and Noromectin, Eprizero, Tauramox and the Norbrook logo are registered trademarks of Norbrook Laboratories Limited. Safe-Guard is a registered trademark of Merck & Co., Inc. or its affiliates. 831-26-098
