Defendazole™ (fenbendazole) Oral Dewormer
As the first FDA-approved generic white drench dewormer, Defendazole™ (fenbendazole) treats and controls many of the common profit-limiting internal parasites that reduce feed efficiency and threaten the health of your herd. With Defendazole™ (fenbendazole), producers can expect the same safety, efficacy and performance advantages as Safe-Guard® (fenbendazole) oral suspension.
Target Species: Beef and dairy cattle, goats
The Defendazole™ Advantage: Performance + Value
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Treats and controls many of the economically impactful lungworms, stomach worms and intestinal worms in beef and dairy cattle.
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Treats and controls adult Haemonchus contortus and Teladorsagia circumcincta in goats.
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Expect the same performance advantages as Safe-Guard® (fenbendazole) oral suspension
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FDA approved
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Dung beetle friendly₁
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48-hour milk discard in cattle
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8-day meat withdrawal in cattle
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6-day meat withdrawal in goats
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Available in 1 Liter and 5 Liter sizes
₁Haylie J Brown, Joseph H Lynch, Teiya Kijimoto, Kevin Shaffer, Elizabeth Rowen, Risk of select parasiticides diflubenzuron, eprinomectin, and fenbendazole to dung-associated beetles, Environmental Entomology, Volume 54, Issue 4, August 2025, Pages 865–876, https://academic.oup.com/ee/article/54/4/865/8198110
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.
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Dosage Form
Ready-to-use Oral Suspension
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Active Ingredient(s)
Fenbendazole Suspension 10% (100 mg/mL)
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Indications
BEEF AND DAIRY CATTLE
2.3 mg/lb (5mg/kg) body weight for the treatment and control of:
Lungworms:
Adult Dictyocaulus viviparus
Stomach Worms:
Adult brown stomach worms (Ostertagia ostertagi)
Adult and fourth stage larvae barberpole worms (Haemonchus contortus & H. placei)
Adult and fourth stage larvae small stomach worms (Trichostrongylus axei)
Intestinal Worms
(Adult and fourth stage larvae):
Hookworms (Bunostomum phlebotomum)
Thread-necked intestinal worms (Nematodirus helvetianus)
Small intestinal worms (Cooperia punctata & C. oncophora)
Bankrupt worms (Trichostrongylus colubriformis)
Nodular worms (Oesophagostomum radiatum)
GOATS
2.3 mg/lb (5 mg/kg) body weight for the treatment and control of:
Stomach Worms
(Adults)
Haemonchus contortus and Teladorsagia circumcincta
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Dosage and Administration
Administer orally. The recommended dose of 2.3 mg/lb (5mg/kg) of body weight is achieved when 2.3 mL of the drug are given for each 100 lb of body weight.
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Storage
Store at temperatures between 59 °F (15 °C) and 86 °F (30 °C). Excursions are permitted up to 104 °F (40 °C) however such exposure should be minimized. Brief exposure to temperatures down to 36 °F (2 °C) may be tolerated. Protect from freezing. Shake well before use.
© 2026 Norbrook Laboratories Limited. Defendazole is a trademark and the Norbrook logo is a registered trademark of Norbrook Laboratories Limited. Safe-Guard is a registered trademark of Merck & Co., Inc. or its affiliates. 831-25-242
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