Dosage and administration
Administer orally. The recommended dose of 2.3 mg/lb (5 mg/kg) of body weight is achieved when 2.3 mL of the drug are given for each 100 lb body weight.
Defendazole
- Manufacturer
- Norbrook Laboratories Limited
- Effective date
- 2026-01-15
- Label type
- OTC ANIMAL DRUG LABEL
- Version
- 1
- Source
- full-release
- Hydrated at
- 2026-06-01 02:45:47
Label at a glance#
ProductDefendazole
Active ingredientFENBENDAZOLE
Label structure7 sections
Contacts and useful links#
Websitewww.fda.gov
www.fda.gov/reportanimalae
www.fda.gov/reportanimalaeLabel contents#
Full prescribing information#
INDICATIONS:
SPL UNCLASSIFIED SECTION
Beef and Dairy Cattle – 2.3 mg/lb (5 mg/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), and 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), and nodular worms (Oesophagostomum radiatum).
SPL UNCLASSIFIED SECTION
Goats – 2.3 mg/lb (5 mg/kg) body weight for the treatment and control of: Stomach worms (adults): Haemonchus contortus and Teladorsagia circumcincta.
DIRECTIONS:
Administer orally. The recommended dose of 2.3 mg/lb (5 mg/kg) of body weight is achieved when 2.3 mL of the drug are given for each 100 lb body weight.
EXAMPLES:
Cattle:
| Body Weight | Amount |
| 100 lb | 2.3 mL |
| 200 lb | 4.6 mL |
| 300 lb | 6.9 mL |
| 400 lb | 9.2 mL |
| 500 lb | 11.5 mL |
| 1000 lb | 23.0 mL |
| 1500 lb | 34.5 mL |
Goats :
| Body Weight | Amount |
| 25 lb | 0.6 mL |
| 50 lb | 1.2 mL |
| 75 lb | 1.7 mL |
| 100 lb | 2.3 mL |
| 125 lb | 2.9 mL |
Do not underdose. Ensure each animal receives a complete dose based on a current body weight. Underdosing may result in ineffective treatment, and encourage the development of parasite resistance.
WARNINGS:
NOT FOR USE IN HUMANS.
KEEP OUT OF REACH OF CHILDREN.
The Safety Data Sheet (SDS) contains more detailed occupational safety information.
Contact Information:
For customer service, adverse effects reporting, and/or a copy of the SDS, call 1-866-591-5777.
For additional information about adverse drug experience reporting for animal drugs, contact FDA at 1-888-FDAVETS, or www.fda.gov/reportanimalae
OTHER WARNINGS:
Parasite resistance may develop to any dewormer, and has been reported for most classes of dewormers.
Treatment with a dewormer used in conjunction with parasite management practices appropriate to the geographic area and the animal(s) to be treated may slow the development of parasite resistance.
Fecal examinations or other diagnostic tests and parasite management history should be used to determine if the product is appropriate for the herd, prior to the use of any dewormer. Following the use of any dewormer, effectiveness of treatment should be monitored (for example, with the use of a fecal egg count reduction test or another appropriate method).
A decrease in a drug's effectiveness over time as calculated by fecal egg count reduction tests may indicate the development of resistance to the dewormer administered. Your parasite management plan should be adjusted accordingly based on regular monitoring.
Restricted drug (California) – use only as directed.
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.
Withdrawal Periods and Residue Warnings:
Milk taken from cows during treatment and for 48 hours after the last treatment must not be used for human consumption. Cattle must not be slaughtered for human consumption within 8 days following last treatment with this drug product. Not for use in beef calves less than 2 months of age, dairy calves, and veal calves. A withdrawal period has not been established for this product in pre-ruminating calves.
Goats must not be slaughtered for human consumption within 6 days following last treatment with this drug product. Because a milk discard time has not been established, do not use in lactating goats.
Consult your veterinarian for assistance in the diagnosis, treatment and control of parasitism.
Made in the UK
Norbrook Laboratories Limited
Newry, Co. Down, BT35 6QQ,
Northern Ireland.
Approved by FDA under ANADA # 200-831
Defendazole™ is a trademark of Norbrook Laboratories Limited
Principal Display Panel - 100 mg/mL Carton Label
NDC 55529-165-08
Defendazole™
(fenbendazole)
Dewormer
for Beef & Dairy Cattle
and Goats
Suspension 10%
(100 mg/mL)
5 Liter
(169 fl oz.)
Norbrook®
Principal Display Panel - 100 mg/mL Jug Label
NDC 55529-165-08
Defendazole™
(fenbendazole)
Dewormer
for Beef & Dairy Cattle
and Goats
Suspension 10%
(100 mg/mL)
5 Liter
(169 fl oz.)
Norbrook®
DailyMed RxNorm Mappings#
| RxCUI | RxNorm string | TTY | SPL version |
|---|---|---|---|
| 2732272 | Defendazole 10 % Oral Suspension | PSN | 1 |
| 867451 | fenbendazole 10 % Oral Suspension | PSN | 1 |
| 2732272 | fenbendazole 100 MG/ML Oral Suspension [Defendazole] | SBD | 1 |
| 867451 | fenbendazole 100 MG/ML Oral Suspension | SCD | 1 |
| 2732272 | Defendazole 10 % Oral Suspension | SY | 1 |
| 2732272 | Defendazole 100 MG/ML Oral Suspension | SY | 1 |
| 867451 | fenbendazole 10 % Oral Suspension | SY | 1 |
DailyMed Package Descriptions#
| Package NDC | Product | Description | Form | Quantity | Strength | SPL version |
|---|---|---|---|---|---|---|
| 55529-165-06 | Defendazole | 1 in 1 CARTON | SUSPENSION | 1 | 1 | |
| 55529-165-06 | Defendazole | 1000 mL in 1 JUG | SUSPENSION | 1000 | 1 | |
| 55529-165-08 | Defendazole | 5000 mL in 1 JUG | SUSPENSION | 5000 | 1 | |
| 55529-165-08 | Defendazole | 1 in 1 CARTON | SUSPENSION | 1 | 1 |
Products#
Every source-derived product name is available through these pages.
- Defendazole
- FENBENDAZOLE
NDC Codes#
| Product NDC | Package NDC |
|---|---|
| 55529-165 | 55529-165-06, 55529-165-08 |
Ingredients#
Every source-derived ingredient row is available through these pages.
| Name | UNII | Kind |
|---|---|---|
| FENBENDAZOLE | 621BVT9M36 | ACTIB |
Source Document#
Reported adverse events (FAERS/openFDA)#
Adverse event summaries are temporarily unavailable. Other product information remains available.