Defendazole

Description

Defend azole™ is a suspension formulation containing fenbendazole at a concentration of 10% (100 mg/mL). The product is available in a 5-liter (169 fl oz) container.

Uses and Indications

This drug is indicated for the treatment of various parasitic infections in beef and dairy cattle as well as goats.

In beef and dairy cattle, the drug is effective against the following conditions:

• Lungworms: Adult Dictyocaulus viviparus.

• Stomach worms, including:

  • Adult brown stomach worms Ostertagia ostertagi.

  • Adult and fourth stage larvae barberpole worms Haemonchus contortus and H. placei.

  • Adult and fourth stage larvae small stomach worms Trichostrongylus axei.

• Intestinal worms (adult and fourth stage larvae), including:

  • Hookworms Bunostomum phlebotomum.

  • Thread-necked intestinal worms Nematodirus helvetianus.

  • Small intestinal worms Cooperia punctata and C. oncophora.

  • Bankrupt worms Trichostrongylus colubriformis.

  • Nodular worms Oesophagostomum radiatum.

For goats, the drug is indicated for the treatment of stomach worms, specifically:

• Adult Haemonchus contortus.

• Adult Teladorsagia circumcincta.

The recommended dosage for both species is 2.3 mg/lb (5 mg/kg) of body weight.

Dosage and Administration

The medication is to be administered orally. The recommended dosage is 2.3 mg per pound (5 mg per kilogram) of body weight. For practical administration, 2.3 mL of the drug should be given for every 100 pounds of body weight.

Healthcare professionals should ensure accurate measurement of the dosage based on the patient's weight to achieve the desired therapeutic effect.

Contraindications

Use of this product is contraindicated in the following situations:

• This product is not intended for use in humans.

• It should not be administered to beef calves less than 2 months of age, dairy calves, or veal calves.

• The use of this product in lactating goats is contraindicated due to the lack of established milk discard time.

Additionally, milk from treated cows must not be consumed by humans during treatment and for 48 hours post-treatment. Cattle should not be slaughtered for human consumption within 8 days after the last treatment, and goats must not be slaughtered within 6 days following the last treatment. Underdosing is also contraindicated; ensure that each animal receives a complete dose based on current body weight.

Warnings and Precautions

The product is strictly contraindicated for use in humans. It is imperative that this product is kept out of reach of children to prevent accidental ingestion or exposure.

For comprehensive occupational safety information, healthcare professionals are advised to consult the Safety Data Sheet (SDS), which provides detailed guidance on handling, storage, and emergency measures related to the product.

Side Effects

Patients should be aware that this product is not intended for use in humans. It is crucial to keep this product out of reach of children to prevent any potential adverse reactions or misuse.

No specific adverse reactions have been reported in clinical trials or postmarketing experiences, as the product is not approved for human use. Therefore, the safety profile in human subjects remains unestablished.

Drug Interactions

There are currently no documented drug interactions associated with the use of this medication. Additionally, there is no information available regarding interactions with laboratory tests. As such, no specific recommendations for dosage adjustments or monitoring are warranted at this time.

Packaging & NDC

The table below lists each NDC Code for Defendazole (fenbendazole) veterinary formulations. Columns show Packaging, Formulation Type, and Active Ingredient Strength.

Pediatric Use

Pediatric patients, specifically beef calves, should not be treated with this product if they are less than 2 months of age. There is no established withdrawal period for this product in pre-ruminating calves. It is essential for healthcare professionals to consult a veterinarian for guidance on the diagnosis, treatment, and control of parasitism in this population.

Geriatric Use

Elderly patients may not have specific information regarding the use of this medication, including dosage adjustments, safety concerns, or special precautions. Therefore, healthcare providers should exercise caution when prescribing this medication to geriatric patients. It is advisable to monitor these patients closely for any adverse effects or changes in therapeutic response, given the lack of targeted data for this population.

Pregnancy

The available data regarding the use of this medication during pregnancy is limited. There are no specific safety concerns outlined in the prescribing information that would contraindicate its use in pregnant patients. Additionally, there are no dosage modifications recommended for pregnant animals, suggesting that the pharmacokinetics may not be significantly altered during pregnancy.

Healthcare professionals should remain vigilant and consider the overall clinical context when prescribing this medication to women of childbearing potential. As with any medication, the potential benefits must be weighed against any unknown risks to fetal outcomes. Further studies may be necessary to fully understand the implications of this medication during pregnancy.

Lactation

Milk taken from cows during treatment and for 48 hours after the last treatment must not be used for human consumption. A withdrawal period has not been established for this product in pre-ruminating calves. Additionally, goats must not be slaughtered for human consumption within 6 days following the last treatment with this drug product. Due to the lack of an established milk discard time, this product should not be used in lactating goats.

Renal Impairment

There is no information available regarding dosage adjustments, special monitoring, or safety considerations for patients with renal impairment. Healthcare professionals should exercise caution and consider the lack of specific guidance when prescribing to patients with reduced kidney function.

Hepatic Impairment

Patients with hepatic impairment should not use this product, as it is not intended for human use. Due to the lack of data regarding the safety and efficacy of this product in individuals with compromised liver function, no dosage adjustments or specific monitoring requirements can be recommended. It is essential to keep this product out of reach of children, and for further information regarding safety, the Safety Data Sheet (SDS) should be consulted for detailed occupational safety information.

Overdosage

In the absence of specific overdosage information, it is essential for healthcare professionals to remain vigilant regarding the potential for overdose with this medication. In cases where an overdose is suspected, immediate medical attention should be sought.

Healthcare providers are advised to monitor patients closely for any signs or symptoms that may indicate an overdose. These may include, but are not limited to, increased severity of known side effects, altered mental status, or any unusual physiological responses.

Management of an overdose should be guided by the clinical presentation of the patient. Supportive care is paramount, and symptomatic treatment should be initiated as necessary. It is recommended that healthcare professionals consult local poison control centers or relevant toxicology resources for specific guidance on the management of overdose cases.

In summary, while no specific overdosage information is provided, healthcare professionals should exercise caution and be prepared to act swiftly in the event of an overdose, ensuring that appropriate measures are taken to safeguard patient health.

Nonclinical Toxicology

No information is available regarding teratogenic effects. Additionally, there is no information provided concerning non-teratogenic effects. The insert does not contain any details related to nonclinical toxicology. Furthermore, there is no information regarding animal pharmacology and toxicology.

Postmarketing Experience

Adverse effects have been reported voluntarily through various channels, including a dedicated hotline at 1-866-591-5777. For additional information regarding adverse drug experience reporting specific to animal drugs, inquiries can be directed to the FDA at 1-888-FDAVETS or through the FDA's website at http://www.fda.gov/reportanimalae.

There have been reports of parasite resistance developing to dewormers, which may occur with any class of dewormer. Additionally, a decrease in the effectiveness of a drug over time, as determined by fecal egg count reduction tests, may suggest the emergence of resistance to the administered dewormer.

Patient Counseling

Healthcare providers should advise patients on the importance of administering the full recommended dose of the medication based on the current body weight of each animal. Underdosing can lead to ineffective treatment and may promote the development of resistance in parasites.

Patients should be encouraged to consult their veterinarian for assistance regarding the diagnosis, treatment, and control of parasitism. It is essential for them to understand that professional guidance is crucial for effective management of their pets' health.

For those seeking more detailed occupational safety information, healthcare providers should inform patients that the Safety Data Sheet (SDS) is available. Patients can obtain a copy of the SDS, report adverse effects, or seek customer service by calling 1-866-591-5777.

Additionally, healthcare providers should make patients aware of the resources available for reporting adverse drug experiences related to animal drugs. Patients can contact the FDA at 1-888-FDAVETS or visit http://www.fda.gov/reportanimalae for further information.

Storage and Handling

The product is supplied in various package configurations, with specific NDC numbers available for identification. It should be stored at temperatures ranging from 59 °F (15 °C) to 86 °F (30 °C). While excursions up to 104 °F (40 °C) are permissible, such exposure should be minimized to maintain product integrity. Brief exposure to temperatures as low as 36 °F (2 °C) may be tolerated, but the product must be protected from freezing conditions.

Prior to use, it is essential to shake the product well to ensure proper mixing and efficacy.

Additional Clinical Information

Fecal examinations and other diagnostic tests, along with a history of parasite management, should be utilized to assess the appropriateness of the dewormer for the herd prior to administration. Following treatment, clinicians are advised to monitor the effectiveness of the dewormer, which can be evaluated through fecal egg count reduction tests or other suitable methods. A noted decrease in drug effectiveness over time may suggest the development of resistance, necessitating adjustments to the parasite management plan based on ongoing monitoring.

The product is administered orally at a recommended dosage of 2.3 mg/lb (5 mg/kg) of body weight, which corresponds to 2.3 mL of the drug for every 100 lb of body weight. Patients should be counseled to consult their veterinarian for guidance on the diagnosis, treatment, and control of parasitism.

Drug Information (PDF)

This document includes the full labeling information for Defendazole, as submitted by Norbrook Laboratories Limited for veterinary use. It may include dosage by species, withdrawal periods, and administration instructions.

View veterinary label (PDF)