Broad-spectrum wormer effective for the removal and control of lungworms, roundworms, stomach worms (barberpole, small stomach and brown stomach worms) and intestinal worms (nodular, hook, small intestinal and tapeworms) in beef cattle. 

Contains 225 mg oxfendazole per ml. 

Administer orally. Dosage: Administer 1 ml per 110 lbs body weight. 1 liter treats 200 - 550 lb cattle. Synanthic dewormer has no known resistance issues. 7 day slaughter withdrawal. Do not use in female dairy cattle of breeding age.


Synanthic Suspension Cattle Dewormer

  • Boehringer Ingelheim


    3239 SATELLITE BLVD., DULUTH, GA, 30096

    Telephone:  800-325-9167
    Fax:  816-236-2717
      THIS SERVICE AND DATA ARE PROVIDED “AS IS”. DVMetrics assumes no liability, and each user assumes full risk, responsibility, and liability, related to its use of the DVMetrics service and data. See the Terms of Use for further details.


    Boehringer Ingelheim Animal Health

    (oxfendazole oral suspension)

    Bovine Dewormer Suspension, 22.5%

    For Animal Use Only

    Approved by FDA under NADA # 140-854

    Each mL contains 225 mg of oxfendazole.

    Consult a veterinarian for assistance in the diagnosis, treatment and control of parasitism.

    Indications: SYNANTHIC Bovine Dewormer Suspension, 22.5%, is a broad-spectrum anthelmintic effective for the removal and control of the following parasites in cattle: lungworms, roundworms (including inhibited forms of Ostertagia ostertagi) and tapeworms, as indicated below:

    Lungworms: Dictyocaulus viviparus (Adult, L4)

    Stomach Worms:

    Barberpole Worms - Haemonchus contortus (Adult)

    Haemonchus placei (Adult)

    Small Stomach Worms - Trichostrongylus axei (Adult)

    Brown Stomach Worms - Ostertagia ostertagi (Adult, L4, inhibited L4)

    Intestinal Worms:

    Nodular Worms - Oesophagostomum radiatum (Adult)

    Hookworms - Bunostomum phlebotomum (Adult)

    Small Intestinal Worms - Cooperia punctata (Adult, L4)

    Cooperia oncophora (Adult, L4)

    Cooperia surnabada (Adult, L4)

    Tapeworms - Moniezia benedeni (Adult)

    Administration and Dosage: SYNANTHIC Bovine Dewormer Suspension, 22.5%, is supplied in 500 mL and one liter packages containing 225 mg of oxfendazole per mL. The recommended dose for cattle is 2.05 mg/lb (4.5 mg/kg) of body weight. SYNANTHIC Bovine Dewormer Suspension, 22.5%, should be administered orally by accurate dose syringe at the rate of 1 mL per 110 lb (50 kg) of body weight. This product should be shaken well immediately prior to use. 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.

    Remove Cap and Protective Seal and Replace with Draw Off Cap Prior to Use. Do Not Squeeze Sides of Bottle. Replace the Draw Off Cap with the Initial Cap after Use.

    Directions: Determine the proper dose according to estimated body weight. Administer orally. The recommended dose of 2.05 mg/lb (4.5 mg/kg) is achieved when 1 mL of the suspension is given for each 110 lb (50 kg) of body weight.


    Cattle Weight


    110 lb (50 kg)

    1.0 mL

    220 lb (100 kg)

    2.0 mL

    330 lb (150 kg)

    3.0 mL

    440 lb (200 kg)

    4.0 mL

    550 lb (250 kg)

    5.0 mL

    660 lb (300 kg)

    6.0 mL

    770 lb (350 kg)

    7.0 mL

    880 lb (400 kg)

    8.0 mL

    990 lb (450 kg)

    9.0 mL

    1100 lb (500 kg)

    10.0 mL

    Treatment may be repeated in 4-6 weeks.


    Residue Warnings: Cattle must not be slaughtered until 7 days after treatment. Because a withdrawal time in milk has not been established, do not use in female dairy cattle of breeding age.


    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/flock, 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.

    Caution: Use only as directed. Keep out of reach of children. Not for human use.

    Safety: There are no contraindications for the use of SYNANTHIC Bovine Dewormer Suspension, 22.5%, in cattle.

    Shake well before use.

    Storage: Store at or below 25°C (77°F). Brief excursions are permitted up to 30°C (86°F). Do not freeze.

    Restricted Drug (California) - Use Only as Directed.

    © 2019 Boehringer Ingelheim Animal Health USA Inc. All rights reserved.

    SYNANTHIC and the Cattle Head Logo are registered trademarks of Boehringer Ingelheim Animal Health USA Inc.

    Marketed by:

    Boehringer Ingelheim Animal Health USA Inc., Duluth, GA 30096

    Net Contents:



    500 mL
    The entire contents treats 110 cattle weighing approximately 500 lbs each.




    1000 mL (1 liter)
    The entire contents treats 220 cattle weighing approximately 500 lbs each.




    CPN: 1028221.4