Polyflex® (ampicillin for injectable suspension) for dairy and beef cattle, including lactating dairy cows

Dosing Guide

How to properly dose POLYFLEX based on cattle body weight.

Product Description

POLYFLEX (ampicillin for injectable suspension) is an antibiotic for the treatment of infections caused by Gram-positive and Gram-negative bacteria, including bacterial pneumonia.

  • Approved for use in dairy and beef cattle and calves.
  • POLYFLEX is a β-lactam class of antibiotics and requires a veterinary prescription.

Features & Benefits

  • POLYFLEX is a fast-acting treatment against respiratory tract infections.
  • Provides bactericidal activity against Gram-positive and Gram-negative bacteria.
  • Labeled for treatment of bacterial pneumonia (shipping fever, calf pneumonia and bovine pneumonia) caused Aerobacter spp., Klebsiella spp., Staphylococcus spp., 
    Streptococcus spp., Pasteurella multocida and E. coli susceptible to ampicillin trihydrate.
  • POLYFLEX offers a more economical alternative to expensive third-generation cephalosporin drugs.

Top Reasons to Use POLYFLEX with Total Confidence

POLYFLEX goes beyond conventional penicillin therapy.  POLYFLEX offers reliable treatment of infections, caused by Gram-positive and Gram-negative bacteria.

1) Fast-acting treatment against respiratory tract infections

  • Labeled for treatment of bacterial pneumonia (shipping fever, calf pneumonia and bovine pneumonia) caused Aerobacter spp., Klebsiella spp., Staphylococcus spp., 
    Streptococcus spp., Pasteurella multocida and E. coli susceptible to ampicillin trihydrate.

2) Short milk and meat withdrawal times

  • Follow the 48-hour milk withholding and six-day slaughter withdrawal times after the last treatment.  POLYFLEX has predictable withdrawal periods when compared to more variable withdrawal periods associated with the use of penicillin.

3) Convenient Dosing at 2mL per 100 lbs*

  • *Start by adding 79 mL sterile water to the bottle.  Gently shake to reconstitute and make 100 mLs of POLYFLEX.  Administer 2 mL per 100 lbs body weight.  This delivers 5 mg ampicillin per lb body weight.
  • For flexible dosing, consult your veterinarian for guidance when using the flexible dosing from 2 mg-5 mg/lb.

4) Economical treatment cost

  • POLYFLEX offers a more economical treatment cost compared to third-generation cephalosporin drugs.

Mixing and Storage

  • POLYFLEX is supplied as 25 grams of ampicillin sterile powder in a glass bottle. 
  • Follow label directions and use sterile water to rehydrate the sterile powder and to create POLYFLEX ampicillin injection for suspension.
  • After rehydration, POLYFLEX can be stored under refrigeration for up to 3 months.

POLYFLEX Dosage and Safety

Dosage Information

  • Approved for use in cattle (including lactating dairy cows) and calves (including non-ruminating veal calves).  Always follow milk and meat withdrawal per the label.
  • Cattle and calves: 2 to 5 mg/lb of body weight once daily by intramuscular (IM) injection.  Do not treat with POLYFLEX for more than seven days.
  • Three days' treatment is usually adequate, but treatment should be continued for 48 to 72 hours after the animal has become afebrile or asymptomatic.

Safety Information

Do not treat cattle for more than 7 days.  Milk from treated cows must not be used for food during treatment, and for 48 hours (4 milkings) after the last treatment.  Cattle must not be slaughtered for food during treatment, and for 144 hours (6 days) after the last treatment.

POLYFLEX has the potential for producing allergic reactions because it is a derivative of 6 aminopenicillanic acid.  If a reaction should occur, discontinue use of POLYFLEX and treat the subject with the usual agents (antihistamines, pressor amines, corticosteroids).

CAUTION: Federal law restricts this drug to use by or on the order of a licensed veterinarian.

Product Resources

Contact Information

  • Boehringer Ingelheim Animal Health USA Inc.

    Cattle Division

    3239 Satellite Blvd NW,
    Duluth, GA 64506

    • Phone 866-638-2226
    • Fax 816-326-9167
    • e-mail

POLYFLEX® is a registered trademark of Boehringer Ingelheim Animal Health USA Inc. ©2019 Boehringer Ingelheim Animal Health USA Inc. Duluth, GA. All Rights Reserved. BOV-1916-ANTB0219