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This page contains information on Orbenin-DC for veterinary use.
The information provided typically includes the following:
  • Orbenin-DC Indications
  • Warnings and cautions for Orbenin-DC
  • Direction and dosage information for Orbenin-DC


This treatment applies to the following species:
Company: Intervet/Merck Animal Health

(cloxacillin benzathine intramammary infusion)


Intramammary Infusion


Orbenin-DC Caution

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


Orbenin-DC (cloxacillin benzathine intramammary infusion) is a stable, nonirritating suspension of cloxacillin benzathine containing the equivalent of 500 mg of cloxacillin per disposable syringe. Orbenin-DC is manufactured by a nonsterilizing process.

Cloxacillin benzathine is a semisynthetic penicillin derived from the penicillin nucleus, 6-amino-penicillanic acid. Cloxacillin benzathine is the benzathine salt of 6-[3-(2-chlorophenyl)-5-methylisoxazolyl-4-carboxamido] penicillanic acid.

The low solubility of Orbenin-DC results in an extended period of activity. Therefore, directions for use should be followed explicitly.

ACTION: Cloxacillin benzathine is bactericidal in action against susceptible organisms during the stage of active multiplication. It acts through the inhibition of biosynthesis of cell wall mucopeptide. It is active against gram-positive organisms associated with mastitis such as Staphylococcus aureus and Streptococcus agalactiae and, because of its resistance to penicillinase, penicillin G-resistant staphylococci which may be the cause of mastitis.

Appropriate laboratory tests should be conducted, including in vitro culturing and susceptibility tests on pretreatment milk samples collected aseptically.

SUSCEPTIBILITY TEST: The Kirby-Bauer* procedure, utilizing antibiotic susceptibility disks, is a quantitative method that may be adapted to determining the sensitivity of bacteria in milk to Orbenin-DC.

For testing the effectiveness of Orbenin-DC in milk, follow the Kirby-Bauer procedure using the 1 mcg oxacillin susceptibility disk. Zone diameters for interpreting susceptibility are:




≤ 10 mm

11-12 mm

≥ 13 mm

*Bauer AW, Kirby WMM, Sherris JC, et al: Antibiotic testing by a standardized single disk method, Am J Clin Path 45:493, 1966. Standardized Disk Susceptibility Test, Federal Register 37:20527-29, 1972.

Orbenin-DC Indications

Orbenin-DC is indicated in the treatment and prophylaxis of bovine mastitis in nonlactating cows due to Staphylococcus aureus and Streptococcus agalactiae.


Because cloxacillin benzathine is relatively insoluble, Orbenin-DC’s activity will be prolonged. Therefore, Orbenin-DC should not be used for the occasional cow which may have a dry period of less than 4 weeks. This precaution will avoid residues in the milk following removal of the colostrum.


For use in dry cows only. Do not use within 4 weeks (28 days) of calving. Treated animals must not be slaughtered for food purposes within 4 weeks (28 days) of treatment.

PRECAUTION: Because it is a derivative of 6-amino-penicillanic acid, Orbenin-DC has the potential for producing allergic reactions. Such reactions are rare; however, should they occur, the subject should be treated with the usual agents (antihistamines, pressor amines).

Dosage and Administration

At the last milking of lactation, milk the cow out normally. Clean and disinfect the teats with alcohol swabs provided in the carton or pail, and infuse 1 syringe of Orbenin-DC, which has been warmed to room temperature, into each quarter. Do not milk out. The cow may be milked as usual when she calves.

The extent of subclinical and latent mastitis in a herd is frequently greater than suspected. In untreated herds a significant buildup of subclinical mastitis may occur during the dry period, which results in clinical severity after a few lactations. The adverse influence of subclinical mastitis on milk yield, the risk of cross-infection, and the chance of clinical mastitis flare-up make it necessary to treat the matter as a herd problem. Clinical studies have proven the value of treating all the cows in heavily infected herds as they are dried off. When the herd infection has been reduced, it may be desirable to be more selective in treating infected quarters.

Each carton contains 12 alcohol swabs to facilitate proper cleaning and disinfecting of the teat orifice.

Each pail contains 144 alcohol wipes to facilitate proper cleaning and disinfecting of the teat orifice.

How Supplied

Orbenin-DC is supplied in cartons of 12 single-dose syringes with 12 alcohol swabs and pails of 144 single dose syringes with 144 alcohol wipes. Each disposable syringe contains 500 mg of cloxacillin as the benzathine salt in 7.5 g of suitable base.

Do Not Store Above 24°C (75°F)

Orbenin-DC™ is a trademark owned by and used under license from SmithKline Beecham.

Approved by FDA under NADA # 055-069

Manufactured by:

G.C. Hanford Mfg. Co., Syracuse, NY 13201

© 2022 Merck & Co., Inc., Rahway, NJ, USA and its affiliates.

All rights reserved.

12 single-dose (7.5 g), disposable syringes

INS15480 05

Rev. 10/2022

144 single-dose (7.5 g), disposable syringes

359106 R3

Rev. 08/2021

CPN: 1047235.6

Intervet Inc.

Customer Service:   800-521-5767
Order Desk:   800-648-2118
Technical Service (Companion Animal):   800-224-5318
Technical Service (Livestock):   800-211-3573
Fax:   973-937-5557
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Copyright © 2023 Animalytix LLC. Updated: 2023-02-28