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


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

(cloxacillin sodium intramammary infusion)


Intramammary Infusion

Dariclox Caution

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


Dariclox (cloxacillin sodium intramammary infusion) is a stable, nonirritating suspension of cloxacillin sodium containing the equivalent of 200 mg of cloxacillin in saturated vegetable oils per disposable syringe. Dariclox is manufactured by a nonsterilizing process.

Cloxacillin is a semisynthetic penicillin derived from the penicillin nucleus, 6-amino-penicillanic acid. Cloxacillin sodium is the monohydrate sodium salt of 5-methyl-3-(o-chlorophenyl)-4-isoxazolyl penicillin.

ACTION: Cloxacillin sodium 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 most gram-positive organisms associated with mastitis. It is effective against Streptococcus agalactiae and nonpenicillinase-producing Staphylococcus aureus, and there is laboratory evidence that indicates cloxacillin is resistant to destruction by penicillinase-producing organisms. Milk cultures and antibiotic susceptibility testing is recommended when using this product.

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 Dariclox.

For testing the effectiveness of Dariclox 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.

Dariclox Indications

Dariclox is indicated in the treatment of bovine mastitis in lactating cows due to Streptococcus agalactiae and nonpenicillinase-producing Staphylococcus aureus.

Clinical experience indicates that antibiotic efficacy in the treatment of mastitis in lactating cows is directly related to the duration of infection. Therefore, treatment should be instituted as early as possible after detection.


Milk taken from animals during treatment and for 48 hours (4 milkings) after the last treatment must not be used for food. Treated animals must not be slaughtered for food purposes within 10 days after the last treatment.

PRECAUTION: Because it is a derivative of 6-amino-penicillanic acid, Dariclox 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

Milk out udder completely. Wash udder and teats thoroughly with warm water containing a suitable dairy antiseptic. Dry thoroughly. Clean and disinfect the teat with alcohol swabs provided in the carton. Remove the syringe tip cover and insert the tip of the syringe into the teat orifice. Express the suspension into the quarter with gentle and continuous pressure. Withdraw the syringe and grasp the end of the teat firmly. Massage the medication up into the milk cistern.

For optimum response the drug should be administered by intramammary infusion in each infected quarter as described above. Treatment should be repeated at 12-hour intervals for a total of 3 doses. The treated quarter should be milked out at the next routine milking.

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

How Supplied

Dariclox is supplied in cartons of 12 single-dose syringes with 12 alcohol swabs. Each 10-mL, disposable syringe contains cloxacillin sodium equivalent to 200 mg of cloxacillin.

Do Not Store Above 24°C (75°F)

NADA #55-070, Approved by FDA

Manufactured by: G.C. Hanford Mfg. Co., Syracuse, NY 13201

© 2015 Intervet Inc., a subsidiary of Merck & Co., Inc., Madison, NJ 07940, USA.

All rights reserved.


191399 R1

CPN: 1047234.4

Intervet Inc.

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