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Pirsue Sterile Solution (Canada)

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

Pirsue Sterile Solution

This treatment applies to the following species:
Company: Zoetis

pirlimycin hydrochloride sterile solution

DIN 02264730

Veterinary Use Only

Lactating Cow Mastitis Treatment


Pirsue® Sterile Solution (pirlimycin hydrochloride) is a lincosaminide antibiotic which has activity against Staphylococcus aureus, Streptococcus dysgalactiae and Streptococcus uberis. Pirlimycin functions by binding to the 50s ribosomal subunit of bacterial ribonucleic acid (RNA) which interferes with protein synthesis within the bacteria. The chemical name of pirlimycin hydrochloride is Methyl(2S - Cis) - 7 - chloro - 6,7,8 - trideoxy - 6[[(4 - ethyl - 2 - piperidinyl)carbonyl]amino] - 1 - thio - L - threo - α - D - galacto - octopyranoside hydrochloride hydrate.


Pirsue Sterile Solution is a clear solution containing 50 mg pirlimycin free base equivalents (as pirlimycin hydrochloride) per 10 mL disposable syringe.

Pirsue Sterile Solution Indications

Pirsue Sterile Solution is indicated for the treatment of clinical and subclinical mastitis in lactating dairy cattle caused by Staphylococcus aureus, and treatment of subclinical mastitis in lactating dairy cattle caused by Streptococcus dysgalactiae and Streptococcus uberis.

DOSAGE: For treatment of clinical mastitis associated with Staphylococcus aureus and for treatment of subclinical mastitis associated with S. aureus, Streptococcus dysgalactiae and Streptococcus uberis: Infuse one (1) syringe (10 mL) into each infected quarter. Repeat this treatment once after a 24-hour interval.

For treatment of subclinical mastitis associated with S. aureus and S. uberis: Infuse each infected quarter daily for 8 consecutive days* (extended duration therapy).

*Note: Herds that have a adopted comprehensive mastitis control program, such as strict hygienic milking practices, use of properly maintained and sanitized milking machines, culling of animals with chronic mastitis, milking infected animals separately or at the end, regular herd-level mastitis pathogens susceptibility testing to select appropriate antimicrobial(s) for lactation and dry cow therapy etc. will likely benefit from extended duration (8 day) Pirsue Sterile Solution therapy. Veterinarians should also take into account other farm management practices to determine if benefits of 8 day treatment regime outweigh potential animal health risks.

Directions For Use

Strict hygienic practices and teat disinfection should be followed for intramammary infusion of Pirsue Sterile Solution. Wash teats thoroughly with warm water containing a suitable dairy antiseptic. Dry the teats thoroughly. Milk out the udder completely. Using an alcohol swab provided, wipe off the end of the affected teat using a separate swab for each teat. Choose the desired insertion length (full or partial) and insert tip into the teat canal; push plunger to dispense the entire contents, massage the quarter to distribute the solution into the milk cistern. Following infusion it is advisable to dip all teats in an approved teat dip.

Multiple risk factors are associated with the success of antimicrobials for the treatment of mastitis caused by Staphylococcus aureus. Cows with multiple infected quarters and/or chronically infected quarters are poor therapeutic candidates.


The syringe is designed to provide the choice of either insertion of the full cannula as has traditionally been practiced, or insertion of no more than 1/8 inch of the cannula, as reported by Eberhart, R.J. et. al. 1987. Current Concepts of Bovine Mastitis, 3rd Edition, National Mastitis Council, Arlington, VA.

a. Full insertion: Remove the white end cap by pulling straight up as shown. Gently insert the full cannula into the teat canal; carefully infuse the product.

b. Partial insertion: Remove the white end cap by pulling straight up as shown. Gently insert the exposed white tip into the teat canal; carefully infuse the product.


Coliform bacteria such as E. coli and Klebsiella spp. are intrinsically resistant to pirlimycin. Pirsue Sterile Solution is therefore not indicated for the treatment of infections due to coliform bacteria, as more severe mastitis may result. Resistance to pirlimycin is detected frequently in some gram-positive pathogens, particularly streptococci, in some Canadian herds. Hence selection of Pirsue Sterile Solution for treatment of mastitis should be based on clinical experience supported by herd level pathogen susceptibility testing.

It should be noted that use of any mastitis therapeutic with limited or strain dependent activity against the common gram-negative environmental bacteria (E. coli, Klebsiella spp.) may be associated with infections caused by these organisms if proper infusion techniques are not followed. Thus, proper aseptic teat preparation prior to use of an intramammary infusion product and proper aseptic infusion techniques are highly recommended to reduce the risk of post-infusion infection with environmental bacteria because of teat end contamination.

Cross-resistance may occur between pirlimycin and other lincosamides or macrolides. As per the Canadian Veterinary Medical Association Guidelines on the Prudent Use of Antimicrobial Drugs in Cattle, veterinarians should periodically monitor herd pathogen susceptibility and therapeutic response, especially for routinely employed treatments, in order to detect changes in microbial susceptibility patterns and to re-evaluate antimicrobial selections.

CAUTIONS: Extended (8 day) therapy of Pirsue Sterile Solution may predispose animals to new intramammary infections with gram-negative environmental pathogens. Adequate teat preparation and sanitation should be followed for intramammary infusion, although this may not prevent all new environmental infections. If redness, swelling or abnormal milk persists, or acute clinical mastitis develops, discontinue use immediately and consult a veterinarian. Cows with systemic clinical signs caused by mastitis should receive other appropriate therapy under direction of a licensed veterinarian. Reinfection: After successful treatment, reinfection may occur unless good herd management, sanitation and mechanical safety measures are practised. Affected cows should be watched carefully to detect reoccurrence of infection and possible spread to other animals.


(1) Milk taken from animals during treatment and within 48 hours after the latest treatment with this drug must not be used for food. (2) Treated animals must not be slaughtered for use in food for at least 21 days after the latest treatment with this drug. (3) Use of this product in a manner other than indicated under DOSAGE may result in violative residues. (4) Avoid contact with the solution. (5) Wash hands and any exposed skin with soap and water immediately after use. Flush eyes with water for 15 minutes immediately after exposure.


Adverse Reactions

New intramammary infections and deaths associated with peracute coliform mastitis have been reported in animals treated, principally for extended duration, with Pirsue Sterile Solution during pre-market clinical studies and post-market surveillance. Most, but not all, adverse reactions were associated with failure to thoroughly clean quarters and to use aseptic infusion technique.

CLINICAL MICROBIOLOGY: Utilizing data that included isolates from cows with mastitis, zone diameter interpretative criteria and minimum inhibitory concentration (MIC) breakpoints were determined using standardized procedures from the Clinical and Laboratory Standards Institute (CLSI). The CLSI accepted interpretative criteria for pirlimycin against gram-positive pathogens are shown in Table 1:

Table 1: CLSI-Accepted Interpretative Criteria for Pirlimycin against Bovine Mastitis Pathogens


Disk Potency

Zone Diameter Interpretative Standards (mm)

MIC Breakpoint (µg/mL)





Staphylococcus aureus

Streptococcus uberis

Streptococcus dysgalactiae

2 µg

≥ 13

≤ 12

≤ 2

≥ 4

S : Susceptible

R : Resistant

EFFICACY: Pirsue Sterile Solution has been proven effective for the treatment of clinical and subclinical mastitis in lactating dairy cattle caused by Staphylococcus aureus and for the treatment of subclinical mastitis in lactating dairy cattle caused by Streptococcus dysgalactiae and Streptococcus uberis.

Pirsue Sterile Solution has not been proven effective for the treatment of cows with palpable udder changes due to chronic mastitis.

The efficacy of extended duration pirlimycin therapy for both clinical and subclinical mastitis was demonstrated in two studies.

In an induced model efficacy study in 34 lactating cows, 106 quarters were infected with Staphylococcus aureus and subsequently treated with pirlimycin daily for 2 (2X) or 8 consecutive days (8X). Both treatment regimens were effective in the treatment of S. aureus mastitis in this study. Extended duration (8X) therapy with pirlimycin significantly increased the efficacy for induced persistent infections. Somatic cell counts (SCC) were significantly reduced in quarters that were successfully cured. This model study confirmed that extended duration therapy significantly improves the bacterial cure rates for persistent/subclinical mastitis.

In a field efficacy study in cows with subclinical infections, cattle were treated with once daily infusions of pirlimycin either for 2 or 8 consecutive days. The extension of therapy duration for pirlimycin provided a significant improvement in bacterial cure rate in cows subclinically infected with S. aureus and Streptococcus uberis and a significant reduction in somatic cell count in quarters that were successfully cured.

Animal Safety

A pivotal target animal safety study indicated that Pirsue Sterile Solution is safe and nonirritating to the bovine. Safety observations were also made during a clinical efficacy study. Udder irritation was not observed in studies which were conducted using proper infusion techniques.

For extended duration therapy, a pivotal study and other field studies investigated target animal safety, and more specifically udder irritation. As demonstrated in previous safety studies, the formulation is safe and non-irritating to the bovine udder. There was a higher incidence of new gram-negative environmental (e.g. E. coli, Klebsiella spp.) mastitis in cows treated with the extended duration (8 day) therapy when compared with animals treated with the standard 2 day treatment regime. It is essential to properly prepare and sanitize all teats and utilize proper intramammary infusion practices to prevent new environmental intramammary infections.


A study was conducted to examine the effect of varying concentrations of pirlimycin in milk on the growth of bacterial starter cultures used to produce fermented milk products.

Pirlimycin did not adversely affect bacterial starter cultures used for the production of fermented milk products at concentrations found following normal label use including proper milk discard periods. Violative levels of pirlimycin (>0.40 ppm) can adversely affect the growth of bacterial starter cultures.


Store at a temperature below 25°C. Protect from freezing.

PRESENTATION: Pirsue Sterile Solution is supplied in unbroken packages of 12 or 144 x 10 mL Plastet™ disposable syringes with 12 or 144 individually wrapped 70% isopropyl alcohol swabs.

Zoetis is a trademark and Pirsue is a registered trademark of Zoetis or its licensors, used under license by Zoetis Canada Inc.

Zoetis Canada Inc., Kirkland QC H9H 4M7



CPN: 1198319.4

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