Pirlimycin: veterinary dose and monograph

At a glance

Drug class

Antibiotic

Also known as

Pirsue

Species with doses

Cattle

Routes

Intramammary

Last reviewed

1 October 2026

Indications

• Clinical and subclinical bovine mastitis — Gram-positive (Staph aureus, CNS, Streptococcus spp.)
• Lactating-cow intramammary therapy for staphylococcal/streptococcal mastitis

Pirlimycin dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Cattle

• Gram-positive mastitis (lactating cow): Plumb’s p.984 (Pirsue label): infuse one syringe per affected quarter after milking and teat-end preparation, repeat after 24 h; may continue daily for up to 8 days. Label withdrawal for the 2-day course: milk 36 h, meat 9 days — extended courses need longer withdrawals (check the label).

Buffalo

No buffalo-specific doses are on file, so buffalo are dosed as cattle.

• Gram-positive mastitis (lactating cow): Plumb’s p.984 (Pirsue label): infuse one syringe per affected quarter after milking and teat-end preparation, repeat after 24 h; may continue daily for up to 8 days. Label withdrawal for the 2-day course: milk 36 h, meat 9 days — extended courses need longer withdrawals (check the label).

Contraindications

Lincosamide/clindamycin hypersensitivity. Gram-negative or Mycoplasma mastitis (limited/no efficacy). Do not give systemically/orally to hindgut fermenters (lincosamide colitis). Observe milk and meat withdrawal. Known hypersensitivity.

Species-specific warnings

Cattle: Strict milk (≈36 h) and meat (≈9 d) withdrawal — verify the specific product and national limits before returning milk to the bulk tank.

Adverse effects

• Local mammary irritation (uncommon)
• Milk/meat residues (observe withdrawal)
• Ineffective against Gram-negatives (a limitation, not a side effect)

Drug interactions

• Macrolides: cross-resistance / antagonism (overlapping ribosomal site)
• No major systemic interactions (intramammary, local use)

Pregnancy and lactation

Used in lactating cows; intramammary local use. Follow product label for dry/pregnant cows (this is a lactating-cow product).

Monitoring

• Mastitis cure — clinical signs, milk appearance, SCC and follow-up culture
• Strict milk and meat withdrawal compliance
• Culture to confirm a Gram-positive pathogen (no value against Gram-negatives/Mycoplasma)
• Aseptic infusion technique (avoid introducing environmental mastitis)

Toxicity and overdose

Local intramammary use has a wide safety margin — toxicity is essentially limited to local irritation and residue/withdrawal issues. (Systemic lincosamides cause colitis in hindgut fermenters, but that is not the intramammary route.)

Management: Supportive; no specific antidote for the local product. Observe withdrawal; manage local irritation symptomatically.

Clinical pearls

• A targeted intramammary lincosamide for Gram-positive (Staph/Strep) mastitis in lactating cows — culture first, since it does nothing for Gram-negative or Mycoplasma mastitis
• Up to 8 days of daily quarter treatment can improve cure of stubborn Staph aureus mastitis
• Aseptic teat-end preparation and partial-insertion technique reduce iatrogenic environmental infection
• Mind the milk/meat withdrawal and verify it against national limits

Mechanism of action

A lincosamide that binds the 50S bacterial ribosomal subunit (23S rRNA), inhibiting peptidyl transferase and bacterial protein synthesis — bacteriostatic against Gram-positive cocci. It distributes well within the mammary gland and concentrates in milk/tissue at the infection site, targeting the staphylococci and streptococci that cause most contagious/environmental mastitis.

Formulations and products

• Intramammary syringe 50 mg/10 mL (Pirsue)
• Pirsue (Zoetis) — Pirlimycin 50 mg/10 mL intramammary, Intramammary syringe

Storage

Intramammary syringes: 15–30 °C, protect from light/heat; use aseptically and discard partially used syringes.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

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Frequently asked questions