Vetdrugs 2.0Bacitracin is a polypeptide antibacterial used locally in skin and sterile ophthalmic preparations. Its activity is directed mainly against susceptible gram-positive bacteria. Veterinary products commonly combine it with other antimicrobials to extend coverage. Its clinical role is local infection control at the treated surface.
Group
Polypeptide topical antibacterial
Mechanism of Action
Bacitracin interferes with dephosphorylation and recycling of the bacterial lipid carrier bactoprenol. This prevents normal transport of peptidoglycan precursors across the cytoplasmic membrane and impairs cell-wall assembly. The resulting antibacterial effect depends on organism susceptibility and local concentration. Companion ingredients in combination products provide additional mechanisms and microbial coverage.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Local antibacterial treatment | Reference only | TOPICAL | Apply the formulation to the affected area; quantity depends on lesion size. Ophthalmic treatment requires a sterile eye product and an examination-directed schedule. | |
| Minor superficial skin injury | Reference only | TOPICAL | Up to 7 days; Apply a small topical amount up to three times daily; usually no more than one week. A suitable dressing may be used. Skin ointment is not an eye preparation. | |
| Ocular surface antibacterial combination | Reference only | TOPICAL | Every 6 h | A sterile bacitracin/neomycin/polymyxin ophthalmic ointment may be applied four times daily for prophylaxis; established infection may require much more frequent examination-directed treatment. Neomycin-containing ointment reactions in cats can be severe. |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Local antibacterial treatment | Reference only | TOPICAL | Apply the formulation to the affected area; quantity depends on lesion size. Ophthalmic treatment requires a sterile eye product and an examination-directed schedule. | |
| Minor superficial skin injury | Reference only | TOPICAL | Up to 7 days; Apply a small topical amount up to three times daily; usually no more than one week. A suitable dressing may be used. Skin ointment is not an eye preparation. | |
| Ocular surface antibacterial combination | Reference only | TOPICAL | Every 6 h | A sterile bacitracin/neomycin/polymyxin ophthalmic ointment may be applied four times daily for prophylaxis; established infection may require much more frequent examination-directed treatment. Neomycin-containing ointment reactions in cats can be severe. |
Indications
- Local treatment of susceptible superficial bacterial skin infections in veterinary patients.
- Prevention of selected superficial bacterial wound infections after minor skin injury using a suitable topical product.
- Treatment of susceptible conjunctival or ocular-surface bacterial infection with a sterile bacitracin-containing ophthalmic preparation.
Contraindications
- Hypersensitivity to bacitracin or formulation ingredients
Adverse effects
- Contact irritation
- Allergic dermatitis
- Rare severe anaphylactic reactions reported in cats after triple-antibiotic ophthalmic ointment
Toxicity
Systemic bacitracin is nephrotoxic; topical and eye formulations must not be injected.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Bacitracin zinc topical ointment 500 units/g Dermatologic ointment; not an ophthalmic preparation. Potency is expressed as bacitracin units. | Other | 500 IU / g | TOPICAL |
| Vetropolycin triple-antibiotic ophthalmic ointment Sterile eye ointment; all active amounts per gram. Watch for hypersensitivity, especially in cats. Not interchangeable with skin ointments. | Other | bacitracin zinc 400 IU / g + neomycin 3.5 mg / g + polymyxin b sulfate 10000 IU / g | TOPICAL |
Monitoring and Administration
Use a sterile ophthalmic formulation for the eye; skin ointments are not interchangeable with ophthalmic ointments.
Reassess persistent infection rather than extending topical antibiotic use indefinitely.
Bacitracin penetrates the cornea poorly and is unsuitable as sole treatment for deep corneal or intraocular infection.
Avoid use on chronic ulcerated canine dermatoses because sensitization may occur. Large-area burns or puncture wounds can increase systemic absorption; deep bites and infections may need systemic treatment. Prevent licking for 20–30 minutes.