Bacitracin
Bacitracin is a local antibacterial used in skin and ophthalmic preparations, frequently with other antimicrobials.
Group
Polypeptide topical antibacterial
Mechanism of Action
Blocks recycling of the lipid carrier needed for bacterial cell-wall synthesis; activity is mainly against Gram-positive organisms.
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
- Susceptible superficial bacterial infection
- Bacterial ocular infection using a sterile ophthalmic product
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.