Chloramphenicol
Also known as: Chloromycetin · Chloroptic · Kemicetine · Minims · Optrex · Chlorogen · Chloramphenicolum · CAP
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Audited v13 dosing evidence
Structured calculator evidenceSusceptible infections (extra-label)
Verified clinician required
- q12h
NA
Governing clinical context (5)
- NOTE: Because of potential adverse effects in animals and human exposure concerns, chloramphenicol should only be used when other antimicrobial agents are not viable options.
- ■ Wear gloves when handling this medicine and avoid contact with the drug, especially around your mouth, nose, or eyes. Avoid crushing pills.
- ■ This medicine is best given with food as it has an extremely bitter taste that can make administration of the tablets difficult.
- ■ This medication is considered to be a hazardous drug as defined by the National Institute for Occupational Safety and Health (NIOSH). Talk with your veterinarian or pharmacist about the use of personal protective equipment when handling this medicine.
- Chloramphenicol tablets should be stored in tight containers at or below 25°C (77°F) and in a dry place. The sodium succinate powder for injection should be stored between 20°C and 25°C (68°F-77°F).
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
A broad-spectrum antibiotic capable of crossing the corneal barrier and entering the anterior chamber.
- Susceptible Organisms: Typically effective against Staphylococcus spp. and Streptococcus spp.
- Resistant Organisms: Pseudomonas spp. are generally resistant.
- Clinical Use: Useful in treating cats with suspected Mycoplasma or chlamydial conjunctivitis. It is one of the few commercially available ophthalmic antibiotics in ointment form.
- Safety Note: Its use in veterinary ophthalmology is becoming less widespread due to the potential for severe toxicity (aplastic anemia) in humans handling the drug.
Mechanism of action
Chloramphenicol is a bacteriostatic antibiotic that inhibits bacterial protein synthesis. It binds reversibly to the 50S ribosomal subunit of susceptible organisms → prevents the binding of aminoacyl tRNA to the ribosome → inhibits peptide bond formation via peptidyl transferase.
Safety & warnings
Contraindications
- Food-producing animals
- Known hypersensitivity to chloramphenicol
Adverse effects
- Fatal aplastic anemia in humans (exposure risk)
- Local irritation (rare)
Precautions
Human Toxicity Warning: Chloramphenicol exposure in humans has resulted in fatal aplastic anemia. Use with extreme caution. Clients must use appropriate safeguards (e.g., wearing gloves) when applying the drug and avoid contact with drops or solutions. Must not be used in any food-producing animal.
Drug interactions
Irreversible inhibition of hepatic cytochrome P450 increases plasma levels of pentobarbital. Recovery takes up to 3 weeks.
Irreversible inhibition of hepatic cytochrome P450 increases plasma levels of phenobarbital. Recovery takes up to 3 weeks.
Irreversible inhibition of hepatic cytochrome P450 increases plasma levels of propofol. Recovery takes up to 3 weeks.
Irreversible inhibition of hepatic cytochrome P450 increases plasma levels of hypoglycaemics.
Accelerates the metabolism of chloramphenicol, decreasing serum levels.
Chloramphenicol may inhibit the bactericidal activity of aminoglycosides.
Chloramphenicol may inhibit the bactericidal activity of beta-lactams.
May competitively inhibit macrolide antimicrobials at the 50S ribosomal subunit.
May competitively inhibit lincosamide antimicrobials at the 50S ribosomal subunit.
Monitoring
- Resolution of clinical signs of conjunctivitis/keratitis
- Owner compliance with safety protocols (glove use)
Pharmacokinetics
Absorption
Can cross the intact corneal barrier and enter the anterior chamber.
Distribution
Achieves therapeutic levels in the anterior chamber, especially if the blood-ocular barrier is compromised.
Overdose
Topical ophthalmic overdose is unlikely to cause systemic toxicity in the animal, but prolonged use may disrupt normal ocular flora.
Available products
Formulations
- Ophthalmic Ointment 1%
- Ophthalmic Drops 0.5%
Human-labeled
- Chloramphenicol 1% Ophthalmic Ointment (Chloromycetin, Chloroptic, generic)
- Chloramphenicol 0.5% Ophthalmic Drops (Chloroptic, generic)
Regulatory status
Banned for use in food-producing animals (Annex IV of Regulation 2377/90).
POM-V. Banned for use in food-producing animals.
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Drops: Refrigerate until dispensed. Ointment: Store at room temperature.
Client information
CRITICAL SAFETY WARNING: Chloramphenicol can cause a rare but fatal blood disorder (aplastic anemia) in humans.
- Handling: You must wear gloves when applying this medication. Wash your hands thoroughly afterward. Avoid any contact with your skin, eyes, or mouth.
- Application: Apply exactly as directed by your veterinarian. Do not touch the tip of the tube or bottle to the eye.
- Restrictions: Never use this medication in animals intended for food.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.