Is chloramphenicol (antibiotic) effective for treating bacterial conjunctivitis?

From the Guidelines

Chloramphenicol eye drops are not the first-line treatment for bacterial conjunctivitis due to their potential side effects and the availability of other effective options. When considering treatment for bacterial conjunctivitis, the primary goal is to reduce morbidity, mortality, and improve quality of life. According to the most recent guidelines, mild bacterial conjunctivitis is usually self-limited and resolves spontaneously without specific treatment in immune-competent adults 1. However, topical antibacterial therapy, such as chloramphenicol, can be associated with earlier clinical and microbiological remission compared to placebo in the early days of treatment 1. Some key points to consider when treating bacterial conjunctivitis include:

• The choice of antibiotic is usually empiric, and a 5- to 7-day course of a broad-spectrum topical antibiotic is usually effective 1.
• There is no clinical evidence suggesting the superiority of any particular antibiotic, making the most convenient or least expensive option a viable choice 1.
• Povidone-iodine 1.25% ophthalmic solution may be as effective as topical antibiotic therapy for treating bacterial conjunctivitis and could be considered when access to antibiotics is limited 1. It's essential to weigh the benefits and risks of using chloramphenicol, particularly its rare but serious side effects like bone marrow suppression when used systemically, although this is less of a concern with topical use. In real-life clinical practice, the decision to use chloramphenicol or other antibiotics should be made on a case-by-case basis, considering the individual patient's needs and circumstances, and prioritizing the reduction of morbidity, mortality, and improvement of quality of life.

From the FDA Drug Label

Chloromycetin Ophthalmic Ointment, 1% (Chloramphenicol Ophthalmic Ointment, USP) is indicated for the treatment of surface ocular infections involving the conjunctiva and/or cornea caused by chloramphenicol-susceptible organisms The particular antiinfective drug in this product is active against the following common bacterial eye pathogens: Staphylococcus aureus Streptococcus, including Streptococcus pneumoniae Escherichia coli Haemophilus influenzae Klebsiella/Enterobacter species Moraxella lucunata (Morax-Axenfeld bacillus) Neisseria species

Chloramphenicol eye drops are effective for treating bacterial conjunctivitis caused by susceptible organisms, including:

• Staphylococcus aureus
• Streptococcus
• Escherichia coli
• Haemophilus influenzae
• Klebsiella/Enterobacter species
• Moraxella lucunata
• Neisseria species 2

From the Research

Effectiveness of Chloramphenicol Eye Drops for Bacterial Conjunctivitis

• Chloramphenicol eye drops have been compared to other antibiotic eye drops in the treatment of bacterial conjunctivitis, with studies showing that they are effective in treating the infection 3, 4, 5, 6, 7.
• A study published in the European journal of ophthalmology found that ciprofloxacin ophthalmic solution was as safe and effective as chloramphenicol ophthalmic solution in treating conjunctivitis and blepharitis of bacterial aetiology, with both agents achieving microbiological improvement rates in excess of 90% after 1 week's treatment 3.
• Another study published in Tidsskrift for den Norske laegeforening found that a simplified dose regimen of chloramphenicol eye drops (four times a day) was as effective as the standard dosage regimen (one drop hourly/every two hours for three days, thereafter every 4-6 hours) in treating acute bacterial conjunctivitis, with 95% of patients in the simplified regimen group and 88% of patients in the standard regimen group being completely cured after nine days of treatment 4.
• Chloramphenicol eye drops have also been compared to fusidic acid eye drops, with a study published in Acta ophthalmologica finding that both treatments were effective in treating acute, purulent conjunctivitis, but with more patients receiving chloramphenicol complaining of trivial side effects such as stinging and local discomfort 5.
• Other studies have compared chloramphenicol eye drops to trimethoprim-polymyxin B sulphate ophthalmic ointment, with results showing that both treatments are effective and well tolerated in treating bacterial conjunctivitis, but with some studies finding efficacy trends favoring one treatment over the other 6, 7.

Dosage and Administration

• The dosage and administration of chloramphenicol eye drops can vary, with some studies using a standard dosage regimen of one drop hourly/every two hours for three days, thereafter every 4-6 hours 4.
• A simplified dose regimen of four times a day has also been shown to be effective in treating acute bacterial conjunctivitis 4.
• The choice of dosage and administration regimen may depend on the specific clinical context and patient population.

Safety and Tolerability

• Chloramphenicol eye drops have been shown to be generally safe and well tolerated, but with some patients experiencing trivial side effects such as stinging and local discomfort 3, 5.
• A rare but serious side effect of chloramphenicol use is aplastic anaemia, which has been reported in some cases 3.
• Other antibiotic eye drops, such as ciprofloxacin and fusidic acid, may have different safety and tolerability profiles compared to chloramphenicol 3, 5.