Ciloxan is an ophthalmic antibiotic marketed under the brand name Ciloxan and contains the active ingredient ciprofloxacin. It belongs to the class of fluoroquinolone antibiotics and is formulated as a 0.3 % eye-drop solution supplied in a plastic bottle. In Hong Kong, Ciloxan is a prescription-only medication regulated by the Department of Health under the Pharmacy and Poisons Ordinance. The product is manufactured by Alcon, a global eye-care company.
Ciprofloxacin works by targeting the DNA replication machinery of bacteria, making it effective against a range of ocular pathogens that cause infections such as bacterial conjunctivitis and corneal ulcers. The 0.3 % concentration is the standard strength for ophthalmic use and is designed for direct instillation into the eye.
Ciloxan’s therapeutic effect stems from the fluoroquinolone class mechanism. Ciprofloxacin inhibits two essential bacterial enzymes:
By blocking these enzymes, ciprofloxacin prevents bacterial DNA from being properly copied or segregated, leading to bacterial cell death. The drug penetrates the corneal epithelium and conjunctival tissues after a drop is applied, achieving therapeutic concentrations at the site of infection. Onset of action is rapid, usually within a few hours, and the antimicrobial effect persists as long as the dosing schedule is maintained.
Ciloxan is approved in Hong Kong for the treatment of bacterial eye infections, specifically:
These indications are based on the drug’s activity against common ocular pathogens such as Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae and Pseudomonas aeruginosa. The medication is intended for adult patients and, when deemed appropriate, for pediatric patients under the supervision of an eye-care professional.
Clinical studies have explored the use of ciprofloxacin ophthalmic solution in situations not formally approved by the Hong Kong regulatory authorities, including:
These applications are considered off-label because they are not listed in the official product labeling. Off-label use should only be undertaken under the direct guidance of an ophthalmologist or other qualified eye-care professional, with careful assessment of individual risk factors.
If any of the above conditions apply, a healthcare professional should evaluate the suitability of Ciloxan on a case-by-case basis.
These reactions are typically mild and self-limiting. If discomfort persists, patients should inform their eye-care provider.
Because Ciloxan is administered topically to the eye, systemic drug interactions are minimal. Potential interactions include:
Patients should disclose all ocular and systemic medications to their provider.
Administration tips
Missed dose
If a dose is missed, apply a drop as soon as remembered and then continue with the regular schedule. Do not double the dose.
Overdose
Symptoms of ocular overdose may include severe burning, excessive tearing, or corneal irritation. If these occur, rinse the eye with sterile saline and seek ophthalmic care promptly.
Discontinuation
Do not stop therapy abruptly if a bacterial infection is being treated; incomplete courses can lead to recurrence or resistance. In most cases, therapy can be tapered under professional supervision without a formal tapering protocol.
Regular follow-up with an ophthalmologist is essential for severe infections such as corneal ulcers.
This article provides educational information about Ciloxan and is not a substitute for professional medical advice. Treatment decisions, including the use of medications for unapproved indications, must be made under the guidance of a qualified healthcare provider. The content is intended for informational purposes and does not constitute medical recommendations. Always consult a physician before starting, stopping, or changing any medication regimen.
It is generally recommended to remove contact lenses before instilling Ciloxan and to wait at least 15 minutes before reinserting them. The antibiotic can adhere to the lens material, reducing its effectiveness and potentially increasing the risk of corneal toxicity.
Once opened, the 0.3 % ciprofloxacin eye-drop bottle should be discarded after 30 days, even if some solution remains, to prevent microbial contamination.
Ciprofloxacin is classified as a pregnancy-category C drug in many regions, meaning risk cannot be ruled out. Use only if the potential benefit outweighs the potential risk, and discuss with a healthcare professional.
Severe pain may indicate a serious adverse reaction such as corneal ulceration. Rinse the eye gently with sterile saline and seek immediate ophthalmic care.
Yes, artificial tears can be used, but they should be administered at least 5 minutes apart from the antibiotic drop to avoid dilution of the medication.
Topical use results in minimal systemic absorption, so clinically significant interactions with oral or intravenous fluoroquinolones are unlikely.
Keep the bottle in a cool, dry place away from direct sunlight. If travelling by air, store it in a carry-on bag to avoid temperature extremes in the cargo hold.
Yes, Ciloxan is a prescription-only medication under Hong Kong’s Pharmacy and Poisons Ordinance and must be dispensed by a licensed pharmacist upon presentation of a valid prescription.
Ciloxan contains ciprofloxacin, a fluoroquinolone that targets DNA gyrase, whereas tobramycin is an aminoglycoside that interferes with bacterial protein synthesis. The spectrum of activity and resistance patterns differ between the two classes.
No. Ciloxan is an antibacterial agent and does not work against viruses. Viral conjunctivitis typically resolves without antibiotics; using an antibacterial eye drop in this scenario offers no benefit and may promote resistance.
