1. Clinical Overview
A sterile, topical ophthalmic solution combining a broad-spectrum bacteriostatic antibiotic (Chloramphenicol) with a potent corticosteroid (Dexamethasone). This combination is primarily used for the treatment of inflammatory ocular conditions where there is a risk of bacterial infection or where such an infection is suspected. It addresses both the infectious and inflammatory components of conditions like bacterial conjunctivitis, blepharitis, and keratitis.
| Onset | Duration | Bioavailability |
|---|---|---|
| Anti-inflammatory effects of dexamethasone may be observed within a few hours. Antimicrobial effects of chloramphenicol begin upon contact with susceptible organisms. | Topical duration is approximately 4-6 hours per instillation. Systemic absorption is minimal. | Topical ocular bioavailability is low (<1% systemically). Primarily acts locally. |
2. Mechanism of Action
Chloramphenicol inhibits bacterial protein synthesis by binding reversibly to the 50S ribosomal subunit, preventing peptide bond formation. Dexamethasone is a potent synthetic glucocorticoid that binds to cytoplasmic glucocorticoid receptors, modulating gene expression to inhibit phospholipase A2, thereby reducing the synthesis of prostaglandins, leukotrienes, and other mediators of inflammation, edema, and capillary dilation.
3. Indications & Uses
- Superficial bacterial infections of the eye with significant inflammation (e.g., Bacterial Conjunctivitis)
- Blepharitis and Blepharoconjunctivitis
- Keratitis (non-viral, non-fungal) where inflammation is prominent
- Post-operative ocular inflammation with risk/evidence of bacterial infection
4. Dosage & Administration
Adult Dosage: One to two drops into the conjunctival sac(s) every 4 to 6 hours. In severe conditions, may be used hourly initially, tapering as inflammation subsides.
Administration: 1. Wash hands. 2. Tilt head back. 3. Gently pull lower eyelid to form a pouch. 4. Instill prescribed drops without touching dropper tip. 5. Close eyes gently for 1-2 minutes, applying gentle pressure to the nasolacrimal duct (inner corner of eye) to minimize systemic absorption. 6. Wait at least 5-10 minutes before instilling any other eye medication.
5. Side Effects
Common side effects may include:
- Transient stinging or burning upon instillation
- Blurred vision temporarily
- Mild irritation/redness
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Other topical ophthalmic NSAIDs (e.g., Ketorolac, Nepafenac) | Increased risk of corneal healing impairment and ulceration. | Major |
| Systemic or other topical corticosteroids | Additive risk of elevated IOP, cataract, and systemic steroid effects. | Moderate |
| Erythromycin, Clindamycin (systemic) | Theoretical antagonism as both inhibit 50S ribosomal subunit; clinical significance for topical use is minimal. | Minor |
| Vitamin B12, Iron supplements, Folic Acid | Chloramphenicol may antagonize the hematopoietic response to these agents. | Moderate (with significant systemic absorption) |
| Warfarin, Acenocoumarol | Chloramphenicol may inhibit metabolism, potentiating anticoagulant effect and increasing INR. | Moderate (with significant systemic absorption) |
7. Patient Counselling
- DO wash hands before and after use.
- DO apply gentle pressure on the inner corner of the eye (nasolacrimal duct) for 1-2 minutes after instillation.
- DO wait at least 5-10 minutes before using any other eye drops.
- DO NOT touch the dropper tip to any surface, including the eye, to avoid contamination.
- DO NOT wear contact lenses during treatment unless advised by the doctor.
- DO NOT share the medication.
- DO NOT use for longer than prescribed (typically not >10 days).
8. Toxicology & Storage
Overdose: Topical overdose is unlikely to cause systemic toxicity. Accidental ingestion may cause: Nausea, vomiting, diarrhea, bone marrow depression. Ocular overdose (excessive drops) may cause increased local side effects like severe irritation, blurred vision.
Storage: Store below 25°C. Protect from light. Keep the bottle tightly closed. Keep out of reach of children. Do not freeze.