1. Clinical Overview
A sterile, multi-ingredient ophthalmic solution indicated for the treatment of superficial bacterial infections of the eye and its adnexa. It combines antibacterial, astringent, and osmotic actions to combat infection, reduce inflammation, and cleanse the eye. This combination is a mainstay in Indian ophthalmology for managing common bacterial conjunctivitis and blepharitis.
| Onset | Duration | Bioavailability |
|---|---|---|
| Sulphacetamide's antibacterial effect begins within minutes of application. Zinc sulfate's astringent effect is immediate. Boric acid's soothing effect is rapid. | Local therapeutic effect lasts approximately 4-6 hours, necessitating multiple daily instillations. | Primarily topical/local action. Systemic absorption through the conjunctiva and nasolacrimal duct is minimal (<1%). |
2. Mechanism of Action
The combination exerts a synergistic multi-target effect. Sulphacetamide sodium is a competitive antagonist of para-aminobenzoic acid (PABA), inhibiting bacterial dihydropteroate synthase, thus preventing folic acid synthesis and arresting bacterial growth. Boric acid provides a mild antiseptic and buffering action, maintaining the pH of the solution and soothing the eye. Sodium chloride acts as an isotonic agent, matching the osmotic pressure of tears to prevent stinging and as a cleansing irrigant. Zinc sulfate acts as a mild astringent and antiseptic, precipitating proteins to reduce exudation and inflammation, and providing a protective coat over the mucous membrane.
3. Indications & Uses
- Acute Bacterial Conjunctivitis
- Bacterial Blepharitis
- Bacterial Keratoconjunctivitis
- Corneal Ulcers (superficial, bacterial)
4. Dosage & Administration
Adult Dosage: 1-2 drops into the affected eye(s) every 3-4 hours during the day. In severe infections, may be used hourly for the first 24-48 hours as directed by a physician.
Administration: 1. Wash hands thoroughly. 2. Tilt head back. 3. Gently pull lower eyelid down to form a pouch. 4. Instill the prescribed number of drops without touching the dropper tip to the eye, eyelid, or any surface. 5. Close eyes gently for 1-2 minutes, applying gentle pressure to the inner corner of the eye (nasolacrimal occlusion) to minimize systemic absorption. 6. Wait at least 10-15 minutes before instilling any other ophthalmic medication.
5. Side Effects
Common side effects may include:
- Transient stinging or burning sensation upon instillation
- Temporary blurred vision
- Mild eye irritation or itching
- Redness (paradoxical or persistent)
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Silver-containing preparations (e.g., Silver Nitrate) | Incompatible; may form insoluble silver sulphacetamide precipitate. | Major |
| Local Anesthetics (e.g., Procaine, Tetracaine) | Antagonism of sulphacetamide's antibacterial effect as these are esters of PABA. | Moderate |
| Oral Sulfonamides or Methotrexate | Potential additive systemic toxicity if significant topical absorption occurs. | Moderate |
| Topical Corticosteroids (e.g., Dexamethasone eye drops) | May mask signs of infection or enhance spread of infection. Use combination only under strict supervision. | Major |
7. Patient Counselling
- DO wash hands before and after use.
- DO complete the full course as prescribed, even if symptoms improve.
- DO wait at least 10-15 minutes between different eye drops.
- DO NOT touch the dropper tip to any surface to avoid contamination.
- DO NOT wear contact lenses during treatment.
- DO NOT share the medication with others.
8. Toxicology & Storage
Overdose: Topical overdose is unlikely but could lead to severe local irritation, corneal damage, punctate keratitis, and increased systemic absorption symptoms (nausea, vomiting, diarrhea, headache, dizziness from sulphacetamide/boric acid).
Storage: Store below 25°C in a cool, dry place. Protect from light. Keep the bottle tightly closed. Do not freeze. Keep out of reach of children. Discard the bottle 4 weeks after opening to prevent microbial contamination. Do not use if the solution is discolored or contains particles.