Dexotas-C

Chloramphenicol (0.5% w/v) + Dexamethasone (0.1% w/v)
Price: ₹35 - ₹55
Mfr: Tas Med India Pvt Ltd | Form: Eye Drops

📋 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 is a mainstay in Indian ophthalmology for managing acute bacterial conjunctivitis with significant inflammation, blepharitis, and post-operative prophylaxis.

💊 Dosage & Administration

Adult: 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. Treatment should not exceed 10 days without re-evaluation.

Note: 1. Wash hands. 2. Tilt head back. 3. Gently pull lower eyelid down to form a pouch. 4. Instill prescribed drops without touching the dropper tip to eye or any surface. 5. Close eyes gently for 1-2 minutes. 6. Apply gentle pressure to the nasolacrimal duct (inner corner of eye) for 1 minute to minimize systemic absorption. 7. Wait at least 5-10 minutes before instilling any other eye medication.

⚠️ Contraindications

  • Hypersensitivity to Chloramphenicol, Dexamethasone, or any component
  • Viral diseases of the cornea and conjunctiva (e.g., Herpes simplex, Varicella)
  • Fungal diseases of the eye
  • Mycobacterial infection of the eye
  • Acute purulent untreated infections (where steroid may mask spread)
  • History of Chloramphenicol-induced blood dyscrasias

🔬 Mechanism of Action

Chloramphenicol exerts its bacteriostatic effect by reversibly binding to the 50S subunit of the bacterial ribosome, inhibiting peptidyl transferase activity and blocking protein synthesis. Dexamethasone is a potent glucocorticoid that binds to cytoplasmic glucocorticoid receptors, translocates to the nucleus, and modulates gene transcription. This leads to the synthesis of lipocortin, which inhibits phospholipase A2, thereby reducing the production of pro-inflammatory mediators like prostaglandins and leukotrienes. It also suppresses migration of polymorphonuclear leukocytes and reverses increased capillary permeability.

🤕 Side Effects

  • Transient stinging or burning upon instillation
  • Blurred vision temporarily
  • Mild irritation/redness

🤰 Special Populations

Pregnancy: Category C (US FDA). Dexamethasone crosses the placenta. Chloramphenicol crosses placenta and has been associated with 'Gray Baby Syndrome' in neonates if used near term. Use only if potential benefit justifies potential fetal risk. Avoid prolonged use, especially in third trimester.

Driving: May cause temporary blurred vision after instillation. Patients should not drive or operate machinery until vision clears.

🔄 Drug Interactions

Other topical ophthalmic steroidsIncreased risk of steroid-related side effects (glaucoma, cataract).Major
Erythromycin, Clindamycin (bacteriostatic)Potential antagonism with Chloramphenicol; avoid concurrent use.Moderate
Phenytoin, Phenobarbital, RifampinInduce hepatic enzymes, may increase metabolism of Dexamethasone, reducing its efficacy.Moderate
Ketoconazole, ItraconazoleInhibit CYP3A4, may increase Dexamethasone levels and side effects.Moderate
WarfarinDexamethasone may alter INR; Chloramphenicol can inhibit warfarin metabolism, increasing bleeding risk.Major
Vaccines (Live attenuated)Dexamethasone may diminish immunological response; avoid concurrent administration.Major

🔁 Alternatives to Dexotas-C

Same composition (Chloramphenicol (0.5% w/v) + Dexamethasone (0.1% w/v)), different brands:

Dexachlor Dexoren-C Dexamycin Ocupol-DX