Gentadex

Gentamicin (0.3%) + Dexamethasone (0.1%)
Price: ₹55 - ₹75 for 5ml bottle
Mfr: Entod Pharmaceuticals Ltd. | Form: Ophthalmic Solution/Drops

📋 Clinical Overview

A sterile, topical ophthalmic solution combining the bactericidal aminoglycoside antibiotic Gentamicin with the potent corticosteroid Dexamethasone. It is primarily indicated for the treatment of steroid-responsive inflammatory ocular conditions where a risk of bacterial infection exists or where such infection is present. The combination provides anti-inflammatory, anti-allergic, and anti-infective actions.

💊 Dosage & Administration

Adult: One or two drops into the conjunctival sac(s) every 4 to 6 hours. In severe disease, drops may be used hourly initially, tapering as inflammation subsides.

Note: 1. Wash hands. 2. Tilt head back. 3. Gently pull lower eyelid 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. Apply gentle pressure to the nasolacrimal duct (inner corner of eye) for 1 minute to minimize systemic absorption. 6. Wait at least 5-10 minutes before instilling any other ophthalmic medication. Do not wear soft contact lenses during treatment.

⚠️ Contraindications

  • Hypersensitivity to gentamicin, other aminoglycosides, dexamethasone, or any component of the formulation
  • Viral diseases of the cornea and conjunctiva (e.g., epithelial herpes simplex keratitis, vaccinia, varicella)
  • Fungal diseases of ocular structures
  • Mycobacterial infection of the eye
  • Acute purulent untreated infections (unless anti-infective therapy is instituted)

🔬 Mechanism of Action

Gentamicin binds irreversibly to the 30S ribosomal subunit of susceptible bacteria, inhibiting protein synthesis and causing bacterial cell death (bactericidal). Dexamethasone is a potent glucocorticoid that induces phospholipase A2 inhibitory proteins (lipocortins), which inhibit the release of arachidonic acid, thereby reducing the production of inflammatory mediators like prostaglandins and leukotrienes. It also suppresses migration of polymorphonuclear leukocytes and reverses increased capillary permeability.

🤕 Side Effects

  • Transient burning or stinging on instillation
  • Blurred vision temporarily after application
  • Mild ocular irritation/itching

🤰 Special Populations

Pregnancy: Category C (US FDA). Dexamethasone may be teratogenic in animal studies. Gentamicin carries risk of fetal ototoxicity. Use only if the potential benefit justifies the potential risk to the fetus. Avoid prolonged use or high doses.

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

🔄 Drug Interactions

Other topical ophthalmic corticosteroidsAdditive risk of elevated IOP and cataract formation.Major
Systemic corticosteroids (e.g., Prednisolone)Increased systemic corticosteroid effects and side effects.Moderate
Other topical aminoglycosides (e.g., Tobramycin) or systemic aminoglycosidesPotential additive ototoxicity and nephrotoxicity if significant systemic absorption occurs.Moderate
Neuromuscular blocking agents (e.g., Succinylcholine)Gentamicin may potentiate neuromuscular blockade.Moderate
Loop diuretics (e.g., Furosemide)Increased risk of ototoxicity and nephrotoxicity with systemic gentamicin.Moderate

🔁 Alternatives to Gentadex

Same composition (Gentamicin (0.3%) + Dexamethasone (0.1%)), different brands:

Genticyn-D Dexamycin D-Gene Ocupol-DX