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Sunday, July 27, 2025

Dexamethasone eye drops


Dexamethasone eye drops are a potent ophthalmic corticosteroid formulation used for the treatment of inflammatory conditions affecting the anterior segment of the eye. They are intended for short-term use due to the risk of ocular complications such as elevated intraocular pressure (IOP), glaucoma, or cataract formation. This ophthalmic preparation exerts powerful anti-inflammatory effects locally, reducing symptoms such as redness, swelling, pain, and irritation associated with ocular inflammation.

Pharmacological Classification

  • Therapeutic class: Ophthalmic anti-inflammatory agent

  • Pharmacological class: Glucocorticoid (corticosteroid)

  • ATC code: S01BA01

  • Regulatory status: Prescription-only (Rx)

Mechanism of Action

Dexamethasone, as a fluorinated synthetic glucocorticoid, inhibits multiple inflammatory pathways in the eye. Its mechanism includes:

  • Suppression of prostaglandin and leukotriene synthesis via inhibition of phospholipase A2

  • Downregulation of inflammatory cytokines and adhesion molecules

  • Stabilization of lysosomal membranes

  • Reduction in capillary permeability and leukocyte infiltration

This leads to a pronounced anti-inflammatory effect, especially useful in treating both non-infectious and post-surgical ocular inflammations.

Formulations and Brand Names

Typical Formulation

  • Concentration: 0.1% dexamethasone phosphate (equivalent to 1 mg/mL)

  • Form: Sterile ophthalmic suspension or solution

  • Packaging: Dropper bottles (typically 5 mL or 10 mL)

Common Brands

  • Maxidex® (Alcon) – suspension

  • Dexafree® – preservative-free single-dose units

  • Ozadex® (intravitreal implant, different route) – for posterior segment inflammation

  • Tobradex® – combination of dexamethasone + tobramycin (antibiotic)

Indications

Dexamethasone eye drops are indicated in:

  • Non-infectious anterior uveitis and iritis

  • Postoperative ocular inflammation (e.g. after cataract or laser surgery)

  • Conjunctivitis (non-infectious allergic or irritative)

  • Keratitis (non-infectious forms)

  • Episcleritis and scleritis (mild to moderate)

  • Corneal injury due to chemicals, radiation, or thermal burns

  • Foreign body reactions

  • Severe allergic conjunctivitis

Not used in primary infectious eye diseases unless under close supervision and combined with antimicrobials.

Dosing and Administration

Typical Adult Dose

  • 1 to 2 drops into the affected eye(s) every 4 to 6 hours

  • In more severe inflammation: 1 to 2 drops hourly during initial treatment

  • Tapering: Once inflammation is controlled, frequency is gradually reduced

  • Maximum duration: Should not exceed 7–14 days unless under ophthalmic supervision

Pediatric Use

  • Can be used with caution under specialist direction

  • Dosing frequency and duration should be limited to the lowest effective schedule

Administration Advice

  • Shake bottle well if using suspension formulations

  • Instill into the conjunctival sac, not directly on the cornea

  • Close eyelids gently for 1–2 minutes after instillation

  • Wait at least 5 minutes between different eye medications

  • Avoid contact lenses during treatment (especially with preserved products)

Contraindications

  • Active ocular viral infections: Herpes simplex keratitis (dendritic), varicella

  • Ocular fungal infections

  • Acute purulent or untreated bacterial conjunctivitis or blepharitis

  • Tuberculosis of the eye

  • Hypersensitivity to dexamethasone or formulation components

  • Unhealed corneal epithelial defects

Precautions and Monitoring

Ocular Monitoring

  • Intraocular pressure (IOP) monitoring during prolonged use (especially in glaucoma patients)

  • Periodic slit-lamp and fundoscopic examination

  • Monitor for delayed wound healing, especially after surgery

  • Watch for secondary infections – bacterial, fungal, or viral

Caution In

  • Glaucoma or family history of glaucoma

  • Cataract patients (risk of posterior subcapsular cataract)

  • Diabetics (risk of increased IOP)

  • Contact lens wearers – risk of corneal ulceration or toxicity with preservatives

Adverse Effects

Local (Ocular)

  • Increased IOP, optic nerve damage

  • Posterior subcapsular cataract (with chronic use)

  • Delayed corneal healing

  • Secondary ocular infection, including masked bacterial or fungal infections

  • Corneal thinning or perforation in prolonged use

  • Transient burning or stinging on application

  • Blurred vision, especially with suspensions

Systemic

  • Minimal systemic absorption with proper use

  • Rare systemic corticosteroid effects with long-term high-frequency dosing

Drug Interactions

Although systemic absorption is minimal, certain precautions apply:

  • Ocular NSAIDs: May increase risk of corneal thinning or ulceration

  • Ocular antihypertensives: Monitor IOP closely

  • Antibiotics: Combined formulations (e.g., Tobradex) reduce infection masking risk

  • Vaccines: Avoid live vaccines concurrently if systemic absorption occurs in significant quantities

Comparison with Other Ophthalmic Corticosteroids (No Tables)

Dexamethasone vs. Prednisolone Acetate

  • Both are high-potency steroids for anterior inflammation

  • Prednisolone acetate may penetrate aqueous humor more effectively

  • Dexamethasone has a longer half-life and is more lipophilic

  • Both can elevate IOP, though dexamethasone may do so more potently

Dexamethasone vs. Fluorometholone

  • Fluorometholone is considered a "soft" steroid with less IOP elevation

  • Preferred in long-term use or post-surgical prophylaxis

  • Dexamethasone is more effective in moderate to severe inflammation

Dexamethasone vs. Loteprednol

  • Loteprednol is an ester-based corticosteroid, rapidly deactivated

  • Lower risk of IOP rise than dexamethasone

  • Loteprednol preferred for chronic use (e.g., allergic conjunctivitis)

Patient Counseling Points

  • Shake bottle before use (if suspension)

  • Use drops exactly as prescribed—do not exceed duration

  • Wash hands before and after application

  • Avoid touching the dropper tip to the eye or any surface

  • Wait 5 minutes between multiple eye medications

  • Do not wear contact lenses during treatment (and 15 minutes after application)

  • Store in a cool, dry place. Some formulations require refrigeration

  • Report vision changes, eye pain, or persistent redness immediately

  • Attend all follow-up eye pressure checks if using longer than 1 week

Use in Special Populations

Pregnancy

  • Use only if benefits outweigh risks

  • Risk of fetal effects minimal with short-term local ocular use

Lactation

  • Limited systemic absorption—generally considered compatible with breastfeeding

Pediatrics

  • Use with strict supervision; higher risk of systemic absorption and ocular side effects

Geriatrics

  • Close monitoring for IOP elevation, cataract development, and secondary infection

Withdrawal and Tapering

Tapering is essential if used for >1 week to avoid rebound ocular inflammation. Do not stop suddenly—reduce dose gradually based on ophthalmologist’s guidance




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