Steroidal and Non-steroidal Anti-inflammatory Eye Drops

Inflammation is the vascular and cellular response of the tissues to injury (endogenous and exogenous stimuli). Response to the injury is by production and release of many inflammatory mediators such as mast cells, lymphocytes, leukocytes, compliment, histamines, plasma kinins, proteolytic enzymes etc.

Various anti-inflammatory drugs developed so far have been directed against these inflammatory mediators. Ophthalmic anti-inflammatory can be broadly classified as corticosteroids, non-steroidal anti-inflammatory (NSAIDs) and immunosuppressive agents.

CORTICOSTEROIDS; the anti-inflammatory effects of corticosteroids are non-specific because they inhibit inflammation without regard to the cause. Their mechanism of action leads to vasacontriction, stabilization of lysosomal membranes, retardation of macrophage movement, prevention of kinin release, inhibition of lymphocyte and neutrophil function, inhibition of prostaglandin synthesis and in prolonged use. They decrease antibody production. They prevent symblepharon formation (adhesion of cornea or sclera and the eyelid) and decrease scarring  by inhibiting fibroblastic proliferation and vascularization that usually occurs in chemical and thermal burns. 

Corticosteroid is indicated in the following conditions; Episcleritis and Scleritis, Anterior and panuveitis, Postoperative eye inflammations, superficial keratitis (non-specific or punctuate), Traumatic eye inflammations, Corneal injury from chemical, radiation and thermal burns, Iritis, Cyclitis, Chalazion, interstitial and disciform keratitis, Vernal and Alergic conjunctivitis, Blepharitis , Hemangioma, ete.

It should not be used in acute superficial herpes simplex keratitis, vaccinia, varicella and other viral eye diseases (cornea and conjunctiva), fungal eye diseases, ocular tuberculosis, hypersensitivity and after uncomplicated removal of superficial corneal foreign body. Topical steroids are not effective in sjogrens keratoconjunctivitis and are only used by pregnant and lactating women potential benefits outweigh potential hazards.

Many of the steroid preparations are formulated as suspensions because of their inability to dissolve in a solution. For topical solutions, instill one to two drops into the lower conjunctival sac every hour during the day and every two hours during the night in acute inflammatory conditions of the eye. In mild to moderate inflammations, instill one drop every four to six hours.

For ointments, apply a thin coating in the lower conjunctival sac three to four times a day in severe inflammation. In mild to moderate cases, one application at bed time may be sufficient to control symptoms. 

Ointments are especially convenient when eye pad is used and may be a preparation of choice when prolonged contact of drug with ocular tissues is needed.

Examples of ophthalmic corticosteroids include the following;

• Hydrocortisone: Commercially available as suspensions, solutions and ointments.
• Prednisolone: Commercially available as suspensions, solutions and ointments.
• Dexamethasone: Commercially available as suspensions, solutions and ointments.
• Betamethasone: Commercially available as solutions and ointments.
• Rimexolone:  Commercially available as suspensions.
• Triamcinolone: Commercially available as suspensions, ointments and periocular injections.
• Fluorometholone: Commercially available as suspensions and ointments.
• Loteprednol Etabonate: Commercially available as solutions.
•  Difluprednate: Commercially available as emulsion.

NON-STEROIDAL ANTI-INFLAMMATORY DRUGS; In the treatment of ocular inflammation, need of NSAIDs was felt due to the complications associated with the more established corticosteroid therapy such as elevation of intraocular pressure, progression of cataract, increased risk of infection, worsening of stromal melting etc. hence the use of NSAIDs is safer than the use of corticosteroid as NSAIDs are relatively free of potential adverse effects of steroids.

Examples include the following;

• Flurbiprofen: Commercially available as solutions.
• Ibuprofen: Commercially available as solutions.
• Ketorolac : Commercially available as solutions.
• Fenoprofen: Commercially available as solutions.
• Ketoprofen: Commercially available as solutions.
• Naproxen: Commercially available as solutions.
• Piroxican: Commercially available as solutions.
• Indomethacin: Commercially available as solutions and suspensions.
• Diclofenac: Commercially available as solutions.
• Bromfenac: Commercially available as solutions.
• Nepafenac: Commercially available as solutions.

IMMUNOSUPPRESSIVE AGENTS: The immunosuppressant drugs should be prescribed with caution and preferably in concert with an oncologist. Patients should be fully informed as to potential risk and benefits. They are indicated when response to conventional corticosteroid therapy have filled or when they present unacceptable side effects. They include the following;

• Cyclophosphamide
• Chlorambucil
• Azathioprine
• Methotrexate
• Cyclosporin 
• AInfliximab

They all come in form of oral tablets or intravenous injections.