Dexamethasone or its sodium phosphate salt is applied topically to the eye or the ear. Potency of the sodium phosphate preparations is expressed in terms of dexamethasone phosphate. Care should be taken to avoid contamination of the tip of the ointment tube or dropper when the drug is used ophthalmically.
For use in the eye, 1 or 2 drops of dexamethasone ophthalmic suspension or dexamethasone sodium phosphate ophthalmic solution may be instilled into the conjunctival sac every hour during the day and every 2 hours during the night for initial therapy in severe cases. In mild or moderate inflammation or when a favorable response is attained in severe cases, dosage may be reduced to 1 drop every 4-8 hours. Alternatively, 1.25-2.5 cm of dexamethasone sodium phosphate ophthalmic ointment may be instilled into the conjunctival sac 3 or 4 times daily initially, and once or twice daily thereafter. The ointment also may be used at night in conjunction with daytime use of a suspension or solution to reduce the frequent applications required with the liquid dosage forms. If improvement does not occur within several days, the drug should be discontinued and other therapy begun. The duration of treatment depends on the type and severity of the disease and may range from a few days to several weeks; long-term therapy should be avoided. When the drug is discontinued, dosage should be gradually tapered to avoid exacerbation of the disease.
For application to the ear, the ear canal should be clean and dry. The pH of the preparation used must be neutral or acidic and should be used sparingly to prevent an accumulation of excess debris in the ear canal. No otic preparations of dexamethasone or its sodium phosphate salt are currently marketed in the US. However, 3 or 4 drops of dexamethasone sodium phosphate ophthalmic solution may be instilled into the ear canal 2 or 3 times daily. Alternatively, a gauze wick saturated with the solution may be packed into the aural canal, kept moist with the solution, and allowed to remain in the canal for 12-24 hours. This treatment may be repeated as needed. Duration of treatment may range from a few days to several weeks. After a favorable response is attained, dosage should be gradually reduced and the solution discontinued.