O. Weijtens, R. Schoemaker, F. Romijn
Oct 1, 2002
Citations
2
Influential Citations
124
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Quality indicators
Journal
Ophthalmology
Abstract
PURPOSE To study the dexamethasone concentration in aqueous humor, vitreous, and serum of patients after repeated topical application of dexamethasone disodium phosphate. DESIGN Prospective nonrandomized comparative trial. PARTICIPANTS Twenty phakic patients scheduled for a first vitrectomy. METHODS All participants received dexamethasone disodium phosphate drops according to an application schedule intended to result in steady-state drug concentrations. Starting on the preoperative day, they received 1 drop of dexamethasone disodium phosphate (0.1%) every 1 hours until the time of vitrectomy (total, 10 or 11 drops). At night, ointment containing dexamethasone (0.3 mg/g) and gentamicin (5 mg/g) was administered once. From 7 AM on, the drop application schedule was resumed. At the start of the vitrectomy, samples were taken from the aqueous humor, vitreous, and blood. MAIN OUTCOME MEASURES The dexamethasone concentrations in the aqueous humor, vitreous, and serum measured by radioimmunoassay. RESULTS The mean dexamethasone concentrations in the aqueous humor, vitreous, and serum were 30.5 ng/ml (range, 7.1-57.7; standard deviation [SD] 15.0), 1.1 ng/ml (range, 0.0-1.6; SD 0.4), and 0.7 ng/ml (range, 0.0-1.2; SD 0.4), respectively. CONCLUSIONS Compared with previously tested administration routes (peribulbar or subconjunctival injection or oral administration), the penetration of dexamethasone into the vitreous after repeated drop application is negligible. Despite the frequent dosing schedule, the dexamethasone concentration in the aqueous humor is far lower than after a subconjunctival injection with dexamethasone disodium phosphate. Systemic uptake is low.