Effects of dapiprazole on the reversal of pharmacologically induced mydriasis.

The ability of a new alpha-adrenergic antagonist, dapiprazole, to reverse mydriasis produced by phenylephrine 2.5% or 10%, tropicamide 0.5%, and the combination of phenylephrine 2.5% and tropicamide 0.5% was investigated. A double masked crossover design was used to study both efficacy of mydriatic reversal and time course. The safety of administration was evaluated as well. Subjects were optometry students and their spouses. The results demonstrate that dapiprazole is safe and effective for reversing mydriasis produced by both concentrations of phenylephrine, and partially effective in reversing mydriasis in eyes treated with tropicamide 0.5%, alone, or in combination with 2.5% phenylephrine.