Tolerability and safety of 0.1% diclofenac plus 0.3% tobramycin fixed-dose ophthalmic solution: a randomized, comparative, controlled study in healthy volunteers.

The purpose of this double-blind, observer-masked, randomized, crossover trial was to compare the tolerability and safety of a fixed-dose ophthalmic solution of 0.3% tobramycin plus 0.1% diclofenac versus Tobrex (tobramycin sulfate ophth) and Voltaren (diclofenac sodium). Control treatments included a saline solution and a control solution of 0.3% tobramycin prepared by Alcon Cusí. Ten healthy volunteers received three consecutive instillations of 1 drop of a given ophthalmic solution at 08:00, 11:00 and 14:00 h to the same eye; after a washout period of 18 h, the next ophthalmic solution was tested according to a randomized sequence. Occurrence, intensity, and duration of ocular irritation and conjunctival hyperemia at baseline and after the three instillations were recorded. Slit lamp biomicroscopy examination, measurement of intraocular pressure (IOP) changes, visual acuity, and examination of the fundus of the eye were performed after each third instillation by an ophthalmologist. Side effect incidence and patient and investigator opinions were also recorded. Results showed that Voltaren instillation induced statistically significant ocular irritation (p = 0.0077); the remaining ophthalmic solutions tested caused no ocular irritation (Physiological Saline Braun, p = 0.9808; Tobrex, p = 0.8826; control 0.3% tobramycin solution, p = 0.8327; and 0.1% diclofenac plus 0.3% tobramycin, p = 0.5399). None of the ophthalmic solutions tested caused severe conjunctival hyperemia. Analysis of the sum of conjunctival parameters of both eyes for all ophthalmic solutions studied showed no statistically significant differences (p = 0.4688). Moderate superficial punctate keratitis was observed after instillation of Voltaren and of 0.1% diclofenac plus 0.3% tobramycin (1 subject each) that spontaneously resolved within 2 days. Slit lamp biomicroscopy, visual acuity and IOP values showed no statistically significant changes. No systemic side effects related to the study treatments were recorded. In conclusion, the ophthalmic solution containing 0.1% diclofenac plus 0.3% tobramycin was well tolerated under the study conditions. Its tolerability was equivalent to that of Braun physiological saline, Tobrex and a control 0.3% tobramycin solution and was better than that of Voltaren.