Intracamerally injected mydriatic agents safer than standard eye drop regimen during cataract surgery performed in older patients.
Considering these benefits, the current investigators wanted to determine the systemic exposure experienced by 271 patients receiving the ICMA formulation (tropicamide 0.02%, phenylephrine 0.31%, and lidocaine 1%) in the operated eye compared with 283 patients treated with the standard topical administration (tropicamide 0.5% and phenylephrine 10%), referred to as the safety set. High-performance liquid chromatography was performed before and after administration of the drug regimens to determine the plasma levels in 15 patients in each group.
The investigators reported that 198 patients in the ICMA group received one 200-microliter dose, which exposed them to a calculated level of 0.04 mg of tropicamide and 0.62 mg of phenylephrine; none received an additional mydriatic. In the rest of the ICMA group, 72 patients received another 100-microliter injection for a maximal dose of 0.06 mg of tropicamide and 0.93 mg of phenylephrine; one patient received a third 100-microliter injection.
In the safety set group, the respective exposures with three drops were calculated to be 0.45 and 10.2 milligrams, 11.3-fold and 16.5-fold higher compared with the ICMA group. When patients required additional drops, which occurred in 9.2% of patients, the exposure was 37.5-fold higher for tropicamide (10 drops, 1.5 mg) and 54.8-fold higher for phenylephrine (10 drops, 34 mg) compared with the recommended ICMA dose, the investigators reported.
Jose Guell, MD
E: [email protected]
Dr. Guell is affiliated with the Autonomous University of Barcelona, Barcelona, Spain.