Treatment of glaucoma using minidrops of clonidine

A single regular (70 microL) or mini (15 microL) eyedrop of 0% (placebo), 0.25%, and 0.50% strengths of clonidine hydrochloride was administered to 16 patients with open-angle glaucoma in a double-masked crossover study. Both the regular drops and minidrops of 0.25% and 0.50% concentrations of the drug substantially lowered the intraocular pressure over a five-hour period as compared with the placebo. Only the regular drops of 0.50% clonidine substantially lowered the systemic BP. These results indicate the value of using a smaller volume of clonidine drop as an ocular hypotensive agent to avoid systemic effects.