A Phase 4 interventional study of Clonidin and Brimonidine in Ocular Physiology and Regional Blood Flow, sponsored by Medical University of Vienna. Completed at 1 site in Austria. Open to male participants aged 19 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2007-02-12.
Sponsored by Medical University of Vienna · Phase 4, Interventional, and Treatment
Brimonidine tartrate is an alpha-2 agonist ocular hypotensive drug that exerts its effect by causing both a decrease in aqueous production and an increase in uveoscleral outflow. It has been proven to reduce increased intraocular pressure in glaucoma and ocular hypertension. As an alpha 2 agonist Brimonidine belongs to the same class of drugs as Clonidine; however, its molecular structure is sufficiently different to make it more selective for the alpha 2 receptor than Clonidine. Unlike Clonidine, Brimonidine does not appear to have an effect on the central nervous system and therefore does not cause sedation or systemic hypotension.
In addition to their known effect of lowering intraocular pressure, alpha 2 adrenoceptor agonists are neuroprotective. It has, however, been shown that Brimonidine is a very potent vasoconstrictor in the ciliary body thus reducing aqueous humor production. Little is, however, known about potential vasoconstrictor effects of Brimonidine in the posterior pole of the eye. This is of clinical importance, because optic nerve head ischemia appears to contribute to glaucoma pathophysiology.
This study is performed to investigate the effects of topical Clonidine vs. topical Brimonidine on choroidal blood flow and intraocular pressure during isometric exercise.
Medical University of Vienna is the lead sponsor of 1,076 studies on the registry; 177 are open to participants now.
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Choroidal pressure-flow relationship
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Medical University of Vienna