Effects of Latanoprost on Choroidal Blood Flow Regulation in Human Subjects
Latanoprost is a synthetic prodrug of 17-phenyl-substituted prostaglandin F2α analog. Used at a dose of one drop per day, it has been reported to produce a 30 to 35% reduction in intraocular pressure. Its mechanism of activation involves augmentation of the eye's natural uveoscleral outflow capacity .
There is evidence that ocular blood flow plays a role in the clinical course of glaucoma. Glaucoma medication that lowers IOP simultaneously increases ocular blood perfusion pressure, which in turn may increase ocular blood flow.
This could well contribute to the partially contradicting results concerning ocular hemodynamic effects of latanoprost. In vitro studies indicate that latanoprost has no effect on ocular vascular tone in therapeutical doses. By contrast, it has been reported in several studies that latanoprost 0.005% increases pulsatile ocular blood flow in patients with primary open angle glaucoma and normal tension glaucoma. This increase in pulsatile ocular blood flow mainly reflects an increase in the choroidal circulation.
Little is known about the potential effect of latanoprost on choroidal blood flow regulation in humans. The present study therefore tries to elucidate whether treatment with latanoprost may alter choroidal blood flow regulation during artificial changes in ocular perfusion pressure. In addition, the present study aims to clarify whether the change in choroidal blood flow after latanoprost administration are due to direct vasoactive effects or due to the increase in ocular perfusion pressure. The second alternative may have important implications on our understanding of glaucoma treatment, because reduction of IOP may then per se result in normalization of ocular blood flow regulation.
|Ocular Physiology Intraocular Pressure Regional Blood Flow||Drug: Latanoprost 0.005%, Xalatan® Drug: Placebo|
|Study Design:||Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary Purpose: Diagnostic
|Official Title:||Effects of Latanoprost on Choroidal Blood Flow Regulation in Human Subjects|
- Choroidal pressure-flow relationship [ Time Frame: in total 4 hours ]
|Study Start Date:||June 2005|
|Study Completion Date:||January 2010|
|Primary Completion Date:||September 2009 (Final data collection date for primary outcome measure)|
Active Comparator: 1
Latanoprost 0.005%, Xalatan®
Drug: Latanoprost 0.005%, Xalatan®
Substance: Latanoprost 0.005%, Xalatan® (Pharmacia Austria Ges.m.b.H. Oberlaaer Straße 251, 1101 Vienna) Dosage form: topical application in one eye Dosage: 1 drop in the evening for 14 days
Placebo Comparator: 2
Vehicle to latanoprost (eyedrops containing the same stabilizers as latanoprost, but no active drug)
Substance: Vehicle to latanoprost (eyedrops containing the same stabilizers as latanoprost, but no active drug) Dosage form: topical application in one eye Dosage: 1 drop in the evening for 14 days
Please refer to this study by its ClinicalTrials.gov identifier: NCT00712400
|Department of Clinical Pharmacology|
|Vienna, Austria, 1090|