Effects of Topical Clonidine vs. Brimonidine on Choroidal Blood Flow and Intraocular Pressure During Isometric Exercise

Regional Blood Flow Clinical Trial

Official title:

Effects of Topical Clonidine vs. Brimonidine on Choroidal Blood Flow and Intraocular Pressure During Isometric Exercise

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00312416
• Other study ID #: OPHT-121203B
• Status: Completed
• Phase: Phase 4
• First received: April 6, 2006
• Last updated: February 9, 2007
• Start date: February 2004
• Est. completion date: December 2004

Study information

• Verified date: February 2007
• Source: Medical University of Vienna
• Contact: n/a
• Is FDA regulated: No
• Health authority: Austria: Federal Ministry for Health and Women
• Study type: Interventional

Clinical Trial Summary

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 18
• Est. completion date: December 2004
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Male
• Age group: 19 Years to 35 Years

Eligibility

Inclusion Criteria:

• Men aged between 19 and 35 years, nonsmokers

• Body mass index between 15th and 85th percentile (Must A et al. 1991)

• Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant

• Normal ophthalmic findings, ametropy < 3 Dpt.

• Intraocular pressure between 10 and 18 mmHg.

Exclusion Criteria:

• Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study

• Treatment in the previous 3 weeks with any drug

• Symptoms of a clinically relevant illness in the 3 weeks before the first study day

• History of hypersensitivity to the trial drug or to drugs with a similar chemical structure

• History or presence of gastrointestinal, liver or kidney disease, or other conditions known to interfere with, distribution, metabolism or excretion of study drugs

• Blood donation during the previous 3 weeks

• History or family history of epilepsy

Study Design

Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Crossover Assignment, Masking: Double-Blind, Primary Purpose: Treatment

Related Conditions & MeSH terms

• Ocular Physiology
• Regional Blood Flow

Intervention

Drug:
• Clonidin

• Brimonidine

Locations

Country	Name	City	State
Austria	Department of Clinical Pharmacology	Vienna

Sponsors (1)

Lead Sponsor	Collaborator
Medical University of Vienna

Country where clinical trial is conducted

Austria, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Choroidal pressure-flow relationship