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

NCT ID: NCT00312416

Last Updated: 2007-02-12

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: PHASE4
• Total Enrollment: 18 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2004-02-29
• Study Completion Date: 2004-12-31

Brief 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.

Conditions

Ocular Physiology; Regional Blood Flow

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: TREATMENT
• Blinding Strategy: DOUBLE

Interventions

Clonidin

Intervention Type: DRUG

Brimonidine

Intervention Type: DRUG

Eligibility Criteria

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

• Minimum Eligible Age: 19 Years
• Maximum Eligible Age: 35 Years
• Eligible Sex: MALE
• Accepts Healthy Volunteers: Yes

Sponsors

Medical University of Vienna

OTHER

Sponsor Role: lead

Principal Investigators

Gabriele Fuchsjäger-Mayrl, M.D.

Role: PRINCIPAL_INVESTIGATOR

Deapartment of Clinical Pharmacology, Medical University of Vienna

Locations

Department of Clinical Pharmacology

Vienna, , Austria

Countries

Austria

Other Identifiers

OPHT-121203B

Identifier Type: -

Identifier Source: org_study_id