Effects of Topical Clonidine vs. Brimonidine on Choroidal Blood Flow and Intraocular Pressure During Isometric Exercise
Information source: Medical University of Vienna
ClinicalTrials.gov processed this data on August 20, 2015
Link to the current ClinicalTrials.gov record.
Condition(s) targeted: Ocular Physiology; Regional Blood Flow
Intervention: Clonidin (Drug); Brimonidine (Drug)
Phase: Phase 4
Status: Completed
Sponsored by: Medical University of Vienna Official(s) and/or principal investigator(s):
Gabriele Fuchsjäger-Mayrl, M.D., Principal Investigator, Affiliation: Deapartment of Clinical Pharmacology, Medical University of Vienna
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.
Clinical Details
Official title: Effects of Topical Clonidine vs. Brimonidine on Choroidal Blood Flow and Intraocular Pressure During Isometric Exercise
Study design: Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Crossover Assignment, Masking: Double-Blind, Primary Purpose: Treatment
Primary outcome: Choroidal pressure-flow relationship
Eligibility
Minimum age: 19 Years.
Maximum age: 35 Years.
Gender(s): Male.
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
Locations and Contacts
Department of Clinical Pharmacology, Vienna 1090, Austria
Additional Information
Starting date: February 2004
Last updated: February 9, 2007
|
