Ocular Hemodynamic Effects of Nitrovasodilators in Healthy Subjects

Medical University of Vienna

Status: Completed

Conditions: Glaucoma

Treatments: Drug: Sodium-nitroprusside; Drug: Nitroglycerin; Drug: Isosorbide-Dinitrate; Drug: Physiologic saline solution (control substance)

Study type: Interventional

Funder types: Other

Identifiers

NCT00810381

OPHT-211097

Details and patient eligibility

About

Glaucoma, one of the most common causes of blindness, is associated with increased intraocular pressure (IOP) and optic nerve head ischemia. Nitrovasodilators are discussed in the treatment of glaucoma. Nitrates relax smooth muscle cells in the vasculature by liberating the vasodilator nitric oxide.

The IOP lowering potential and the vasodilator action in retinal and choroidal vessels of nitrates is still a matter of controversy. Previous studies on the ocular hemodynamic effects of nitrates showed partially contradicting results. In addition the IOP lowering effect of nitrates is still unclear. However, recent studies show that long acting nitrates may preserve optic nerve deterioration and visual field loss.

Therefore, the role of nitrovasodilators in control of ocular blood flow and intraocular pressure has to be elucidated. For this purpose the investigators plan to test the hypothesis that nitrovasodilators improve ocular blood supply to the optic nerve head at doses which do not affect systemic hemodynamics.

Enrollment: 14 patients

Sex: Male

Ages: 19 to 35 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Men aged between 19 and 35 years, nonsmokers
• Body mass index between 15th and 85th percentile (Must et al. 1991)
• Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
• Normal laboratory values unless the investigator considers an abnormality to be clinically irrelevant
• Normal ophthalmic findings, ametropia < 3 Dpt.

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
• History of migraine
• Blood donation during the previous 3 weeks

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Triple Blind

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14 participants in 4 patient groups, including a placebo group

1

Active Comparator group

Description:

Nitroglycerin: (Perlinganit, Nycomet Heilmittelwerke, Vienna, Austria): 0, 0.25, 0.5, 1, 1.5 and 2 µg/kg/min, each infusion step for 20 minutes

Treatment:

Drug: Nitroglycerin

2

Active Comparator group

Description:

Isosorbide-Dinitrate: (Isoket 0,1 %, Gebro Broschek, Fieberbrunn, Austria): 0, 0.5, 1, 2, 4 and 6 µg/kg/min , each infusion step for 20 minutes

Treatment:

Drug: Isosorbide-Dinitrate

3

Active Comparator group

Description:

Sodium-Nitroprusside: (Nipruss, Sanol-Schwarz, Monheim, Germany): 0, 0.25, 0.5, 1, 2 and 4 µg/kg/min, each infusion step for 20 minutes

Treatment:

Drug: Sodium-nitroprusside

4

Placebo Comparator group

Description:

Physiologic saline solution

Treatment:

Drug: Physiologic saline solution (control substance)