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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.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| 1 | Active Comparator | 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 |
|
| 2 | Active Comparator | 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 |
|
| 3 | Active Comparator | 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 |
|
| 4 | Placebo Comparator | Physiologic saline solution |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Nitroglycerin | Drug | intravenous infusion; 0, 0.125, 0.25, 0.5, 1 and 2 µg/kg/min; 20 minutes per infusion step |
|
| Measure | Description | Time Frame |
|---|---|---|
| Optic disc blood flow (laser Doppler flowmetry) | in total 24x on 4 study days |
| Measure | Description | Time Frame |
|---|---|---|
| Intraocular pressure | in total 8x in 4 study days | |
| Choroidal blood flow (laser Doppler flowmetry) | in total 24x on 4 study days | |
| Fundus pulsation amplitude in the macula (laser interferometry) |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Hans-Georg Eichler, MD | Department of Clinical Pharmacology, Medical University of Vienna | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Department of Clinical Pharmacology, Medical University of Vienna | Vienna | 1090 | Austria |
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| ID | Term |
|---|---|
| D005901 | Glaucoma |
| ID | Term |
|---|---|
| D009798 | Ocular Hypertension |
| D005128 | Eye Diseases |
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| ID | Term |
|---|---|
| D005996 | Nitroglycerin |
| D007547 | Isosorbide |
| D009599 | Nitroprusside |
| D035061 | Control Groups |
| ID | Term |
|---|---|
| D009574 | Nitro Compounds |
| D009930 | Organic Chemicals |
| D013012 | Sorbitol |
| D013402 | Sugar Alcohols |
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| Isosorbide-Dinitrate | Drug | intravenous infusion; 0, 0.5, 1, 2, 4, and 6 µg/kg/min; 20 minutes per infusion step |
|
| Sodium-nitroprusside | Drug | intravenous infusion; 0, 0.25, 0.5, 1, 2, and 4 µg/kg/min; 20 minutes per infusion step |
|
| Physiologic saline solution (control substance) | Drug | intravenous infusion, infusion period 120 minutes |
|
| in total 24x on 4 study days |
| Fundus pulsation amplitude in the optic disc (laser interferometry) | in total 24x on 4 study days |
| Blood pressure, pulse rate | on 4 study days |
| D000438 |
| Alcohols |
| D002241 | Carbohydrates |
| D005292 | Ferricyanides |
| D003486 | Cyanides |
| D000838 | Anions |
| D007477 | Ions |
| D004573 | Electrolytes |
| D007287 | Inorganic Chemicals |
| D005290 | Ferric Compounds |
| D058085 | Iron Compounds |
| D006856 | Hydrogen Cyanide |
| D017672 | Nitrogen Compounds |
| D015340 | Epidemiologic Research Design |
| D004812 | Epidemiologic Methods |
| D008919 | Investigative Techniques |
| D012107 | Research Design |
| D008722 | Methods |