The effect of nipradilol, an alpha-beta blocker, on retinal blood flow in healthy volunteers.
OBJECTIVE
To study the effects of topically applied nipradilol, an alpha-beta blocker recently developed in Japan as an ocular hypotensive drug, on retinal blood flow (RBF) in healthy volunteers.


METHODS
Seven healthy volunteers (mean age, 33 years) underwent measurement of RBF using a newly developed stabilized laser Doppler velocimetry system. In a double-blind trial, retinal arterial blood flow, intraocular pressure (IOP), and blood pressure (BP) were measured before and after the instillation of nipradilol or saline every hour for 5 hours.


RESULTS
Retinal arterial blood flow and the diameter of the retinal artery significantly (p< 0.05) increased at 4 hours after instillation in nipradilol-treated eyes. Retinal blood velocity did not change significantly. Nipradilol evoked a significant (p< 0.05) bilateral decrease in IOP. Mean BP decreased significantly (p< 0.05) 3 hours after instillation. Ocular perfusion pressure (OPP), calculated from the mean BP and IOP, did not change significantly during the study.


CONCLUSIONS
Topical nipradilol significantly increased retinal arterial blood flow in healthy volunteers, not through a secondary effect dependent on a change in OPP, but likely through the vasodilatory action of the drug.
Kida
T
T
Department of Ophthalmology, Osaka Medical College, Osaka, Japan. opt038@poh.osaka-med.ac.jp
Sugiyama
T
T
Harino
S
S
Kitanishi
K
K
Ikeda
T
T
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000328:Adult; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D004311:Double-Blind Method; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects; D017078:Laser-Doppler Flowmetry; D008297:Male; D009883:Ophthalmic Solutions; D011412:Propanolamines / Q000494:pharmacology*; D012161:Retinal Artery / Q000187:drug effects / Q000502:physiology*; D014664:Vasodilation / Q000187:drug effects
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D000959:Antihypertensive Agents; D009883:Ophthalmic Solutions; D011412:Propanolamines; C036089:nipradilol