Schmetterer L, Strenn K, Findl O, Breiteneder H, Graselli U, Agneter E, Eichler H G, Wolzt M
Department of Clinical Pharmacology, Vienna University School of Medicine, Austria.
Clin Pharmacol Ther. 1997 May;61(5):583-95. doi: 10.1016/S0009-9236(97)90138-7.
There is evidence that ocular blood flow plays a critical role in the clinical course of glaucoma. Hence a reduction in ocular blood flow due to topical antiglaucoma treatment should be avoided. The purpose of this study was to characterize the effect of antiglaucoma drugs on ocular hemodynamics.
In a double-blind, placebo-controlled, randomized crossover study, we investigated the effects of single topical doses of five beta-blocking agents (befunolol, betaxolol, levobunolol, metipranolol, and timolol), two adrenergic agents (clonidine and dipivefrin [INN, dipivefrine]), and a parasympathomimetic agent (pilocarpine) on ocular and systemic hemodynamics in healthy subjects (n = 10). Fundus pulsation amplitudes in the macula and the optic disc were measured to characterize pulsatile choroidal and optic disc blood flow, respectively. Moreover, central retinal and ophthalmic artery blood flow velocities were measured by Doppler ultrasound.
Befunolol, metipranolol, timolol, clonidine, and dipivefrin reduced fundus pulsations in the macula and the optic disc (-9% to -14% versus baseline). In contrast, betaxolol, levobunolol, and pilocarpine had no effect on fundus pulsations. Antiglaucoma drugs had no effect on either blood flow velocities in the central retinal or the ophthalmic artery or systemic hemodynamics.
Our results indicate that befunolol, metipranolol, timolol, clonidine, and dipivefrin reduce choroidal and optic disc blood flow. This could be caused by drug diffusion to the choroid, which may cause vasoconstriction. Ocular blood flow reduction was not observed with betaxolol, levobunolol, or pilocarpine. The lack of effect of all drugs under study on central retinal blood flow velocity might partially be the result of autoregulative mechanisms. Because optic nerve head blood flow likely plays a critical role in the clinical course of glaucoma, the use of antiglaucoma drugs, which reduce blood flow, should be reconsidered.
有证据表明眼血流在青光眼临床病程中起关键作用。因此应避免局部抗青光眼治疗导致眼血流减少。本研究的目的是描述抗青光眼药物对眼血流动力学的影响。
在一项双盲、安慰剂对照、随机交叉研究中，我们调查了单次局部应用五种β受体阻滞剂（倍他洛尔、倍他洛尔、左布诺洛尔、美替洛尔和噻吗洛尔）、两种肾上腺素能药物（可乐定和地匹福林[国际非专利药品名称，地匹福林]）以及一种拟副交感神经药物（毛果芸香碱）对健康受试者（n = 10）眼和全身血流动力学的影响。测量黄斑和视盘的眼底搏动幅度，分别以表征脉络膜和视盘的搏动性血流。此外，通过多普勒超声测量视网膜中央动脉和眼动脉的血流速度。
倍他洛尔、美替洛尔、噻吗洛尔、可乐定和地匹福林降低了黄斑和视盘的眼底搏动（与基线相比降低了-9%至-14%）。相比之下，倍他洛尔、左布诺洛尔和毛果芸香碱对眼底搏动无影响。抗青光眼药物对视网膜中央动脉或眼动脉的血流速度或全身血流动力学均无影响。
我们的结果表明，倍他洛尔、美替洛尔、噻吗洛尔、可乐定和地匹福林会减少脉络膜和视盘血流。这可能是由于药物扩散至脉络膜，从而可能导致血管收缩。倍他洛尔、左布诺洛尔或毛果芸香碱未观察到眼血流减少。所研究的所有药物对视网膜中央血流速度均无影响，这可能部分是由于自身调节机制。由于视神经乳头血流可能在青光眼临床病程中起关键作用，应重新考虑使用会减少血流的抗青光眼药物。
