Purpose: To estimate the short-term effects of pentoxifylline on ocular blood flow in healthy volunteers.
Methods: In ten healthy subjects, either 200 or 400 mg of pentoxifylline or placebo was administered intravenously over 90 minutes in a randomized, double-blind, placebo-controlled, three-way crossover study design. Noninvasive measurements of blood pressure, pulse rate, flow variables in the radial artery, ocular fundus pulsations, and whole blood viscosity and filterability were performed at baseline and at 30-minute intervals until four hours after the start of drug infusion. Ocular fundus pulsation amplitude, which has been shown to estimate the pulsatile component of the ocular blood flow, was recorded with a laser interferometer in the macula, the optic disk, and a peripheral region.
Results: Fundus pulsation amplitude significantly increased after infusion of pentoxifylline, with maximum effect 150 to 180 minutes after the start of the infusion. This effect was dose-dependent and more pronounced in the macula (+17%, P < .001 vs baseline, after 200 mg; and +27%, P < .001 vs baseline, after 400 mg of pentoxifylline) and the peripheral region (+14%, P < .001; and +26%, P < .001) than in the optic disk (+11%, P < .002; and +13%, P < .001). Viscosity but not filterability of whole blood dose-dependently decreased. Peak systolic flow velocity in the radial artery decreased after infusion of 400 mg of pentoxifylline. Blood pressure and pulse rate were unchanged during the observation period.
Conclusions: These findings demonstrate that pentoxifylline increases pulsatile ocular blood flow in healthy volunteers. Our results support the possibility that pentoxifylline could be used therapeutically in several eye diseases, such as diabetic retinopathy.