Effect of sildenafil citrate (viagra) on the ocular circulation☆
Section snippets
Patients and methods
A randomized, placebo-controlled, crossover study of the effects of sildenafil citrate (Viagra; Pfizer, Inc, New York, New York) was performed in 15 healthy male volunteers with normal eyes. Volunteers aged 30 years or older (39 ± 8 years, average ± SD) with visual acuity of 20/25 or better were included in the investigation. All subjects had a normal intraocular pressure of 21 mm Hg or less and a normal eye examination. None of the subjects was receiving nitrate therapy. Subjects provided
Results
Experiments were designed to determine the effects of sildenafil on ocular blood flow. In comparison with placebo, no significant change in mean foveolar choroidal blood flow (ANOVA, P = .88) was observed after sildenafil treatment. Mean foveolar choroidal blood flow at baseline, 1 hour, and 5 hours, was 14.3 ± 3.3 arbitrary units (± SD), 13.4 ± 3.1 arbitrary units, and 13.1 ± 2.7 arbitrary units after sildenafil treatment, and 14.1 ± 3.6 arbitrary units, 13.1 ± 3.6 arbitrary units, and 13.2 ±
Discussion
Nitrate compounds are a group of vasoactive drugs widely used for the treatment of cardiac ischemic diseases because of their vasodilatory ability.13 However, similar to the effect of sildenafil, nitrates work by means of nitric oxide–mediated dilation of arteries and veins.14 Because the mechanism of action of sildenafil and nitrates both use the nitric oxide–cyclic guanosine monophosphate pathway, patients taking nitrates should not receive sildenafil.15 The combination of both drugs can have
Acknowledgements
The authors thank Dr Maureen Maguire for her statistical consultation supported by National Institutes of Health Clinical Vision Research Development Award EY10964.
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2022, Survey of OphthalmologyCitation Excerpt :Pulsatile ocular blood flow measures general ocular hemodynamics of which the choroid is the major part, so it is an indirect measure of choroidal blood flow.101 Grunwald and coworkers reported that nitrate compounds increased optic nerve head (ONH) blood flow and produced retinal venous vasodilatation69,70, but when they conducted a randomized, double blind, crossover clinical trial on 15 healthy subjects on sildenafil 100mg using laser doppler flowmetry, optic nerve rim or foveolar choroidal blood flow did not change significantly.74 They also measured the diameter of two major temporal veins and one retinal artery from digitized photographic negatives and found no significant changes in retinal vascular caliber.72
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This investigation was supported by a grant from Pfizer, Inc, New York, New York.