Visual short-term effects of Viagra: double-blind study in healthy young subjects.
OBJECTIVE
To investigate short-term visual effects of a single 100-mg dose of Viagra (sildenafil citrate) in healthy men.


METHODS
Randomized, double-blind, placebo-controlled clinical trial of drug effects on normal volunteers conducted by a single center.


METHODS
Twenty men, aged 20 to 40 years, were treated with either a placebo or 100 mg sildenafil. Visual function tests included electroretinogram (ERG) recordings, on-/off- and 3.3 Hz-flicker-ERG recordings, anomaloscope matches, and measurements of cone contrast sensitivities and transient tritanopia.


RESULTS
Most visual tests did not differ between the sildenafil and placebo groups. However, statistically significant increases in sensitivity during transient tritanopia were observed as well as significant prolongations in the implicit times of scotopic a-wave, photopic b-wave, and 3.3 Hz-flicker a-wave and b-wave ERG recordings. The magnitude of the differences correlated with peak sidenafil plasma concentration. Although rod amplitudes of the ERG recordings tended to be higher and cone amplitudes lower in the sildenafil group after drug ingestion, the differences were nonsignificant. There were no reports of visual side effects, and all electrophysiologic and psychophysical measurements returned to the normal range within 24 hours.


CONCLUSIONS
A single oral dose of 100-mg sildenafil given to healthy young men led to small but statistically significant transient changes of outer and inner retinal function, as detected by ERG and psychophysical methods. Although the acute effects were fully reversible within 24 hours, it would be worthwhile to compare them with those induced by other PDE5 and PDE6 inhibitors.
Jägle
Herbert
H
Department of Pathophysiology of Vision and Neuro-Ophthalmology, University Eye Hospital, Schleichstrasse 12-16, D-72076 Tübingen, Germany. herbert.jaegle@uni-tuebingen.de
Jägle
Christine
C
Sérey
Ludwig
L
Yu
Alice
A
Rilk
Albrecht
A
Sadowski
Bettina
B
Besch
Dorothea
D
Zrenner
Eberhart
E
Sharpe
Lindsay T
LT
D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000037:antagonists & inhibitors*; D000328:Adult; D015350:Contrast Sensitivity / Q000187:drug effects; D004311:Double-Blind Method; D004596:Electroretinography / Q000187:drug effects; D006801:Humans; D008297:Male; D010726:Phosphodiesterase Inhibitors / Q000008:administration & dosage / Q000009:adverse effects* / Q000493:pharmacokinetics; D010879:Piperazines / Q000008:administration & dosage / Q000009:adverse effects* / Q000493:pharmacokinetics; D011687:Purines; D012160:Retina / Q000187:drug effects* / Q000503:physiopathology; D000068677:Sildenafil Citrate; D013450:Sulfones; D014786:Vision Disorders / Q000139:chemically induced* / Q000503:physiopathology; D014792:Visual Acuity / Q000187:drug effects
D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate; D015106:3',5'-Cyclic-GMP Phosphodiesterases