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Clinical Trials
April 2009

Retinal Effects of 6 Months of Daily Use of Tadalafil or Sildenafil

Author Affiliations

Author Affiliations:Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana (Drs Cordell, Costigan, and Sides and Ms Klise); Department of Ophthalmology, Stanford University Medical Center, Stanford, California (Dr Marmor); Midwest Eye Institute, Methodist Medical Plaza North, and Department of Ophthalmology, Indiana University School of Medicine, Indianapolis (Dr Maturi); Casey Eye Institute, Oregon Health and Science University, Portland (Dr Weleber); University of Ottawa Eye Institute, Ottawa Hospital, Ottawa, Canada (Dr Coupland); Fundus Photograph Reading Center, University of Wisconsin, Madison (Dr Danis); Quality of Life Medical & Research Center, Tucson, Arizona (Dr McGettigan); and Charlotte Eye, Ear, Nose and Throat Associates, Charlotte, North Carolina (Dr Antoszyk).



Arch Ophthalmol. 2009;127(4):367-373. doi:10.1001/archophthalmol.2009.36

Objective  To assess changes in electroretinography (ERG) and other retinal function parameters during 6 months of daily use of tadalafil, sildenafil citrate, or placebo.

Methods  Subjects were randomized to use of a placebo (n = 82), 5 mg of tadalafil (n = 85), or 50 mg of sildenafil (n = 77) daily for 6 months. Electroretinographs were recorded using the International Society for Clinical Electrophysiology of Vision (ISCEV) protocol and standardized ERG equipment at all 15 study sites. Other tests of ocular anatomy and visual function were performed at each assessment.

Main Outcome Measures  The primary outcome was the average mean change for both eyes from baseline to endpoint in ERG b-wave amplitude using dark-adapted combined standard response to a bright ISCEV standard flash. Secondary endpoints were other ERG parameter changes, visual acuity, number of errors in color discrimination testing, mean deviation in automated visual field testing, and intraocular pressure (IOP).

Results  No significant differences were found between treatment/placebo groups for the primary outcome, most other ERG variables, visual function, IOP, or anatomic assessments. The medications were well tolerated.

Conclusions  No abnormalities in ERG or visual function and no treatment-related findings suggestive of drug toxicity are associated with daily administration of tadalafil or sildenafil for 6 months.

Application to Clinical Practice  Assessed visual safety of tadalafil/sildenafil administered daily over a prolonged period.

Trial Registration  clinicaltrials.gov Identifier: NCT00333281

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