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ERG evaluation of daily, high-dose sildenafil usage
Christopher I Zoumalan1, Roham T Zamanian, Ramona L Doyle
1Department of Ophthalmology, Stanford University School of Medicine, Boswell Building, Stanford, CA 94305-5308, USA.
Documenta Ophthalmologica. Advances in Ophthalmology
|September 27, 2008
Summary
Chronic daily sildenafil use in pulmonary arterial hypertension (PAH) patients showed modest lengthening of cone implicit times. These electroretinogram (ERG) changes appear not to be seriously toxic to vision.
Area of Science:
- Ophthalmology
- Pharmacology
Background:
- Sildenafil, initially for erectile dysfunction, is now approved for pulmonary arterial hypertension (PAH).
- Previous studies noted transient ERG changes in healthy individuals with large single sildenafil doses.
Purpose of the Study:
- To investigate electroretinogram (ERG) changes in PAH patients using sildenafil chronically on a daily basis.
- To assess the safety of long-term, high-dose sildenafil on visual function in PAH patients.
Main Methods:
- Examined five PAH subjects on daily sildenafil for 1-4 years.
- Performed full-field ERG, multifocal ERG (mfERG), and color testing.
- Three subjects underwent testing off and on medication.
Main Results:
- Color vision remained normal during chronic sildenafil use.
- ERG and mfERG amplitudes were normal, but cone implicit times were modestly lengthened.
- mfERG showed minor amplitude increase and implicit time decrease upon re-dosing, suggesting short-term reversibility.
Conclusions:
- Chronic daily sildenafil use in PAH patients is associated with modest lengthening of cone implicit times.
- These visual changes show potential for short-term reversibility.
- Long-term sildenafil use at these doses does not appear to pose a serious threat to vision.
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