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No Impact On Ocular Health With High-Dose Sildenafil For Pulmonary Hypertension: Presented at ARVO

By Cameron Johnston

FT. LAUDERDALE, FL -- May 7, 2003 -- Despite the use of sildenafil citrate (Viagra) to treat pulmonary hypertension, researchers remained concerned about the potential ocular side effects that have been seen in some patients using sildenafil for its more common purpose, treating erectile dysfunction.

In a presentation here at the Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO), it was shown that very high doses of sildenafil can be used over an extended period of time without fear of ocular adverse events.

According to Dr. Ralph Becker, of the department of neuro-ophthalmology at the University Eye Hospital, University of Giessen, in Germany, the concern with using sildenafil to treat pulmonary hypertension is that it is known to inhibit the phosphodiesterase 6 (PDE6) enzyme which is necessary for the phototransduction cascade. This can lead to retinal toxicity and the appearance of a bluish haze and decreased sensitivity to light. Moreover, when treating patients with pulmonary hypertension, the dose of sildenafil that is used is several times higher than one would normally use to treat erectile dysfunction so the risk could be that much greater.

In his study, 23 patients, mean age 60, who had had pulmonary hypertension for a mean of 10 years were treated with 150 mg/day of oral sildenafil for a period of 3 months.

There were no changes in visual acuity or light perception, nor were there any complaints of hazing or objects taking on a bluish tinge, he said. There were no changes seen on fundoscopic examination or on a slit lamp examination that looked at episcleral and conjunctival blood vessels. No changes in intra-ocular pressure were seen either.

Dr. Becker said treating pulmonary hypertension with sildenafil has to be seen as a last resort, but in this case, these patients had already exhausted all other forms of therapy. Besides, he added, without sildenafil therapy, they were faced with a severely limited quality of life for the remaining time they had left to live. "This study at least takes away a lot of the worry about treating these patients with sildenafil - we know it's not going to have an impact on their vision or hurt their eyes," he said.


[Study title: Ocular Effects of Sildenafil on Patients With Pulmonary Hypertension. Abstract: 1292/B188.]

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