Sildenafil (Viagra) and ophthalmology

Sildenafil citrate (Viagra) is a new oral medication that inhibits phosphod iesterase-5 (PDE5) in the corpus cavernosum to facilitate penile erection f or the treatment of male impotence. The drug also has a mild inhibitory eff ect on PDE6, which controls the level of cyclic guanosine monophosphate in the retina, and it may cause a perception of bluish haze or increased light sensitivity in some patients. Long-term retinal damage has not been report ed, but long-term electroretinographic studies have not been performed. Sil denafil causes a mild lowering of blood pressure and is absolutely contrain dicated in patients taking any form of nitrate medication. A number of card iovascular deaths and retinal vascular events in patients taking sildenafil have been reported, but so far the rate of these complications does not ex ceed expectation for an elderly population. Ophthalmologists should alert p atients to the ocular side effects and potential risks of this new drug unt il further clinical experience has been obtained. (C) 1999 by Elsevier Scie nce Inc. All rights reserved.