rss
Br J Ophthalmol 90:927 doi:10.1136/bjo.2006.094375
  • Mailbox

NAION and treatment of erectile dysfunction: reply from Pfizer

  1. R E Sobel1,
  2. J C Cappelleri2
  1. 1Pfizer Inc, Worldwide Development, 150 E 42nd Street, MS#150-3-72, New York, NY 10017, USA
  2. 2Pfizer Inc, Global Research and Development, Groton, CT, USA
  1. Correspondence to: Rachel E Sobel Pfizer Inc, Worldwide Development, 150 E 42nd Street, MS#150-3-72, New York, NY 10017, USA; rachel.sobel{at}pfizer.com
  • Accepted 9 March 2006

McGwin et al1 suggest that treatment of erectile dysfunction with sildenafil (Viagra) or tadalafil (Cialis), two phosphodiesterase inhibitors (PDE5-I), may increase the odds of non-arteritic anterior ischaemic optic neuropathy (NAION) in men with a history of myocardial infarction (MI) or hypertension (HTN). We believe, however, that this study is fraught with significant limitations (as the authors acknowledge) that preclude drawing any conclusions about this relation.

Case-control studies are susceptible to several biases that must be carefully considered and controlled for in the study design, implementation, and analysis.2 For example, accurate and complete ascertainment of exposure is critical in a …

Register for free content


Free sample
This recent issue is free to all users to allow everyone the opportunity to see the full scope and typical content of BJO.
View free sample issue >>

Don't forget to sign up for content alerts so you keep up to date with all the articles as they are published.