Ocular safety of Viagra, (sildenafil citrate)

A. M. Laties, Frederick (Fritz) Fraunfelder, A. J. Flach, W. Tasman

Research output: Contribution to journalArticle

47 Citations (Scopus)

Abstract

To date, sildenafil citrate (Viagra) gives every evidence of being a safe drug for the eye despite a series of expressed concerns. A review of how its ocular safety profile has been identified offers insights into the strengths and weaknesses of present systems and resources for judging the ocular safety of Viagra or, for that matter, of any new drug. Such insights include: The great value of careful, informed assessment of preclinical information gleaned from laboratory experiments. By and large, such assessments point the way toward appropriate clinical evaluation. For Viagra, early in its development it was noted that besides exerting a major inhibitory effect on the intended target, the vascular-associated enzyme phosphodiesterase 5 (PDE5), the drug also exerts a lesser but definite inhibitory effect on the closely related PDE6, located in the retina. For this reason, preclinical evaluation of the drug included electroretinography plus postmortem histology. In addition, an extended eye examination was incorporated into clinical protocols. The often chaotic but invaluable information stream that becomes available once marketing approval has been gained and large populations begin to use a drug. False alarms, misattribution, and erroneous information are the order of the day. Nevertheless, as information accumulates, patterns of response clarify and the true nature of special susceptibility for subpopulations, if any, becomes apparent. A role for the astute clinician remains: Subtle changes or unusual risks for subpopulations can be missed entirely for long periods of time. A manifest need for improvement in evaluation of postmarketing side-effects. This need has led to the establishment of a new discipline: pharmacoepidemiology. In ophthalmology, the National Registry of Drug Induced Ocular Side-Effects maintains a constant and invaluable surveillance. Examples are supplied to illustrate each of these major points: Our presentation will include data gleaned from clinical trials plus postmarketing information on the incidence, duration, and type of color vision defects observed at different doses of Viagra.

Original languageEnglish (US)
Pages (from-to)115-128
Number of pages14
JournalTransactions of the American Ophthalmological Society
Volume97
StatePublished - 1999
Externally publishedYes

Fingerprint

Safety
Pharmaceutical Preparations
Pharmacoepidemiology
Color Vision Defects
Type 5 Cyclic Nucleotide Phosphodiesterases
Electroretinography
Preclinical Drug Evaluations
Ophthalmology
Clinical Protocols
Marketing
Blood Vessels
Registries
Retina
Histology
Sildenafil Citrate
Clinical Trials
Incidence
Enzymes
Population

ASJC Scopus subject areas

  • Ophthalmology

Cite this

Ocular safety of Viagra, (sildenafil citrate). / Laties, A. M.; Fraunfelder, Frederick (Fritz); Flach, A. J.; Tasman, W.

In: Transactions of the American Ophthalmological Society, Vol. 97, 1999, p. 115-128.

Research output: Contribution to journalArticle

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