Central effects of sildenafil (Viagra) on auditory selective attention and verbal recognition memory in humans: a study with event-related brain potentials

World J Urol. 2001 Feb;19(1):46-50. doi: 10.1007/pl00007092.


The purpose of this study was to assess possible central side-effects of sildenafil (Viagra) on attention and memory functions. Sildenafil and placebo were administered in young male subjects in a double-blind balanced cross-over design. Behavioral patterns and event-related brain potentials (ERP) were recorded in a spatial auditory attention and a visual word recognition task. While behavioral patterns did not reveal any overt effects of sildenafil, auditory ERPs were indicative of an enhanced ability to focus attention (amplitude enhancement of Nd-effect) and to select relevant target stimuli in the sildenafil condition (P3 component). In the memory task, CNS-effects of sildenafil were evident in a reduction of a negativity in the 150-250 ms range. No overt effects on behavior were observed. Nevertheless, the data reveal CNS-effects of sildenafil necessitating further studies.

MeSH terms

  • Adult
  • Attention / drug effects*
  • Central Nervous System / drug effects*
  • Central Nervous System / physiology*
  • Cross-Over Studies
  • Double-Blind Method
  • Evoked Potentials / drug effects*
  • Humans
  • Male
  • Memory / drug effects*
  • Phosphodiesterase Inhibitors / pharmacology*
  • Piperazines / pharmacology*
  • Purines
  • Sildenafil Citrate
  • Sulfones


  • Phosphodiesterase Inhibitors
  • Piperazines
  • Purines
  • Sulfones
  • Sildenafil Citrate