• Althof SE. When an erection alone is not enough: biopsychosocial obstacles to lovemaking. Int J Impot Res. 2002;14(suppl 1): S99S104.
  • Aytaç IA, McKinlay JB, Krane RJ. The likely worldwide increase in erectile dysfunction between 1995 and 2025 and some possible policy consequences. BJU Int. 1999;84: 5056.
  • Brock G., Nehra A., Lipshultz LI, Karlin GS, Gleave M., Seger M., Padma-Nathan H.. Safety and efficacy of vardenafil for the treatment of men with erectile dysfunction after radical retropubic prostatectomy. J Urol. 2003;170: 12781283.
  • Carson C., Hatzichristou DG, Carrier S., Lording D., Lyngdorf P., Aliotta P., Auerbach S., Murdock M., Wilkins HJ, McBride TA, Colopy MW. Erectile response with vardenafil in sildenafil non-responders: a multicenter, double-blind, 12-week, flexible-dose, placebo-controlled erectile dysfunction clinical trial. BJU Int. 2004;94: 13011309.
  • Goldstein I., Young JM, Fischer J., Bangerter K., Segerson T., Taylor T., Vardenafil Diabetes Study Group. Vardenafil, a new phosphodiesterase type 5 inhibitor in the treatment of erectile dysfunction in men with diabetes: a multicenter double-blind placebo-controlled fixed-dose study. Diabetes Care. 2003;26: 777783.
  • Hatzichristou D., Montorsi F., Buvat J., Laferriere N., Bandel TJ, Porst H., European Vardenafil Study Group. The efficacy and safety of flexible-dose vardenafil (Levitra) in a broad population of European men. Eur Urol. 2004;45: 634641.
  • Hellstrom WJG, Gittelman M., Karlin G., Segerson T., Thibonnier M., Taylor T., Padma-Nathan H.. Vardenafil for treatment of men with erectile dysfunction: efficacy and safety in a randomized, double-blind, placebo-controlled trial. J Androl. 2002;23: 763771.
  • Lue TF. Erectile dysfunction. N Engl J Med. 2000;342: 18021813.
  • McCullough AR, Barada JH, Fawzy A., Guay AT, Hatzichristou D.. Achieving treatment optimization with sildenafil citrate (Viagra) in patients with erectile dysfunction. Urology. 2002;60: 2838.
  • National Institutes of Health. NIH Consensus Conference. Impotence. NIH Consensus Development Panel on Impotence. J Am Med Assoc. 1993;270: 8390.
  • Padma-Nathan H., Giuliano F.. Oral drug therapy for erectile dysfunction. Urol Clin N Am. 2001;28: 321334.
  • Padma-Nathan H., McMurray JG, Pullman WE, Whitaker JS, Saoud JB, Ferguson KM, Rosen RC, IC351 On-Demand Dosing Study Group. On-demand IC351 (Cialis) enhances erectile function in patients with erectile dysfunction. Int J Impot Res. 2001;13: 29.
  • Porst H., Rosen R., Padma-Nathan H., Goldsetin I., Giuliano F., Ulbrich E., Bandel T.. The efficacy and tolerability of vardenafil, a new, oral, selective phosphodiesterase type 5 inhibitor, in patients with erectile dysfunction: the first at-home clinical trial. Int J Impot Res. 2001;13: 192199.
  • Porst H., Young JM, Schmidt AC, Buvat J., International Vardenafil Study Group. Efficacy and tolerability of vardenafil for treatment of erectile dysfunction in patient subgroups. Urology. 2003;62: 519523.
  • Potempa A-J, Ulbrich E., Bernard I., Beneke M., Vardenafil Study Group. Efficacy of vardenafil in men with erectile dysfunction: a flexible-dose community practice study. Eur Urol. 2004;46: 7379.
  • de Tejada Sáenz I, Angulo J., Cuevas P., Fernández A., Moncada I., Allona A., Lledó E., Körschen HG, Niewöhner U., Haning H., Pages E., Bischoff E.. The phosphodiesterase inhibitory selectivity and the in vitro and in vivo potency of the new PDE5 inhibitor vardenafil. Int J Impot Res. 2001;13: 282290.