Background:

Vardenafil is a potent and selective inhibitor of phosphodiesterase type5 (PDE5) with the IC50 value of 0.7 nM in enzymatic assay in vitro[1].

Vardenafil has shown a greater selective inhibition towards PDE5 than PDEs from bovine, with the IC50 values of 180nM,>10000nM, 2500nM, 4000nM and 11nM for PDE1, PDE2, PDE3, PDE4 and PDE6, respectively. Besides, Vardenafil has been reported to significantly enhance the SNP-induced, ACh-induced and transmural electrical stimulation-induced relaxation of human trabecular smooth muscle. Vardenafil has been revealed to increase the amount of cGMP in human corpus cavernosum. Apart from these, Vardenafil has also enhanced the length of penile in the conscious rabbit [1].

参考文献:
[1] Saenz de Tejada I1, Angulo J, Cuevas P, Fernández A, Moncada I, Allona A, Lledó E, K?rschen HG, Niew?hner 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 Oct;13(5):282-90.