Table 4.

Comparison of Selectivity Ratios of PDE-5 Inhibitors

	Selectivity Ratio
PDE Family	Sildenafil	Vardenafil	Tadalafil
PDE-1	80	257	> 10,000
PDE-2	>7500	> 10,000	> 10,000
PDE-3	4400	3600	> 10,000
PDE-4	1800	5700	> 10,000
PDE-5	1	1	1
PDE-6	10	224	780
PDE-7	5160	No data	> 10,000
PDE-8	> 10,000	No data	> 10,000
PDE-9	2796	No data	> 10,000
PDE-10	1123	447	> 10,000
PDE-11	346	203	5.5

PDE, phosphodiesterase.

Data from Corbin JD, Francis SH. Int J Clin Pract. 2002;56:453–459⁴⁴; Bischoff E et al. Int J Impot Res. 2001;13(suppl 4):S41⁴⁵; Eardley I et al. Int J Clin Pract. 2002;56:300–304⁴⁶; Omrod D et al. Drugs Aging. 2002;19:217–227.⁴⁷