Vardenafil dihydrochloride (Levitra) is a new type PDE inhibitor with IC50 of 0.7 and 180 nM for PDE5 and PDE1, respectively.

PDE1:180 nM (Cell-free), PDE5:0.7 nM (Cell-free)

Vardenafil specifically inhibits the hydrolysis of cGMP by PDE5 with an IC50 of 0.7 nM (6.6 nM). Vardenafil significantly enhances the SNP-induced relaxation of human trabecular smooth muscle at 3 nM (10 nM). Vardenafil also significantly potentiates both ACh-induced and transmural electrical stimulation-induced relaxation of trabecular smooth muscle. Vardenafil (100 mM) increases cyclic GMP levels in rat hippocampal slices. Vardenafil, tadalafil, and Sildenafil each competitively inhibit cGMP hydrolysis by phosphodiesterase-5 (PDE5), thereby fostering cGMP accumulation and relaxation of vascular smooth muscle.

Vardenafil dose-dependently potentiates erectile responses to intravenously administered sodium nitroprusside in rabbit. Vardenafil (3 mg/kg, p.o.) results in an improved object discrimination performance in rats. Vardenafil (30 mg/L, p.o.) increases both iNOS and proliferating cell nuclear antigen expression (SM cell replication) in rats, with normalization of the dynamic infusion cavernosometry drop rate and SM/collagen ratio. Vardenafil induces powerful preconditioning-like cardioprotective effect against ischemia/reperfusion injury through the opening of mitochondrial K(ATP) channels in the heart of rabbit. Vardenafil protects the ischemic myocardium against reperfusion injury through a mechanism dependent on mitochondrial K(ATP) channel opening.