A Rho-kinase inhibitor, soluble guanylate cyclase activator and nitric oxide-releasing PDE5 inhibitor: novel approaches to erectile dysfunction

Approximately 50% of men aged over 40 suffer from male erectile dysfunction. Treatment options have widened since the launch of the phosphodiesterase type 5 (PDE5) inhibitor, sildenafil citrate (Viagra(TM)). However, a certain portion of the patient population, such as diabetics, do not gain significant benefit from PDE5 inhibitors, possibly due to a lack of endogenous nitric oxide. Therefore, new treatment modalities based on the absence of endogenous nitric oxide have been developed. Among them are Rho-kinase inhibitors, soluble guanylate cyclase activators and nitric oxide-releasing PDE5 inhibitors. The available data concerning these compounds will be summarised and their therapeutic potential for male erectile dysfunction will be discussed.