PDE5 inhibitors in non-urological conditions

Phosphodiesterase type-5 (PDE5) inhibitors are widely used as first-line therapy for erectile dysfunction (ED). Their efficacy and safety combined with an increasing understanding of cyclic guanosine monophosphate (cGMP)-regulated mechanisms, have triggered a number of attempts to determine their effects and potential benefits in non-urological conditions. In recent years, extensive and diverse preclinical and clinical evidence has been made available. PDE5 inhibition has shown collateral benefits for a multitude of risk factors or diseases associated with, or accompanying ED. To date, PDE5 inhibition has been shown to be effective for the treatment of idiopathic pulmonary arterial hypertension and both sildenafil and tadalafil are approved for this indication. However, PDE5 inhibitors appear to have the potential of further expanding their indications. Importantly, accumulating data show that the therapeutic potential extends to the cardiovascular, gastrointestinal, cutaneous and nervous system and that these agents may be beneficial in a multitude of conditions such as Raynaud's phenomenon, heart failure, essential hypertension and stroke. PDE5 inhibitors are a conceptually attractive therapeutic class of agents with pleiotropic effects. The present review discusses recent findings regarding the effects of PDE5 inhibitors on non-urological conditions and highlights current and future clinical applications beyond ED.