PDE5A and diabetes mellitus: Phosphodiesterase-5 inhibitors like sildenafil have the potential to interact with nitratesfound in some pharmaceutical drugs prescribed for conditions like diabetes, high bloodpressure, or high cholesterol, and can lower blood pressure to dangerous levels.25 Men who are prescribed nitrates arecontraindicated to take PDE5 inhibitors and may turn to an all-natural dietary supplement tomanage erectile dysfunction, unaware that they are consuming active pharmaceuticalingredients.