A combination drug called a sildalist 120mg Tablet usually has two active ingredients: tadalafil and sildenafil. The main conditions treated by this combination are premature ejaculation (PE) and erectile dysfunction (ED).PDE5 (phosphodiesterase type 5) is inhibited by sildenafil, the active component of drugs like Viagra. This indicates that it inhibits the enzyme responsible for the breakdown of cyclic guanosine monophosphate (cGMP). During sexual stimulation, cGMP helps relax the penile blood vessels, increasing blood flow and facilitating erection.