There are factors that affect how quickly Sildenafil starts to work, and how long it may last. Always talk to your physician about the risks and benefits of any treatment. Sildenafil treats erectile dysfunction by increasing blood flow to the penis during sexual stimulation. Avanafil Stendra. Our futuristic methods offer a new and updated approach to achieving optimum health and wellness, through our online digital health platform, also known as telemedicine.In fact, a recent review of studies found that some counterfeit drugs contained a very high, dangerous level of sildenafil that far exceeded a typical . Sildenafil is in a class of medications called phosphodiesterase (PDE) inhibitors. Sildenafil treats erectile dysfunction by increasing blood flow to the penis during sexual stimulation. . Products and services Erectile dysfunction: Viagra and other oral medications By Mayo Clinic Staff Medicines that you take by mouth are called oral .