A phone or video consultation is sometimes required for legal purposes. You need a prescription from a doctor to obtain sildenafil. In some cases, online ED providers accept health insurance. Stendra avanafil : This is an as-needed medication taken 30 minutes before sex and can last up to six hours. Follow-up support: Make sure you can get the help you need if questions or concerns arise after ordering. Popular ED medications found online include: Viagra sildenafil : As the first FDA-approved PDE5 inhibitor for ED, sildenafil is taken 30 minutes to four hours before sexual intercourse to help achieve and maintain an erection. Flibanserin is not approved in Australia. · Viagra comes as an oral tablet that contains the active drug sildenafil. Sildenafil is also available in generic form. Viagra is classified as a phosphodiesterase type 5 (PDE5) inhibitor. Sildenafil (Viagra) is a medicine used to treat erectile dysfunction (ED, also called impotence). Sildenafil works by helping to relax the blood vessels in the penis, allowing more blood to flow in and cause an erection. You should take sildenafil about an hour before planned sexual activity, so it has time to work. AdFree & Private Online Consultant with Real Doctors. Reliable E.D. Meds Shipped Discreetly. Save Time & Money with Online Prescription for Viagra, Cialis, Sildenafil and TadalafilK+ visitors in the past monthFree Shipping · Real Doctors · Discreet Packaging · Personalized PlanTypes: Sexual Health · Premature Ejaculation · Privacy Policy.