They’re often the first line of treatment for trouble getting or keeping an erection, called erectile dysfunction ED. You can take it in a small dose daily or in a larger dose as needed. Avanafil Stendra. Generic versions of sildenafil, vardenafil and tadalafil are available. Grapefruit and Seville oranges may interact with vardenafil and cause side effects. It lasts 4 to 5 hours, or longer if you have mild to moderate ED.Levitra is not a cure for ED and you still need to be aroused for the medication to work. Levitra and its generic version (vardenafil) are available in doses of: milligrams. 5 milligrams. AdComplete the Online Consultation with our Doctor. Personalize Your Needs. If Appropriate, Get a Prescription for ED from RexMD®. Free Shipping AvailableFree Shipping · Discreet Packaging · Personalized Plan · Real DoctorsSexual health: Premature Ejaculation · Erectile Dysfunction · Breakouts. Roman is a telehealth prescription service and online pharmacy that provides prescription Cialis for ED and a host of other conditions, like hair loss, cold sores, and premature ejaculation. When.