Some services offer a subscription option where they’ll send your medications every month at a discount. It works for up to 36 hours. Kidney disease that needs to be treated with dialysis. You can take it in a small dose daily or in a larger dose as needed. Both options require valid medical documentation, but some online services only require a health questionnaire to be filled out and reviewed for approval—meaning no face-to-face video interaction is needed. You should also call your insurance company to see if they cover erectile dysfunction medications. It’s available in 25 mg, 50 mg, and mg tablets and lasts up to 18 hours.Overdose. Ask your doctor. Q&A. Drug Images. What is Viagra? If you have erectile dysfunction (ED), your doctor may recommend that you take Viagra. It’s a prescription drug that’s used in adult. To purchase generic Viagra (sildenafil) and brand-name Viagra through Optum Store, you must fill out a questionnaire, upload a photo ID, and provide a recent blood pressure reading. The. The four main medicines taken by mouth for erectile dysfunction are: Avanafil (Stendra). Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide.