Recent heart or blood vessel problems. If you have an erection that lasts more than 4 hours, get medical help right away. Medicines that you take by mouth are called oral medicines. It lasts 4 to 5 hours, or longer if you have mild to moderate ED. Some examples of nitrates are nitroglycerin Nitro-Dur, Nitrostat, others , isosorbide mononitrate Monoket and isosorbide dinitrate Bidil. This medicine works best when you take it on an empty stomach an hour before sex. You can take it in a small dose daily or in a larger dose as needed.Learn more about what VIAGRA® (sildenafil citrate), a prescription treatment for ED. The original little blue pill prescribed by doctors for over 20 years Clinically proven to treat men with erectile dysfunction (ED) Ongoing commitment to product quality and safety monitoring. Learn More. IF YOU CHOOSE BRAND-NAME VIAGRA, MAKE SURE YOU GET. AdEnjoy Greater Libido & Performance. Fast Express test1.ruries: Various · Best Sellers · Aphrodisiacs · All Products · Ubulawu Dream Herbs. Sildenafil is used to treat male sexual function problems (impotence or erectile dysfunction-ED). In combination with sexual stimulation, sildenafil works by increasing blood flow to the penis to.