Generic Viagra (sildenafil) is available as a , , , and milligram (mg) pill and in liquid form. It’s meant to be taken as Author: James Roland.Patients should always ask their doctors for medical advice about adverse events. Vardenafil usually works for 4 to 5 hours. Some examples of nitrates are nitroglycerin Nitro-Dur, Nitrostat, others , isosorbide mononitrate Monoket and isosorbide dinitrate Bidil. Its effects might last longer if you have mild to moderate ED. Rarely reported side effects include: an erection that will not go away priapism. If you have an erection that lasts more than 4 hours, get medical help right away. It works for up to 36 hours.Sildenafil Prices, Coupons and Patient Assistance Programs. Sildenafil is a member of the agents for pulmonary hypertension drug class and is commonly used for Erectile . Estimate Shipping. $ Certified online pharmacy offering generic Viagra /50mg. Pick the right dosage and enjoy free shipping, discreet packaging, and other amazing features. Cialis is only available by prescription in the United States. Viagra: Additionally, a study from Trusted Source. found that combining L-arginine and sildenafil (Viagra) worked better for.In some patients, the use of VIAGRA with alpha-blockers can lead to a drop in blood pressure or to fainting medicines called HIV protease inhibitors, such as ritonavir Norvir , indinavir sulfate Crixivan , saquinavir Fortovase or Invirase , or atazanavir sulfate Reyataz some types of oral antifungal medicines, such as ketoconazole Nizoral and itraconazole Sporanox some types of antibiotics, such as clarithromycin Biaxin , telithromycin Ketek , or erythromycin other medicines that treat high blood pressure other medicines or treatments for ED VIAGRA contains sildenafil, which is the same medicine found in another drug called REVATIO. A newer form of the medicine that dissolves on the tongue might work faster than the pill that you swallow. Some people may also have ringing in their ears tinnitus or dizziness. These medicines are called PDE5 inhibitors. This boosts blood flow and helps you get an erection from sexual activity. Oral ED medicines might not work or might be dangerous if you also take any of the following: Nitrate medicines. These medicines all work well for ED.