If it is not treated right away, priapism can permanently damage your penis sudden vision loss in one or both eyes. The Korean Court system made a ruling against Pfizer in June , allowing for the unhindered domestic production of generic prescription sildenafil. Also tell your doctor if you have or have ever had pulmonary veno-occlusive disease PVOD; blockage of veins in the lungs ; a stomach ulcer; heart, kidney, or liver disease; a heart attack; heart failure; angina chest pain ; an irregular heartbeat; a stroke; chest pain; high or low blood pressure; high cholesterol; a bleeding disorder; blood circulation problems; blood cell problems such as sickle cell anemia a disease of the red blood cells , multiple myeloma cancer of the plasma cells , or leukemia cancer of the white blood cells ; conditions affecting the shape of the penis e. You’ll also need to fill out a medical questionnaire with answers about your medical history, current medications, and lifestyle habits. The best time to take sildenafil is about 1 hour before sexual activity, but you can take the medication any time from 4 hours to 30 minutes before sexual activity. Read our editorial process.According to price-comparison site , generic Revatio will cost you as little as $ per pill, depending on where you fill your prescription. That’s compared with more than $50 per. Our lowest price per pill £ This is the highest dose of Viagra. Viagra mg is the most effective dosage, but it also has the greatest risk of side effects. You may want to try Viagra mg if the standard 50mg dose didn’t work well enough for you, but you didn’t get any serious side effects. Price without insurance: starts at $6 per dose for 10 doses. Doses: 20, 25, 50, and mg. Supply: 30, 90, or days. Sildenafil is the generic form of Viagra and Revatio. It’s chemically.