Your doctor may adjust your dose as needed and tolerated. If it is not treated right away, priapism can permanently damage your penis sudden vision loss in one or both eyes. Exercise can help with underlying conditions that play a part in erectile dysfunction in a number of ways, including reducing stress, helping you lose weight and increasing blood flow. Should I see a specialist? Visit Mayo Clinic Men’s Health to get started.Ways to save on Viagra. Save at least $5 per month on your prescription. Save at least $5 per month on your prescription. Call to get more information on how they can financially assist you with your prescription. You may be able to lower your total cost by filling a greater quantity at one time. Your doctor or other health care professional can recommend one for you based on these factors, other health conditions you have and any other medicines you take. Sildenafil . Contact your doctor or seek emergency medical attention if your erection is painful or lasts longer than 4 hours. A prolonged erection (priapism) can damage the penis. Stop using Viagra and get emergency medical help if you have sudden vision loss. Before taking this medicine. You should not use Viagra if you are allergic to sildenafil, or.