Do not start these medications while taking sildenafil without discussing it with your healthcare provider. Ask your pharmacist or doctor for a copy of the manufacturer’s information for the patient. Sildenafil treats erectile dysfunction by increasing blood flow to the penis during sexual stimulation. If you are taking sildenafil to treat erectile dysfunction, follow your doctor’s directions and the guidelines in this paragraph. When choosing one, tell your doctor or other health care professional what your preferences are, such as cost, ease of use, how long the drug’s effects last and side effects. Sildenafil may cause side effects. Side effects Side effects of oral ED medicines are often mild.Prescription needed: yes; Accepts insurance: limited number of carriers accepted; Location. Typical dosing for Sildenafil (Viagra) The typical dose is to take 50 mg of sildenafil (Viagra) by mouth, about 1 hour before sex, as needed. The maximum recommended dose is . 25 milligrams (mg) 50 mg mg Typical dosages The following information describes commonly recommended dosages for ED. However, be sure to take the dosage your .