Your doctor will tell you not to take sildenafil if you are taking street drugs containing nitrates. Some medications should not be taken with sildenafil. If we combine this information with your protected health information, we will treat all of that information as protected health information and will only use or disclose that information as set forth in our notice of privacy practices. Sildenafil treats erectile dysfunction by increasing blood flow to the penis during sexual stimulation. Sildenafil may cause side effects.The price you’ll pay for sildenafil may vary based on the strength and form of the drug your doctor prescribes for you. The price may also depend on which condition is being . The average cost for 30 Tablet(s), mg each of the generic (sildenafil citrate) is $ You can buy sildenafil citrate at the discounted price of $ by using the MDRx . Side Effects. Dizziness, headache, flushing, or stomach upset may occur. Vision changes such as increased sensitivity to light, blurred vision, or trouble telling blue and green colors apart may.