Be sure to let your doctor and pharmacist know that you are taking these medications before you start taking sildenafil. Continue to take sildenafil even if you feel well. Without physical action to the penis, such as that occurring during sexual intercourse, sildenafil will not work to cause an erection. Push the plunger of the syringe, then insert the tip into the bottle while holding the bottle upright on a flat surface. The following information includes only the average doses of this medicine. Keep out of the reach of children. You may take this medicine with or without food.In combination with sexual stimulation, sildenafil works by increasing blood flow to the penis to help a man get and keep an test1.ru drug does not protect against sexually transmitted.  · Adults 65 years of age and older—25 mg as a single dose no more than once a day, 1 hour before sexual intercourse. Alternatively, the medicine may be taken 30 minutes to 4 hours before sexual intercourse. Your doctor may adjust your dose if needed. Children—Use is not recommended. Generic Viagra (sildenafil) is an alternative to the branded Viagra drug that can be used for treating erectile dysfunction (ED). It’s now sold by many manufacturers, including online.